nbic 2004 addendum

National Board Inspection Code

An American National Standard

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ANSI/NB-23RecognizedInternationally

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Library of Congress Catalog Card No. 52-44738Printed in the United States of America

All Rights Reserved

© 2004The National Board of Boiler

and Pressure Vessel Inspectors

Headquarters1055 Crupper Avenue

Columbus, Ohio 43229-1183614.888.8320

614.847.1828 FAX

Testing Laboratory7437 Pingue Drive

Worthington, Ohio 43085-1715614.888.8320

614.848.3474 FAX

Training and Conference Center1065 Crupper Avenue

Columbus, Ohio 43229-1183614.888.8320

614.847.5542 FAX

Note: Pages ii through xvi are not part of this American National Standard

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THE NATIONAL BOARD OF BOILER AND PRESSURE VESSEL INSPECTORS

BOARD OF TRUSTEES

OFFICERS D.A. Douin – Chairman

R. Reetz – First Vice ChairmanM. Mooney – Second Vice Chairman

D.E. Tanner – Secretary-Treasurer

MEMBERS AT LARGE

R.R. CateE.D. EastmanD.J. JenkinsY. Nagpaul

ADVISORY COMMITTEE W. Carey

Representing organized labor

W.D. DotyRepresenting the welding industry

C.A. NeumannRepresenting boiler and pressure vessel users

M.H. JawadRepresenting boiler manufacturers

G. McRaeRepresenting pressure vessel manufacturers

S. RudnickasRepresenting authorized inspection agencies (insurance companies)

E.J. HovekeRepresenting National Board stamp holders

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COMMITTEE ON NATIONAL BOARD INSPECTION CODE

R. MarvinState of Wasington

C.A. NeumannEastman Kodak Company

M.R. PetersonState of Alaska

J.T. PillowAPComPower Inc.

H.M. RichardsSouthern Company

J. RichardsonConsultant - Dresser Inc.

J. SekelyWayne Crouse, Inc.

R. SnyderConsultant

H. StaehrFactory Mutual Global

S. Staniszewski Jr.U.S. Department of Transportation

R.C. SulzerBabcock & Wilcox

H.N. TiterMIRANT Mid-Atlantic

M.J. WheelState of Vermont

C.S. Withers, ChairThe National Board of Boiler andPressure Vessel Inspectors

R.V. Wielgoszinski, Vice ChairHartford Steam Boiler Inspection andInsurance Co. of Connecticut

R. Ferrell, SecretaryThe National Board of Boiler andPressure Vessel Inspectors

S.E. BaconConoco Phillips

D.A. CanonicoCanonico & Associates

W. CareyInternational Brotherhood of Boilermakers

R.R. CateState of Louisiana

D. CookState of California

W.D. DotyDoty and Associates, Inc. P.D. EdwardsStone & Webster, Inc.

G.W. GalanesMidwest Generation EME, LLC

P.C. HackfordState of Utah

C. HopkinsSeattle Boiler Works

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NBIC Subcommittee on Overpressure Protection

D.A. Bowers Jr., ChairmanVelan Valve

C.A. Neumann, Vice ChairEastman Kodak Company

J.F. Ball, P.E., SecretaryThe National Board of Boiler andPressure Vessel Inspectors

M. BrodeurInternational Valve & Instr. Corporation

S. CammeresiAllied Valve

J.A. CoxDeluca Test Equipment

D.B. DeMichaelDuPont Company

R.W. DonalsonAnderson, Greenwood & Co.

F. HartFlowserve US, Inc.

R.D. MarvinState of Washington

T. ParksState of Texas

D.K. ParrishFM Global

J. RichardsonDresser Industries, Inc.

NBIC Subcommittee on Mandatory Appendices

P.D. Edwards, ChairmanStone & Webster, Inc.

R. Sullivan, SecretaryThe National Board of Boiler andPressure Vessel Inspectors








B. SchulteReliant Energy, Inc.


R. C. SulzerBabcock & Wilcox

R.A. WacjerDupont

M. WebbXcel Energy

R.V. WielgoszinskiHartford Steam Boiler Inspection andInsurance Company of Connecticut

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NBIC Subcommittee on Nonmandatory Appendices

H.M. Richards, ChairmanSouthern Company


R.R. CateState of Louisiana

W.D. DotyDoty & Associates, Inc

G.W GalanesMidwest Generation EME, LLC


J.P. LarsonOneBeacon Insurance


C.A. NeumannEastman Kodak Company

J. RichardsonConsultant – Dresser, Inc.

R. SnyderArise, Inc.

H. StaehrFactory Mutual Global




J.M. YagenDYNEGY Midwest Generation

NBIC Subcommittee on Part RA

C.A. Neumann, ChairmanEastman Kodak Company

R. Sullivan, SecretaryThe National Board of Boiler andPressure Vessel Inspectors



J. RichardsonConsultant – Dresser Inc.

B. SchulteReliant Energy, Inc.

R. SnyderArise, Inc.


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NBIC Subcommittee on Part RB

R. R. Cate, ChairmanState of Louisiana

H. Staehr, Vice ChairFactory Mutual Global

J.F. Ball, SecretaryThe National Board of Boiler andPressure Vessel Inspectors




J. M. RichardsSouthern Company



R.A. WackerDupont

NBIC Subcommittee on Parts RC & RD

R.V. Wielgoszinski, ChairHartford Steam Boiler Inspection andInsurance Co. of Connecticut




W.D. DotyDoty & Associates, Inc.

P.D. EdwardsStone & Webster, Inc.

D. FoxThe Oncor Group

G.W. GalanesMidwest Generation EME, LLC


B. JuarezOneBeacon Insurance

J.P. LarsonOneBeacon Insurance


R.C. SulzerBabcock & Wilcox

M. WebbXcel Energy


J.M. YagenDYNEGY Midwest Generation

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NATIONAL BOARD MEMBERSAlabama ............................................................................................................................................................. Ralph P. PateAlaska ..........................................................................................................................................................Mark R. PetersonArizona .......................................................................................................................................................................................Arkansas ......................................................................................................................................................... Gary R. Myrick California ....................................................................................................................................................... Donald C. CookColorado .....................................................................................................................................................Randall D. AustinConnecticut ........................................................................................................................................................ Allan E. PlattDelaware ........................................................................................................................................................ James B. HarlanFlorida .........................................................................................................................................................................................Georgia ..................................................................................................................................................................Earl EverettHawaii ................................................................................................................................................................Yash NagpaulIllinois ............................................................................................................................................................ David A. DouinIndiana .....................................................................................................................................................................Dan WillisIowa ...................................................................................................................................................................Robert B. WestKansas ..........................................................................................................................................................Donald J. JenkinsKentucky ........................................................................................................................................................ Rodney HandyLouisiana ..........................................................................................................................................................Robert R. CateMaine .............................................................................................................................................................. John H. BurpeeMaryland .............................................................................................................................................................. Karl J. KraftMassachusetts .................................................................................................................................................. Mark MooneyMichigan ...................................................................................................................................................... Robert J. Aben Jr.Minnesota ...........................................................................................................................................................Joel T. AmatoMississippi ................................................................................................................................................ Henry T. McEwenMissouri ............................................................................................................................................................. James L. PrattMontana ......................................................................................................................................................................................Nebraska .........................................................................................................................................................Daniel E. BurnsNevada .........................................................................................................................................................Gerard F. MankelNew Hampshire ........................................................................................................................................... Wayne BrighamNew Jersey .............................................................................................................................................. Milton WashingtonNew Mexico ...............................................................................................................................................................................New York .......................................................................................................................................................New York .......................................................................................................................................................New York Paul A. ConklinNorth Carolina ............................................................................................................................................. Jack M. Given Jr.North Dakota ......................................................................................................................................................Robert ReetzOhio ...................................................................................................................................................................Dean T. JaggerOklahoma .............................................................................................................................................. Marion L. HollowayOregon ................................................................................................................................................................. Ray AndrusPennsylvania ...................................................................................................................................................John D. PaytonRhode Island ............................................................................................................................................ Benjamin AnthonySouth Dakota ............................................................................................................................................... Howard D. PfaffTennessee ..........................................................................................................................................................Martin R. TothTexas ....................................................................................................................................................................... Terry ParksUtah .............................................................................................................................................................. Pete C. HackfordVermont ...................................................................................................................................................... Malcolm J. WheelVirginia ..............................................................................................................................................................Fred P. BartonWashington ................................................................................................................................................ Robert D. MarvinWest Virginia ...............................................................................................................................................Arthur E. Adkins Wisconsin ............................................................................................................................................... Michael J. Verhagen

Chicago, IL .....................................................................................................................................................Chicago, IL .....................................................................................................................................................Chicago, IL Michael J. RyanDetroit, MI .......................................................................................................................................................Michael BarberLos Angeles, CA ..................................................................................................................................................Los Angeles, CA ..................................................................................................................................................Los Angeles, CA Jovie AclaroMilwaukee, WI ............................................................................................................................................. Randal S. Pucek

Alberta ................................................................................................................................................................ Ken K.T. LauBritish Columbia ..........................................................................................................................................Malcolm BishopManitoba ......................................................................................................................................................... I. Wayne MaultNew Brunswick ...................................................................................................................................................New Brunswick ...................................................................................................................................................New Brunswick Dale E. RossNewfoundland & Labrador ................................................................................................................... E. Dennis EastmanNorthwest Territories ....................................................................................................................................Steve DonovanNova Scotia ...................................................................................................................................................Charles J. CastleNunavet Territory ................................................................................................................................E. William BachellierOntario ..................................................................................................................................................................Rick D. MilePrince Edward Island ...................................................................................................................................Kenneth HynesQuebec .......................................................................................................................................................... Madiha M. KotbSaskatchewan ..............................................................................................................................................Nicholas SurteesYukon Territory .............................................................................................................................................. Daniel C. Price

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NATIONAL BOARD INSPECTION CODE

2004 EDITION INCLUDING 2004 ADDENDUM

DATE OF ISSUE — DECEMBER 31, 2004

This code was developed under procedures accredited as meeting the criteria for American National Standards. The Consensus Committee that approved the code was balanced to assure that individuals from competent and concerned interests had an opportunity to partici-pate. The proposed code was made available for public review and comment which provided an opportunity for additional public input from industry, academia, regulatory and jurisdictional agencies, and the public-at-large. The National Board does not “approve,” “rate,” or “endorse” any item, construction, propri-etary device, or activity.

The National Board does not take any position with respect to the validity of any patent rights asserted in connection with any items mentioned in this document, and does not undertake to insure anyone utilizing a standard against liability for infringement of any applicable Letters Patent, nor assume any such liability. Users of a code are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their own responsibility.

Participation by federal agency representative(s) or person(s) affiliated with industry is not to be interpreted as government or industry endorsement of this code.

The National Board accepts responsibility for only those interpretations issued in accordance with governing National Board procedures and policies which preclude the issuance of inter-pretations by individual committee members.

The footnotes in this document are part of this American National Standard.

R

NRRR

NB B

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®

R®

The above National Board symbols are registered with the U.S. Patent Office.

“National Board” is the abbreviation for The National Board of Boiler and Pressure Vessel Inspectors.

No part of this document may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher.

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FOREWORD

The National Board of Boiler and Pressure Vessel Inspectors is an organization comprised of Chief Inspectors for the states, cities and territories of the United States and provinces and territories of Canada. It is organized for the purpose of promoting greater safety to life and property by securing concerted action and maintaining uniformity in the construction, installation, inspection, repair and alteration of pressure retaining items, thereby assur-ing acceptance and interchangeability among jurisdictional authorities responsible for the administration and enforcement of various codes and standards.

In keeping with the principles of promoting safety and maintaining uniformity, the National Board originally published The National Board Inspection Code (NBIC) in 1946, establishing rules for inspection and repairs to boilers and pressure vessels. The National Board Inspection Code (NBIC) Committee is charged with the responsibility for maintaining and revising the NBIC. In the interest of public safety, the NBIC Committee decided, in 1995, to revise the scope of the NBIC to include rules for the repair or alteration to pressure-retaining items.

The NBIC Committee’s function is to establish rules of safety governing the repair, alteration and inspection of pressure-retaining items, and to interpret these rules when questions arise regarding their intent. In formulating the rules, the NBIC Committee considers the needs of users, repair organizations, and Inspectors. The objective of the rules is to afford reasonably certain protection of life and property so as to give a reasonably long, safe period of usefulness. Advancements in design and material and the evidence of experience are recognized.

The rules established by the NBIC Committee are not to be interpreted as approving, recom-mending, or endorsing any proprietary or specific design, or as limiting in any way the repair organization’s freedom to choose any method of repair or alteration that conforms to the NBIC rules.

The NBIC Committee meets regularly to consider revisions of the rules, new rules, and requests for interpretations. Requests for interpretation must be addressed to the Secretary in writing and must give full particulars in order to receive consideration and a written inter-pretation (see Mandatory Appendix 1 covering preparation of technical inquiries). Proposed revisions to the Code resulting from inquiries will be presented to the NBIC Committee for appropriate action.

Proposed revisions to the Code approved by the NBIC Committee are submitted to the American National Standards Institute and published on the National Board Web site to invite comments from all interested persons. After the allotted time for public review and final approval, revisions are published annually in Addenda to the NBIC.

Repair organizations or users of pressure-retaining items are cautioned against making use of revisions that are less restrictive than former requirements without having assurance that they have been accepted by the jurisdiction where the pressur-retaining item is installed.

The general philosophy underlying the NBIC is to parallel those provisions of the original code of construction, as they can be applied to a repair or alteration.

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The NBIC does not contain rules to cover all details of repair or alteration. Where complete details are not given, it is intended that the repair organization, subject to the acceptance of the Inspector, provide details for the repair or alteration which will be as safe as otherwise provided by the rules in the original code of construction.

Repairs not conforming to the rules of the original code of construction or the NBIC must receive specific approval of the jurisdiction, who may establish requirements for design, inspection, testing and documentation.

There are instances where the NBIC serves to warn a repair organization or Inspector against pitfalls; but the Code is not a handbook, and cannot substitute for education, experience, and sound engineering judgment.

It is intended that this Edition of the NBIC and any subsequent Addenda not be retroactive. Unless the jurisdiction imposes the use of an earlier edition, the latest effective Edition and Addenda is the governing document.

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INTRODUCTION

It is the purpose of the National Board Inspection Code (NBIC) to maintain the integrity of pres-sure-retaining items after they have been placed into service by providing rules for inspection, repair and alteration, thereby ensuring that these objects may continue to be safely used.

The NBIC is intended to provide guidance to jurisdictional Inspectors, users, and organizations performing repairs and alterations, thereby encouraging the uniform administration of rules pertaining to pressure-retaining items.

It provides guidance for the process of inspection, repair and alteration but does not provide details for all conditions found in pressure-retaining items. Where complete details are not provided in this Code, the Code user is advised to seek technical guidance.

ADDENDA

Colored-sheet Addenda, which include revisions and additions to this Code, are published annually. Addenda are permissive on the date issued and become effective six months after the date of issue. The addenda will be sent automatically to purchasers of the Code up to the publication of the next issue.

INTERPRETATIONS

On request, the NBIC Committee will render an interpretation of any requirement of this Code. Interpretations are not part of this Code or its addenda.

JURISDICTIONAL PRECEDENCE

Reference is made throughout this Code to the requirements of the “jurisdiction”. Where any provision herein presents a direct or implied conflict with any jurisdictional regulation, the jurisdictional regulation shall govern.

AMERICAN PETROLEUM INSTITUTE

The American Petroleum Institute promulgates codes and standards for the inspection, repair, alteration, rerating and fitness for service assessment of pressure vessels and piping used by the petroleum and chemical process industries. These codes and standards include:

API 510 Pressure Vessel Inspection Code: Maintenance Inspection, Rating, Repair and Altera-tion.

API 570 Piping Inspection Code: Inspection, Repair, Alteration and Rerating of Inservice Pip-ing Systems.

API 579 Fitness-for-Service

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It is the intent of the NBIC that this Code cover installations other than those covered by API codes and standards unless the jurisdiction rules otherwise.

UNITS OF MEASUREMENT

Both inch-pound units and SI units are used in the NBIC. The value stated in inch-pound units or SI units are to be regarded separately as the standard. Within the text, the SI units are shown in parentheses.

US customary units or SI units may be used with this edition of the NBIC, but one system shall be used consistently throughout a repair or alteration of pressure-retaining items. The original code of construction should be used as the basis for selecting the units of measurement for repair or alteration or pressure-retaining items.

ORGANIZATION

1. This book is divided into seven parts

a. Part RA describes the administrative requirements for the accreditation of repair orga-nizations.

b. Part RB provides guidelines for inservice inspection of pressure containing items (boil-ers, pressure vessels, piping).

c. Part RC provides requirements that apply to repairs and alterations of pressure-retain-ing items.

d. Part RD gives guidance for welding methods as alternatives to postweld heat treat-ment. Some repair methods are described to further give guidance to the owner user, inspector, and repair organizations.

e. Mandatory appendices as identified by numerals contain specific rules that are not covered in Parts RA, RB, RC and RD. Their requirements are mandatory when appli-cable.

f. Nonmandatory appendices as identified by letters provide information and suggested good practices. The information provided is not mandatory. However, if used, shall be used in its entirety to the extent applicable.

g. Interpretations are provided for information only and are not part of this code.

2. Tables, charts and figures provide relevant illustrations or supporting information for text passages, and are designated with numbers corresponding to the paragraph they illustrate or support. Multiple tables, charts or figures referenced by the same paragraph will have additional numbers reflecting the order of reference.

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TABLE OF CONTENTS

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Foreword .......................................................................................................................................... xi

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Introduction ...................................................................................................................................xiii

Part RA Administrative Requirements .............................................................................1

Part RB Inservice Inspection of Pressure-Retaining Items ...........................................31

Part RC Repairs and Alterations ......................................................................................89

Part RD Repair Methods ..................................................................................................105

Part RE Repair of Pressure Relief Valves ......................................................................125

Mandatory Appendices

Appendix 1 Preparation of Technical Inquiries to the National Board Inspection Code Committee .............................................................................135

Appendix 2 Stamping and Nameplate Information ..........................................................137

Appendix 3 Steam Locomotive Firetube Boiler Inspection, Repair and Storage ...........141

Appendix 4 Glossary of Terms ..............................................................................................175

Appendix 5 National Board Forms .......................................................................................181

Appendix 6 Examples of Repairs and Alterations ..............................................................213

Appendix 7 Procedures to Extend the “VR” Certifi cate of Authorization Stamp to ASME “NV” Stamped Pressure Relief Devices ............................217

Appendix 8 Inspection, Repair and Alteration of Graphite Pressure Equipment .........221

Appendix 9 Repair, Alteration and Inspection of Fiber-Reinforced Thermosetting Plastic Pressure Equipment ...................................................233

Nonmandatory Appendices

Appendix A Standard Welding Procedures .........................................................................277

Appendix B Recommended Preheat Temperatures ............................................................287

Appendix C Historical Boilers ................................................................................................291

Appendix D Recommended Guide for the Design of a Test System for Pressure Relief Devices in Compressible Fluid Service ...............................349

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Appendix E Recommended Procedures for Repairing Pressure Relief Valves ..............355

Appendix F Pressure Differential Between Safety or Safety Relief Valve Setting and Boiler or Pressure Vessel Operating Pressure ...........................361

Appendix G Safety Valves on the Low Pressure Side of Steam Pressure-Reducing Valves ................................................................................365

Appendix H Recommended Guide for the Inspection of Pressure Vessels in LP Gas Service ...............................................................................................371

Appendix I Installation Requirements ................................................................................377

Appendix J Guide to Jurisdictions for Authorization of Owners-Users to Make Adjustments to Pressure Relief Valves ............................................435

Appendx K Inspection, Repairs and Alterations for Yankee Dryers ...............................439

Interpretations ..............................................................................................................................453

Index ..............................................................................................................................507

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Administrative Requirements

Part RA

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PART RA — ADMINISTRATIVE REQUIREMENTS

TABLE OF CONTENTS

RA-1000 General ................................................................................................................... 3 RA-1010 Scope ....................................................................................................................... 3 RA-1020 Accreditation Process ........................................................................................... 3

RA-2000 Accreditation of Repair Organizations .............................................................. 3 RA-2010 Scope ....................................................................................................................... 3 RA-2020 Scope Issuance and Revision to Pressure-Retaining Items ..............................3 RA-2030 Scope Issuance and Revision to Pressure Relief Valves ...................................4

RA-2100 “R” Administrative Rules and Procedures ........................................................4 RA-2110 Scope ....................................................................................................................... 4 RA-2120 Prerequisites for Issuing a National Board Certifi cate of Authorization ...... 4 RA-2130 Procedure for Obtaining or Renewing a National Board Certifi cate of Authorization .................................................................................................... 5 RA-2140 National Board “R” Symbol Stamp .....................................................................6 RA-2150 Quality System .......................................................................................................6

RA-2200 “VR” Administrative Rules and Procedures .................................................... 9 RA-2210 Scope ....................................................................................................................... 9 RA-2220 Issuance and Renewal of the “VR” Certifi cate and Stamp ........................... 10 RA-2230 Use of the “VR” Stamp ...................................................................................... 12 RA-2240 Certifi cate of Authorization Contents ............................................................. 13 RA-2250 Quality System .................................................................................................... 13

RA-2300 “NR” Accreditation Requirements ................................................................... 18 RA-2310 Scope ..................................................................................................................... 18 RA-2320 Prerequisites for Issuing a National Board “NR” Certifi cate of Authorization .................................................................................................. 19 RA-2330 Procedure for Obtaining or Renewing a National Board “NR” Certifi cate of Authorization .............................................................................. 19 RA-2340 National Board “NR” Symbol Stamp .............................................................. 21 RA-2350 Quality System Program .................................................................................. 22 RA-2360 Outline of Requirements for a Quality System Program for Qualifi cation for the National Board “NR” Symbol Stamp .......................... 22 RA-2370 Interface With the Owner’s Repair/Replacement Program ........................ 29

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RA-1000 GENERAL

RA-1010 SCOPE

This part describes the administrative require-ments for the accreditation of repair organiza-tions and for the accreditation of Owner-User Inspection Organizations.1

The National Board administers three specific accreditation programs as shown below:

“R” ........ Repairs and Alterations to Pressure-Retaining Items

“VR” ..... Repairs to Pressure Relief Valves

“NR” ..... Repair and Replacement Activities for Nuclear Items

RA-1020 ACCREDITATION PROCESS

Any organization may apply to the National Board to obtain a Certificate of Authoriza-tion for the requested scope of activities. A review shall be conducted to evaluate the organization’s quality system. The individual assigned to conduct the evaluation shall meet the qualification requirements prescribed by the National Board. Upon completion of the evaluation, any deficiencies within the organization’s quality system will be docu-mented and a recommendation will be made to the National Board regarding issuance of a Certificate of Authorization.

RA-2000 ACCREDITATION OF REPAIR ORGANIZATIONS

RA-2010 SCOPE

The National Board administers accreditation programs for authorization of organizations performing repairs and alterations to pres-sure-retaining items and/or pressure relief valves.

As part of the accreditation process, an appli-cant’s quality system is subject to a review. National Board procedures provide for the confidential review resulting in recommen-dations to issue or not issue a Certificate of Authorization.

When the quality system requirements of the appropriate section of Part RA have been met, a Certificate of Authorization and appropri-ate National Board symbol stamp shall be issued.

The accreditation programs provide require-ments for organizations performing repairs and alterations to pressure-retaining items. Depending upon the expected scope of ac-tivities at the time of review, organizations may be authorized to perform design only, metallic or non-metallic repairs, and/or al-terations either in the shop only, field only, or shop and field. Repairs and/or alterations to metallic and non-metallic pressure-retaining items are made by welding, bonding and/or mechanical assembly.

RA-2020 SCOPE ISSUANCE AND REVISION TO PRESSURE- RETAINING ITEMS

Any scope revision shall require authorized inspection agency acceptance of quality system changes. These changes shall be sub-mitted to the National Board for acceptance. A program review may be required by the National Board or the jurisdication to assure

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1 Caution, some jurisdictions may independently ad-minister a program of authorization for organiza-tions to perform repairs and alterations within that jurisdiction.

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quality system requirements are met for scope changes. Upon acceptance of the changes, the National Board will issue a Certificate of Authorization with a revised scope.

RA-2030 SCOPE ISSUANCE AND REVISION TO PRESSURE RELIEF VALVES

The “VR” accreditation program provides requirements for organizations performing repairs to pressure relief valves. For scope is-suance and revisions, refer to RA-2200.

RA-2100 “R” ADMINISTRATIVE RULES AND PROCEDURES

RA-2110 SCOPE

This section provides requirements that must be met by organizations in order to obtain a National Board Certificate of Authorization to use the “R” Symbol Stamp for the repair or alteration of pressure-retain-ing items. Organizations may be authorized to perform repairs only, or repairs and altera-tions.

For further information contact:

Accreditation DepartmentThe National Board of Boiler and Pressure Vessel Inspectors1055 Crupper AvenueColumbus, OH 43229-1183

Phone — 614.888.8320Fax — 614.847.1828

The issuance of the “R” Stamp is not re-stricted to organizations whose primary business is to repair and alter pressure retaining items, nor to manufacturers of pres-sure-retaining items. Owners and Users of pressure-retaining items and other organiza-tions that qualify in accordance with these rules may also obtain the “R” Stamp.

Owners or users may be accredited for both a repair and inspection program provided the owner or user complies with the requirements of the “R” program and the National Board requirements for an Owner-User Inspection Organization. The requirements of RA-2120(a) do not apply if the owner or user chooses to use the Owner-User Inspection Organization to accept the repair quality system when:

a. There is no conflict with jurisdictional requirements.

b. The line of authority for the Owner-User Inspection Organization shall be indepen-dent of the organization responsible for execution of “R” program work.

c. The process and Inspector limitations are described in the written Owner-User Inspection Organization’s quality system manual.

RA-2120 PREREQUISITES FOR ISSUING A NATIONAL BOARD CERTIFICATE OF AUTHORIZATION

Before an organization can obtain a National Board “R” Certificate of Authorization, the organization shall:

a. Have and maintain an Inspection Agree-ment with an Authorized Inspection Agency,

b. Have, in the English language, a written Quality System which complies with the requirements of this section and includes the expected scope of activities,

c. Have the current edition of the National Board Inspection Code, and

d. Have available a copy of the code of construction appropriate to the intended scope of work.

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RA-2130 PROCEDURE FOR OBTAINING OR RENEWING A NATIONAL BOARD CERTIFICATE OF AUTHORIZATION

Prior to issuance or renewal of a National Board “R” Certificate of Authorization, the organization and its facilities are subject to a review of its Quality System. The implemen-tation of the Quality System shall be satis-factorily demonstrated by the organization. The National Board reserves the absolute right to cancel, refuse to issue or renew such authorization.

Organizations desiring to obtain a National Board Certificate of Authorization shall apply to the National Board using forms obtained from the National Board. Application for renewal shall be made prior to the expira-tion date of the Certificate of Authorization. Applications may be obtained from the National Board.

When an organization has plants or shops in more than one location, the organization shall submit separate applications for each plant or shop. The organization may perform repairs or alterations in its plants, shops, or in the field, provided such operations are described in the organization’s Quality System.

Upon notification of the review dates from the National Board, it is the responsibility of the organization to make arrangements for the review.

The Review Team, as a minimum, shall consist of one representative each from the Authorized Inspection Agency and the Ju-risdiction.2

The Review Team shall conduct an evalu-ation of the organization’s Quality System. The organization shall demonstrate sufficient implementation of the Quality System to provide evidence of the organization’s knowl-edge of welding, nondestructive examination, postweld heat treatment, and other repair or alteration activities performed appropriate for the requested scope of work. The demonstra-tion may be performed using current work, a demonstration mock-up, or a combination of both.

A recommendation to issue, renew or with-hold the National Board Certificate of Autho-rization shall be included in a Review Report prepared by the Review Team. The completed Review Report shall be forwarded to the Na-tional Board.

If proper administrative fees are paid and all other requirements are met, a Cer-tificate of Authorization will be issued evidencing permission to use the “R” Symbol Stamp. The Certificate shall expire on the triennial anniversary date.

When an organization holding a National Board Certificate of Authorization changes ownership, name, location or address, the National Board shall be notified. The Cer-tificate of Authorization may be revised by submitting an application for National Board “R” Certificate of Authorization; however, a re-review may be required.

The holder of an ASME Code Symbol Stamp, whose facilities were reviewed by the juris-diction, (with the exception of “V”, “UV”, “HV”, “NV”, “RP”, and “H” [cast iron]) may obtain National Board authorization without a review of its facilities, provided:

a. The organization has a Quality System to cover the scope of the repairs or altera-

2 Jurisdiction: The National Board member jurisdiction where the organization is located. Alternatively, where the jurisdiction elects not to perform the review or where there is no jurisdiction or where the jurisdiction is the organization’s Authorized Inspection Agency, the National Board of Boiler and Pressure Vessel Inspectors will represent the jurisdiction. At the jurisdiction’s discretion, the jurisdiction may choose to be a member of the review team if the jurisdiction chooses not to be the team leader.

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tions to be made, subject to review by the jurisdiction; and

b. The application for the “R” Certificate of Authorization is submitted within twelve months from the issuance of the ASME Certificate of Authorization. The initial Certificate of Authorization shall be is-sued to expire concurrent with the ASME Certificate of Authorization. Subsequent certificates shall be renewed upon a suc-cessful review and implementation of its quality system by a National Board representative.

The jurisdiction may audit the Quality Sys-tem and activities of an organization upon a valid request from an owner, user, inspection agency or the National Board.

The NBIC Committee may at any time change the rules for the issuance of Certificates of Authorization and use of the “R” Symbol Stamp. These rules shall become binding on all certificate holders.

RA-2140 NATIONAL BOARD “R” SYMBOL STAMP

All “R” Symbol Stamps shall be obtained from the National Board of Boiler and Pressure Vessel Inspectors. Authoriza-tion to use the “R” Symbol Stamp may be granted by the National Board at its absolute discretion.

The “R” Symbol Stamp is furnished on loan by the National Board for a nominal fee. Each organization shall agree, if authorization to use the “R” Symbol Stamp is granted, that the “R” Symbol Stamp is at all times the property of the National Board and will be promptly returned upon demand. If the organization discontinues the use of the “R” Symbol Stamp, inspection agreement with an Authorized Inspection Agency, or if the Certificate of Au-thorization has expired and no new certificate

has been issued, the “R” Symbol Stamp shall be returned to the National Board.

The organization’s Quality System shall pro-vide for adequate control of the “R” Symbol Stamp. Provisions may be made for the is-suance of the “R” Symbol Stamp for use at various field locations.

The holder of a Certificate of Authoriza-tion may obtain more than one “R” Symbol Stamp provided the organization’s Quality System describes how the use of such stamps is controlled from the location shown on the certificate.

An organization shall not permit others to use the “R” Symbol Stamp loaned to it by the National Board.

RA-2150 QUALITY SYSTEM

A holder of a National Board Certificate of Authorization shall have and maintain a written Quality System. The System shall satisfactorily meet the requirements of the NBIC and shall be available for review. The Quality System may be brief or voluminous, depending on the circumstances. It shall be treated confidentially by the National Board.

RA-2151 OUTLINE OF REQUIREMENTS FOR A QUALITY SYSTEM FOR QUALIFICATION FOR THE NATIONAL BOARD “R” SYMBOL STAMP

The following is a guide to features of a Quality System that should be included in the organization’s Quality System Manual. Each organization should address the fea-tures as needed for the scope of work to be performed:

a. Title Page The name and complete address of the

company to which the National Board

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Certificate of Authorization is issued shall be included on the Title Page of the Qual-ity System Manual.

b. Contents Page The manual should contain a page listing

the contents of the manual by subject, number (if applicable) and revision num-ber of each document.

c. Scope of Work The manual shall clearly indicate the scope

and type of repairs or alterations the orga-nization is capable of and intends to carry out.

d. Statement of Authority and Responsibility A dated Statement of Authority, signed

by an officer of the organization, shall be included in the manual. Further, the State-ment of Authority shall include:

1. A statement that all repairs or altera-tions carried out by the organization shall meet the requirements of the NBIC and the jurisdiction as appli-cable.

2. A statement that if there is a disagree-ment in the implementation of the Quality System, the matter is to be referred for resolution to a higher authority in the company.

3. The title of the individual who will be responsible to ensure that (1) above is followed and has the freedom and authority to carry out the responsi-bil-ity.

e. Manual Control The manual shall include the necessary

provisions for revising and issuing docu-ments to maintain the manual current. The title of the individual authorized to approve revisions shall be included in the manual. Revisions must be accepted by the Authorized Inspection Agency prior to

issuance of the manual and implementa-tion.

f. Organization1. An organizational chart shall be in-

cluded in the manual. It shall include the title of the heads of all departments or divisions that perform functions which can affect the quality of the re-pair or alteration and it shall show the relationship between each department or division.

2. The manual shall identify the title of those individuals responsible for preparation, implementation or verification of the Quality System. The responsibilities shall be clearly defined and the individuals shall have the organizational freedom and authority to fulfill those responsibilities.

g. Drawings, Design and Specifications The manual shall contain controls to

ensure that all design information, applicable drawings, design calcula-tions, specifications and instructions are prepared or obtained, controlled and in-terpreted in accordance with the original code of construction.

h. Repair and Alteration Methods The manual shall include controls for

repairs and alterations, including the selection of the welding procedure speci-fication, materials, nondestructive ex-amination methods, preheat and postweld heat treatment. Special requirements for Graphite and Fiber Reinforced pressure vessels shall be addressed.

i. Materials The manual shall describe the method

used to assure that only acceptable materi-als (including welding material) are used for repairs and alterations. The manual shall include a description of how exist-ing material is identified and new mate-

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rial is ordered, verified and identified. The manual shall identify the title of the individual(s) responsible for each function and a brief description of how the function is to be performed.

j. Method of Performing Work The manual shall describe the methods for

performing and documenting repairs and alterations in sufficient detail to permit the Inspector to determine at what stages specific inspections are to be performed. The method of repair or alteration must have prior acceptance of the Inspector.

k. Welding, NDE and Heat Treatment The manual shall describe controls for

welding, nondestructive examination and heat treatment. The manual is to indicate the title of the individual(s) responsible for the welding procedure specification and its qualification, and the qualification of welders and welding operators. It is essential that only welding procedure specifications and welders or welding operators qualified, as required by the NBIC, be used in the repair or al-teration of pressure-retaining items. It is also essential that welders and welding operators maintain their proficiency as required by the NBIC, while engaged in the repair or alteration of pressure-retain-ing items. The manual shall also describe controls for assuring that the required WPS or SWPS is available to the welder or welding operator prior to welding. Similar responsibility for nondestructive examination and heat treatment shall be described in the manual.

l. Examinations and Tests Reference shall be made in the manual for

examinations and tests upon completion of the repair or alteration.

m. Calibration The manual shall describe a system for the

calibration of examination, measuring and test equipment used in the performance of repairs and alterations.

n. Acceptance and Inspection of Repair or Alteration

The manual shall specifically indicate that before the work is started, acceptance of the repair/alteration shall be obtained from an Inspector who will make the required inspections and confirm NBIC compliance by signing and dating the ap-plicable NBIC Code Report Form3 upon completion of the work.

o. Inspections The manual shall make provisions for

the Inspector to have access to all draw-ings, design calculations, specifications, procedures, process sheets, repair or alteration procedures, test results and other documents as necessary to assure compliance with the NBIC. A copy of the current manual shall be available to the inspector.

p. Report of Repair or Alteration Form The manual shall indicate the title of the

individuals responsible for preparing, signing and presenting the NBIC Report Forms to the Inspector. The distribution of the NBIC Report Forms shall be described in the manual.

q. Exhibits Any forms referenced in the manual shall

be included. The form may be a part of the referencing document or included as an appendix. For clarity, the forms may be completed and identified as examples. The name and accepted abbreviations of the “R” Certificate Holder shall be in-cluded in the manual.

3 NBIC Report Form: National Board Form R-1 for Repairs, Form R-2 for Alterations, or Form R-3 for Parts Fabricated by Welding.


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r. Construction Code The manual shall include provisions for

addressing the requirements that pertain to the specific construction code for the equipment being repaired or altered.

s. Nonconforming Items There shall be a system acceptable to the

Inspector for the correction of noncon-formities. A nonconformity is any con-dition which does not comply with the applicable rules of the NBIC, construction code, jurisdictional requirements or the quality system. Nonconformities must be corrected or eliminated before the repaired or altered component can be considered in compliance with the NBIC.

RA-2200 “VR” ADMINISTRATIVE RULES AND PROCEDURES

RA-2210 SCOPE

These administrative rules and procedures are provided for those who wish to obtain a National Board Certificate of Authoriza-tion for use of the “VR” (Repair of Pressure Relief Valves) symbol stamp. It should be noted that the issuance of the “VR” stamp is not restricted to companies whose primary business is the repair of pressure relief valves nor to manufacturers or assemblers that hold an ASME “V”, “HV”, “UV” or “NV” Code symbol stamp. Owners and users of boilers and pressure vessels and other orga-nizations that qualify in accordance with the National Board Rules and Regulations may also obtain the “VR” Certificate and stamp. In order to provide due process in the issuance, renewal and revocation of “VR” symbol stamps and certificates of authoriza-tion, the National Board Appeals Committee procedures provide an affected “VR” Certifi-cate of Authorization applicant the right of appeal or to provide additional information which may affect the Committee’s decision.


Pressure Relief DepartmentThe National Board of Boiler and Pressure Vessel Inspectors7437 Pingue DriveWorthington, OH 43085-1715

Phone — 614.888.8320Fax — 614.848.3474

RA-2212 JURISDICTIONAL PARTICIPATION

The National Board member jurisdiction in which the “VR” organization is located is encouraged to participate in the review and demonstration of the applicant’s quality system. The jurisdiction may require partici-pation in the review of the repair organiza-tion and the demonstration and acceptance of the repair organization’s quality system manual.

RA-2213 GENERAL RULES

The general rules of the National Board “VR” certification program apply only to the repair of National Board capacity certified ASME Code Section I “V” stamped, Section IV “HV” marked and Section VIII “UV” stamped pres-sure relief valves that:

a. Have been in service or have been exposed to environmental or other condi-tions such that there is reason to question their ability to perform equivalent to the standards for new valves; or

b. Any or all of the valve’s external adjust-ment seals have been broken, opened or otherwise disturbed regardless of the valve’s age or service status.

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RA-2214 REPAIR OF NUCLEAR VALVES

Provided that the requirements of Appendix 7 and applicable requirements of these rules are met, the “VR” certificate may be extended to apply to the repair of any ASME Code Section III, Class 1, 2 or 3 pressure relief devices which have been capacity certified by the National Board and have been in service, regardless of their intended function, in a nuclear system.

RA-2215 TECHNICAL INQUIRIES

Refer to Appendix 1 for information on pre-paring technical inquiries on the subject of valve repair.

RA-2220 ISSUANCE AND RENEWAL OF THE “VR” CERTIFICATE AND STAMP

RA-2221 GENERAL

Authorization to use the stamp bearing the official National Board “VR” symbol as shown in Appendix 2 will be granted by the National Board pursuant to the provisions of the fol-lowing administrative rules and procedures. Appendix 7 provides rules for the repair of ASME Section III “NV” stamped pressure relief devices.

RA-2222 ISSUANCE OF CERTIFICATE

Repair organizations, manufacturers, assemblers or users that make repairs to the American Society of Mechanical Engineers (ASME) Code symbol stamped or marked (as applicable) and The National Board of Boiler and Pressure Vessel Inspectors (National Board) capacity certified pressure relief valves may apply to the National Board for a Certifi-cate of Authorization to use the “VR” symbol.

The National Board may at any time, through the NBIC Committee, modify the regulations concerning the issuance and use of such Valve Repair symbol. All such modified regulations shall become binding upon holders of valid Valve Repair Certificates of Authorization.

Authorization to use the “VR” stamp may be granted or withheld by the National Board in its absolute discretion. If authorization is granted and proper administrative fees paid, a certificate of authorization will be issued evidencing permission to use such a symbol, expiring on the triennial anniversary date. The certificate will be signed by the Chairman of the National Board Board of Trustees, the executive director or any other duly autho-rized officer.

The certificate shall list the physical, per-manent address of record for the certificate holder’s shop/plant. For field-only scopes, this address of record shown on the Certifi-cate of Authorization is where administrative, technical and quality aspects of the business are controlled.

RA-2223 RENEWAL OF CERTIFICATE

The certificate of authorization is renewable every three (3) years subject to a review of the quality system by a representative of the National Board, review and acceptance of the representative’s report by the National Board and successful completion of capacity verifi-cation tests. See RA-2256 for exceptions. The applicant should apply to the National Board for renewal of authorization and reissuance of the certificate prior to the date of expiration. The National Board reserves the absolute right to cancel, refuse to issue or renew such authorization.

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RA-2224 REVIEW OF APPLICANT’S FACILITY

Before issuance or renewal of pressure relief “VR” Certificates of Authorization, the repair organization, its written quality system and its facilities are subject to a review and verifica-tion of implementation of its quality system by a representative of the National Board. The implementation demonstration shall include, as a minimum, disassembly, inspec-tion, repair, application of special processes, reassembly, setting and testing of valves within the scope of the applicant’s quality system.

The applicant shall repair and submit for verification testing one (1) valve for each Code section (except Section III) and test fluid (steam, air/gas, liquid) which will appear on the certificate of authorization. A minimum of two (2) valves are required regardless of Code sections or test fluid. The valves shall be within the capabilities of the National Board accepted laboratory. When an applicant is using the provisions of RE-2020, the appli-cant shall submit one additional Section VIII steam valve set on air for verification testing on steam.

The applicant shall have the latest edition and addenda of the National Board Pressure Relief Device Certifications publication NB-18, The NBIC and the ASME Code section(s) that the organization is including in its scope.

It is the responsibility of the valve repair orga-nization to make arrangements for this review. Certificates cannot be issued or renewed until the National Board is in receipt of approval of this review. Wherever possible, National Board reviews of valve repair organizations shall be coordinated with ASME reviews, when applicable.

For field only repair scopes, the review shall encompass both the applicant’s address of record and f ie ld repair

demonstration site. The demonstration site shall be representative of that typically en-countered by the applicant (See RA-2226).

RA-2225 VERIFICATION TESTING

Before the “VR” Certificate of Authoriza-tion and stamps may be issued or renewed, the demonstration valves must successfully complete capacity and operational verifica-tion tests at a National Board accepted test-ing laboratory. See RA-2226 and RA-2256 for exceptions. The valves shall be typical of those repaired by the organization and within the capabilities of the testing laboratory. Tests conducted at the accepted testing laboratory shall be witnessed by a rep-resentative of the National Board. The purpose of the tests is to ensure that the re-pairs have been satisfactorily carried out and the function and operation of the valves meet the requirements of the section of the ASME Code to which they were manufactured. Valves not meeting the function or operational requirements of the section of the ASME Code to which they were manufactured shall be considered to have failed. Replacement valves shall be repaired and selected for testing as stated above, at a rate of two (2) valves for each one (1) that failed.

a. If either or both of these replacement valves fail to meet the above criteria, the applicant shall document the cause of the noted deficiencies and actions taken to guard against future occurrence. Upon acceptance of this information by the National Board, one (1) additional valve for each replacement valve that failed shall be repaired and tested. The valve(s) shall be of the same ASME Code section, fluid and set pressure scope as the valve previously failing to meet the test requirement.

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b. Failure of this valve(s) to meet the ASME Code to which the valve was manufactured shal l be cause for consideration by the National Board of revocation of the “VR” Certificate of Au-thorization or acceptance of alternative corrective action.

RA-2226 VERIFICATION TESTING ALTERNATIVES

In such cases where all valves repaired by the applicant for a specified ASME Code section or test fluid exceed the capabilities of the accepted testing laboratory, valves for that ASME Code section or test fluid shall be selected as specified in RA-2224 and a dem-onstration test shall be successfully performed in lieu of verification testing specified in RA-2225 above. The demonstration tests shall be conducted at a facility mutually agreeable to the National Board representative, the fa-cility owner and the applicant. The purpose of these tests is to demonstrate, in the pres-ence of a National Board representative, that the repaired valves shall have adequate seat tightness at the maximum expected operating pressure prior to lifting, shall open within the required set pressure tolerance, operate con-sistently without chatter and reclose within the required blowdown.

If a valve lift-assist device is used by the ap-plicant to establish set pressure after repairs, this device must also be used to set the dem-onstration valves.

If either of these valves fail to meet the above criteria, then replacement valves shall be re-paired and tested at a rate of two (2) valves for each one (1) that failed.

a. If either or both of these replacement valves fail to meet the above criteria, the applicant shall document the cause of the noted deficiencies and actions taken to guard against future occurrence. Upon

acceptance of this information by the Na-tional Board, one (1) additional valve for each replacement valve that failed shall be repaired and tested. The valve(s) shall be of the same ASME Code section, fluid and set pressure scope as the valve previously failing to meet the test requirement.

b. Failure of this valve(s) to meet the ASME Code to which the valve was manufactured shall be cause for con-sideration by the National Board of revocation of the “VR” Certificate of Authorization or acceptance of alternative corrective action.

RA-2230 USE OF THE “VR” STAMP

RA-2231 TECHNICAL REQUIREMENTS

The administrative requirements of Part RA-2200 for use of the “VR” stamp shall be used in conjunctin with the technical require-ments for valve repair as described in Part RE of the NBIC. Those requirements shall be man-datory when a “VR” repair is performed.

RA-2232 STAMP USE

Each “VR” symbol stamp shall be used only by the repair firm within the scope, limitations and restrictions under which it was issued.

RA-2233 RETURN OF STAMP

Each applicant shall agree, if authorization to use the stamp is granted, that the stamp is at all times the property of the National Board and will be promptly returned upon demand. If the applicant discontinues the repair of such valves or if the “VR”Certificate of Authoriza-

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tion issued to such applicant has expired and no new certificate has been issued, the stamp will be returned to the National Board.

RA-2234 MULTIPLE LOCATIONS

A holder of a National Board “VR” stamp shall not permit any others to use the “VR” symbol stamp loaned to it by the National Board. When a repair organization, manufacturer or user has a repair department and/or equipment in fixed plants or shops located in more than one geographical area, it must submit separate applications for each plant or shop with the addresses of all such repair locations.

RA-2240 CERTIFICATE OF AUTHORIZATION CONTENTS

Qualification for repair location (shop, shop and field, or field only), code section (Section I, III, IV, and/or VIII valves), special processes and test media shall be specified on the repair organization’s “VR” Certificate of Authoriza-tion.

RA-2241 CHANGES TO CERTIFICATES OF AUTHORIZATION

When a “VR” Certificate Holder intends to change the address of record (location), the certificate holder shall notify the National Board in writing prior to relocating. The new facilities and related quality system for the new location shall be reviewed in accordance with RA-2224. Issuance of a new Certificate of Authorization is subject to the procedures herein.

When a “VR” Certificate Holder intends to change ownership or scope, the certificate holder shall notify the National Board in writing prior to the change. A review, in

accordance with RA-2224, may be required depending upon the nature and extent of the change to the quality system manual, repair procedures or facilities. Issuance of a new Certificate of Authorization is subject to the procedures herein.

RA-2242 ISSUANCE OF MORE THAN ONE “VR” SYMBOL STAMP TO A CERTIFICATE OF AUTHORIZATION HOLDER

The holder of a Certificate of Authorization may obtain more than one “VR” symbol stamp provided its quality system manual controls the use of such stamps from the ad-dress of record shown on the Certificate of Authorization.

RA-2250 QUALITY SYSTEM

RA-2251 GENERAL

Each applicant for a new or renewed “VR” Certificate of Authorization shall have and maintain a quality system which shall estab-lish that all of these rules and administra-tive procedures and applicable ASME Code requirements, including material control, fabrication, machining, welding, examina-tion, setting, testing, inspection, sealing and stamping will be met.

RA-2252 WRITTEN DESCRIPTION

A written description, in the English language, of the system the applicant will use shall be available for review and shall contain, as a minimum, the features set forth in RA-2255. This description may be brief or voluminous, depending upon the circumstances, and shall be treated confidentially. In general, the qual-ity system shall describe and explain what documents and procedures the repair firm will use to validate a valve repair.

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date, description and section of revision, company approval and National Board acceptance.

c. Contents Page The contents page should list and refer-

ence, by paragraph and page number, the subjects and exhibits contained therein.

d. Statement of Authority and Responsibility A statement of authority and responsibil-

ity shall be dated and signed by an officer of the company. It shall include:

1. A statement that the “VR” stamp shall be applied only to pressure relief valves which meet both of the follow-ing conditions:

a. Are stamped with an ASME “V”, “UV”, or “NV” Code symbol or marked with an ASME “HV” symbol and have been capacity certified by the National Board; and

b. H a v e b e e n d i s a s s e m b l e d ,

inspected and repaired by the certificate holder such that the valves’ condition and perfor-mance are equivalent to the standards for new valves.

2. The title of the individual responsible to ensure that the quality system is followed and who has authority and freedom to effect the responsibility;

3. A statement that if there is a disagree-ment in the implementation of the written quality system, the matter is to be referred to a higher authority in the company for resolution; and

4. The title of the individual authorized to approve revisions to the written quality system and the method by which such revisions are to be sub-

RA-2253 REVIEW

A review of the applicant’s quality system will be performed by a representative of the National Board. The review will include a demonstration of the implementation of the provisions of the applicant’s quality system.

RA-2254 MAINTENANCE OF CONTROLLED COPY

Each applicant to whom a “VR” Certificate of Authorization is issued shall maintain thereafter a controlled copy of the accepted quality system manual with the National Board. Except for changes which do not affect the quality system, revisions to the qual-ity system manual shall not be implemented until such revisions are accepted by the Na-tional Board.

RA-2255 OUTLINE OF REQUIREMENTS FOR A QUALITY SYSTEM

The following establishes the minimum re-quirements of the written description of the quality system. It is required that each valve repair organization develop its own quality system which meets the requirements of its organization. For this reason it is not possible to develop one quality system which could ap-ply to more than one organization. The writ-ten description shall include, as a minimum, the following features:

a. Title Page The title page shall include the name and

address of the company to which the National Board Certificate of Authoriza-tion is to be issued.

b. Revision Log A revision log is required to assure revi-

sion control of the quality system manual. The log should contain sufficient space for

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mitted to the National Board for ac-ceptance before implementation.

e. Organization Chart A chart showing the relationship between

management, purchasing, repairing, inspection and quality control personnel is required and shall reflect the actual organization in place.

f. Scope of Work

1. The scope of work section shall in-dicate the scope and type of valve repairs, including conversions, the organization is capable of and intends to perform. The location of repairs (shop, shop and field, or field only), ASME Code Section(s) to which the repairs apply, the test medium (air, gas, liquid or steam, or combinations there-of) and special processes (machining, welding, postweld heat treatment or nondestructive examination, or com-binations thereof) shall be specifically addressed.

2. The types and sizes of valves to be repaired, pressure ranges and other limitations, such as engineering and test facilities, should also be addressed.

g. Drawings and Specification Control The drawings and specification control

system shall provide procedures assur-ing that the latest applicable drawings, specifications and instructions required are used for valve repair, including con-versions, inspection and testing.

h. Material and Part Control The material and part control section shall

describe purchasing, receiving, storage and issuing of parts.

1. State the title of the individual re-sponsible for the purchasing of all material.

2. State the title of the individual respon-sible for certification and other records as required.

3. All incoming material and parts shall be checked for conformance with the purchase order and, where applicable, the material specifications or draw-ings. Indicate how material or part is identified and how identity is main-tained by the quality system.

i. Repair and Inspection Program The repair and inspection program sec-

tion shall include reference to a document (such as a report, traveler or checklist) which outlines the specific repair and inspection procedures used in the repair of pressure relief valves. Repair proce-dures shall require verification that the critical parts meet the valve manufactur-ers specification. Appendix E outlines recommended procedures covering some specific items. Provisions shall be made to retain this document for a period of at least five (5) years.

.1. Each valve or group of valves shall

be accompanied by the document re-ferred to above for processing through the plant. Each valve shall have a unique identifier (e.g., repair serial number, shop order number, etc.) ap-pearing on the repair documentation and repair nameplate such that trace-ability is established.

2. The document referred to above shall describe the original nameplate information, including the ASME Code symbol stamping and the repair nameplate information, if applicable. In addition, it shall include material checks, replacement parts, conversion parts (or both), reference to items such as the welding procedure specifica-tions (WPS), fitup, NDE technique, heat treatment and pressure test methods to be used. Application of the

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“VR” stamp to the repair nameplate shall be recorded in this document. Specific conversions performed with the new Type/Model number shall be recorded on the document. There shall be a space for “signoffs” at each operation to verify that each step has been properly performed.

3. The system shall include a method of controlling the repair or replacement of critical valve parts. The method of identifying each spring shall be indicated.

4. The system shall also describe the con-trols used to ensure that any personnel engaged in the repair of pressure relief valves are trained and qualified in ac-cordance with RE-3000.

j. Welding, NDE and Heat Treatment (when applicable) The quality system manual shall indicate

the title of the person(s) responsible for and describe the system used in the selec-tion, development, approval and quali-fication of welding procedure specifica-tions, and the qualification of welders and welding operators in accordance with the provisions of RE-1100 through RE-1160.

The quality system manual may include controls for the “VR” Certificate Holder to have the pressure relief valve part re-paired by a National Board “R” Certificate Holder, per RC-2032 provided the follow-ing documentation is provided to the “R” Certificate Holder:

1. Code of Construction, year built

2. Part identification

3. Part material specified, and

4. “VR” Certificate Holder’s unique iden-tifier as required by RA-2255(i)(1).

The completed Form R-1 shall be noted on and attached to the “VR” Certificate Holder’s document required in RA-2255(i). Similarly, NDE and heat treatment tech-niques must be covered in the quality system manual. When outside services are used for NDE and heat treatment, the quality system manual shall describe the system whereby the use of such services meet the requirements of the applicable section of the ASME Code.

k. Valve Testing, Setting and Sealing The system shall include provisions that

each valve shall be tested, set and all external adjustments sealed according to the requirements of the applicable ASME Code section and the National Board. The seal shall identify the “VR” Certificate Holder making the repair. Abbreviations or initials shall be permitted, provided such identification is acceptable to the National Board.

l. Valve Repair Nameplates An effective valve stamping system shall

be established to ensure proper stamping of each valve as required by RE-1061. The manual shall include a description of the nameplate or a drawing.

m. Calibration of Measurement and Test Equip-ment

1. The calibration of measurement and test gage system shall include the periodic calibration of measuring instruments, pressure gages and the measuring elements of lift assist de-vices (e.g., load cells, pressure trans-ducers).

2. Pressure gages used for setting valves are to be checked periodically (indi-cate time schedule) by the person au-thorized (indicate title) in the depart-ment. The calibration standard used (master gage or dead weight tester) is to be indicated and results recorded.

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3. All calibration standards shall be calibrated against certified equipment having known valid relationships to nationally recognized standards.

n. Manual Control The quality system shall include:

1. Measures to control the issuance of and revisions to the quality system manual;

2. Provisions for a review of the sys-tem in order to maintain the manual current with these rules and the applicable sections of the ASME Code;

3. The title(s) of the individual(s) respon-sible for control, revisions and review of the manual;

4. Provision of a controlled copy of the written quality system manual to be submitted to the National Board.

Revisions shall be submitted for accep-tance by the National Board prior to being impletmented.

o. Nonconformities The system shall establish measures

for the identification, documentation, evaluation, segregation and disposition of nonconformities. A nonconformity is a condition of any material, item, product or process in which one or more charac-teristics do not conform to the established requirements. These may include, but are not limited to, data discrepancies, proce-dural and/or documentation deficiencies or material defects. Also, the title(s) of the individual(s) involved in this process shall be included.

p. Exhibits Forms used in the quality system shall

be included in the manual with a written description. Forms exhibited should be

marked SAMPLE and completed in a manner typical of actual valve repair procedures.

q. Testing Equipment The system shall include a means to con-

trol the development, addition or modifi-cation of testing equipment to ensure the requirements of RE-2010(b) are met.

r. Field Repairs (see RE-1070) If field repairs are included in the scope of

work, the system shall address any differ-ences or additions to the quality system required to properly control this activity, including the following:

1. Provisions for annual audits of field activities shall be included.

2. Provisions for receipt and inspection of replacement parts, including parts received from the owner-user, shall be addressed.

3. If owner-user personnel will assist with repairs, provisions for the use of owner-user personnel shall be in-cluded.

4. Provisions for use of owner-user measurement and test equipment, if applicable, shall be addressed.

RA-2256 ASME “V”, “HV” OR “UV” CERTIFICATE HOLDERS

A manufacturer holding a valid ASME Cer-tificate of Authorization for use of an ASME “V”, “HV” or “UV” Code symbol stamp may obtain the “VR” Certificate of Authorization for the repair of pressure relief valves covered by the ASME Certificate of Authorization and which meet the requirements of RA-2213. This can be accomplished without a review of the facilities provided there is a written quality system to cover the scope of the repairs to be made and the repairs are carried out at the

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same location where the ASME valves are manufactured. Unless the repaired valves are tested on the same facilities and to the same procedures as new valves, two (2) repaired valves shall be selected by a National Board representative for verification tests.

The initial Certificate of Authorization shall be issued to expire concurrent with the ASME Certificate of Authorization. Subsequent cer-tificates shall be renewed upon a successful review and verification of implementation of its quality system by a National Board rep-resentative. This review shall be performed concurrently with the ASME Certificate re-newal review.

A manufacturer may also perform field re-pairs of pressure relief valves covered by the ASME Certificate of Authorization provided the provisions of RE-1070 are met.

Assemblers holding ASME Certificates of Authorization shall qualify for the “VR” Cer-tificate of Authorization as required elsewhere in these rules.

The quality system manual shall be submitted for review and acceptance by the National Board.

In order for an ASME Code symbol stamp holder to qualify for the National Board “VR” stamp, the following areas to the written quality system usually require attention. a. Statement of Authority and Responsibility This should clearly indicate that valve

repairs are carried out in accordance with the requirements and the rules of the National Board and the quality system manual. In addition, the scope and type of valve repairs covered by the manual should be indicated.

b. Organization Unless the functions which affect the

quality of valve repairs are carried out by individuals other than those responsible for manufacturing or assembly, it should not be necessary to revise the organization chart.

c. General Quality Functions Usually quality system requirements re-

garding valve repairs may be controlled in the same manner as for ASME manu-facturing or assembly provided applicable shop and/or field activities are covered. If this is the case, the applicant for the “VR” stamp should include in its quality system manual a separate section covering valve repairs which references the applicable section of the manual. For a more explicit explanation see RA-2255, Written Descrip-tion of the Quality System.

RA-2300 “NR” ACCREDITATION REQUIREMENTS

RA-2310 SCOPE

This section provides requirements that must be met for an organization to obtain a National Board Certificate of Authoriza-tion to use the “NR” Symbol Stamp for the Repair/Replacement activities performed in accordance with this Part and ASME Section XI requirements.


Accreditation DepartmentThe National Board of Boiler and Pressure Vessel Inspectors1055 Crupper AvenueColumbus, OH 43229-1183

Phone — 614.888.8320Fax — 614.847.1828

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The issuance of the “NR” stamp is not restricted to organizations whose primary business is to perform repair/replacement activities nor to manufacturers or assemblers that hold an ASME “N” type Code symbol stamp. Owners and users of nuclear compo-nents and other organizations that qualify in accordance with these rules may also obtain the “NR” stamp.

RA-2320 PREREQUISITES FOR ISSUING A NATIONAL BOARD “NR” CERTIFICATE OF AUTHORIZATION

Before an organization can obtain a National Board “NR” Certificate of Authorization, the organization shall:

a. Have and maintain an inspection agree-ment with an accredited Nuclear Inspec-tion Agency in accordance with NB-360,4 NB-369,5 and ASME Section XI.

b. Have in the English language a written Quality System Program that complies with the requirements of this section and addresses controls for the intended scope of activities,

c. Have a current edition and addenda of the NBIC, and

d. Have available copies of the original code of construction appropriate to the intended scope of work and the appli-cable edition and addenda of ASME Section XI, as required by the regulatory authority.6

RA-2330 PROCEDURES FOR OBTAINING OR RENEWING A NATIONAL BOARD “NR” CERTIFICATE OF AUTHORIZATION

Prior to issuance or renewal of a National Board “NR” Certificate of Authorization, the organization and its facilities are subject to a review of its Quality System Program. The implementation of the Quality System Pro-gram shall be satisfactorily demonstrated by the organization. The National Board reserves the absolute right to cancel, refuse to issue or renew such authorization. The National Board will return fees paid for the unexpired term of the certificate.

Organizat ions desir ing to obtain a National Board Certificate of Authorization shall apply to the National Board using forms obtained from the National Board. Applica-tion for renewal shall be made prior to the expiration date of the Certificate of Autho-rization.

These procedures also apply to qualified organizations that make repairs to ASME Section III “NV” pressure relief devic-es. An organization that holds a valid “NR” Certificate of Authorization shall, for the purpose of these procedures, be known as an authorized nuclear repair organization.

Authorized Nuclear Inspection Agencies and Inspectors referred to in these procedures shall meet the requirements of and have been qualified and commissioned in accordance with the National Board Rules for Commissioned Inspectors.

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3 NB-360, Criteria for Acceptance of Authorized Inspection Agencies for New Construction.

4 NB-369, Qualification and Duties for Authorized Inspec-tion Agencies (AIAs) Performing In-Service Inspection Activities and Qualification of Inspectors of Boilers and Pressure Vessels.

5 Regulatory Authority. A federal government agency, such as the United States Nuclear Regulatory Commission, empowered to issue and enforce regualtions concerning the design, construction, and operation of nuclear power plants.

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Repair/replacement activities performed under the “NR” Certificate of Authorization must be in accordance with the provisions of the NBIC, Section XI of the ASME Code and the rules of the jurisdiction.

Each authorized nuclear repair organization shall maintain a documented Quality System Program which meets the requirements of RA-2360. The Quality System Program shall be commensurate with the scope of the orga-nization’s activities and shall be acceptable to the jurisdiction, the Authorized Nuclear Inspection Agency and the National Board.

Before an “NR” Certificate of Authorization will be issued or renewed, the applicant must have the Quality System Program and the implementation of the program reviewed and found acceptable by representatives of the National Board, the jurisdiction and the accreditated Authorized Nuclear Inspection Agency. If the applicant is an ASME “N” type certificate of authorization holder, has demonstrated within the last 12 months the implementation of the quality program and can verify by documentation that the organi-zation is capable of implementing its quality program as being in compliance with this part, a further verification implementation by the survey team may not be necessary.

Applicants that do not hold valid ASME “N” type certificates of authorization shall demonstrate, by documentation and ac-tual implementation, that they are capable of performing repair/replacement activities in accordance with the requirements of Section XI and the scope of their application for an “NR”Certificate of Authorization.

For National Board authorization to repair ASME “NV”/”NB” stamped pressure relief devices, the applicant shall hold a valid “VR” Certificate of Authorization for the repair of

ASME Section III pressure relief valves and also meet the applicable requirements for “NR” certification and Appendix 7.

When these requirements have been met, the applicant may be issued an “NR” Certificate of Authorization which clearly outlines the scope of work for Section III pres-sure relief devices.

The jurisdiction will be the National Board member jurisdiction in which the applicant is located. If the implementation of the Quality System Program takes place outside of the jurisdiction where the applicant’s program was reviewed, the National Board member in the jurisdiction where the implementation takes place may participate in this portion of the survey. At the request of the jurisdiction, the National Board representative may also act for said jurisdiction.

Where there is no National Board member jurisdiction, the applicant’s Quality System Program shall be acceptable to representatives of the National Board and the Authorized Nuclear Inspection Agency.

The applicant shall request the Nation-al Board to evaluate the Quality System Program and implementation prior to the issuance of an “NR” Certificate of Au-thorization. The National Board, when requested through the appropriate form, will arrange for an evaluation of the ap-plicant’s Quality System Program. The program will be evaluated on the basis of its compliance with the National Board rules for certification. The program shall be adequate to control the intended scope of work. The “NR” Certificate of Authorization which is issued shall specify the scope and limits of work for which the applicant is certified.

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Revisions to the Quality System Pro-gram shall be acceptable to the Autho-rized Nuclear Inspector Supervisor of the Authorized Nuclear Inspection Agency before implementation.

The “NR” Certificate of Authorization holder shall be subject to an audit annually by the Authorized Nuclear Inspection Agency to assure compliance with the Quality System Program.

Upon notification of the survey dates from the National Board, it is the responsibility of the organization to make arrangements for the survey.

The Survey Team, as a minimum, shall consist of one representative each from the National Board, Authorized Nuclear Inspection Agency and jurisdiction.

A recommendation to issue, renew or with-hold the National Board Certificate of Au-thorization for the “NR” Symbol Stamp shall be included in a summary report prepared by the survey team leader. The completed summary report shall be forward-ed to the National Board.

If proper administrative fees are paid and all other requirements are met, an “NR” Certificate of Authorization will be issued evidencing authorization to use the “NR” Symbol Stamp. The Certificate shall expire on the triennial anniversary date.

When an organization holding a National Board Certificate of Authorization changes ownership, name or address, the National Board shall be notified. The Certificate of Authorization may be revised by submitting an application for National Board “NR” Cer-tificate of Authorization.

The National Board may at any time change the rules for the issuance of the Certificate of Authorization and use of the “NR” Symbol Stamp. These rules shall become binding on all certificate holders.

RA-2340 NATIONAL BOARD “NR” SYMBOL STAMP

All “NR” Symbol Stamps shall be obtained from the National Board of Boiler and Pres-sure Vessel Inspectors. Authorization to use the “NR” Symbol Stamp may be granted by the National Board at its absolute discretion.

The National Board, for a nominal fee, fur-nishes the “NR” Symbol Stamp. Each orga-nization shall agree, if authorized to use the “NR” Symbol Stamp, that the “NR” Symbol Stamp is at all times the property of the Na-tional Board and will be promptly returned upon demand. If the organization discontin-ues the use of the “NR” Symbol Stamp or if the Certificate of Authorization has expired and no new Certificate of Authorization has been issued, the “NR” Symbol Stamp shall be returned to the National Board.

The organization’s Quality System Program shall provide for adequate control of the “NR” Symbol Stamp.

The organization authorized to use the “NR” Symbol Stamp may obtain more than one “NR” Symbol Stamp provided the organiza-tion’s Quality System Program describes how the use of such stamps are controlled from the location shown on the “NR” Certificate of Authorization.

The organization shall not permit other or-ganizations to use the “NR” Symbol Stamp loaned to it by the National Board.

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RA-2350 QUALITY SYSTEM PROGRAM

A holder of a National Board Certificate of Authorization shall have and maintain a writ-ten Quality System Program. The system shall satisfactorily meet the requirements of the NBIC, jurisdictional requirements and shall be available for review. The Quality System Program may be brief or voluminous, depend-ing on the circumstances. It shall be treated confidentially by the National Board.

RA-2360 OUTLINE OF REQUIREMENTS FOR A QUALITY SYSTEM PROGRAM FOR QUALIFICATION FOR THE NATIONAL BOARD “NR” SYMBOL STAMP

These rules set forth the requirements for planning, managing and implementing the organization’s Quality System Programs for controlling the quality of activities performed during repair/replacement activities of com-ponents and systems in nuclear power plants within the scope of the applicable edition and addenda of Section XI of the ASME Code. These rules are to be the basis for evaluating such programs prior to the issuance of the National Board “NR” Certificate of Autho-rization.

a. Organization

1. The authority and responsibility of those in charge of the Quality System Program and activities affecting qual-ity shall be clearly established and documented. The person and orga-nization performing Quality System

functions shall have sufficient and well-defined responsibility, authority and organizational freedom to:

a. Identify quality problems;

b. Initiate action which results in solutions;

c. Verify implementation of solutions to those problems;

d. Control further processing, de-livery or installation of a noncon-forming item, deficiency or unsat-isfactory condition until proper disposition has been made.

2. The person and organization respon-sible for defining and for measuring the overall effectiveness of the Quality System Program shall be designated sufficiently independent from the pressure of production, have direct access to responsible management at a level where appropriate action can be required and report regularly on the effectiveness of the program. Assurance of quality requires man-agement measures which provide that the individual or group assigned the responsibility of inspection, test-ing, checking or otherwise verifying that an activity has been correctly performed, is independent of the in-dividual or group directly responsible for performing the specific activity. The specific responsibilities of the Quality Assurance organization of the “NR” Certificate Holder shall include the review of written procedures and monitoring of all activities concerned with the Quality System Program as covered in these rules.

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b. Quality System Program

1. Before becoming a holder of an “NR” Certificate of Authorization, the appli-cant shall establish a Quality System Program for the control of the quality of work to be performed. The program shall define the organizational struc-ture within which the Quality System Program is to be implemented and shall clearly delineate the responsi-bilities, levels of authority and lines of communication for the various individuals involved. The program shall be documented in detail in a Quality System Manual which shall be a major basis for demonstration of compliance with the NBIC. The applicant’s Quality System Program shall be documented by written poli-cies, procedures and instructions and shall be based on the organization’s scope of work to be performed.

2. The applicant’s program need not be in the same format or sequential arrangement as the requirements in these rules as long as all applicable program requirements have been covered. The program shall provide for the accomplishment of activities affecting quality under suitably controlled conditions. Controlled con-ditions include the use of appropriate equipment, suitable environmental conditions for accomplishing the activity and assurance that prereq-uisites for the activity have been satisfied. The program shall take into account the need for special controls, processes, test equipment, tools and skills to attain the required quality and need for the verification of quality by inspection and test. The program shall provide for ready detection of nonconforming material and items

and for timely and positive corrective actions.

3. The program shall provide for in-doctrination and training of person-nel performing activities affecting quality as necessary to assure that suitable proficiency is achieved and maintained. It shall be the responsibil-ity of the “NR” Certificate Holder to assure that all personnel performing quality functions within the scope of these rules, including personnel of subcontracted services, are qualified as specified in these rules. The assign-ment of qualified personnel shall be at the discretion of the “NR” certificate holder.

4. The “NR” Certificate Holder shall be responsible for advising his Autho-rized Nuclear Inspection Agency of any proposed changes to the Quality System Manual and shall have ac-ceptance of the Authorized Nuclear Inspection Agency’s Authorized Nuclear Inspector Supervisor before putting such changes into effect. The “NR” Certificate Holder shall make a current copy of the Quality System Manual available to the Au-thorized Nuclear Inspector. The “NR” Certificate Holder shall be responsible for promptly notifying the Authorized Nuclear Inspector of such accepted changes, including evidence of ac-ceptance by the Authorized Nuclear Inspection Agency.

5. The quality of all repair/replace-ment activities shall be controlled at all points necessary to assure con-formance with the requirements of these rules and the “NR” Certificate Holder’s Quality System Manual.

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6. The certificate holder shall make available to the Authorized Nuclear Inspector such drawings and process sheets as are necessary to make the Quality System Program intelligible.

c. Design Control ASME Section XI establishes that the

owner is responsible for design in connec-tion with repair/replacement activities. The “NR” Certificate Holder must ensure that the design specification, drawings or other specifications or instructions fur-nished by the owner satisfy the code edi-tion and addenda of the owner’s design specification. To satisfy this requirement, the “NR” Certificate Holder shall establish requirements that correctly incorporate the owner’s design specification require-ments into their specification, drawings, procedures and instructions which may be necessary to carry out the work. The “NR” Certificate Holder’s system shall include provisions to assure that the ap-propriate quality standards are specified and included in all quality records. These records shall be reviewed for compliance with the owner’s design specification and the requirements of Section XI of the ASME Boiler and Pressure Vessel Code.

If the “NR” Certificate Holder’s specifica-tions, drawings, procedures and instruc-tions conflict with the owner’s design specification, a system must be imple-mented that will resolve or eliminate the deficiency. This system must be reconciled with the owner and the “NR” Certificate Holder in accordance with IWA-4000 of Section XI of the ASME Code.

d. Procurement Document Control Documents for procurement of materials,

items and subcontracted services shall include requirements to the extent nec-

esary to assure their compliance with the owner’s design specifications and IWA-4000 of Section XI of the ASME Code. To the extent necessary, procurement docu-ments shall require suppliers to maintain a Quality System Program consistent with the applicable requirements of the edition and addenda of the code of construction to which the items are constructed. Mea-sures shall be established to assure that all purchased material, items and services conform to these requirements.

e. Instructions, Procedures and Drawings Activities affecting quality shall be pre-

scribed by documented instructions, procedures or drawings of a type appro-priate to the circumstances and shall be accomplished in accordance with these instructions, procedures or drawings. Instructions, procedures or drawings shall include appropriate quantitative and qualitative criteria for determining that activities affecting quality have been satisfactorily accomplished. The “NR” Certificate Holder shall maintain a writ-ten description of procedures, instructions or drawings used by his organization for control of quality and examination requirements detailing the implementa-tion of the Quality System requirements. Copies of these procedures shall be read-ily available to the Authorized Nuclear Inspector.

f. Document Control The program shall include measures to

control the issuance, use and disposition of documents, such as specifications, instructions, procedures and drawings, in-cluding changes thereto. These measures shall assure that the latest applicable doc-uments, including changes, are reviewed for adequacy and approved for release by authorized personnel and distributed for use at the location where the prescribed activity is performed.

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g. Control of Purchased Material, Items and Services

Measures shall be established to assure that all purchased material, items and services conform to the requirements of the owner’s design specifications and applicable edition and addenda of the code of construction and Section XI of the ASME Code. These measures shall include identification for material trace-ability. Provisions shall be identified for source evaluation and objective evidence shall be provided evidencing quality standards for material examination upon receipt.

h. Identification and Control of Material and

Items

1. Measures shall be established for iden-tification and control of material and items, including partially fabricated assemblies. These measures shall as-sure that identification is maintained and traceable, either on the material or component, or on records throughout the repair/replacement activity. These measures shall be designed to prevent the use of incorrect or defective items and those which have not received the required examinations, tests or inspec-tions.

2. Permanent or temporary unit identi-fication marks shall be applied using methods and materials which are legible and not detrimental to the component or system involved. Such identification shall be located in areas that will not interfere with the func-tion or quality aspects of the item.

3. Certified Material Test Reports shall be identified as required by the appli-cable material specification in Section II of the ASME Code and shall satisfy

any additional requirements specified in the original code of construction. The Certified Material Test Report or Certificate of Compliance need not be duplicated in the checklist or documents. Checklist documents shall provide a record that the Certified Material Test Report and Certificates of Compliance have been received, reviewed and found acceptable. When the “NR” Certificate Holder Scope au-thorizes the organization to perform examinations and tests in accordance with the original code of construction, the “NR” Certificate Holder shall cer-tify compliance either on a Certified Material Test Report or Certificate of Conformance that the material satis-fies the original code of construction requirements.

i. Control of Processes

1. The “NR” Certificate Holder shall operate under a controlled system such as process sheets, checklists, travelers or equivalent procedures. Measures shall be established to assure that processes such as welding, nondestructive examination and heat treating are controlled in accordance with the rules of the applicable section of the ASME Code and are accom-plished by qualified personnel using qualified procedures.

2. Process sheets, checklists, travelers or equivalent documentation shall be prepared, including the document numbers and revisions to which the process conforms, with space provided for reporting results of completion of specific operations at checkpoints of repair/replacement activities.

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2. Test procedures shall include provi-sions for assuring that prerequisites for the given test have been met, that adequate instrumentation is available and used and that necessary moni-toring is performed. Prerequisites may include calibrated instrumenta-tion, appropriate equipment, trained personnel, condition of test equipment and the item to be tested, suitable environmental conditions and provi-sions for data acquisition.

3. Test results shall be documented and evaluated to assure that test require-ments have been satisfied.

l. C o n t r o l o f M e a s u r i n g a n d Te s t Equipment

Measures shall be established and doc-umented to assure that tools, gages, instruments and other measuring and testing equipment and devices used in activities affecting quality are of the proper range, type and accuracy to verify conformance to established requirements. A procedure shall be in effect to assure that they are calibrated and properly adjusted at specified periods or use intervals to maintain accuracy within specified limits. Calibration shall be trace-able to known national standards, where these standards exist, or with the device manufacturer’s recommendation.

m. Quality Records

1. The owner is responsible for des-ignating records to be maintained. Measures shall be established for the “NR” Certificate Holder to maintain these records [See m(2)] required for Quality Assurance of repair/replacement activities. These shall include documents such as records of materials, manufac-

j. Examinations, Tests and Inspections

1. In-process and final examinations and tests shall be established to assure conformance with specifications, drawings, instructions and proce-dures which incorporate or reference the requirements and acceptance limits contained in applicable design documents. Examination activities to verify the quality of work shall be per-formed by persons other than those who performed the activity being examined. Such persons shall not report directly to the immediate su-pervisors responsible for the work being examined.

2. Process sheets, travelers or check-lists shall be prepared, including the document numbers and revision to which the examination or test is to be performed, with space provided for recording results.

3. Mandatory hold/inspection points at which witnessing is required by the “NR” Certificate Holder ’s representative or the Authorized Nuclear Inspector shall be indi-cated in the controlling documents. Work shall not proceed beyond mandatory hold/inspection points without the consent of the “NR” Certificate Holder’s representative or the Authorized Nuclear Inspector, as appropriate.

k. Test Control

1. Testing shall be performed in ac-cordance with the owner’s written test procedures which incorporate or reference the requirements and acceptance limits contained in appli-cable design documents.

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turing, examination and test data taken before and during repair/replacement activity, procedures, specifications and drawings used shall be fully identified by perti-nent material or item identification numbers, revision numbers and issue dates. The records shall also include related data such as qualification of personnel, procedures, equipment and related repairs. The “NR” Cer-tificate Holder shall take such steps as may be required to provide suitable protection from deterioration and damage for all records while in his care. Also it is required that the “NR” Certificate Holder have a system for connection or amending records that satisfies the owner’s requirements. These records may be either the origi-nal or a reproduced, legible copy and shall be transferred to the owner at his request.

2. Records to be maintained as required in RA-2360(m)(1) above may include the following:

a. An index that details the location and who is responsible for main-taining the records;

b. Data reports, properly executed, for each replacement component, part, appurtenance, piping system and piping assembly when re-quired by the design specification or the owner;

c. The required as-constructed draw-ings certified as to correctness;

d. Copies of applicable Certified Material Test Reports and Certifi-cates of Compliance;

e. As-built sketch(es) including tabulations of materials repair/re-placement procedures and instruc-tions to achieve compliance with Section XI of the ASME Code;

f. Nondestructive examination reports including results of ex-aminations. These reports shall identify the ASNT, SNT-TC-1A, CP-189 or ACCP level of personnel for interpreting the examination results. Final radiographs shall be included where radiography has been performed;

g. Records of all heat treatments. These records may be either the heat treatment charts or a sum-mary description of heat treat-ment time and temperature data certified by the “NR” Certificate Holder. Heat treatments per-formed by the material manufac-turer to satisfy requirements of the material specifications may be reported on the Certified Material Test Report;

h. Any and all non-conformance reports shall satisfy IWA-4000 of Section XI of the ASME Code and shall be reconciled by the owner prior to certification of the Form NR-1 or NVR-1 as applicable.

3. After a repair/replacement activity, all records including audit reports required to verify compliance with the applicable engineering documents and the “NR” Certificate Holder’s Quality System Program, except those required by the owner or listed in (2)(a) through (g) above, shall be maintained at a place mutually agreed upon by the owner and the “NR” Cer-tificate Holder. These records shall be

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maintained for a period of five years after completion of the repair/replace-ment activity.

4. The original of the completed Form NR-1 or Form NVR-1, as applicable, shall be registered with the National Board and, if required, a copy for-warded to the jurisdiction where the nuclear power plant is located.

n. Examination or Test Status Measures shall be established to indicate

examination and test status of parts, items or components during the repair/replacement activity. The system used shall provide positive identification of the part, item or component by means of stamps, labels, routing cards or other acceptable methods. The system shall include any procedures or instructions to achieve compliance. Also, measures shall be provided for the identification of acceptable and non-acceptable items. They shall also include procedures for control of status indicators, including the authority for application and removal of status indicators.

o. Nonconforming Materials or Items Measures shall be established to control

materials or items which do not conform to requirements in order to prevent their inadvertent use, including measures to identify and control the proper installation of items and to preclude nonconformance with the requirements of these rules. These measures shall include procedures for identification, documentation, segre-gation and disposition. Nonconforming items shall be reviewed for acceptance, rejection or repair in accordance with documented procedures. The responsi-bility and authority for the disposition of nonconforming items shall be defined. Repaired or modified items shall be reex-

amined in accordance with the applicable procedures. Measures which control fur-ther processing of a nonconforming or defective item, pending a decision on its disposition, shall be established and maintained. Ultimate disposition of non-conforming items shall be documented.

p. Corrective Action

1. Measures shall be established to assure that conditions adverse to quality such as failures, malfunctions, deficiencies, deviations, defective material and equipment and other nonconformances are promptly iden-tified and corrected.

2. In the case of significant conditions adverse to quality, the measures shall also assure that the cause of these con-ditions be determined and corrected to preclude repetition. The identifica-tion of significant conditions adverse to quality, the cause and condition and the corrective action taken shall be documented and reported to the appropriate levels of management.

3. The requirements shall also extend to the performance of subcontractors’ corrective action measures.

q. Audits A comprehensive system of planned and

periodic audits shall be carried out by the “NR” certificate holder’s organization to assure compliance with the Quality System Program and to determine its ef-fectiveness. Audits shall be performed in accordance with written procedures or checklists by personnel not having direct responsibilities in the areas being au-dited. Audit results shall be documented by the auditing personnel for review by management having responsibility in that area. Follow-up action, including re-audit of deficient areas, shall be taken

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where indicated. Audit results shall be made available to the Authorized Nuclear Inspector.

r. Authorized Nuclear Inspector Measures shall be taken to reference the

commissioned National Board Authorized Nuclear Inspector, qualified in accordance with the National Board Rules for Commis-sioned Inspectors, to ensure that the latest documents including the Quality System Program will be made available to the inspector. The Authorized Nuclear Inspec-tor shall be consulted prior to the issu-ance of a repair/replacement program in order that he may select any inspection or hold points in the program. The Au-thorized Nuclear Inspector shall not sign Form NR-1 or Form NVR-1, as applicable, unless he is satisfied that all work car-ried out is in accordance with the NBIC, ASME Section XI and any jurisdictional requirements.

RA-2370 INTERFACE WITH THE OWNER’S REPAIR/ REPLACEMENT PROGRAM

Interface with the owner’s repair/replace-ment program shall meet the following:

a. The repair/replacement program shall be subject to the acceptance of the jurisdiction and the owner’s ANII.

b. Repair/replacement activities of nuclear components shall meet the requirements of Section XI of the ASME Boiler and Pressure Vessel Code and the jurisdic-tion where the nuclear power plant is located.

c. Documentation of the repair/replacement activities of nuclear components shall be recorded on the National Board Report of Nuclear Repair/Modification or Replace-ment activities, Form NR-1 or Form NVR-

1, as applicable. The completed forms shall be signed by a representative of the authorized nuclear repair organization and the Authorized Nuclear Inspector if the repair/replacement activity meets the requirements of ASME Section XI. For repair/replacement activities that involve design changes as specified in RA-2360(c), Form NR-1 or Form NVR-1, as applicable, shall indicate the responsible organization satisfying the owner’s design specification requirements.

d. The authorized nuclear repair organiza-tion shall provide a copy of the signed Form NR-1 or Form NVR-1, as applicable, to the owner, if required, the jurisdiction and the Authorized Nuclear Inspection Agency. The original Form NR-1 or Form NVR-1, as applicable, shall be registered with the National Board by the authorized nuclear repair organization.

e. The authorized nuclear repair organiza-tion shall provide a nameplate/stamp-ing for repair/replacement activities for each nuclear component unless otherwise required by the Owner’s Quality System Program. The required information and format shall be as shown in Appendix 2.

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31

Inservice Inspection of Pressure-Retaining Items

Part RB

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PART RB — INSERVICE INSPECTION OF PRESSURE-RETAINING ITEMS

RB-1000 General Requirements for Inservice Inspection of Pressure-Retaining Items ...............................................................................36 RB-1010 Scope ......................................................................................................................36 RB-1020 Administration .....................................................................................................36 RB-1030 Stamping ...............................................................................................................36 RB-1040 Reference to Other Codes and Standards ........................................................37 RB-1050 Conclusions ..........................................................................................................37

RB-2000 Personnel Safety and Inspection Activities ......................................................37 RB-2010 Scope ......................................................................................................................37

RB-2100 Personnel Safety ...................................................................................................38 RB-2110 Equipment Operation .........................................................................................38 RB-2120 Vessel Entry Requirements .................................................................................38

RB-2200 Inspection Activities ............................................................................................38 RB-2210 Preparation for Internal Inspection ...................................................................38 RB-2220 Pre-inspection Activities .....................................................................................39 RB-2230 Post-inspection Activities ...................................................................................40

RB-3000 Inspection and Test Methods .............................................................................40 RB-3010 Scope ......................................................................................................................40

RB-3100 Nondestructive Examination Methods (NDE) ................................................40 RB-3110 Visual .....................................................................................................................41 RB-3120 Magnetic Particle .................................................................................................41 RB-3130 Liquid Penetrant ..................................................................................................41 RB-3140 Ultrasonic ..............................................................................................................41 RB-3150 Radiography .........................................................................................................42 RB-3160 Eddy Current ........................................................................................................42 RB-3170 Metallographic .....................................................................................................42 RB-3180 Acoustic Emission ...............................................................................................43

RB-3200 Testing ...................................................................................................................43 RB-3210 Pressure Testing ...................................................................................................43 RB-3220 Leak Testing ..........................................................................................................44

RB-3300 Material Preparation – General Guidelines .....................................................44

RB-4000 Causes of Deterioration and Failure Mechanisms ..........................................44 RB-4010 Scope ......................................................................................................................44 RB-4020 General ..................................................................................................................44

RB-4100 Corrosion ..............................................................................................................44 RB-4110 Macroscopic Corrosion Environments .............................................................44 RB-4120 Microscopic Corrosion Environments ..............................................................46

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RB-4200 Control of Corrosion ...........................................................................................46 RB-4210 Process Variables ..................................................................................................46 RB-4220 Engineering Design .............................................................................................46 RB-4230 Protection ..............................................................................................................47 RB-4240 Material Selection ................................................................................................47 RB-4250 Coatings ................................................................................................................47

RB-4300 Conclusion ............................................................................................................47

RB-4400 Failure Mechanisms ............................................................................................47 RB-4410 Fatigue ...................................................................................................................47 RB-4420 Creep .....................................................................................................................48 RB-4430 Temperature .........................................................................................................48 RB-4440 Hydrogen Attack .................................................................................................48 RB-4450 Hydrogen Embrittlement ...................................................................................49 RB-4460 Bulges And Blisters .............................................................................................50 RB-4470 Overheating ..........................................................................................................50 RB-4480 Cracks ....................................................................................................................50

RB-4500 Specific Inspection Requirements .....................................................................50

RB-5000 Inspection of Boilers ............................................................................................50 RB-5010 Scope ......................................................................................................................50

RB-5100 General Conditions .............................................................................................51

RB-5200 Pre-Inspection Activities .....................................................................................51

RB-5300 Condition of Installation .....................................................................................51 RB-5310 General ..................................................................................................................51

RB-5400 Inspections ............................................................................................................51 RB-5410 External Inspection ..............................................................................................51 RB-5420 Internal Inspection ...............................................................................................51 RB-5430 Evidence of Leakage ............................................................................................52

RB-5500 Inspection Requirements – General ..................................................................53 RB-5510 Corrosion ..............................................................................................................53 RB-5520 Inspection of Piping, Parts and Appurtenances ..............................................54 RB-5600 Specific Inspection Requirements for Boiler Types .........................................57

RB-5700 Inservice Inspection Activities ...........................................................................63

RB-6000 Inspection of Pressure Vessels ...........................................................................63 RB-6010 Scope ......................................................................................................................63


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RB-6200 Inspections – General Requirements ................................................................63 RB-6210 Condition of Installation .....................................................................................63 RB-6220 External Inspection ..............................................................................................63 RB-6230 Internal Inspection ...............................................................................................65 RB-6240 Inspection of Parts and Appurtenances ...........................................................65 RB-6250 Gages, Safety Devices and Controls .................................................................65

RB-6300 Records Review ....................................................................................................66

RB-6400 Inspections For Specific Types of Pressure Vessels .........................................67 RB-6410 General ..................................................................................................................67 RB-6420 Deaerators .............................................................................................................67 RB-6430 Compressed Air Vessels ......................................................................................67 RB-6440 Expansion Tanks ..................................................................................................68 RB-6450 Liquid Ammonia Vessels ....................................................................................69 RB-6460 Inspection of Pressure Vessels with Quick Actuating Closures ....................70 RB-6470 Graphite Pressure Equipment ...........................................................................72 RB-6480 Fiber Reinforced Vessels .....................................................................................72 RB-6490 Propane LP Gas Vessels ......................................................................................72

RB-6500 Nondestructive Examination (NDE) ................................................................72

RB-6600 Remaining Life and Inspection Intervals .........................................................72


RB-7000 Inspection of Piping Systems .............................................................................72 RB-7010 Scope ......................................................................................................................72


RB-7200 Assessment of Piping Design .............................................................................73

RB-7300 Inspection ..............................................................................................................73 RB-7310 External Inspection of Piping .............................................................................73 RB-7320 Internal Inspection of Piping .............................................................................74 RB-7330 Evidence of Leakage ............................................................................................74 RB-7340 Provisions for Expansion and Support ............................................................74 RB-7350 Gages, Safety Devices, Controls ........................................................................74


RB-8000 Inspection of Pressure Relief Devices ...............................................................75 RB-8010 Scope ......................................................................................................................75

RB-8100 Safety Considerations .........................................................................................75

RB-8200 Device Data ...........................................................................................................75 RB-8210 Device Condition .................................................................................................76

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RB-8300 Installation Condition .........................................................................................76

RB-8400 Testing and Operational Inspection ..................................................................77 RB-8410 Recommended Inspection and Test Frequencies ............................................78

RB-8500 Additional Inspection Information ...................................................................80 RB-8510 Boilers ....................................................................................................................80 RB-8520 Pressure Vessels and Piping ...............................................................................81 RB-8530 Rupture Disks .......................................................................................................81

RB-8600 Requirements for Shipping and Transporting .................................................83


RB-9000 Methods for Estimating Remaining Service Life and Inspection Intervals ...........................................................................................83 RB-9010 Scope ......................................................................................................................83

RB-9100 Conditions That Affect Remaining Service Life ..............................................84 RB-9110 Method for Estimating Remaining Service Life for Exposure to Elevated Temperature ...................................................................................84 RB-9120 Method for Estimating Inspection Interval for Exposure to Elevated Temperature ..................................................................................85 RB-9130 Method for Estimating Remaining Service Life for Exposure to Corrosion ........................................................................................................85 RB-9140 Method for Estimating Inspection Interval for Exposure to Corrosion .......88

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RB-1000 GENERAL REQUIREMENTS FOR INSERVICE

INSPECTION OF PRESSURE- RETAINING ITEMS

RB-1010 SCOPE

Part RB provides guidelines and require-ments for conducting inservice inspection and testing of pressure-retaining items and pressure relief devices. Appropriately, this Part includes precautions for the safety of inspection personnel. The safety of the In-spector is the most important aspect of any inspection activity.

Understanding the potential damage/dete-rioration mechanisms that can affect the me-chanical integrity of a pressure-retaining item and knowledge of the inspection methods that can be used to find these damage mechanisms are essential to an effective inspection. This Part includes a general discussion of various damage mechanisms and effective inspection methods. In addition, some specific guidance is given on how to estimate the remaining life of a pressure-retaining item and determine the appropriate inspection interval.

RB-1020 ADMINISTRATION

Jurisdictional requirements describe the fre-quency, scope, type of inspection, whether internal, external or both and type of docu-mentation required for the inspection. The Inspector shall have a thorough knowledge of jurisdictional regulations where the item is installed, as inspection requirements may vary.

RB-1030 STAMPING

AuthorizationWhen the stamping on a pressure-retaining item becomes indistinct or the nameplate is lost, illegible or detatched, but traceability

to the original pressure-retaining item is still possible, the Inspector shall instruct the owner or user to have the stamped data replaced. All re-stamping shall be done in accordance with the original code of construction, except as modified herein. Requests for permission to re-stamp or replace nameplates shall be made to the jurisdiction in which the pres-sure-retaining item is installed. Application must be made on the Replacement of Stamped Data Form NB-136 (Appendix 5). Proof of the original stamping and other such data, as is available, shall be furnished with the re-quest. Permission from the jurisdiction is not required for the reattachment of nameplates that are partially attached. When traceability cannot be established, the jurisdiction shall be contacted.

When there is no jurisdiction, the replacement of stamped data shall be authorized and wit-nessed by a National Board Commissioned Inspector and the completed Form NB-136 shall be submitted to the National Board.

Replacement of Stamped DataThe restamping or replacement of data shall be witnessed by a National Board Commis-sioned Inspector and shall be identical to the original stamping.

The restamping or replacement of a code sym-bol stamp shall be done only by the original manufacturer and witnessed by a National Board Commissioned Inspector.

Replacement nameplates shall be clearly marked “replacement.”

ReportingForm NB-136 shall be filed with the jurisdic-tion (if required) or the National Board by the owner or user together with a facsimile of the stamping or nameplate, as applied, and shall also bear the signature of the National Board Commissioned Inspector who witnessed the replacement.

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RB-1040 REFERENCE TO OTHER CODES AND STANDARDS

Other existing inspection codes, standards and practices pertaining to the inservice in-spection of pressure-retaining items can pro-vide useful information and references rela-tive to the inspection techniques listed in Part RB. Additionally, supplementary guidelines for assisting in the evaluation of inspection results and findings are also available. Some acceptable guidelines are as follows:

a. National Board BULLETIN – National Board Classic Articles Series

b. American Society of Mechanical Engi-neers – ASME Boiler & Pressure Vessel Code Section V (Nondestructive Examination)

c. American Society of Mechanical Engi-neers – ASME Boiler & Pressure Vessel Code Section VI (Recommended Rules for the Care and Operation of Heating Boilers)

d. American Society of Mechanical Engi-neers – ASME Boiler & Pressure Vessel Code Section VII (Recommended Guidelines for the Care of Power Boilers Subsection C6 - Inspection)

e. American Society of Mechanical Engineers – ASME B31G (Manual for Determining the Remaining Strength of Corroded Pipe-lines)

f. American Petroleum Institute – API 572

Inspection of Pressure Vessels

g. American Petroleum Institute – API 574 Inspection Practices for Piping System Components

h. American Petroleum Institute – API 579 Fitness-For-Service

RB-1050 CONCLUSIONS

During any inspections or tests of pressure-retaining items, the actual operating and maintenance practices should be noted by the Inspector and a determination made as to their acceptability.

Defects or deficiencies in the condition, oper-ating and maintenance practices of the boiler, pressure vessel or piping system equipment should be discussed with the owner or user at the time of inspection and recommenda-tions made for correction of any such defects or deficiencies.

RB-2000 PERSONNEL SAFETY AND INSPECTION ACTIVITIES

Visual examination is the basic method used when conducting an inservice inspection of pressure-retaining items. Additional exami-nation and test methods may be required at the discretion of the inspector to provide ad-ditional information to assess the condition of the pressure-retaining item. See RB-3000.

RB-2010 SCOPE

A proper inspection of a pressure-retaining item requires many pre-inspection planning activities including: safety considerations, an inspection plan that considers the potential damage mechanisms, selection of appropri-ate inspection methods and awareness of the jurisdictional requirements. This section describes pre-inspection and post-inspection activities applicable to all pressure-retaining items. Specific inspection requirements for pressure-retaining items are identified in RB-5000 for boilers, RB-6000 for pressure ves-sels and RB-7000 for piping.

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RB-2100 PERSONNEL SAFETY

Personnel safety is the joint responsibility of the owner or user and the Inspector. All appli-cable safety regulations shall be followed. This includes governmental, state, regional and/or local rules and regulations. Owner or user programs, safety programs of the Inspector’s employer or similar regulations also apply. In the absence of such rules, prudent and gener-ally accepted engineering safety procedures satisfactory to the Inspector shall be employed by the owner or user.

RB-2110 EQUIPMENT OPERATION

The Inspector should not operate equipment. Operation shall be conducted only by compe-tent individuals familiar with the equipment and qualified to perform such tasks.

RB-2120 VESSEL ENTRY REQUIREMENTS

No pressure-retaining item shall be entered until it has been properly prepared for inspec-tion. The owner or user and inspector shall determine that pressure-retaining items may be entered safely. This shall include:

a. Potential hazards associated with entry into the object have been identified by the owner or user and are brought to the attention of the Inspector, along with ac-ceptable means or methods for dealing with each of these hazards;

b. Coordination of entry into the object by the Inspector and owner or user representative(s) working in or near the object;

c. If personal protective equipment is re-quired to enter an object, the necessary equipment is available and the Inspector is properly trained in its use;

d. An effective energy isolation program (lock out and/or tag out) is in place and in effect that will prevent the unexpected energizing, start up or release of stored energy.

The Inspector shall be satisfied that a safe atmosphere exists before entering the pres-sure-retaining item. The oxygen content of the breathable atmosphere shall be between 19.5% and 23.5%.

The Inspector shall not be permitted to enter an area if toxic, flammable or inert gases, va-pors or dusts are present and above acceptable limits without appropriate personal protective equipment. This may include, among other items, protective outer clothing, gloves, eye protection and foot protection. The Inspector shall have the proper training governing the selection and use of any personal protective clothing and equipment necessary to safely perform each inspection. Particular attention shall be afforded respiratory protection if the testing of the atmosphere of the object reveals any hazards.

RB-2200 INSPECTION ACTIVITIES

RB-2210 PREPARATION FOR INTERNAL INSPECTION

The owner or user has the responsibility to prepare a pressure-retaining item for internal inspection. Requirements of occupational safety and health regulations (federal, state, local or other), as well as the owner-user’s own program and the safety program of the Inspector’s employer are applicable. The pres-sure-retaining item should be prepared in the following manner or as deemed necessary by the Inspector:

a. When a vessel is connected to a common header with other vessels or in a system where liquids or gases are present, the

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vessel shall be isolated by closing, locking and/or tagging stop valves in accordance with the owner’s or user’s procedures. When toxic or flammable materials are involved, additional safety precautions may require removing pipe sections or blanking pipelines before entering the vessel. The means of isolating the vessel shall be acceptable to the Inspector and in compliance with applicable occupa-tional safety and health regulations and procedures. For boilers or fired pressure vessels, the fuel supply and ignition sys-tem shall be locked out and/or tagged out, in accordance with the owner or user procedures.

b. The vessel shall be allowed to cool or warm at a rate to avoid damage to the vessel. When a boiler is being prepared for internal inspection, the water should not be withdrawn until it has been suf-ficiently cooled at a rate to avoid damage to the boiler.

c. The vessel shall be drained of all liquid and shall be purged of any toxic or flam-mable gases or other contaminants that were contained in the vessel. Mechanical ventilation using a fresh air blower or fan shall be started after the purging op-eration and maintained until all pockets of “dead air,” which may contain toxic, flammable or inert gases are reduced to acceptable limits. During air purging and ventilation of vessels involved with flam-mable gases, the concentration of vapor in air may pass through the flammable range before a safe atmosphere is obtained. All necessary precautions shall be taken to eliminate the possibility of explosion or fire.

d. Manhole and hand hole plates, washout plugs, inspection plugs and any other items requested by the Inspector shall be removed;

e. The Inspector shall not enter a vessel until all safety precautions have been taken. The temperature of the vessel shall be such that the inspecting personnel will not be exposed to excessive heat. Vessel surfaces should be cleaned as necessary.

f. If requested by the Inspector or required by regulation or procedure, a responsible person (attendant) shall remain outside the vessel at the point of entry while the In-spector is inside and shall monitor activity inside and outside and communicate with the Inspector as necessary. The attendant shall have a means of summoning rescue assistance, if needed, and to facilitate res-cue procedures for those inside the vessel without personally entering the vessel.

NOTE: If a vessel has not been properly prepared for an internal inspection, the inspector shall decline to make the inspec-tion.

RB-2220 PRE-INSPECTION ACTIVITIES

Prior to conducting the inspection, a review of the known history of the pressure-retaining item and a general assessment of current con-ditions shall be performed. This shall include a review of information such as:

a. Date of last inspection;

b. Current jurisdictional inspection certifi-cate;

c. ASME Code Symbol Stamping or mark of code of construction;

d. National Board and/or jurisdiction regis-tration number;

e. Operating conditions and normal contents of the vessel (discuss any unique hazards with the owner or user).

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f. Previous inspection report, operating logs and test records;

g. Records of wall thickness checks, espe-cially where corrosion or erosion is a consideration;

h. Review of repairs or alterations for com-pliance with applicable requirements;

i. Observation of the condition of the com-plete installation, including maintenance and operation, to form an opinion of the care the equipment receives;

j. Before starting the inspection, the area should be reviewed for potential hazards such as exposure to falling objects and safety of any scaffolding. When a pressure test is to be performed, the precautions in RB-3000 should be followed.

The following activities should be performed as required to support the inspection:

a. Pressure gage should be removed for test-ing, unless there is other information to assess its accuracy.

b. Pressure relief devices should be inspected in accordance with RB-8000.

RB-2230 POST-INSPECTION ACTIVITIES

Any defects or deficiencies in the condition, operating and maintenance practices of the pressure-retaining item and auxiliary equip-ment should be discussed with the owner or user and recommendations made for correc-tion.

Documentation of inspection shall contain pertinent data such as description of item,

classification, identification numbers, in-spection intervals, date inspected, type of inspection, and test performed and any other information required by the inspection agency, jurisdiction and/or owner-user. The Inspector shall sign, date and note any defi-ciencies, comments or recommendations on the inspection report. The Inspector should retain and distribute copies of the inspection report, as required.

RB-3000 INSPECTION AND TEST METHODS

RB-3010 SCOPE

This part describes acceptable inspection and test methods that are available to the Inspec-tor during inspection of pressure-retaining items.

RB-3100 NONDESTRUCTIVE EXAMINATION METHODS

(NDE)

Listed below is a variety of nondestructive examination methods that may be employed to assess the condition of pressure-retaining items. The skill, experience and integrity of the personnel performing these examinations are essential to obtain meaningful results. The Inspector should review the methods and pro-cedures to be employed to assure compliance with jurisdictional requirements.

Generally, some form of surface preparation will be required prior to use of these examina-tion methods. When there is doubt as to the extent of a defect or detrimental condition found in a pressure-retaining item, the Inspec-tor is cautioned to seek competent technical advice and supplemental NDE.

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RB-3110 VISUAL

Visual examination is an inspection method to ascertain the surface condition of the pres-sure-retaining item. The Inspector should be aware of recognizing various surface features and comparing these features with damage mechanisms listed in RB-4000 that could in-dicate exposure of the pressure-retaining item to harmful corrosion or elevated temperature service.

In some cases the Inspector may have limited or no access while performing an inspection of the pressure-retaining item. Subject to ap-proval of the jurisdiction, remote camera or fiber optic devices may be considered accept-able methods to view and record the surface condition of the pressure-retaining item.

RB-3120 MAGNETIC PARTICLE

The magnetic particle examination method can be used only on ferromagnetic materials to reveal surface discontinuities and to a lim-ited degree, those located below the surface. It uses the principle that magnetic lines of force will attract magnetizable material. The sensitivity of this method decreases rapidly with depth below the surface being examined and, therefore, it is used primarily to examine for surface discontinuities.

In order to use this method, a magnetic field has to be established within the material to be examined. This can be done directly by bringing a strong magnetic field into close proximity of the item being examined or by inducing a magnetic field in the object by pass-ing electric current through the object.

If there is a discontinuity at or near the surface, it will deflect the magnetic lines of force out of the object, thus creating a north pole (mag-

netic lines leave the north pole of a magnet). The magnetic lines of force will reenter the test object on the other side of the discontinuity, thereby creating a south pole (magnetic lines enter the south pole of a magnet). Since a north and a south pole have been created they will attract magnetizable objects. Iron powder is placed on the discontinuity is held in place by the lines of force and will be visible on the surface of the test object.

RB-3130 LIQUID PENETRANT

The liquid penetrant examination method is used to detect discontinuities that are open to the surface of the material being examined. This method may be used on both ferrous and nonferrous materials. Liquid penetrant examination may be used for the detection of surface discontinuities such as cracks, seams, laps, cold shuts, laminations and porosity.

Liquid penetrant examination works by ap-plying a colored liquid (penetrant) to the object to be examined. Time is allowed for the liquid to fill any voids that are open to the sur-face. Excess penetrant is then removed and a “developer” is applied in a uniform, thin coat-ing. The developer acts as a blotter and draws the penetrant out of the discontinuity. The developer is usually of a contrasting color to the penetrant. The penetrant indications will appear as colored figures on a background of the developer.

Liquid penetrant examination is portable, fast and requires minimal operator training.

RB-3140 ULTRASONIC

Ultrasonic testing is used for volumetric examination of welds and base materials (metallic and non-metallic) for detection of

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flaws. This method depends on sound waves of very high frequency being transmitted through metal and reflected at any boundary, such as a metal to air boundary at the surface of the metal, or metal crack boundary at a discontinuity. High frequency sound waves can detect small irregularities but are easily absorbed, particularly by coarse-grained materials. Sound waves can be introduced into a part either normal to the surface or at predetermined angles. Factors such as mate-rial composition, surface condition, choice of equipment and ability of the operator affect the results of ultrasonic inspection. Ultrasonic testing can also be used to measure material thickness.

RB-3150 RADIOGRAPHY

Radiography is a volumetric method that can detect discontinuities throughout a material. This method is commonly used to examine for surface and subsurface discontinuities. The use of this method may be restricted due to the configuration of the welded joint or the limitations of the radiographic equipment. Radiography will not give an indication of the depth of discontinuity unless special pro-cedures are used.

The method uses a high energy gamma ray or x-ray source to penetrate the material to be examined. The rays are absorbed, reflected and refracted by the material but some of the energy passes completely through. The energy of rays that pass completely through is determined by the thickness and other physi-cal properties of the material.

Radiography uses film to detect the rays which penetrate the material. The higher the energy of the rays, the darker the film will become, similar to exposing photographic film to sunlight.

Most discontinuities (cracks, porosity and inclusions) reduce the amount of base ma-terial available to absorb (attenuate) x-rays or gamma rays, thus allowing more energy to pass through the material. Most discon-tinuities will appear as dark shapes on the radiographic film.

The technique used for radiography depends largely on the equipment used and what experience has shown will produce the best results. It is not the function of the technician to indicate the procedure to be followed, provided the procedure and films satisfy all requirements of the applicable section of the ASME Code. The radiographic film provides a permanent record of the results of the ex-amination.

RB-3160 EDDY CURRENT

Examination method that measures changes in a magnetic field caused by discontinuities. Eddy current can also detect a loss of material on inaccessible surfaces and be used to detect changes in hardness of a material. There are three general types of eddy current coils: the concentric coil which surrounds the part to be tested (e.g., tubing); the probe coil which is brought adjacent to the part to be tested; and the bobbin coil which is inserted into the part to be tested (e.g., tubing).

RB-3170 METALLOGRAPHIC

Method of locally polishing, etching and viewing the surface of a pressure-retaining item with either acetate tape (e.g., replication) or a field microscope to determine the condi-tion of the metal microstructure.

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RB-3180 ACOUSTIC EMISSION

Acoustic emission is a method of detecting and monitoring discontinuities in a pressure-retaining item or load-bearing structure. This method utilizes wave guides, transducers, cables and a sophisticated data acquisition system to collect transient acoustic emissions generated by the rapid release of energy from localized sources within the material being tested. Signal amplitude, frequency and loca-tion are collected for many hours of operation at various loads or pressures. Analysis of the data can determine if any part of the system requires additional nondestructive examina-tion with a more sensitive test method.

RB-3200 TESTING

All testing should be performed by experi-enced personnel using written procedures acceptable to the Inspector.

RB-3210 PRESSURE TESTING

During an inspection of a pressure-retaining item, there may be certain instances where inservice conditions have adversely affected the tightness of the component or the inspec-tion discloses unusual, hard to evaluate forms of deterioration that may affect the safety of the vessel. In these specific instances, a pres-sure test using air, water or other suitable test medium may be required at the discretion of the Inspector to assess leak tightness of the pressure-retaining item.

The Inspector is cautioned that a pressure test will not provide any indication of the amount of remaining service life or the future reliability of a pressure-retaining item. The pressure test in this instance only serves to determine if the pressure-retaining item con-tains defects which will not allow the item to retain pressure. In certain instances, pressure tests of inservice components may reduce the

remaining service life of the component due to causing permanent deformation of the item.

If an inservice pressure test is required, the following precautions shall be met:

a. The test pressure should not exceed 90% of the set pressure of the lowest setting pressure relief device on the component to avoid damage to pressure relief devices.

b. Test pressure should be selected or ad-justed in agreement between the Inspector and the owner-user. When the original test pressure includes consideration of corro-sion allowance, the test pressure may be further adjusted based upon the remain-ing corrosion allowance.

c. The metal temperature during a pressure test should not be less than 60°F (16°C) unless the owner-user provides informa-tion on the toughness characteristics of the vessel material to indicate the accept-ability of a lower test temperature.

d. The metal temperature shall not be more than 120°F (50°C) unless the owner-user specifies the requirement for a higher test temperature. If the owner-user specifies a test temperature higher than 120°F (50°C), then precautions shall be taken to afford the Inspector close examination without risk of injury.

e. When contamination of the vessel contents by any medium is prohibited or when a pressure test is not practical, other testing methods described below may be used provided the precautionary requirements of the applicable section of the original construction code or other standards are followed. In such cases, there shall be agreement as to the testing procedure be-tween the owner-user and the Inspector.

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RB-3220 LEAK TESTING

Leak testing for the purpose of detecting any leakage may be performed when a pressure test cannot be performed. Some methods or techniques for leak testing may include bub-ble test (direct pressure or vacuum), helium mass spectrometer, pressure change or flow measurement. Use of leak test procedures shall be in agreement between the owner-user and the Inspector. Use of written procedures and experienced personnel is required when performing leak tests. The Inspector shall review the written procedure to become fa-miliar with limitations, adequacy, methods and acceptance standards identified.

RB-3300 MATERIAL PREPARATION – GENERAL GUIDELINES

Materials to be inspected shall be suitably prepared so surface irregularities will not be confused with or mask any defects. Material conditioning such as cleaning, buffing, wire brushing or grinding may be required by pro-cedure or, if requested, by the Inspector. In-sulation or component parts may be required by the Inspector to be removed.

RB-4000 CAUSES OF DETERIORATION AND

FAILURE MECHANISMS

RB-4010 SCOPE

This section describes causes of deterioration such as corrosion and erosion and failure mechanisms such as cracking, fatigue, creep and temperature gradients that are applicable to pressure-retaining items. Further informa-tion concerning metallurgical properties of steels and nonferrous alloys are described in ASME Section II, Part D, of the Boiler and Pressure Vessel Code, Appendix 6, titled Met-allurgical Phenomena.

RB-4020 GENERAL

All metals and alloys are susceptible to cor-rosion. Corrosion is deterioration that occurs when a metal reacts with its environment. Corrosion can be classified based on three factors:

a. Nature wet – liquid or moisture present dry – high temperature gasses

b. Mechanism – electrochemical or direct chemical reactions

c. Appearance – either uniform or local-ized

RB-4100 CORROSION

RB-4110 MACROSCOPIC CORROSION ENVIRONMENTS

Macroscopic corrosion types are among the most prevalent conditions found in pressure-retaining items causing deterioration. The following corrosion types are found.

a. Uniform Corrosion (General) The most common form of corrosion is

the uniform attack over a large area of the metal surface. Safe working pressure is directly related to the remaining material thickness and failures can be avoided by regular inspection.

b. Galvanic Corrosion Two dissimilar metals in contact with each

other and with an electrolyte (i.e., a film of water containing dissolved oxygen, nitrogen and carbon dioxide) constitute

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an electrolyte cell, and the electric current flowing through the circuit may cause rapid corrosion of the less noble metal (the one having the greater electrode po-tential). This corrosion mechanism is most active when there are large differences between the electrode potentials of the two metals, but galvanic corrosion may also exist with relatively minor changes of alloy composition (i.e., between a weld metal and the base metal). Natural (i.e., an oxide coating on aluminum) or protective coatings may inhibit galvanic corrosion, but in most instances the metals or alloys must be selected on the basis of intrinsic resistance to corrosion. In pressure vessels the effects of galvanic corrosion are most noticeable at rivets welds, or at flanged and bolted connections.

c. Erosion Corrosion Movement of a corrodent over a metal

surface increases the rate of attack due to mechanical wear and corrosion. This cor-rosion is generally characterized as having an appearance of smooth bottomed shal-low pits and may also exhibit a directional pattern related to the path taken by the corrodent.

d. Crevice Corrosion Environmental conditions in a crevice can,

with time, become different to those on a nearby clean surface. A more aggressive environment may develop within the crevice and cause local corrosion. Crevices commonly exist at gasket surfaces, lap joints, bolts, rivets, etc. They are also cre-ated by dirt deposits, corrosion products, scratches in paint, etc. Crevice corrosion is usually attributed to one or more of the following:

1. Changes in aciditiy in the crevice;

2. Lack of oxygen in the crevice;

3. Buildup of detrimental ions in the crevice;

4. Depletion of a corrosion inhibitor in the crevice.

e. Pitting Corrosion Pitting corrosion is the formation of holes

in an otherwise relatively unattacked sur-face. Pitting is usually a slow process caus-ing isolated, scattered pitting over a small area that does not substantially weaken the vessel. It could, however, eventually cause leakage.

f. Line Corrosion This is a condition where pits are con-

nected, or nearly connected, to each other in a narrow band or line. Line corrosion frequently occurs in the area of intersec-tion of the support skirt and the bottom of the vessel or liquid-vapor interface.

g. Exfoliation and Selective Leaching Exfoliation is a subsurface corrosion that

begins on a clean surface but spreads below it. It differs from pitting in that the attack has a laminated appearance. These attacks are usually recognized by a flaky and sometimes blistered surface.

Selective leaching is the removal of one element in an alloy. This corrosion mecha-nism is detrimental because it yields a porous metal with poor mechanical prop-erties.

h. Grooving This type of corrosion is a form of metal

deterioration caused by localized cor-rosion and may be accelerated by stress concentration. Grooving may be found adjacent to riveted lap joints or welds and on flanged surfaces, particularly the flanges of unstayed heads.

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RB-4120 MICROSCOPIC CORROSION ENVIRONMENTS

Microscopic corrosion environments are not visible to the naked eye. The following cor-rosion types are among the most prevalent conditions found in pressure-retaining items causing deterioration.

a. Intergranular Corrosion Corrosion attack by a corrodent is usu-

ally relating to the segregation of specific elements or the formation of a compound in the grain boundary. It usually attacks the grain boundary that has lost an ele-ment necessary for adequate corrosion resistance. In severe cases entire grains are dislodged causing the surface to ap-pear rough to the naked eye and will feel sugary because of the loose grains. Sus-ceptibility to intergranular corrosion is usually a by-product of heat treatment.

b. Stress Corrosion Cracking The action of tensile stress and a corrodent

results in the cracking of metals. This is most serious because periods of time (of-ten years) may pass before cracks become visible. The cracks then propagate quite rapidly and result in unexpected failures. Stresses that cause cracking arise from cold working, welding, thermal treatment or may be externally applied during ser-vice. The cracks can follow intergranular or transgranular paths and often have a tendency for branching.

The principal variables affecting stress cor-rosion cracking are tensile stress, service temperature, solution chemistry, dura-tion of exposure and metal properties. Modifying any one of these parameters sufficiently can reduce or eliminate the possibility of stress corrosion cracking oc-curring in service. As an example, austen-

itic stainless steels used in water wetted service are susceptible to stress corrosion cracking.

c. Corrosion Fatigue This is a special form of stress corrosion

cracking caused by repeated cyclic stress-ing. When fatigue is in the presence of a corrodent, the resulting failure is corro-sion fatigue. Such failures are common to pressure-retaining items subjected to continued vibration.

RB-4200 CONTROL OF CORROSION

There are many ways to control and avoid corrosion such as control of process variables, engineering design, protection, material selec-tion, and coatings.

RB-4210 PROCESS VARIABLES

Some of the more common process variables that influence corrosion are listed below:

• Concentration of major constituents • Impurities• Temperature• pH• Velocity• Inhibitors• Startup and downtime operations

RB-4220 ENGINEERING DESIGN

Crevice, galvanic, erosion and stress corro-sion cracking are the types of corrosion most controllable by proper design of equipment. Procedures and situations such as welding, end-grain attack and drainage are also con-trolled by proper design techniques.

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RB-4230 PROTECTION

Protective methods such as cathodic and anodic corrosion control can minimize at-tack and thereby reduce replacement costs or permit the use of less expensive or thinner materials.

RB-4240 MATERIAL SELECTION

Chemical and physical properties of a mate-rial will enable selection of the best one for a specific application. The final choice will often be a compromise between the desired physi-cal properties and economic factors. A check-list for material selection would include:

• Evaluating requirements to be met (prop-erties, design, appearance, mechanical, physical)

• Material selection considerations• Corrodent variables• Application of equipment• Experience of materials

RB-4250 COATINGS

Metallic and inorganic materials are typical coatings for controlling corrosion. Selection of materials depends on the corrodent, method of application, type of base material and the nature of bonding between the base material and coating. The success or failure of a coating will often depend on the surface preparation. Techniques for applying metallic coatings could include:

• Hot dipping• Metal spraying• Cladding• Cementation• Vapor deposition• Electroplating• Plating• Welding

Inorganic coatings would include:

• Porcelain, ceramic• Glass• Cement• Rubber• Paint• Phosphates

RB-4300 CONCLUSION

By carefully selecting materials and protection methods, we can predict and control corrosive attack. However, there may be unexpected failures as a result of one or more of the fol-lowing:

• Poor choice of materials• Operating conditions different from those

anticipated• Defective fabrication• Improper design• Inadequate maintenance• Defective material

Corrective actions will depend on which fac-tors caused the problems making it important to diagnose the reason for failure. Early de-tection of corrosion problems is important to prevent failures and can be achieved by per-forming regular inspections and encouraging employees to be observant and communicate their observations.

RB-4400 FAILURE MECHANISMS

RB-4410 FATIGUE

Stress reversals (such as cyclic loading) in parts of equipment are common, particularly at points of high secondary stress. If stresses are high and reversals frequent, failure of parts may occur because of fatigue. Fatigue failures in pressure vessels may also result from cyclic

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temperature and pressure changes. Locations where metals having different thermal coef-ficients of expansion are joined by welding may be susceptible to thermal fatigue.

RB-4420 CREEP

Creep may occur if equipment is subjected to temperatures above those for which the equipment is designed. Since metals become weaker at higher temperatures, such distor-tion may result in failure, particularly at points of stress concentration. If excessive temperatures are encountered, structural property and chemical changes in metals may also take place, which may permanently weaken equipment. Since creep is dependent on time, temperature and stress, the actual or estimated levels of these quantities should be used in any evaluations.

RB-4430 TEMPERATURE

At subfreezing temperatures, water and some chemicals handled in pressure vessels may freeze and cause failure. Carbon and low alloy steels may be susceptible to brittle failure at ambient temperatures. A number of failures have been attributed to brittle fracture of steels that were exposed to temperatures below their transition temperature and that were exposed to pressures greater than 20% of the required hydrostatic test pressure. However, most brittle fractures have occurred on the first application of a particular stress level (that is, the first hydrostatic test or overload). Special attention should be given to low alloy steels because they are prone to temper embrittle-ment. Temper embrittlement is defined as a loss of ductility and notch toughness due to postweld heat treatment or high temperature service, above 700°F (370°C).

RB-4440 HYDROGEN ATTACK

Hydrogen attack occurs in a high-tempera-ture, high-pressure hydrogen environment that can degrade the mechanical strength of carbon steels and low alloy steels. This type of damage is called hydrogen attack. It is caused by hydrogen permeating the steel and reacting with carbon to form methane. Since carbon is a strengthening agent in steel, its removal by the reaction with hydrogen causes the steel to lose strength. In addition, methane can become trapped within the steel at high pressures, eventually forming bubbles, fissures (cracks) and/or blisters.

Damage caused by hydrogen attack is pre-ceded by an incubation period with no notice-able change in properties. After the incubation period, decarburization and/or blistering and fissuring will occur. The length of the incuba-tion period varies with temperature, pressure and alloy content of the steel. Damage is re-versible during the incubation period, during which no loss of mechanical properties will have occurred. Once permanent degradation begins, the damage is irreversible.

Hydrogen attack is a concern primarily in refinery and petrochemical plant equipment handling hydrogen and hydrogen-hydro-carbon streams at temperatures above about 450°F (230°C) and pressures above 100 psi (700 kPa). A guideline for selection of steels to avoid hydrogen attack is given in API Publication 941, “Steels for Hydrogen Service at Elevated Temperatures and Pressures in Pe-troleum Refineries and Petrochemical Plants.” Also widely known as the “Nelson Curves,” API 941 shows that the severity of hydrogen attack depends on temperature, hydrogen partial pressure, exposure time and steel composition. Additions of chromium and molybdenum to the steel composition increase resistance to hydrogen attack.

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It is important to understand that hydrogen attack is different from hydrogen embrittle-ment, which is discussed next. Hydrogen attack occurs in the absence of liquid water at elevated temperatures (above 450°F [230°C]). Hydrogen embrittlement primarily occurs as a result of corrosion reactions occurring in aqueous solutions at temperatures generally below about 200°F (95°C).

RB-4450 HYDROGEN EMBRITTLEMENT

Hydrogen embrittlement is a loss of strength and/or ductility in steels caused by atomic hy-drogen dissolved in the steel. It is a low tem-perature phenomenon, seldom encountered above 200°F (95°C), and most often occurs as a result of hydrogen evolved from aqueous cor-rosion reactions. It can vary in its appearance and can occur in differing environments, thus giving rise to the various terms by which it is known, including sulfide stress cracking, wet hydrogen sulfide cracking, hydrogen stress cracking, blistering, blister cracking, hydro-gen-induced cracking (HIC), stress-oriented hydrogen-induced cracking (SOHIC) and others. Weld underbead cracking (also known as delayed cracking and cold cracking) is also a form of hydrogen embrittlement, however in this case, the hydrogen comes from the welding operation rather than from a corro-sion reaction.

Some forms of hydrogen embrittlement re-quire an applied stress or residual stress for cracking to occur (sulfide stress cracking, SOHIC, weld underbead cracking), while others occur in the absence of applied or re-sidual stress, the internal pressure from the recombined hydrogen gas being sufficient to cause the damage (blistering, HIC).

Susceptibility to sulfide stress cracking and similar forms of hydrogen embrittlement depends on the strength of the steel. Higher

strength steels are more susceptible. The strength level at which susceptibility arises depends on the severity of the environment that the steel is exposed to. Hydrogen sulfide, hydrogen cyanide and arsenic, in aqueous solutions, all greatly increase the severity of the environment towards hydrogen embrittle-ment by increasing the amount of hydrogen that is absorbed by the steel during the cor-rosion reaction. In hydrogen sulfide environ-ments, cracking can generally be avoided by using steels with a strength level below that equivalent to a hardness of Rockwell C-22.

Similarly, weld underbead cracking is caused by hydrogen dissolved in a hard, high strength, weld-heat-affected zone. Use of low hydrogen welding practice to minimize dis-solved hydrogen, and/or use of high preheat and/or postweld heat treatment to reduce heat-affected-zone hardness, will reduce the likelihood of weld underbead cracking in a susceptible steel.

Hydrogen embrittlement is reversible as long as no physical damage, e.g., cracking, has oc-curred in the steel. If the atomic hydrogen is removed from the steel before any damage oc-curs, for example, by heating for a short time in the absence of hydrogen to between 300°F (150°C) and 400°F (205°C), normal mechanical properties will be restored.

Cracking that can occur in vessels operating in aqueous hydrogen sulfide service (i.e., wet hydrogen sulfide cracking) will not always be readily apparent upon visual inspection. Other methods, such as magnetic particle (in-cluding wet fluorescent) or liquid penetrant, may be required to reveal the cracks.

Welding procedures, repair methods and inspection procedures must include careful consideration of potential failure in corrosive environments, including the various forms of hydrogen embrittlement.

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RB-4460 BULGES AND BLISTERS

A bulge may be caused by overheating of the entire thickness of the metal, thereby lower-ing the strength of the metal which is then deformed by the pressure. Bulges may also be caused by creep or temperature gradients.

A blister may be caused by a defect in the metal, such as a lamination, where the side exposed to the fire overheats but the inner side retains its strength due to cooling effect of water or other medium. Blisters may also be caused by a hydrogen environment. See RB-4450.

RB-4470 OVERHEATING

Overheating is one of the most serious causes of deterioration. Deformation and possible rupture of pressure parts may result.

Particular attention should be given to sur-faces exposed to fire. It should be observed whether any part has become deformed due to bulging or blistering. If a bulge or blister reduces the integrity of the component or when evidence of leakage is noted coming from those defects, proper repairs must be made.

RB-4480 CRACKS

Cracks may result from flaws existing in mate-rial. The design and operating conditions may also cause cracking. Cracking can be caused by fatigue of the metal due to continual flex-ing and may be accelerated by corrosion. Fire cracks are caused by the thermal differential when the cooling effect of the water is not adequate to transfer the heat from the metal surfaces exposed to the fire. Some cracks re-sult from a combination of all these causes mentioned.

Cracks noted in shell plates and fire cracks that run from the edge of the plate into the rivet holes of girth seams should be repaired. Thermal fatigue cracks determined by engi-neering evaluation to be self arresting may be left in place.

Areas where cracks are most likely to appear should be examined. This includes the liga-ments between tube holes, from and between rivet holes, any flange where there may be repeated flexing of the plate during operation and around welded connections.

Lap joints are subject to cracking where the plates lap in the longitudinal seam. If there is any evidence of leakage or other distress at this point, the Inspector shall thoroughly examine the area and, if necessary, have the plate notched or slotted in order to determine whether cracks exist in the seam. Repairs of lap joint cracks on longitudinal seams are prohibited.

Where cracks are suspected, it may be neces-sary to subject the pressure-retaining item to nondestructive examination to determine their location.

RB-4500 SPECIFIC INSPECTION REQUIREMENTS

Specific inspection requirements for pressure-retaining items to determine corrosion dete-rioration and possible prevention of failures are identified in RB-5000 for boilers, RB-6000 for pressure vessels, and RB-7000 for piping.

RB-5000 INSPECTION OF BOILERS

RB-5010 SCOPE

This section provides guidelines for external and internal inspection of boilers used to con-

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tain pressure. This pressure may be obtained from an external source or by the application of heat from a direct or indirect source or a combination thereof.

RB-5100 GENERAL CONDITIONS

Boilers are designed for a variety of service conditions. The temperature and pressure at which they operate should be considered in establishing inspection criteria. This part is provided for guidance of a general nature. There may be occasions where more detailed procedures will be required.

The condition of the complete installation, in-cluding maintenance and operation, can often be used by the Inspector as a guide in forming an opinion of the care given to the boiler.

Usually the conditions to be observed by the Inspector are common to both power and heating boilers, however, where appropriate, the differences are noted.

RB-5200 PRE-INSPECTION ACTIVITIES

A review of the known history of the boiler shall be performed. This shall include a review of information contained in RB-2000 and other items listed below.

RB-5300 CONDITION OF INSTALLATION

RB-5310 GENERAL

The general condition of the boiler room or boiler location should be assessed using appropriate jurisdictional requirements and overall engineering practice. Items that are usually considered are lighting, adequacy of

ventilation for habitability, combustion air, housekeeping, personal safety and general safety considerations.

RB-5400 INSPECTIONS

RB-5410 EXTERNAL INSPECTION

The external inspection of a boiler is made to determine if it is in a condition to operate safely. Some items to consider are:

a. The boiler fittings, valves and piping should be checked for compliance with ASME Code or other standards or equiva-lent requirements;

b. Adequacy of structure, boiler supports and any associated support steel;

c. Boiler casing should be free from cracks, combustion gas or fluid leaks, excessive corrosion or other degradation that could interfere with proper operation;

d. Soot blowers, valving and actuating mechanisms;

e. Gaskets on observation doors, access doors, drums, handhole and manhole covers and caps;

f. Valves and actuators, either chains, mo-tors and/or handwheels;

g. Leakage of fluids or combustion gases.

RB-5420 INTERNAL INSPECTION

When a boiler is to be prepared for internal inspection, the water shall not be withdrawn until the setting has been sufficiently cooled at a rate to avoid damage to the boiler as well as additional preparations identified in RB-2120 and RB-2210.

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The owner or user shall prepare a boiler for internal inspection in the following manner:

Before opening the manhole(s) and enter-ing any part of the boiler that is connected to a common header with other boilers, the required steam or water system stop valves (including bypass) must be closed, locked out and/or tagged in accordance with the owner-user’s procedures and drain valves or cocks between the two closed stop valves opened. After draining the boiler, the blowoff valves shall be closed, locked out and/or tagged out in accordance with the owner-user’s proce-dures. Alternatively, lines may be blanked or sections of pipe removed. Blowoff lines, where practicable, shall be disconnected between pressure parts and valves. All drains and vent lines shall be open.

The Inspector shall review all personnel safety requirements as outlined in RB-2000 prior to entry.

NOTE: If a boiler has not been properly pre-pared for an internal inspection, the inspector shall decline to make the inspection.

RB-5430 EVIDENCE OF LEAKAGE

It is not normally necessary to remove in-sulating material, masonry, or fixed parts of a boiler for inspection, unless defects or deterioration are suspected or are commonly found in the particular type of boiler being inspected. Where there is evidence of leak-age showing on the covering, the Inspector shall have the covering removed in order that a thorough inspection of the area may be made. Such inspection may require removal of insulating material, masonry or fixed parts of the boiler.

For additional information regarding a leak in a boiler or the extent of a possible defect, a pressure test may be required.

a. To determine tightness, the test pressure need be no greater than the maximum allowable working pressure stamped on the pressure-retaining item.

b. During a pressure test where the test pressure will exceed the set pressure of a pressure relief device, the device shall be prepared as recommended by the valve manufacturer.

c. The temperature of the water used to ap-ply a pressure test should not be less than 70°F (20°C) and the maximum tempera-ture during inspection should not exceed 120°F (50°C). A lower water temperature could be used if the owner can provide in-formation on the toughness characteristics of the material to indicate acceptability of the lower test temperature.

d. Hold-time for the pressure test shall be 10 minutes prior to the examination by the Inspector.

e. Hold-time for the examination by the Inspector shall be the time necessary for the Inspector to conduct the inspections.

f. When the introduction of water for a hydrostatic test will cause damage to a boiler or boiler component, other testing media or vacuum testing may be used provided the precautionary requirements of the applicable section of the original code of construction or other standards are followed. In such cases, there shall be agreement as to the testing procedure between the owner and the Inspector.

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RB-5500 INSPECTION REQUIREMENTS — GENERAL (See RB-4000)

RB-5510 CORROSION

Corrosion causes deterioration of the metal surfaces. It can affect large areas or it can be localized in the form of pitting. Isolated, shallow pitting is not considered serious if not active.

The most common causes of corrosion in boilers are the presence of free oxygen and dissolved salts in the feedwater. Where active corrosion is found, the Inspector should advise the owner or user to obtain competent advice regarding proper feedwater treatment.

For the purpose of estimating the effect of severe corrosion over large areas on the safe working pressure, the thickness of the remain-ing sound metal should be determined by ultrasonic examination or by drilling.

Grooving is a form of metal deterioration caused by localized corrosion and may be accelerated by stress concentration. This is es-pecially significant adjacent to riveted joints.

All flanged surfaces should be inspected, particularly the flanges of unstayed heads. Grooving in the knuckles of such heads is common since there is slight movement in heads of this design which causes a stress concentration.

Some types of boilers have ogee or reversed-flanged construction which is prone to groov-ing and may not be readily accessible for examination. The Inspector should insert a mirror through an inspection opening to ex-

amine as much area as possible. Other means of examination such as the ultrasonic method may be employed.

Grooving is usually progressive and when it is detected, its effect should be carefully evalu-ated and corrective action taken.

The fireside surfaces of tubes in horizontal firetube boilers usually deteriorate more rap-idly at the ends nearest the fire. The Inspector should examine the tube ends to determine if there has been serious reduction in thickness. The tube surfaces in some vertical tube boilers are more susceptible to deterioration at the upper ends when exposed to the heat of com-bustion. These tube ends should be closely examined to determine if there has been a serious reduction in thickness. The upper tube sheet in a vertical “dry top” boiler should be inspected for evidence of overheating.

Pitting and corrosion on the waterside sur-faces of the tubes should be examined. In vertical firetube boilers, excessive corrosion and pitting is often noted at and above the water level.

The surfaces of tubes should be carefully ex-amined to detect corrosion, erosion, bulges, cracks or evidence of defective welds. Tubes may become thinned by high velocity im-pingement of fuel and ash particles or by the improper installation or use of soot blowers. A leak from a tube frequently causes serious corrosion or erosion on adjacent tubes.

In restricted fireside spaces, such as where short tubes or nipples are used to join drums or headers, there is a tendency for fuel and ash to lodge at junction points. Such deposits are likely to cause corrosion if moisture is present and the area should be thoroughly cleaned and examined.

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RB-5520 INSPECTION OF PIPING, PARTS, AND

APPURTENANCES

RB-5521 BOILER PIPING

Piping should be inspected in accordance with RB-7000.

RB-5522 WATERSIDE DEPOSITS

All accessible surfaces of the exposed metal on the waterside of the boiler should be inspected for deposits caused by water treatment, scale, oil or other substances. Oil or scale in the tubes of watertube boilers is particularly detrimen-tal since this can cause an insulating effect resulting in overheating, weakening and pos-sible metal fatigue by bulging or rupture.

Excessive scale or other deposits should be removed by chemical or mechanical means.

RB-5523 STAYS AND STAYBOLTS

All stays, whether diagonal or through, should be inspected to determine whether or not they are in even tension. Staybolt ends and the stayed plates should be examined to determine whether cracks exist. In addition, stayed plates should be inspected for bulging in the general area of the stay. Each staybolt end should be checked for excessive cold working (heading) and seal welds as evidence of a possible leakage problem. Stays or stay-bolts which are not in tension or adjustment should be repaired. Broken stays or staybolts shall be replaced.

The Inspector should test firebox staybolts by tapping one end of each bolt with a hammer and, where practicable, a hammer or other heavy tool should be held on the opposite end

to make the test more effective. An unbroken bolt should give a ringing sound while a bro-ken bolt will give a hollow or non-responsive sound. Staybolts with telltale holes should be examined for evidence of leakage, which will indicate a broken or cracked bolt. Broken staybolts shall be replaced.

RB-5524 FLANGED OR OTHER CONNECTIONS

The manhole and reinforcing plates, as well as nozzles or other connections flanged or bolted to the boiler, should be examined for evidence of defects both internally and exter-nally. Whenever possible, observation should be made from both sides, internally and exter-nally, to determine whether connections are properly made to the boiler.

All openings leading to external attachments, such as water column connections, low water fuel cut-off devices, openings in dry pipes and openings to safety valves, should be examined to ensure they are free from obstruction.

RB-5525 MISCELLANEOUS

The piping to the water column should be carefully inspected to ensure that water cannot accumulate in the steam connection. The position of the water column should be checked to determine that the column is placed in accordance with ASME Code or other standard or equivalent requirements.

The gas side baffling should be inspected. The absence of the proper baffling or defec-tive baffling can cause high temperatures and overheat portions of the boiler. The location and condition of combustion arches should be checked for evidence of flame impingement, which could result in overheating.

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Any localization of heat caused by improper or defective installation or improper operation of firing equipment should be corrected before the boiler is returned to service.

The refractory supports and settings should be carefully examined, especially at points where the boiler structure comes near the setting walls or floor, to ensure that deposits of ash or soot will not bind the boiler and pro-duce excessive strains on the structure due to the restriction of movement of the parts under operating conditions.

When tubes have been rerolled or replaced, they should be inspected for proper work-manship. Where tubes are readily accessible, they may have been over rolled. Conversely, when it is difficult to reach the tube ends they may have been under rolled.

Drums and headers should be inspected in-ternally and externally for signs of leakage, corrosion, overheating and erosion. Inspect blowdown piping and connections for expan-sion and flexibility. Check header seals for gasket leakage.

Soot blower mechanical gears, chains, pul-leys, etc. should be checked for broken or worn parts. Inspect supply piping to the soot blowers for faulty supports, leakage and ex-pansion and contraction provisions. Check design for proper installation to allow for complete drainage of condensate which may cause erosion.

Valves should be inspected on boiler feedwa-ter, blowdown, drain and steam systems for gland leakage, operability, tightness, handle or stem damage, body defects and general corrosion.

RB-5526 GAGES

Ensure that the water level indicated is correct by having the gage tested as follows:

a. Close the lower gage glass valve then open the drain cock and blow the glass clear.

b. Close the drain cock and open the lower gage glass valve. Water should return to the gage glass immediately.

c. Close the upper gage glass valve then open the drain cock and allow the water to flow until it runs clean.

d. Close the drain cock and open the upper gage glass valve. Water should return to the gage glass immediately.

If the water return is sluggish, the test should be discontinued. A sluggish response could indicate an obstruction in the pipe connec-tions to the boiler. Any leakage at these fit-tings should be promptly corrected to avoid damage to the fittings or a false waterline indication.

Each hot water boiler should be fitted with a temperature gage at or near the boiler outlet that will at all times indicate the water tem-perature.

Where required, all the pressure gages shall be removed, tested, and their readings com-pared to the readings of a standard test gage or a dead weight tester.

The location of a steam pressure gage should be noted to determine whether it is exposed to high temperature from an external source or to internal heat due to lack of protection by a proper siphon or trap. The Inspector should check that provisions are made for blowing out the pipe leading to the steam gage.

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The pressure indicated on the pressure gage should be compared with other gages on the same system or with a standard test gage, if necessary. The Inspector should observe the reading during tests; for example, the reduc-tion in pressure when testing the low water fuel cutoff control or safety valve on steam boilers. Defective gages should be promptly replaced.

RB-5527 PRESSURE RELIEF DEVICES

See RB-8000 for the inspection of safety de-vices (pressure relief valves) used to prevent overpressure of boilers.

RB-5528 CONTROLS

Verify operation of low water protection devices by observing the blowdown of these controls or the actual lowering of boiler water level under carefully controlled conditions with the burner operating. This test should shut off the heat source to the boiler. The re-turn to normal condition such as the restart of the burner, the silencing of an alarm or stopping of a feed pump should be noted. A sluggish response could indicate an obstruc-tion in the connections to the boiler.

The operation of a submerged low water fuel cutoff mounted directly in a steam boiler shell should be tested by lowering the boiler water level carefully. This should be done only after being assured that the water level gage glass is indicating correctly.

On a high-temperature water boiler, it is often not possible to test the control by cutoff indica-tion, but where the control is of the float type externally mounted, the float chamber should be drained to check for the accumulation of sediment.

In the event controls are inoperative or the correct water level is not indicated, the boiler

should be taken out of service until the unsafe condition has been corrected.

All automatic low water fuel cut-off and water feeding devices should be examined by the Inspector to ensure that they are prop-erly installed. The Inspector should have the float chamber types of control devices disas-sembled and the float linkage and connections examined for wear. The float chamber should be examined to ensure that it is free of sludge or other accumulation. Any necessary correc-tive action should be taken before the device is placed back into service. The Inspector should check that the operating instructions for the devices are readily available.

Check that the following controls/devices are provided:

a. Each automatically fired steam boiler is protected from over pressure by not less than two pressure operated controls, one of which may be an operating control.

b. Each automatically fired hot water boiler is protected from over-temperature by not less than two temperature operated controls, one of which may be an operat-ing control.

c. Each hot water boiler is fitted with a ther-mometer that will, at all times, indicate the water temperature at or near the boiler outlet.

RB-5529 RECORDS REVIEW

A review of the boiler log, records of main-tenance and feedwater treatment should be made by the Inspector to ensure that regular and adequate tests have been made on the boiler and controls.

The owner or user should be consulted re-garding repairs or alterations, if any, which have been made since the last inspection. Such

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repairs or alterations should be reviewed for compliance with the jurisdictional require-ments, if applicable.

RB-5600 SPECIFIC INSPECTION REQUIREMENTS FOR

BOILER TYPES

The following details are unique to specific type boilers and should be considered when performing inspections along with the general requirements as previously outlined.

RB-5601 WATERTUBE BOILERS

Typically constructed of drums, headers and tubes, boilers of this type are used to produce steam or hot water commonly in large quan-tities. They range in size and pressure from small package units to extremely large field erected boilers with pressures in excess of 3000 psig (20 MPa gage). These boilers may be fired by many types of fuels such as wood, coal, gas, oil, trash and black liquor.

There are many locations both internal and external where moisture and oxygen com-bine causing primary concern for corrosion. The fuels burned in this type of boiler may contain ash, which can form an abrasive grit in the flue gas stream. The abrasive action of the ash in high velocity flue gas can quickly erode boiler tubes. Their size and type of construction poses mechanical and thermal cyclic stresses.

Unique parts associated with this type of construction such as casing, expansion sup-ports, superheater, economizer, soot blowers, drums, headers and tubes should be inspected carefully and thoroughly in accordance with RB-5500, as applicable.

RB-5602 BLACK LIQUOR (KRAFT OR SULFATE) RECOVERY BOILERS

Boilers of this type are used in the pulp and paper industry. Black liquor is a by-product of pulping processing. It contains organic and inorganic constituents and is concen-trated from about 10% solids to at least 58% solids for firing in the recovery boilers. The organic material that is dissolved in the pulp-ing process combusts and the spent pulping chemicals form a molten pool in the furnace. The molten material, or “smelt,” drains from the furnace wall through smelt spouts into a smelt dissolving tank for recovery of the chemicals. Ultimately, the by-product of the recovery process is steam used for processing and power. Gas or oil auxilliary burners are used to start the self-sustaining black liquor combustion process and may be used to pro-duce supplemental steam if sufficient liquor is not available.

The recovery combustion process requires a reducing atmosphere near the furnace floor and an oxidizing atmosphere in the upper furnace for completion of combustion. Pres-sure parts within the furnace require protec-tion from the reducing atmosphere and from sulfidation. The rate of corrosion within the furnace is temperature dependent. Boilers operating up to 900 psi (6 MPa) typically have plain carbon steel steam generating tubes with pin studs applied to the lower furnace to retain a protective layer of refractory or “fro-zen” smelt. Above 900 psi (6 MPa) the lower furnace tubes will typically have a special corrosion protection outer layer. The most common is a stainless steel clad “composite tube.” Other protection methods are corrosion resistant overlay welding, thermal or plasma spray coating and diffusion coating.

The unique hazard of these boilers is the potential for an explosion if water should be combined with the molten smelt. The primary source of water is from pressure part failure,

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permitting water to enter the furnace. The owner’s inspection program is carefully de-veloped and executed at appropriate intervals to ensure pressure part failure that could ad-mit water to the furnace be avoided. A second source of water is the liquor fuel. Permitting black liquor of 58% or lower solids content to enter the furnace can also result in an explo-sion. The black liquor firing controls include devices which monitor and automatically divert the liquor from the furnace if solids content is 58% or lower.

In addition to the general inspection re-quirements for all watertube type boilers, particular awareness in the following areas is necessary:

• Furnace — the type and scope of wall, roof and water screen tube inspection is dependent on materials of construction, type of construction and mode of boiler operation. In all cases, furnace wall open-ing tubes need inspection for thinning and cracking. The typical water-cooled smelt spout can admit water to the furnace if the spout fails. Common practice is to replace these spouts in an interval shorter than that in which failure is known to occur.

• Water — percentage of solids contained in the black liquor before entering the furnace should be closely monitored. Verify the black liquor firing system will automatically divert the liquor if solids drop to or below 58%.

• Corrosion/erosion — the potential conse-quences of corrosion or erosion (smelt-water explosion due to pressure-retain-ing part failure) requires a well planned and executed inspection program by the owner. Maintenance of boiler water qual-ity is crucial to minimizing tube failure originating from the water side.

• Tubes — depending on type of construc-tion, inspect for damage such as loss of corrosion protection, thinning, erosion, overheating, warping, elongation, bulg-ing, blistering and misalignment. If floor tubes may have been mechanically dam-aged or overheated, clean the floor and perform appropriate type of inspection for suspected damage. Excursions in water treatment may result in scale and sludge on internal surfaces, creating conditions of poor heat transfer and ultimately causing crack or rupture of tube.

• Welds — leaks frequently originate at welds. The owner and repair agency should carefully plan and inspect all re-pair welds that could admit water to the furnace. Tube butt welds that could admit water to the furnace should be examined by a volumetric NDE method acceptable to the inspector. Tube leaks at attachment welds may originate from the internal stress-assisted corrosion (SAC). Minor up-sets in boiler water quality and improper chemical cleaning may initiate SAC.

• Emergency Response to Water Entering Fur-nace — operators of Kraft recovery boilers should have a plan to immediately termi-nate all fuel firing and drain water from the boiler if a tube is known or suspected to be leaking into the furnace. This system may be called “Emergency Shutdown Pro-cedure” or “ESP.” The inspector should confirm the ESP is tested and maintained such that it will function as intended and that operators will activate the system when a leak into the furnace occurs or is suspected.

• Overheating — tube rupture due to over-heating from low water level may admit water to the furnace. The inspector should verify a redundant low-water protection scheme is provided and maintained.

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Specific procedures for inspection of black liquor recovery boilers are detailed in:

• American Forest and Paper Association “Recovery Boiler Reference Manual for Own-

ers and Operators of Kraft Recovery Boilers,” sponsored by the Operations/Mainte-nance Subcommittee of the Recovery Boiler Committee, Volumes I (revised June 1991), II (revised June 1991), and III (first edition October 1984.)

• The Black Liquor Recovery Boiler Adviso-ry Committee, Recommended Practices:– Emergency Shutdown Procedure

(ESP) and Procedure for Testing ESP– Safe Firing of Black Liquer Recovery

Boilers– System for Black Liquor Boilers– Safe Firing of Black Liquor in Black

Liquor Recovery Boilers– Safe Firing of Auxilliary Fuel in Black

Liquer Recovery Boilers– Thermal Oxidation of Waste Streams

in Black Liquor Recovery Boilers– Instrumentatin Checklist and Clas-

sification Guide for Instruments and Control Systems used in the Operation of Black Liquer Recovery Boilers

– Recommended Guidelines for Person-nel Safety

• Technical Association of the Pulp & Paper Industry (TAPPI), Technical Information Papers:– 0402-12, Guidelines to Assure Quality

Radiography of Boiler Tubes and Pipe Weldments in the Paper Industry

– 0402-13, Guidelines for Specification and Inspection of Electric Resistance Welded (ERW) and Seamless Boiler Tube for Criti-cal and Non-Critical Service

– 0402-15, Installation and Repair of Pin Studs in Black Liquor Recovery Boilers;

Part I: Guidelines for Accurate Tube Thickness Testing

Part II: Default Layouts for Tube Thick-ness Surveys in Various Boiler Zones

– 0402-21, Ultrasonic Technician Perfor-mance Test for Boiler Tube Inspection

– 0402-30, Inspection for Cracking of Com-posite Tubes in Black Liquor Recovery Boilers

– 0402-31, Guidelines for Evaluating the Quality of Boiler Tube Butt Welds with Ultrasonic Testing

– 0402-33, Guideline for Obtaining High Quality Readiographic Testing (RT) of Butt Welds in Boiler Tubes

RB-5603 ORGANIC AND INORGANIC FLUID BOILERS AND

VAPORIZERS

These boilers are similar to standard firetube or watertube boilers with one major differ-ence, these boilers use an inorganic or organic fluid as the heat transfer medium instead of water. The prime advantage of this boiler is that the transfer medium can carry a much larger number of BTU’s permitting greater operational efficiency. As a result, these boilers may operate at substantially higher tempera-tures. Because of higher operating tempera-tures, the possibility of steam explosion exists if the fluid medium becomes contaminated with water. There must be no water connec-tion to this type boiler.

Due to the unique design and material consid-erations of organic and inorganic fluid boilers and vaporizers, the following list are common areas of inspection.

• Design – specific requirements outlined in construction codes must be met, such as gage glasses shall be flat glass type with reinforced steel frames. Gage cocks shall not be used. Codes should be reviewed for specific design criteria.

• Corrosion – the heat transfer medium is typically non-corrosive and, therefore,

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corrosion occurs from moisture outside the boiler or system. Moisture may enter from an unprotected stack, washing down of equipment or leakage of sprinklers or other water lines.

• Leakage – any minute signs of leakage could signify serious problems since the fluid or its vapors can be hazardous.

• Thermal temperature – higher than average operational temperatures may cause metal creep which can lead to leakage.

RB-5604 WASTE HEAT BOILERS

Waste heat boilers are usually of firetube or watertube type and obtain their heat from an external source or process in which a portion of the BTU’s have been utilized. Generation of electrical energy is usually the primary application of waste heat boilers. The biggest disadvantage of this type of boiler is that it is not fired on the basis of load demand. Since the boiler does not have effective control over the amount of heat entering the boiler, there may be wide variations or fluctuations of metal temperatures. Waste process gasses are usually in a temperature range of 400°F (205°C) to 800°F (425°C), where combustion gasses of conventional fired boilers are at about 2000°F (1095°C). Special design con-siderations are made to compensate for lower combustion gas temperatures such as the use of finned high-efficiency heat absorbing tubes, and by slowing the velocity of gasses through the boiler.

Due to the unique design and material consid-erations of waste heat boilers, the following are common areas of inspection.

• Corrosion – chemicals in waste heat gasses may create corrosive conditions and react adversely when combined with normal gasses of combustion. Water or steam leakage can create localized corrosion.

Extreme thermal cycling can cause cracks and leakage at joints.

• Erosion – typically waste heat flow is very low and erosion is not a problem, how-ever, when waste heat is supplied from an internal combustion engine, exhaust gasses can be high enough to cause ero-sion.

• Vibration – in some process applications and all engine waste heat applications, the boiler may be subjected to high vibration stresses.

• Acid attack – in sulfuric acid processes refractory supports and steel casings are subject to acid attack. Piping, filters, heat exchangers, valves, fittings and appur-tenances are subject to corrosive attacks because these parts are not normally made of corrosion resistant materials.

• Dry operation – in certain applications waste heat boilers are operated without water. Care must be taken not to expose carbon steel material to temperatures in excess of 800°F (425°C) for prolonged pe-riods. Carbides in the steel may precipitate to graphite at elevated temperatures.

RB-5605 CAST-IRON BOILERS

Cast-iron boilers are widely used in a variety of applications to produce low pressure steam and hot water heat. Cast-iron boilers should only be used in applications that allow for nearly 100% return of condensate or water, and are not typically used in process-type service. These boilers are designed to operate with minimum scale, mud, or sludge, which could occur if makeup water is added to this system.

Due to the unique design and material con-siderations of cast-iron boilers, the following are common areas of inspection.

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• Scale and sludge – since combustion occurs at or near the bottom, accumulation of scale or sludge close to the intense heat can cause overheating and lead to crack-ing.

• Feedwater – makeup feedwater should not come in contact with hot surfaces. Supply should be connected to a return pipe for tempering.

• Section alignment – misalignment of sec-tions can cause leakage. Leakage or cor-rosion between sections will not allow normal expansion and contraction which may cause cracking.

• Tie rods or draw rods – used to assemble the boiler and pull the sections together. These rods must not carry any stress and need to be loose allowing for section growth during heat up. Expansion wash-ers may be used and nuts should be just snugged allowing for expansion.

• Push nipple or seal area – corrosion or leak-age is likely at the push nipple opening usually caused by the push nipple being pushed into the seat crooked, warping due to overheating, tie rods too tight and push nipple corrosion/erosion.

• Corrosion – fire sides of sections can cor-rode due to ambient moisture coupled with acidic flue gas deposits.

• Soot – inadequate oxygen supply or im-properly adjusted burner can allow for soot buildup in fireside passages. A reduc-tion in efficiency and hot spots may occur. Soot, when mixed with water, can form acidic solutions harmful to the metal.

RB-5606 ELECTRIC BOILERS

This type boiler is heated by an electrical en-ergy source, either by use of electric resistant

coils or induction coils. These boilers are used to service small or medium size loads and may be used in either high or low pressure steam or hot water applications.

Due to the unique design and material con-siderations of electric boilers, the following are common areas of inspection.

• Weight stress of the elements – some elec-trodes and elements can be quite heavy, especially if covered with scale deposits. These elements will scale sooner and at a faster rate than internal surfaces. Ex-cessive weight puts severe stress on the attachment fittings and welds at support points.

• Thermal shock – heaters are constantly cycling on and off creating temperature gradients.

• Leakage – any leakage noted at the opening where electrodes or elements are inserted is extremely dangerous due to the possible exposure of electrical wires, contacts and breakers.

RB-5607 FIRED COIL WATER HEATERS

These heaters are used for rapid heating of po-table water or hot water service. This design utilizes a coil through which the water being heated is passed. This type of heater has very little volume and may be used in conjunction with a hot water storage vessel.

Due to the unique design and material con-siderations of fired coil water heaters, the fol-lowing are common areas of inspection.

• Erosion – size and velocity of water flow through the coil combines to create wear and thinning of the coils. If a tempera-ture differential is created within the coil, bubbles or steam may cause grooving or cavitation.

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• Corrosion – this type of system uses 100% makeup which contains free oxygen creating opportunities for extensive cor-rosion.

• Vibration – operation of the burner creates a certain amount of vibration. Creation of steam, hot spots or lack of flow may create a water hammer causing extensive vibration and mechanical stresses.

• Scale – due to the large volume of makeup, significant amounts of scale forming par-ticles will adhere to the hot surfaces.

RB-5608 FIRED STORAGE WATER HEATERS

Fired storage water heaters are vertical pres-sure vessels containing water to which heat is applied. Typically gas burners are located directly beneath the storage vessel. These heaters should be insulated and fitted with an outer jacket and may be lined with porcelain, glass, galvanized metal, cement or epoxy.

Due to the unique design and material con-siderations of fired storage water heaters, the following are common areas of inspection.

• Corrosion – moisture may be trapped between the insulation and outer jacket which may cause corrosion of the pressure boundary.

• Mud and sludge – there is 100% makeup of water allowing for accumulation of mud and sludge to build up in the bottom por-tions of the vessel. Any buildup can cause overheating and failure of the metal in this area.

• Scale – loose scale may accumulate in areas adjacent to the burner and lower por-tions of the vessel, interfering with heat

transfer process and causing localized overheating. Scale and sludge can also shield temperature control probes giving false readings and allowing overheating of the water.

• Thermal cycling – heated water is con-tinually replaced with cold water causing thermal stress within the vessel.

• Lining – loss of lining or coating will al-low for rapid deterioration of the pressure boundary.

• Pressure – if water supply pressure ex-ceeds 75% of set pressure of safety relief valve, a pressure reducing valve may be required.

• Expansion – if the water heater can be isolated by such use as a check valve, it is recommended that an expansion tank be provided.

RB-5609 FIRETUBE BOILERS

Some of the more common firetube boilers are Scotch Marine, Horizontal Return (HRT), Vertical Firetube, Locomotive, and Firebox.

These boilers are used as heating boilers or power boilers. Due to the unique design and material considerations, firetube boilers are subject to thermal stresses due to cycling which may cause tube leakage and corrosion of joints. The following list are common areas of inspection.

• Waterside – scale buildup on and around the furnace tube. Scale on or around the firetubes in the first pass after the furnace (gas temperatures >1800°F [980°C]). Scale and corrosion buildup on stay rods hiding the actual diameter. Corrosion pitting on all pressure boundaries.

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• Fireside – As previously mentioned tube to tube sheet joint leakage. Look for rust trails left by weeping joints. When in doubt where the leakage is coming from, perform a liquid penetrant exam. Take note of refractory locations protecting steel that is not water-cooled. Condensa-tion of combustion gas dripping out of the fireside gaskets during a cold boiler start up is expected. However, if it con-tinues after the water temperature in the boiler is at least 150°F (65°C), then further investigation to determine the source of water shall be conducted.

RB-5700 INSERVICE INSPECTION ACTIVITIES

Any defect or deficiency in the condition, op-erating and maintenance practices of a boiler should be discussed with the owner or user at the time of inspection and, if necessary, recommendations made for the correction of such defect or deficiency. Follow-up in-spections should be performed as needed to determine if deficiencies have been corrected satisfactorily.

RB-6000 INSPECTION OF PRESSURE VESSELS

RB-6010 SCOPE

This part provides guidelines for inservice inspection of pressure vessels used to contain pressure either internal or external. This pres-sure may be obtained from an external source or by the application of heat from a direct or indirect source or a combination thereof.


Pressure vessels are designed for a variety of service conditions. The media that a pres-

sure vessel contains and the temperature and pressure at which it operates should be considered in establishing inspection criteria. Usage, materials and installation conditions should be considered in determining damage mechanisms that will affect the mechanical integrity of a pressure vessel as described in RB-4000. The general requirements for safety, pre-inspection and post-inspection activities are specified in RB-2000 and should be followed in conjunction with the specific requirements outlined in this section when performing inspections of pressure vessels. There may be occasions where more detailed procedures will be required.

RB-6200 INSPECTIONS – GENERAL REQUIREMENTS

RB-6210 CONDITION OF INSTALLATION

The type of inspection given to pressure vessels should take into consideration the condition of the vessel and the environment in which it operates. This inspection may be either external or internal and use a variety of nondestructive examination methods as described in RB-3000. The inspection method may be performed when the vessel is oper-ating on-stream or depressurized, but shall provide the necessary information that the essential sections of the vessel are of a condi-tion to continue to operate for the expected time interval. On-stream inspection, including while under pressure, may be used to satisfy inspection requirements provided the accu-racy of the method can be demonstrated.

RB-6220 EXTERNAL INSPECTION

The purpose of an external inspection is to provide information regarding the overall condition of the pressure vessel. The following should be reviewed:

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a. Insulation or Other Coverings If it is found that external coverings such

as insulation and corrosion-resistant lin-ings are in good condition and there is no reason to suspect any unsafe condi-tion behind them, it is not necessary to remove them for inspection of the vessel. However, it may be advisable to remove small portions of the coverings in order to investigate attachments, nozzles and material conditions.

NOTE: Precautions should be taken when removing insulation while vessel is under pressure.

b. Evidence of Leakage Any leakage of gas, vapor or liquid should

be investigated. Leakage coming from behind insulation coverings, supports or settings or evidence of past leakage should be thoroughly investigated by removing any covering necessary until the source of leakage is established.

c. Structural Attachments The pressure vessel mountings should be

checked for adequate allowance for ex-pansion and contraction, such as provided by slotted bolt holes or unobstructed saddle mountings. Attachments of legs, saddles, skirts or other supports should be examined for distortion or cracks at welds.

d. Vessel Connections Manholes, reinforcing plates, nozzles or

other connections should be examined for cracks, deformation or other defects. Bolts and nuts should be checked for corrosion or defects. Weep holes in reinforcing plates should remain open to provide visual evidence of leakage as well as to prevent pressure buildup between the vessel and the reinforcing plate. Accessible flange faces should be examined for distortion and to determine the condition of gasket-seating surfaces.

e. Miscellaneous Conditions

1. Abrasives – The surfaces of the vessel should be checked for erosion.

2. Dents – Dents in a vessel are defor-mations caused by their coming in contact with a blunt object in such a way that the thickness of metal is not materially impaired. Dents can create stress risers that may lead to crack-ing.

3. Distortion – If any distortion is sus-pected or observed, the overall dimen-sions of the vessel shall be checked to determine the extent and seriousness of the distortion.

4. Cuts or Gouges – Cuts or gouges can cause high stress concentrations and decrease the wall thickness. Depend-ing upon the extent of the defect, it may be necessary to repair.

5. Surface Inspection – The surfaces of shells and heads should be examined for possible cracks, blisters, bulges and other evidence of deterioration, giving particular attention to the skirt and to support attachment and knuckle regions of the heads.

6. Weld Joints – Welded joints and the adjacent heat affected zones should be examined for cracks or other defects. Magnetic particle or liquid penetrant examination is a useful means for do-ing this.

7. Riveted Vessels – On riveted vessels, examine rivet head, butt strap, plate and caulked edge conditions. If rivet shank corrosion is suspected, hammer testing for soundness or spot radiogra-phy at an angle to the shank axis may be useful.

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RB-6230 INTERNAL INSPECTION

A general visual inspection in vessels is the first step in making an internal inspection of pressure vessels that are susceptible to cor-rosion. Vessels should be inspected for the conditions identified in RB-4000.

The following should be reviewed:

a. Vessel Connections Threaded connections should be inspected

to ensure that an adequate number of threads are engaged. All openings leading to any external fittings or controls should be examined as thoroughly as possible to ensure they are free from obstructions.

b. Vessel Closures Any special closures including those on

autoclaves, normally termed quick actu-ating (quick opening) closures (RB-6460) which are used frequently in the operation of a pressure vessel, should be checked by the Inspector for adequacy and wear. A check should also be made for cracks at areas of high stress concentration. Door safety interlock mechanisms, “man inside” alarm and associated audible and visual alarms should be verified. The man inside alarm is a safety cable running the length of the internal workspace that can be pulled by the operator, thereby shutting down all autoclave functions and initiat-ing audible and visual alarms.

c. Vessel Internals Where pressure vessels are equipped with

removable internals, these internals need not be completely removed provided as-surance exists that deterioration in regions rendered inaccessible by the internals is not occurring to an extent that might con-stitute a hazard or to an extent beyond that found in more readily accessible parts of the vessel.

If a preliminary inspection reveals un-safe conditions such as loose or corroded internals or badly corroded internal lad-ders or platforms, steps should be taken to remove or repair such parts so that a detailed inspection may be made.

d. Corrosion The type of corrosion (local pitting or uni-

form), its location and any obvious data should be established. Data collected for vessels in similar service will aid in locat-ing and analyzing corrosion in the vessel being inspected. The liquid level lines, the bottom and the shell area adjacent to and opposite inlet nozzles are often locations of most severe corrosion. Welded seams and nozzles and areas adjacent to welds are often subjected to accelerated corro-sion.

RB-6240 INSPECTION OF PARTS AND APPURTENANCES

Parts and appurtenances to be inspected de-pend upon the type of vessel and its operating conditions. The Inspector should be familiar with the operating conditions of the vessel and with the causes and characteristics of potential defects and deterioration.

RB-6250 GAGES, SAFETY DEVICES, AND CONTROLS

RB-6251 GAGES

The pressure indicated by the required gage should be compared with other gages on the same system. If the pressure gage is not mounted on the vessel itself, it shall be installed in such a manner that it correctly indicates the actual pressure in the vessel. When required, the accuracy of pressure gages should be verified by comparing the

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readings with a standard test gage or a dead weight tester.

The location of a pressure gage should be observed to determine whether it is exposed to high temperature from an external source or to internal heat due to lack of protection by a proper siphon or trap. Provisions should be made for blowing out the pipe leading to the steam gage

RB-6252 SAFETY DEVICES

See RB-8000 for the inspection of safety de-vices (pressure relief valves and non-closing devices such as rupture disks) used to prevent the overpressure of pressure vessels.

RB-6253 CONTROLS/DEVICES

Any control device attached to a vessel should be demonstrated by operation or the Inspector should review the procedures and records for verification of proper operation.

Temperature measuring devices shall be checked for accuracy and general condition.

RB-6300 RECORDS REVIEW (Reference RB-2000)

The Inspector shall review any pressure ves-sel log, record of maintenance, corrosion rate record or any other examination results. The Inspector should consult with the owner or user regarding repairs or alterations made, if any, since the last internal inspection. The Inspector shall review the records of such repairs or alterations for compliance with applicable requirements.

A permanent record shall be maintained for each pressure vessel. This record should in-clude the following:

a. An ASME Manufacturer’s Data Report or, if the vessel is not ASME Code stamped, other equivalent specifications.

b. Form NB-5 Boiler or Pressure Vessel Data Report - First Internal Inspection, may be used for this purpose. It shall show the following identification numbers as ap-plicable.

National Board No. Jurisdiction No. Manufacturer Serial No. Owner-User No.

c. Complete pressure-relieving device in-formation including safety or safety relief valve spring data or rupture disk data and date of latest inspection.

d. Progressive record including, but not limited to, the following:

1. Location and thickness of monitor samples and other critical inspection locations.

2. Limiting metal temperature and loca-tion on the vessel when this is a factor in establishing the minimum allow-able thickness.

3. Computed required metal thicknesses and maximum allowable working pressure for the design temperature and pressure relieving device opening pressure, static head and other load-ings.

4. Test pressure if tested at the time of inspection.

5. Scheduled (approximate) date of next inspection.

6. Date of installation and date of any

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significant change in service condi-tions (pressure, temperature, character of contents or rate of corrosion).

7. Drawings showing sufficient details to permit calculation of the service rating of all components on pressure vessels used in process operations subject to corrosive conditions. Detailed data with sketches where necessary may serve this purpose when drawings are not available.

RB-6400 INSPECTIONS FOR SPECIFIC TYPES OF PRESSURE

VESSELS

RB-6410 GENERAL Inspection and examination requirements identified below should also include the ad-ditional requirements mentioned above.

RB-6420 DEAERATORS

The deaerator is used to remove undesirable gases in the system and is exposed to the fol-lowing: harmful gases, fluctuation in tempera-ture and pressure, erosion and vibration. The air and water atmosphere in the deaerator has a corrosive effect and may contain high con-centrations of hydrogen ions, which can cause hydrogen cracking, hydrogen embrittlement or corrosion fatigue. The water entering the deaerator sometimes carries acids or oil which can cause acidic attacks on the metal.

Inspection shall consist of the following:

a. Welds – Inspect all longitudinal and cir-cumferential welds, including the Heat Affected Zone (HAZ), visually along their entire length. Examine nozzle and attachment welds for erosion, corrosion

or cracking. Inspect with special attention all exposed internal welds at or below the normal water line.

b. Shell – Inspect exterior surfaces for corro-sion or leaks. Inspect interior for pitting, corrosion, erosion, thinning, wastage of metal, cracks, etc.

c. Spray Nozzles and Trays – Inspect all nozzles and spray areas for erosion, wear, wastage and broken parts or supports. Check to see that nozzles are not plugged and that all lines to nozzles are open. In-spect all trays for holes, erosion, wastage, broken or defective brackets, and broken support attachments.

d. Condenser and Vents – Examine all vent lines to see that they are open to assure proper exiting of the gases. Inspect the condenser unit to verify it is operable and not plugged with scale or sludge. Check for corrosion, pitting, erosion and broken parts.

e. Supports – Inspect all support structures for mechanical damage, cracks, loose bolting and bent or warped components. Check all welds, especially attaching sup-ports to the pressure boundary.

RB-6430 COMPRESSED AIR VESSELS

Compressed air vessels include receivers, separators, filters and coolers. Considerations to be concerned include temperature vari-ances, pressure limitations, vibration and condensation. Drain connections should be verified to be free of any foreign material that may cause plugging.

Inspection shall consist of the following:

a. Welds – Inspect all welds for cracking or gouging, corrosion and erosion. Particular

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attention should be given to the welds that attach brackets supporting the compres-sor. These welds may fail due to vibra-tion.

b. Shells/Heads – Externally, inspect the base material for environmental deteriora-tion and impacts from objects. Hot spots and bulges are signs of overheating and should be noted and evaluated for ac-ceptability. Particular attention should be paid to the lower half of the vessel for corrosion and leakage. For vessels with manways or inspection openings, an in-ternal inspection shall be performed for corrosion, erosion, pitting, excessive dirt buildup and leakage around inspection openings. UT thickness testing may be used where internal inspection access is limited or to determine actual thickness when corrosion is suspected.

c. Fittings and Attachments – Inspect all fit-tings and attachments for alignment, support, deterioration, damage and leak-age around threaded joints. Any internal attachments such as supports, brackets, or rings shall be visually examined for wear, corrosion, erosion and cracks.

d. Operation – Check the nameplate to deter-mine the allowed working pressure and temperature of the vessel. Assure the set pressure of the safety valve does not ex-ceed that allowed on the nameplate and determine that the capacity of the safety valve is greater than the capacity of the compressor. Ensure there is a functioning manual or automatic condensate drain.

e. Quick-Closure Attachments – Filter-type vessels usually have one quick type closure head for making filter changes. Carefully examine the seating surfaces for wear, erosion and corrosion. Visually

inspect the bolts for wear and stretch. Any safety interlocks associated with the closure shall be checked for function and proper working order.

RB-6440 EXPANSION TANKS

The purpose of an expansion tank is to provide an air cushion to a system that will allow for expansion and contraction due to temperature, thus minimizing fluctuations in pressure due to temperature variances. These vessels are susceptible to corrosion due to the air and water interface.

Inspection shall consist of the following;

a. Design/Operation – Verify from the name-plate the Code of construction, tempera-ture and pressure ratings to assure juris-dictional and system compatibility. It is common to find expansion tanks water logged due to leakage of air out of the tank, therefore it is important to verify the water level either by sight glass or sound-ing the tank.

b. Surface Conditions – Check all surfaces external and internal, if possible, for any leaks, corrosion, erosion, cracks and dents that may lead to failure. Thickness checks may be applicable to determine wastage of base material.

c. Supports and Attachments – These vessels are usually suspended from the ceiling by hangers or straps causing concentration of stresses in these areas. Specifically inspect for corrosion, wear and cracks in these areas. If the vessel is fitted with a water sight glass, inspect for visual cleanliness, water leakage and gasket tightness.

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RB-6450 LIQUID AMMONIA VESSELS

Special attention should be placed on these vessels because the media is corrosive.

It is known that vessels in liquid ammonia ser-vice are susceptible to stress corrosion crack-ing (SCC) in areas of high stress. High strength and coarse-grained materials seem to be more at risk of SCC than are fine-grained or more moderate strength materials, although no commonly used steels appear to be immune to the problem. Postweld heat treatment of new or weld-repaired vessels or cold formed heads is beneficial in reducing the incidence of SCC. The presence of 0.2% minimum water in the liquid ammonia also inhibits SCC. Any leak should be thoroughly investigated and the necessary corrective action initiated.

Inspection of Parts and AppurtenancesWhere existing openings permit, perform a visual internal inspection of the vessel. Look for any obvious cracks (very advanced SCC) and note areas which are subject to high stress such as welds, welded repairs, head-to-shell transitions, sharp interior corners and inte-rior surfaces opposite external attachments or supports. It is not intended that the vessel provide for access. It is understood that inter-nal inspections will be made if there is access to the internal surfaces.

a. If valves or fittings are in place, check to ensure that these are complete and func-tional. Parts made of copper, zinc, silver or alloys of these metals are unsuitable for ammonia service and should be replaced with parts of steel or other suitable materi-als.

b. Fittings should be removed or otherwise protected from power buffing or light sandblasting when preparing the interior surface of the vessels for inspection.

c. All interior welds and highly stressed areas should be examined by the wet fluo-rescent magnetic particle-testing method (WFMT) using an A/C yoke for magne-tization. Note that weld cracks are often transverse in orientation. It is extremely important to ensure that the NDE method used will disclose cracks in any orienta-tion.

d. If cracks are discovered, a calculation must be made to determine what depth of grinding may be carried out for crack removal (without encroaching on the minimum thickness required by the con-struction standard or equivalent).

e. Where possible, crack removal by grind-ing is the preferred method of repair. Since the stresses at the crack tips are quite high, even very fine cracking should be elimi-nated.

f. Where crack depth is such that removal requires weld repair, a weld procedure should be employed that will minimize HAZ hardening and residual stresses. Whenever possible, weld repairs — re-gardless of their size — should be post-weld heat treated.

g. Re-inspect by WFMT to ensure complete crack removal.

h. It is not intended to inhibit or limit the use of other evaluation methods. It is recog-nized that acoustic emission and fracture mechanics are acceptable techniques for assessing structural integrity of vessels. Analysis by fracture mechanics may be used to assess the structural integrity of vessels when complete removal of all ammonia stress cracks is not practical. If alternative methods are used, the above recommendation that all cracks be re-moved, even fine cracks may not apply.

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c. Gages and Pressure Relieving Devices The Inspector should note the pressure

indicated by the gage and compare it with other gages on the same system. If the pressure gage is not mounted on the vessel itself, it should be ascertained that the gage is on the system and installed in such a manner that it correctly indicates actual pressure in the vessel.

See RB-8000 for the inspection of safety devices (pressure relief valves) used to prevent the overpressure of liquid am-monia vessels. Pressure-relief devices in ammonia service cannot be tested in place using system pressure. Bench testing is required.

RB-6460 INSPECTION OF PRESSURE VESSELS WITH QUICK-

ACTUATING CLOSURES

This part describes guidelines for inspection of pressure vessels equipped with quick-ac-tuating closures. Due to the many different designs of quick-actuating closures, potential failures of components that are not specifically covered should be considered. The scope of inspection should include areas affected by abuse or lack of maintenance and a check for inoperable or bypassed safety and warning devices.

Temperatures above that for which the quick-actuating closure was designed can have an adverse effect on the safe operation of the device. If parts are found damaged and excessive temperatures are suspected as the cause, the operating temperatures may have exceeded those temperatures recommended by the manufacturer. Rapid fluctuations in temperatures due to rapid start-up and shut-down may lead to cracks or yielding caused by excessive warping and high thermal stress. A careful observation should be made of the condition of the complete installation, includ-

ing maintenance and operation, as a guide in forming an opinion of the care the equipment receives. The history of the vessel should be established, including: year built, materials of construction, extent of postweld heat treat-ment, previous inspection results and repairs or alterations performed. Any leak should be thoroughly investigated and the necessary corrective action initiated.

Inspection of Parts and Appurtenances

a. Seating surfaces of the closure device, including but not limited to the gaskets, O-rings or any mechanical appurtenance to ensure proper alignment of the closure to the seating surface, should be inspected. This inspection can be made by using powdered chalk or any substance that will indicate that the closure is properly strik-ing the seating surface of the vessel flange. If this method is used, a check should be made to ensure that:

1. Material used will not contaminate the gasket or material with which it comes into contact.

2. The substance used should be com-pletely removed after the examina-tion.

b. The closure mechanism of the device should be inspected for freedom of move-ment and proper contact with the locking elements. This inspection should indicate that the movable portions of the locking mechanism are striking the locking ele-ment in such a manner that full stroke can be obtained. Inspection should be made to ensure that the seating surface of the locking mechanism is free of metal burrs and deep scars, which would indicate mis-alignment or improper operation. A check should be made for proper alignment of the door hinge mechanisms to ensure that adjustment screws and locking nuts are

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properly secured. When deficiencies are noted, the following corrective actions should be initiated:

1. If any deterioration of the gasket, O-ring, etc., is found, the gasket, O-ring, etc., should be replaced im-mediately. Replacements should be in accordance with the vessel manufac-turer’s specifications.

2. If any cracking or excessive wear is discovered on the closing mechanism, the owner or user should contact the original manufacturer of the device for spare parts or repair information. If this cannot be accomplished, the owner or user should contact an orga-nization competent in quick-actuating closure design and construction prior to implementing any repairs.

3. Defective safety or warning devices should be repaired or replaced prior to further operation of the vessel.

4. Deflections, wear or warping of the sealing surfaces may cause out-of-roundness and misalignment. The manufacturer of the closure should be contacted for acceptable tolerances for out-of-roundness and deflection.

The operation of the closure device through its normal operating cycle should be observed while under control of the operator. This should indicate if the operator is following posted procedures and if the oper-ating procedures for the vessel are adequate.

Gages, Safety Devices, and Controls

a. The required pressure gage should be installed so that it is visible from the op-erating area located in such a way that

the operator can accurately determine the pressure in the vessel while it is in opera-tion. The gage dial size should be of such a diameter that it can be easily read by the operator. This gage should have a pressure range of at least 1-1/2 times, but not more than four times, the operating pressure of the vessel. There should be no intervening valve between the vessel and gage.

b. The pressure gage should be of a type that will give accurate readings, especially when there is a rapid change in pressure. It should be of rugged construction and capable of withstanding severe service conditions. Where necessary, the gage should be protected by a siphon or trap.

c. Pressure gages intended to measure the operating pressure in the vessel are not usually sensitive or easily read at low pressures approaching atmospheric. It may be advisable to install an auxiliary gage which reads inches of water (mm of mercury) and is intended to measure pressure from atmospheric through low pressures. This gives assurance that there is zero pressure in the vessel before open-ing. It would be necessary to protect the auxiliary low pressure gage from the higher operating pressures.

d. Provisions should be made to calibrate pressure gages or to have them checked against a master gage as frequently as necessary.

e. A check should be made to ensure that the closure and its holding elements must be fully engaged in their intended operating position before pressure can be applied to the vessel. A device should be provided that prevents the opening mechanism from operating unless the vessel is com-pletely depressurized.

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f. Quick-actuating closures held in position by manually operated locking devices or mechanisms and which are subject to leakage of the vessel contents prior to dis-engagement of the locking elements and release of the closure, shall be provided with an audible and/or visible warning device to warn the operator if pressure is applied to the vessel before the closure and its holding elements are fully engaged and to warn the operator if an attempt is made to operate the locking device before the pressure within the vessel is released. Pressure tending to force the closure clear of the vessel must be released before the closure can be opened for access.

RB-6470 GRAPHITE PRESSURE EQUIPMENT

See Appendix 8 for inspection requirements.

RB-6480 FIBER REINFORCED VESSELS

See Appendix 9 for inspection requirements.

RB-6490 PROPANE LP GAS VESSELS

See Appendix H for inspection require-ments.

RB-6500 NONDESTRUCTIVE EXAMINATION (NDE)

NDE may be employed to assess the condi-tion of the pressure vessel as described in RB-3000. These examination methods should be performed by experienced and qualified individuals using procedures acceptable to the Jurisdiction. Generally, some form of sur-face preparation will be required prior to the use of these examination methods: magnetic

particle, liquid penetrant, ultrasonic, radiog-raphy, eddy current, visual, metallographic examination and acoustic emission. When there is doubt as to the extent of a defect or detrimental condition found in a pressure vessel, the Inspector may require additional NDE.

RB-6600 REMAINING LIFE AND INSPECTION INTERVALS

New pressure vessels are placed in service to operate under their design conditions for a period of time determined by the service con-ditions and the corrosion rate. If the pressure vessel is to remain in operation, the allowable conditions of service and the length of time before the next inspection shall be based on the conditions of the vessel as determined by the inspection. See RB-9000 for determining remaining life and inspection intervals.


Any defect or deficiency in the condition, operating and maintenance practices of the pressure vessel should be discussed with the owner or user at the time of inspection and, if necessary, recommendations made for the correction of such defect or deficiency. Fol-low-up inspections should be performed as needed to determine if deficiencies have been corrected satisfactorily.

RB-7000 INSPECTION OF PIPING SYSTEMS

RB-7010 SCOPE

This section provides guidlines for internal and external inspection of piping and piping systems.

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Piping systems are designed for a variety of service conditions. The media that a piping system contains, the temperature at which it operates and the piping corrosion history should be considered in establishing piping inspection criteria. Particular attention should be given to piping systems that are subject to corrosion, high temperatures and hazardous fluid or gasses. Piping operating beyond de-sign temperature limits can cause sufficient deterioration of piping material properties due to graphitization, embrittlement and creep to render the piping system unfit for continued service (RB-4000).

Any externally or internally corroded piping should be evaluated for integrity and repaired or replaced as necessary.

Requirements specified for inspection activi-ties and safety are identified in RB-2000 and should be reviewed and followed as appli-cable.

RB-7200 ASSESSMENT OF PIPING DESIGN

All pipe material and fittings should be prop-erly rated for the maximum service conditions to which they are subjected under normal operating conditions. The design corrosion allowance of the piping system should be considered when reviewing the current piping thickness data.

If a piping system has a previous history of ultrasonic wall thickness measurements, the Inspector should review this data and request additional wall thickness measurements if warranted.

RB-7300 INSPECTION

RB-7310 EXTERNAL INSPECTION OF PIPING

Piping should be externally inspected for the following:

a. Evidence of leakage. (RB-7330)

b. Provision for expansion and adequate support. (RB-7340)

c. Proper alignment of piping joints and bolt-ed connections. Check for missing bolts or studs, nuts and improper or inadequate bolted connection thread engagement. Also check visible gasket and gasket align-ment condition. Threaded connections should also be inspected for inadequate or excessive thread engagement.

d. Past or present evidence of excessive vibration or cyclic activity such as loose or missing piping supports or piping in-sulation. If such activity is present, piping and piping joints should be inspected for potential fatigue cracking.

e. Evidence of general corrosion, excessive external pitting, corrosion scale buildup, exfoliation, erosion, cuts, dents, distortion or other detrimental conditions such as pipe sweating, water hammer damage or hot spots. Ultrasonic thickness measure-ments should be taken in suspect areas to ensure adequate remaining piping wall thickness.

f. Evidence of corrosion under piping in-sulation (CUI) or other weather related damage to piping coatings.

g. Evidence of freeze damage such as bulg-ing, striations or surface fissures.

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h. Dead leg or stagnant piping internal corrosion issues. Ultrasonic thickness measurements should be taken in suspect locations. Radiography is also useful to assess internal deposits and subsequent corrosion in no flow piping locations.

RB-7320 INTERNAL INSPECTION OF PIPING

Where the internal surfaces of piping, valves and gasket surfaces are accessible to visual examination, internal inspection should in-clude an examination of all available surfaces. Nondestructive examination for internal corrosion may be used to supplement the inspection. Boroscope or camera inspections are also useful to augment piping internal inspections.

a. Internal pipe surfaces should be cleaned before inspection, if necessary.

b. The internal surfaces of piping, piping welds and connections, fittings, valves and gasket surfaces should be inspected for localized corrosion, pitting, erosion, blistering, cracking and impingement damage.

RB-7330 EVIDENCE OF LEAKAGE

A leak should be thoroughly investigated and corrective action initiated. Leaks beneath piping insulation should be approached with caution, especially when removing insulation from a pressurized piping system for inspec-tion.

A pressure test may be required to obtain ad-ditional information regarding the extent of a defect or detrimental condition.

To determine tightness, the test pressure need be no greater than the normal operating pressure. The metal temperature should be

not less than 70°F (20°C) and the maximum temperature during inspection should not exceed 120°F (50°C). The potential corrosive effect of the test fluid on the piping material should be considered.

RB-7340 PROVISIONS FOR EXPANSION AND SUPPORT

Visual inspection should include a check for evidence of improper piping support or support design. Piping supports should not be bottomed out or fully extended. Piping supports should keep piping in alignment and prevent piping from colliding with other piping or stationary objects. The alignment of connections between anchored equip-ment should be observed to determine if any change in position of the equipment due to settling, excessive cyclic activity, steady state stresses beyond design allowances or other causes has placed an undue strain on the pip-ing or its connections. Inadequate support or the lack of provision for expansion may cause broken attachment welds, cracks or leakage at fittings. Missing, damaged or loose insulation materials may be an indication of vibration or pipe movements resulting from improper support.

Piping support locations should be closely inspected at the support points for external and crevice corrosion concerns.

RB-7350 GAGES, SAFETY DEVICES, CONTROLS

RB-7351 GAGES

Piping system pressure gages should be removed for testing unless there is other information to assess their accuracy. Faulty pressure gages should be recalibrated or re-placed as necessary.

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RB-7352 SAFETY DEVICES

See RB-8000 for information on the inspection of pressure-relieving devices used to prevent the over pressure of piping systems.

RB-7353 CONTROLS

Piping connections utilizing a quick-discon-nect coupling should be checked to ensure that the coupling and its holding elements are fully engaged in their intended operating position. Means should be provided that warn the operator against disengaging the coupling or prevent the opening mechanism from operating unless the piping is completely depressurized.


Any defect or deficiency in the condition, operating and maintenance practices of a piping system should be discussed with the owner or user at the time of inspection and, if necessary, recommendations made for the correction of such defect or deficiency. Fol-low-up inspections should be performed as needed to determine if deficiencies have been corrected satisfactorily.

RB-8000 INSPECTION OF PRESSURE RELIEF DEVICES

RB-8010 SCOPE

The most important appurtenances on any pressurized system are the pressure relief de-vices provided for overpressure protection of that system. These are devices such as safety valves, safety relief valves pilot valves, and rupture disks or other non-reclosing devices which are called upon to operate and reduce an overpressure condition.

These devices are not designed or intended to control the pressure in the system during normal operation. Instead, they are intended to function when normal operating controls fail or abnormal system conditions are en-countered.

Periodic inspection and maintenance of these important safety devices is critical to ensure their continued functioning and to provide assurance that they will be available when called upon to operate.

Inspection areas of concern include:

a. safety considerationsb. device datac. condition of the deviced. condition of the installatione. testing and operational inspection.

RB-8100 SAFETY CONSIDERATIONS

Inspectors are cautioned that the operation of these safety devices involve the discharge of high pressure and/or high temperature fluids. Extreme caution should be used when work-ing around these devices due to hazards to personnel. Suitable hearing protection should be provided during testing because extremely high noise levels, which may be encountered, can damage hearing.

RB-8200 DEVICE DATA

Nameplate marking or stamping of the de-vice should be compared to stamping on the protected pressure-retaining item. For a single device, the set pressure shall be no higher than the maximum allowable working pressure (MAWP) marked on the protected pressure-retaining item or system.

If multiple devices are provided, the dif-ference between set pressures shall not ex-ceed that permitted by the original code of

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construction. The set pressure of additional devices may exceed the MAWP, as permitted by the original code of construction.

Verify nameplate capacity and, if possible, compare to system capacity requirements.

Check identification on seals and ensure they match nameplates or other identification (repair or reset nameplate) on the valve or device.

RB-8210 DEVICE CONDITION

Check for evidence that the valve or device is leaking or not sealing properly.

Seals for adjustments should be intact and show no evidence of tampering.

Connecting bolting should be tight and all bolts intact.

The valve should be examined for deposits or material buildup.

Evidence of rust or corrosion should be checked.

Check for damaged or misapplied parts.

If a drain hole is visible, ensure it is not clogged with debris or deposits.

Check for test gags left in place after pressure testing of the unit.

Bellows valves shall be checked to ensure the bonnet vent is open or piped to a safe location. The vent shall not be plugged since this will cause the valve set pressure to be high if the bellows develops a leak. Leakage noted from the vent indicates the bellows is damaged and will no longer protect the valve from the effects of back pressure.

RB-8300 INSTALLATION CONDITION

Inspect inlet piping and ensure it meets the requirements of the original code of construc-tion. For pressure relief valves, check that the inlet pipe size is not smaller than the device inlet size.

Inspect discharge piping and ensure it meets the original code of construction. Check that the discharge pipe size is not smaller than the device outlet size.

Check that the valve drain piping is open.

Check drainage of discharge piping.

Check that inlet and discharge piping are not binding or placing excessive stress on the valve body which can lead to distortion of the valve body and leakage or malfunction.

Check the condition and adequacy of piping supports. Discharge piping should be sup-ported independent of the device itself.

Check for possible hazards to personnel from the valve discharge or discharge pipe.

Check that there are no intervening isolation valves between the pressure source and the valve inlet or between the valve outlet and its point of discharge. (Isolation valves may be permitted in some pressure vessel service. See RB-8520 and jurisdictional requirements. Isolation valves are not permitted for power boilers, heating boilers or water heaters).

A change-over valve which is used to install two pressure relief devices on a single vessel location, for the purpose of switching from one device to a spare device, is not consid-ered a block valve if it is arranged such that there is no intermediate position which will isolate both pressure relief devices from the protected system. Change-over valves should be carefully evaluated to ensure they do not have excessive pressure drop which could affect the pressure relief device operation or capacity.

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These devices are commonly used in pressure vessel service. They may also be used in some boiler applications. It is recommended that the jurisdiction be contacted to determine their acceptability on boiler applications.

RB-8400 TESTING AND OPERATIONAL INSPECTION

Pressure relief valves must be periodically tested to ensure that they are free to oper-ate and will operate in accordance with the requirements of the original code of construc-tion. Testing should include device set or opening pressure, reclosing pressure where applicable, and seat leakage evaluation. Tol-erances specified for these operating require-ments in the original code of construction shall be used to determine the acceptability of test results.

Testing may be accomplished by the owner on the unit where the valve is installed or at a qualified test facility. In many cases, testing on the unit may be impractical, especially if the service fluid is hazardous or toxic. Test-ing on the unit may involve the bypassing of operating controls and should only be performed by qualified individuals under carefully controlled conditions. It is recom-mended that a written procedure be available to conduct this testing.

a. The Inspector should assure that calibrated equipment has been used to perform this test and the results should be documented by the owner.

b. If the testing was performed at a test facility, the record of this test should be reviewed to ensure the valve meets the requirements of the original code of con-struction. Valves which have been in toxic, flammable or other hazardous services shall be carefully decontaminated before being tested. In particular, the closed bon-net of valves in these services may contain

fluids which are not easily removed or neutralized. If a test cannot be safely per-formed, the valve shall be disassembled, cleaned and decontaminated, repaired, and reset.

If a valve has been removed for testing, the inlet and outlet connections should be checked for blockage by product buildup or corrosion.

Valves may be tested using lift assist devices when testing at full pressure may cause dam-age to the valve being tested or it is impractical to test at full pressure due to system design considerations. Lift assist devices apply an auxiliary load to the valve spindle or stem, and using the measured inlet pressure, ap-plied load and other valve data allow the set pressure to be calculated. If a lift assist device is used to determine valve set pressure, the conditions of RA-2283 shall be met. It should be noted that false set pressure readings may be obtained for valves which are leaking ex-cessively or otherwise damaged.

If valves are not tested on the system using the system fluid, the following test mediums shall be used:

a. High pressure boiler safety valves, high temperature hot water boiler safety relief valves, low pressure steam heating boil-ers: steam;

b. Hot water heating boiler safety relief valves: steam, air, or water;

c. Hot water heater temperature and pres-sure relief valves: air or water;

d. Air and gas service process safety relief valves: air, nitrogen or other suitable gas;

e. Liquid service process pressure relief valves: water or other suitable fluid;

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f. Process steam service safety relief valves: steam or air with manufacturer’s steam to air correction factor.

NOTE: Valves being tested after a repair must be tested on steam except as permit-ted by RA-2282.

As an alternative to a pressure test, the valve may be checked by the owner for freedom of operation by activating the test or “try” lever (manual check). For high pressure boiler and process valves this test should be performed only at a pressure greater than 75% of the stamped set pressure of the valve or the lift-ing device may be damaged. This test will only indicate that the valve is free to operate and does not provide any information on the actual set pressure. All manual checks should be performed with some pressure under the valve in order to flush out debris from the seat which could cause leakage.

NOTE: The manual check at 75% or higher is based on lift lever design requirements for ASME Section I and VIII valves. Code design requirements for lifting levers for Section IV valves require that the valve be capable of being lifted without pressure.

If a valve is found to be stuck closed, the system should immediately be taken out of service until the condition can be corrected, unless special provisions have been made to operate on a temporary basis (such as ad-ditional relief capacity provided by another valve).

If a pressure test indicates the valve does not open within the requirements of the original code of construction, but otherwise is in ac-ceptable condition, minor adjustments (de-fined as no more than twice the permitted set pressure tolerance) shall be made by an organization that meets the requirements of RA-2200 to reset the valve to the correct opening pressure. All adjustments shall be resealed with a seal identifying the respon-

sible organization and a tag identifying the organization and the date of the adjustment shall be installed.

If a major adjustment is needed, this may indicate the valve is in need of repair or has damaged or misapplied parts. Its condition should be investigated accordingly.

Systems with multiple valves will require the lower set valves to be held closed to permit the higher set valves to be tested. A test clamp or “gag” should be used for this purpose. The spring compression screw shall not be tightened. It is recommended that the test clamps be applied in accordance with the valve manufacturer’s instructions when the valve is at or near the test temperature and be applied hand tight only to avoid damage to the valve stem or spindle.

Upon completion of set pressure testing, all pressure relief valves gags shall be re-moved.

RB-8410 RECOMMENDED INSPECTION AND TEST

FREQUENCIES

Power Boilers

a. Pressure less than 400 psig (3 MPa): Man-ual check every 6 months; pressure test annually to verify nameplate set pressure or as determined by operating experience as verified by testing history.

b. Pressure greater than 400 psig (3 MPa): Pressure test to verify nameplate set pres-sure every three years or as determined by operating experience as verified by testing history.

Pressure tests should be performed prior to bringing the boiler down for planned internal inspection so needed repairs or adjustments can be made while the boiler is down.

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High Temperature Hot Water BoilersPressure test annually to verify nameplate set pressure or as determined by operating experience as verified by testing history. For safety reasons, removal and testing on a steam test bench is recommended. Such testing will avoid damaging the safety valve by discharge of a steam water mixture, which could occur if the valve is tested in place.

Low Pressure Steam Heating BoilersManual check quarterly; pressure test annu-ally prior to steam heating season to verify nameplate set pressure.

Hot Water Heating BoilersManual check quarterly; pressure test annu-ally prior to steam heating season to verify nameplate set pressure.

NOTE: The frequencies specified for the testing of pressure relief valves on boilers is primarily based on differences between high pressure boilers which are continuously manned and lower pressure automatically controlled boilers that are not monitored by a boiler operator at all times. When any boiler experiences an over-pressure condition such that the safety or safety relief valves actuate, the valves should be inspected for seat leakage and other damage as soon as possible and any deficiencies corrected.

Water Heaters Manual check every two months. Due to the relatively low cost of safety valves for this service, it is recommended that a defective valve be replaced with a new valve if a repair or resetting is indicated.

Pressure Vessels and PipingFrequency of test and inspection of pressure relief devices for pressure vessel and piping service is greatly dependent on the nature of the contents and operation of the system and only general recommendations can be given. Inspection frequency should be based on previous inspection history. If valves are

found to be defective or damaged by system contents during inspection, intervals should be shortened until acceptable inspection re-sults are obtained. Where test records and/or inspection history are not available, the fol-lowing inspection and test frequencies are suggested.

Service Inspection Frequency

Steam .......................................Annual

Air & Clean .............................Every three years Dry Gasses

Pressure relief valves .............Every five years in combination with rupture disks

Propane, Refrigerant .............Every five years

All others ................................Per inspection history

Establishment of Inspection and Test IntervalsWhere a recommended test frequency is not listed, the valve user and Inspector must de-termine and agree on a suitable interval for inspection and test. Some items to be consid-ered in making this determination are:

a. Jurisdictional requirements;

b. Records of test data and inspections from similar processes and similar devices in operation at that facility;

c. Recommendations from the device manu-facturer. In particular, when the valve includes a non-metallic part such as a diaphragm, periodic replacement of those parts may be specified;

d. Operating history of the system. Systems with frequent upsets where a valve has actuated require more frequent inspec-tion;

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e. Results of visual inspection of the device and installation conditions. Signs of valve leakage, corrosion or damaged parts all indicate more frequent operational inspec-tions;

f. Installation of a valve in a system with a common discharge header. Valves dis-charging into a common collection pipe may be affected by the discharge of other valves by the corrosion of parts in the out-let portion of the valve or the buildup of products discharged from those valves;

g. Ability to coordinate with planned system shutdowns. The shutdown of a system for other maintenance or inspection activities is an ideal time for the operational inspec-tion and test of a pressure relief valve;

h. Critical nature of the system. Systems which are critical to plant operation or where the effects of the discharge of fluids from the system are particularly detrimen-tal due to fire hazard, environmental dam-age or toxicity concerns all call for more frequent inspection intervals to ensure devices are operating properly;

i. Where the effects of corrosion, blockage by system fluid or ability of the valve to operate under given service conditions are unknown (such as in a new process or installation), a relatively short inspection interval, not to exceed one year or the first planned shutdown, whichever is shorter, shall be established. At that time the de-vice shall be visually inspected and tested. If unacceptable test results are obtained the inspection interval shall be reduced by 50% until suitable results are obtained.

Establishment of Service IntervalsThe above intervals are guidelines for periodic inspection and testing. Typically if there are no adverse findings a pressure relief valve would be placed back in service until the next inspection. Any unacceptable conditions that are found by the inspection shall be corrected

immediately by repair or replacement of the device. Many users will maintain spare pres-sure relief devices so the process or system is not affected by excessive downtime.

Pressure relief valves are mechanical devices which require periodic preventive mainte-nance even though external inspection and test results indicate acceptable performance. There may be wear on internal parts, galling between sliding surfaces or internal corro-sion and fouling which will not be evident from an external inspection or test. Periodic re-establishment of seating surfaces and the replacement of soft goods such as o-rings and diaphragms are also well advised preventa-tive maintenance activities which can prevent future problems. If the valve is serviced, a complete disassembly, internal inspection and repair as necessary, such that the valves condition and performance are restored to a like new condition, should be done by an organization meeting the requirements of RA-2200.

Service records with test results and findings should be maintained for all over pressure protection devices. A service interval of no more than three inspection intervals or ten years, whichever is less, is recommended to maintain device condition. Results of the internal inspection and maintenance findings can then be used to establish future service intervals.

RB-8500 ADDITIONAL INSPECTION INFORMATION

The following additional items should be considered for the specified services.

RB-8510 BOILERS

If boilers are piped together with maximum allowable working pressures differing by more than six percent, additional protective devices may be required on the lower pressure

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units to protect them from overpressure from the higher pressure unit.

Hot-Water Heating Boilers and Water Heaters

a. These units generally do not use any wa-ter treatment and therefore may be more prone to problems with deposits form-ing which may impair a safety device’s operation. Particular attention should be paid to signs of leakage through valves or buildups of deposits.

b. Hot-water boilers tend to have buildups of corrosion products since the system is closed with little makeup. These products can foul or block the valve inlet.

c. Water heaters will have cleaner water due to continuous makeup. However, these valves usually have a thermal ele-ment which will cause the valve to open slightly when the water is heated and not removed from the system. When this hot water evaporates in the discharge piping, calcium deposits may tend to form in the valve inlet and outlet.

RB-8520 PRESSURE VESSELS AND PIPING

Standard practice for overpressure protection devices is to not permit any type of isola-tion valve either before or after the device. However, some pressure vessel standards permit isolation valves under certain con-trolled conditions when shutting down of the vessel to repair a damaged or leaking valve would be difficult. If isolation block valves are employed, their use should be carefully controlled by written procedures and the block valves should have provisions to be either car-sealed or locked in an open posi-tion when not being used. For ASME Section VIII, Div. 1 pressure vessels, see UG-135, Ap-pendix M, and jurisdictional rules for more information.

RB-8530 RUPTURE DISKS

Rupture disks or other non-reclosing devices may be used as sole relieving devices or in combination with safety relief valves to pro-tect pressure vessels.

The selection of the correct rupture disk device for the intended service is critical to obtaining acceptable disk performance. Different disk designs are intended for constant pressure, varying pressure or pulsating pressure. Some designs include features that make them suitable for back pressure and/or internal vacuum in the pressure vessel.

The margin between the operating pressure and the burst pressure is an important fac-tor in obtaining acceptable performance and service life of the disk. Flat and pre-bulged solid metal disks are typically used with an operating pressure which is no more than 60% to 70% of the burst pressure. Other designs are available that increase the operating pressure to as much as 90% of the burst pressure. Disks which have been exposed to pressures above the normal operating pressure for which they are designed are subject to fatigue or creep and may fail at unexpectedly low pressures. Disks used in cyclic service are also subject to fatigue and may require a greater operating margin or selection of a device suitable for such service.

The disk material is also critical to obtaining acceptable service life from the disk. Disks are available in a variety of materials and coat-ings and materials which are unaffected by the process fluid should be used. Disks that experience corrosion may fail and open at an unexpectedly low pressure.

Disk designs must also be properly selected for the fluid state. Some disk types are not suitable for use in liquid service. Some disks may have a different flow resistance when used in liquid service which may affect the sizing of the disk.

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Information from the rupture disk manufac-turer, including catalog data and installation instructions, should be consulted when select-ing a disk for a particular service.

For rupture disks and other non-reclosing devices, the following additional items should be considered during inspections.

a. The rupture disk nameplate informa-tion, including stamped burst pressure and coincident temperature, should be checked to ensure it is compatible with the intended service. The coincident tem-perature on the rupture disk shall be the expected temperature of the disk when the disk is expected to burst and will usually be related to the process temperature, not the temperature on the pressure vessel nameplate.

b. Markings indicating direction of flow should be carefully checked to ensure they are correct. Some rupture disks when in-stalled in the incorrect position may burst well above the stamped pressure.

c. The marked burst pressure for a rupture disk installed at the inlet of a safety relief valve shall be equal to or less than the safety relief valve set pressure. A marked burst pressure of 90% to 100% of the safety relief valve set pressure is recommended. A disk with a non-fragmenting design which cannot affect the safety relief valve shall be used.

NOTE: If the safety relief valve set pres-sure is less than the vessel MAWP, the marked burst pressure may be higher than the valve set pressure, but no higher than the MAWP.

d. Check that the space between a rupture disk and a safety relief valve is supplied with a pressure gage, try cock or telltale indicator to indicate signs of leakage through the rupture disk. The safety relief valve shall be inspected and the leaking

disks shall be replaced if leakage through the disk is observed.

e. If a rupture disk is used on a valve outlet, the valve design must be of a type not in-fluenced by back pressure due to leakage through the valve. Otherwise, for non-toxic and non-hazardous fluids, the space between the valve and the ruptured disk shall be vented or drained to prevent the accumulation of pressure.

f. For rupture disks installed on the valve inlet, the installation should be reviewed to ensure that the combination rules of the original code of construction have been applied. A reduction in the valve capacity up to 10% is expected when used in com-bination with a non-reclosing device.

g. The frequency of inspection for rupture disks and other non-reclosing devices is greatly dependent on the nature of the contents and operation of the system and only general recommendations can be given. Inspection frequency should be based on previous inspection history. If devices have been found to be leaking, defective or damaged by system contents during inspection, intervals should be shortened until acceptable inspection re-sults are obtained. With this in mind, the inspection frequency guidelines specified in RB-8410(f) are suggested for similar services.

Rupture disks are often used to isolate pressure relief valves from services where fouling or plugging of the valve inlet oc-curs. This tendency should be considered in establishing the inspection frequency.

Since these devices are for one time use, a visual inspection is the only inspection that can be performed. Rupture disks which are installed using a specified bolt-ing torque procedure cannot be re-used after inspection and must be replaced.

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It is recommended that all disks be peri-odically replaced to prevent unintended failure while in service due to deteriora-tion of the device.

RB-8600 REQUIREMENTS FOR SHIPPING AND TRANSPORTING

The improper shipment and transport of pres-sure relief devices can have detrimental affects on device operation. Pressure relief devices should be treated with the same precautions as instrumentation, with care taken to avoid rough handling or contamination prior to installation.

The following practices are recommended:

a. Flanged valves should be securely bolted to pallets in the vertical position to avoid side loads on guiding surfaces.

b. Threaded valves should be securely pack-aged and cushioned during transport.

c. Valve inlet and outlet connection, drain connections and bonnet vents should be protected during shipment and storage to avoid internal contamination of the valve. Ensure all covers and/or plugs are removed prior to installation.

d. Lifting levers should be wired or secured so they cannot be moved while the valve is being shipped or stored. These wires shall be removed before the valve is placed in service.

e. Rupture disks should be carefully checked for damage prior to installation and handled by the disk edges, if possible. Any damage to the surface of the disk can affect the burst pressure.


Any defect or deficiency in the condition, operating and maintenance practices for pres-sure relief devices should be discussed with the owner or user at the time of inspection and, if necessary, recommendations made for the correction of such defect or deficiency. Follow-up inspections should be performed as needed to determine if deficiencies have been corrected satisfactorily.

RB-9000 METHODS FOR ESTIMATING REMAINING

SERVICE LIFE AND INSPECTION INTERVALS

RB-9010 SCOPE

New pressure-retaining items are placed in service to operate under their intended design for a period of time determined by the service conditions, which can include exposure to corrosion, creep or other forms of degradation. If the pressure-retaining item is to remain safe in operation, the allowable conditions of service and the length of time before the next inspection must be identified. There are various methods that can be used to assess the condition of a pressure-retaining item to establish remaining service life and to ultimately determine the next inspection interval. In some cases, a visual inspection of the pressure-retaining item will suffice. However, more comprehensive condition assessment methods may be required, up to and including a comprehensive engineering evaluation performed by a competent techni-cal source.

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RB-9100 CONDITIONS THAT AFFECT REMAINING SERVICE LIFE

There are a variety of conditions that may affect the remaining service life of a pressure-retaining item. These should be evaluated and the inspection interval reviewed for possible adjustment.

The common conditions are listed below:

a. Deterioration This includes bulging, sagging, stress

corrosion cracking, corrosion pitting (lo-cal or general), creep rupture, thermal or mechanical fatigue, hydrogen blister-ing, high temperature hydrogen attack, carburization, graphitization or erosion. Deterioration may also be caused by mechanical forces such as thermal shock, cyclic temperature changes, vibration, pressure surges, excessive temperature, external loading and faulty material and fabrication.

b. Corrosion Rate Not a Consideration When the corrosion rate of a pressure-re-

taining item is known to be zero, the item need not be inspected internally provided all of the following conditions are met and complete external inspections, including thickness measurements, are made peri-odically on the vessel:

1. The noncorrosive character of the content, including the effect of trace components, has been established by at least five years comparable ser-vice experience with the fluid being handled.

2. No questionable condition is disclosed by the periodic external inspection.

3. The operating temperature of the pres-sure-retaining item does not exceed the lower limits for the creep range of the vessel metal.

NOTE: The lower temperature limit for the creep range for carbon steel is at least 700°F (370°C). The limit for alloy steel is often higher. The limit for other metals depends upon the specific material composition. Special-ized metallurgical advice should be obtained for alloy steels and non-fer-rous metals.

4. The pressure-retaining item is pro-tected against inadvertent contamina-tion.

RB-9110 METHOD FOR ESTIMATING REMAINING SERVICE LIFE FOR EXPOSURE TO

ELEVATED TEMPERATURE

When creep damage is suspected in a pres-sure-retaining item, an assessment of remain-ing service life should be discussed with the owner-user. This assessment may include but is not limited to the following methods:

a. Dimensional measurements of the item to check for creep swell.

b. Measurement of oxide scale and wall thickness for use in engineering analysis to determine remaining service life. Creep life can be predicted through an empirical approach which uses available data for the pressure-retaining component. Total number of operating hours to the present is needed. Oxide scale thickness (steam side) can be measured directly from ma-terial samples or be measured in situ using ultrasonic techniques.

c. Metallographic examination to determine the extent of exposure to creep damage in service.

d. Removal of a material sample for creep rupture testing. A test matrix is selected to yield the most meaningful results from the

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material sample. Test specimens are ma-chined from the sample and tested under representative loads and temperatures (as selected in the test matrix). Creep strain vs. time and temperature vs. time to rupture data are recorded.

RB-9120 METHOD FOR ESTIMATING INSPECTION INTERVAL FOR EXPOSURE TO ELEVATED TEMPERATURE

The Inspector is cautioned to seek competent technical advice to determine which of the above condition assessment methods can be used to assure safe operation of the pressure-retaining item and determination of the next inspection interval.

RB-9130 METHOD FOR ESTIMATING REMAINING SERVICE LIFE FOR EXPOSURE TO

CORROSION

When the pressure-retaining item is exposed to service temperatures below the creep range and the corrosion rate controls the remaining service life of the pressure-retaining item, the remaining life shall be calculated by the for-mula below or by other industry acceptable methods as approved by the jurisdictional authority.

��

��

��

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t(actual) = thickness in inches (mm) mea-sured at the time of inspection for the limiting section used in the determination of t(required).

t(required) = minimum allowable thickness in inches (mm) for the limiting section of the pressure vessel or zone. It shall be the greater of the following:

1. The calculated thickness, exclusive of the corrosion allowance, required for the pres-sure relieving device set pressure, static head or other loading and design tempera-ture, or

2. The minimum thickness permitted by the provision of the applicable section of the original code of construction.

Corrosion Rate = inches (mm) per year of metal removal as a result of corrosion.

Any suitable nondestructive examination method may be used to obtain thickness measurements provided the instruments em-ployed are calibrated in accordance with the manufacturer’s specification or an acceptable national standard.

a. If suitably located existing openings are available, measurements may be taken through the openings.

b. When it is impossible to determine thick-ness by nondestructive means, a hole may be drilled through the metal wall and thickness gage measurements taken.

For new pressure-retaining items for which service conditions are being changed, one of the following methods shall be employed to determine the probable rate of corrosion from which the remaining wall thickness, at the time of the next inspection, can be esti-mated:

a. The corrosion rate as established by data collected by the owner or user on pres-sure-retaining items in the same or similar service;

b. If data for the same or similar service are not available, the corrosion rate as esti-mated from the Inspector’s knowledge and experience with pressure-retaining items in similar service;

c. If the probable corrosion rate cannot be de-termined by either of the above methods, on-stream thickness determinations shall

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be made after approximately 1,000 hours of service. Subsequent sets of thickness measurements shall be taken after addi-tional similar intervals until the corrosion rate is established.

Corrosion Resistant LiningWhen part or all of the pressure-retaining item has a corrosion resistant lining, the interval between inspections of those sections so pro-tected may be based on recorded experience with the same type of lining in similar service, but shall not exceed ten years. If there is no experience on which to base the interval be-tween inspections, performance of the liner shall be monitored by a suitable means such as the use of removable corrosion probes of the same material as the lining, ultrasonic examination or radiography. To check the effectiveness of an internal insulation liner, metal temperatures may be obtained by sur-veying the pressure vessel with temperature measuring or indicating devices.

Two or More ZonesWhen a pressure-retaining item has two or more zones and the required thickness, corrosion allowance or corrosion rate differ so much that the foregoing provisions give significant differences in maximum periods between inspections for the respective zones (e.g., the upper and lower portions of some fractionating towers), the period between inspections may be established individually for each zone on the basis of the condition ap-plicable thereto, instead of being established for the entire vessel on the basis of the zone requiring the more frequent inspection.

Above-Ground VesselsAll pressure vessels above ground shall be given an external examination after operat-ing the lesser of five years or quarter life, preferably while in operation. Inspection shall include determining the condition of the exterior insulation, the supports and the general alignment of the vessel on its sup-

ports. It is not necessary to remove any insula-tion if the temperature of the entire pressure vessel shell is maintained sufficiently low or sufficiently high to preclude the presence of water. Pressure vessels which are known to have a remaining life of over ten years, or which are prevented from being exposed to external corrosion (such as being installed in a cold box in which the atmosphere is purged with an inert gas or by the temperature being maintained sufficiently low or sufficiently high to preclude the presence of water), need not have the insulation removed for the exter-nal inspection. However, the condition of the insulating system and/or the outer jacketing, such as the cold box shell, shall be observed periodically and repaired if necessary.

Interrupted ServiceThe periods for inspection referred above, assume that the pressure-retaining item is in continuous operation, interrupted only by normal shutdown intervals. If a pressure-re-taining item is out of service for an extended interval, the effect of the environmental conditions during such an interval shall be considered.

If the pressure-retaining item was improperly stored, exposed to a detrimental environment or the condition is suspect, it shall be given an inspection before being placed into service.

The date of next inspection, which was estab-lished at the previous inspection, may need to be revised if deterioration occurred during the period of interrupted service.

Circumferential StressesFor a corroded area of considerable size in which the circumferential stresses govern the MAWP, the least thicknesses along the most critical plane of such area may be averaged over a length not exceeding:

a. The lesser of one-half the pressure vessel diameter, or 20 in. (500 mm) for vessels

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with inside diameters of 60 in. (1500 mm) or less, or

b. The lesser of one-third the pressure vessel diameter, or 40 in. (1000 mm), for vessels with inside diameters greater than 60 in. (1500 mm), except that if the area contains an opening, the distance within which thicknesses are averaged on either side of such opening, shall not extend beyond the limits of reinforcement as defined in the section of the ASME Code for ASME Stamped vessels and for other vessels in their applicable Codes of Construction.

Longitudinal StressesIf because of wind loads or other factors the longitudinal stresses would be of importance, the least thicknesses in a length of arc in the most critical plane perpendicular to the axis of the pressure vessel shall be averaged for computation of the longitudinal stresses. The thicknesses used for determining corrosion rates at the respective locations shall be the most critical value of average thickness.

PittingWidely scattered pits may be disregarded provided that:

a. Their depth is not more than one-half the required thickness of the pressure-retain-ing item wall (exclusive of corrosion al-lowance);

b. The total area of the pits does not exceed

7 sq. in. (4,500 mm2) within any 8 in. (200 mm) diameter circle; and

c. The sum of their dimensions along any straight line within this circle does not exceed 2 in. (50 mm).

Weld Joint Efficiency FactorWhen the surface at a weld having a joint efficiency factor of other than one (1) is cor-roded, as well as surfaces remote from the

weld, an independent calculation using the appropriate weld, joint efficiency factor must be made to determine if the thickness at the weld or remote from the weld, governs the maximum allowable working pressure. For the purpose of this calculation, the surface at a weld includes 1 in. (25 mm) on either side of the weld, or two times the minimum thick-ness on either side of the weld, whichever is greater.

Ellipsoidal and Torispherical Heads

a. When measuring the corroded thickness of ellipsoidal and torispherical heads, the governing thickness may be:

1. that of the knuckle region with the head rating calculated by the appro-priate head formula; or

2. that of the central portion of the dished region, in which case the dished re-gion may be considered a spherical segment, whose allowable pressure is calculated by the formula for spherical shells in the ASME Code for ASME stamped vessels and for other vessels in their applicable Codes of Construc-tion.

b. The spherical segment of both ellipsoidal and torispherical heads shall be consid-ered to be that area located entirely within a circle whose diameter is equal to 80% of the shell diameter. The radius of the dish of a torispherical head is to be used

TABLE RB-9130-1

Values of Spherical Radius Factor, K1

K1D = Equivalent spherical radiusD/2h = axis ratio(Interpolation permitted for intermediate values.)

D/2h –3.00 2.80 2.60 2.40 2.20 2.00 1.80 1.60 1.40 1.20 1.00

K1 –1.36 1.27 1.18 1.08 0.99 0.90 0.81 0.73 0.65 0.57 0.50

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as the radius of the segment (equal to the diameter of the shell for standard heads, though other radii have been permitted). The radius of the spherical segment of ellipsoidal heads shall be considered to be the equivalent spherical radius K1D where D is the inside diameter of the shell (equal to the major axis) and K1 is given in Table RB-9130-1. In the table, h is one-half the length of the minor axis (equal to the inside depth of the ellipsoidal head) measured from the tangent line (headbend line). For many ellipsoidal heads, D/2h = 2.0.

Adjustments in Corrosion RateIf, upon measuring the wall thickness at any inspection, it is found that an inaccurate rate of corrosion has been assumed, the corrosion rate to be used for determining the inspection frequency shall be adjusted to conform with the actual rate found.

Riveted Pressure VesselsFor a pressure vessel with riveted joints, in which the strength of one or more of the joints is a governing factor in establishing the maximum allowable working pressure, consideration shall be given as to whether and to what extent corrosion will change the possible modes of failure through such joints. Also, even though no additional thickness may have originally been provided for cor-rosion allowance at such joints, credit may be taken for the corrosion allowance inherent in the joint design.

RB-9140 METHOD FOR ESTIMATING INSPECTION INTERVAL FOR EXPOSURE TO CORROSION

The maximum period between internal in-spections or a complete inservice evaluation of pressure-retaining items shall not exceed one-half of the estimated remaining service life of the vessel or ten years, whichever is

less. Where the remaining service life is less than four years, the inspection interval may be the full remaining safe operating life up to a maximum of two years.

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Repairs and Alterationsof Pressure-Retaining Items

Part RC

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PART RC — REPAIRS AND ALTERATIONS OF PRESSURE-RETAINING ITEMS

TABLE OF CONTENTS

RC-1000 General Requirements ....................................................................................... 91 RC-1010 Scope ..................................................................................................................... 91 RC-1020 Construction Standards ..................................................................................... 91 RC-1030 Accreditation ....................................................................................................... 91 RC-1040 Materials .............................................................................................................. 91 RC-1050 Replacement Parts .............................................................................................. 91 RC-1060 Authorization ...................................................................................................... 92 RC-1070 Inspector ............................................................................................................... 92 RC-1090 Welding ................................................................................................................ 93

RC-1100 Heat Treatment .................................................................................................... 94 RC-1110 Nondestructive Examination ............................................................................ 94 RC-1120 Pressure Gages, Measurement, Examination and Test Equipment ............. 95 RC-1130 Acceptance Inspection ....................................................................................... 95 RC-1140 Stamping .............................................................................................................. 95 RC-1150 Registration of Documentation ........................................................................ 95

RC-2000 Additional Requirements for Repairs .............................................................. 96 RC-2010 Scope ..................................................................................................................... 96 RC-2020 Drawings .............................................................................................................. 96 RC-2030 Authorization ...................................................................................................... 96 RC-2050 Examination and Test ......................................................................................... 97 RC-2060 Stamping .............................................................................................................. 98 RC-2070 Documentation .................................................................................................... 98 RC-2080 Repair of ASME Code Section VIII, Division 2, Pressure Vessels ................ 99

RC-3000 Additional Requirements for Alterations ..................................................... 100 RC-3010 Scope ................................................................................................................... 100 RC-3020 Design ................................................................................................................. 100 RC-3030 Examination and Test ....................................................................................... 101 RC-3040 Stamping ............................................................................................................ 103 RC-3050 Documentation .................................................................................................. 103


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RC-1000 GENERAL REQUIREMENTS

RC-1010 SCOPE

This part provides general requirements that apply to repairs and alterations to pres-sure-retaining items and shall be used in conjunction with RC-2000 and RC-3000.

RC-1020 CONSTRUCTION STANDARDS

When the s tandard govern ing the original construction is the ASME Code, repairs and alterations shall conform, insofar as possible, to the section and edition of the ASME Code most applicable to the work planned.

When the s tandard govern ing the original construction is not the ASME Code, repairs or alterations shall con-form, insofar as possible, to the edition of the construction standard or specifica-tion most applicable to the work. Where this is not possible or practicable, it is permissible to use other codes, standards or specifications, including the ASME Code provided the “R” Certificate Holder has the concurrence of the Inspector and the juris-diction where the pressure-retaining item is installed.

RC-1030 ACCREDITATION

Organizations performing repairs or alterations shall be accredited as described in Part RA, as appropriate for the scope of work to be performed.

RC-1040 MATERIALS

The materials used in making repairs or alterations shall conform to the original code of construction including the material specification requirements. Carbon or alloy steel having a carbon content of more than 0.35% shall not be welded unless permitted by the original code of construction. The “R” Certificate Holder is responsible for verify-ing identification of existing materials from original data, drawings or units records and identification of the materials to be installed. Consideration shall be given to the condition of the existing material, especially in the weld preparation area.

For corrugating rolls manufactured per the requirements of paragraph UF-7 of Section VIII, Div. 1, restoration of worn corrugating roll surfaces by weld overlay is permitted for all classes of SA-649 forging material and an exception to the 0.35% carbon limit is per-mitted. The requirements to qualify welding procedures and welder performance shall be those in ASME Section IX for hard facing (water resistance) and corrosion resistance overlays.

RC-1050 REPLACEMENT PARTS

Replacement parts which will be subject to internal or external pressure that consist of new materials which may be formed to the required shape by casting, spinning, forg-ing, die forming and on which no fabrica-tion welding is performed shall be supplied as material. Such parts shall be marked with the material and part identification and the name or trademark of the parts manufacturer. In lieu of full identification marking on the material or part, the part

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manufacturer may use a coded marking sys-tem traceable to the original marking. Such markings shall be considered as the parts manufacturer’s certification that the part complies with the original code of construc-tion. Examples include seamless or welded tubes or pipe, forged nozzles, heads or tube sheets or subassemblies attached together mechanically.

Replacement parts which will be subject to internal or external pressure that are preas-sembled by attachment welds shall have the welding performed in accordance with the original code of construction. The supplier or manufacturer shall certify that the mate-rial and fabrication are in accordance with the original code of construction. This certi-fication shall be supplied in the form of bills of material and drawings with statement of certification. Examples include boiler furnace wall or floor panel assemblies, prefabricated openings in boiler furnace walls, such as burner openings, air ports, inspection open-ings or sootblower openings.

When ASME is the original code of construction, replacement parts subject to internal or external pressure fabricated by welding, which require shop inspec-tion by an Authorized Inspector shall be fabricated by an organization having an appropriate ASME Certificate of Authoriza-tion. The item shall be inspected and stamped as required by the applicable section of the ASME Code. A completed ASME Manufac-turer’s Partial Data Report shall be supplied by the manufacturer.

When the original code of construction is other than ASME, replacement parts subject to inter-nal or external pressure, fabricated by welding shall be manufactured by an organization certified as required by the original code of construction. The item shall be inspected and stamped as required by the original code of

construction. Certification to the original code of construction as required by the original code of construction or equivalent shall be supplied with the item. When this is not possible or practicable, the organization fabricating the part may have a National Board Certificate of Authorization; replacement parts shall be documented on Form R-3 and the “R” symbol stamp applied as described in Appendix 2.

RC-1060 AUTHORIZATION

The Inspector’s authorization to perform a repair or alteration shall be obtained prior to initiation of a repair or alteration to a pres-sure-retaining item.

RC-1070 INSPECTOR

Inspection and certification shall be made by an Inspector employed by one of the following:

a. A Jurisdictional Authorized Inspection Agency,

b. The Authorized Inspection Agency of the “R” Certificate Holder making the repair or alteration,

c. The Authorized Inspection Agency which insures the pressure-retaining item, or

d. The Owner-User Inspection Organi-zation. An Inspector employed by an Owner-User Inspection Organization may authorize and accept work only on pressure-retaining items owned-used by the company. The company’s organization and inspection procedures shall have the specific approval of the Jurisdiction or in the absence of a Jurisdiction, by the National Board.


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RC-1090 WELDING

Welding shall be performed in accordance with the requirements of the original code of construction used for the pressure-retaining item.

RC-1091 WELDING PROCEDURE SPECIFICATIONS

Welding shall be performed in accordance with Welding Procedure Specifications (WPS) qualified in accordance with the original code of construction. When this is not possible or practicable, the WPS may be qualified in accordance with Section IX of the ASME Code.

RC-1092 STANDARD WELDING PROCEDURE SPECIFICATIONS

An “R” Certificate Holder may use one or more applicable Standard Welding Procedure Specifications shown in Appendix A without supporting procedure qualification records (PQRs) since SWPs are prequalified and the PQR will not be supplied.

RC-1093 PERFORMANCE QUALIFICATION

Welders or welding operators shall be qualified for the welding processes that are used. Such qualification shall be in accordance with the requirements of the original code of construction or Section IX of the ASME Code. Use of Standard Welding Procedure Specifi-cation shown in Appendix A is permitted for performance qualification testing.

RC-1094 WELDING RECORDS

The “R” Certificate Holder shall maintain a record of the results obtained in welding procedure qualifications, except for those qualifications for which the provisions of RC-1092 are used and of the results obtained in welding performance qualifications. These records shall be certified by the “R” Certificate Holder and shall be available to the inspector.

RC-1095 WELDERS’ IDENTIFICATION

The “R” Certificate Holder shall establish a system for the assignment of a unique identification mark to each welder/weld-ing operator qualified in accordance with the requirements of the NBIC. The “R” Cer-tificate Holder shall also establish a written procedure whereby all welded joints can be identified as to the welder or welding opera-tor who made them. This procedure shall use one or more of the following methods and be acceptable to the Inspector. The welder’s or welding operator’s identification mark may be stamped (low stress stamp) adjacent to all welded joints made by the individual or, in lieu of stamping, the “R” Certificate Holder may keep a record of welded joints and the welders or welding operators used in making the joints.

RC-1096 WELDERS’ CONTINUITY

The performance qualification of a welder or welding operator shall be affected when one of the following conditions occur:

a. When the welder or welding operator has not welded using a specific process during a period of six (6) months or more, their qualifications for that process shall expire.

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b. When there is specific reason to question their ability to make welds that meet the specification, the qualification which sup-ports the welding that is being performed shall be revoked. All other qualifications not questioned remain in effect.

RC-1100 HEAT TREATMENT

RC-1101 PREHEATING

Preheating may be employed during weld-ing to assist in completion of the welded joint (Appendix B). The need for and the temperature of preheat are dependent on a number of factors such as chemical analysis, degree of restraint of the items being joined, material thickness and mechanical proper-ties. The welding procedure specification for the material being welded shall specify the preheat temperature requirements.

RC-1102 POSTWELD HEAT TREATMENT

Postweld heat treatment shall be per-formed as required by the original code of construction in accordance with a written procedure. The procedure shall contain the parameters for postweld heat treatment. Lo-cal PWHT that is not specified by the original code of construction may be performed in accordance with an Alternative Post Weld Heat Treatment Method described in RD-1070 with acceptance by the Inspector and, when required, by the Jurisdiction.

RC-1103 ALTERNATIVE POSTWELD HEAT TREATMENT METHODS

Under certain conditions, postweld heat treatment in accordance with the original code of construction may be inadvisable or

impractical. In such instances, alternative methods of postweld heat treatment or special welding methods acceptable to the Inspector may be used. Methods which may be used as alternatives to postweld heat treat-ment are described in Part RD.

RC-1110 NONDESTRUCTIVE EXAMINATION

The nondestructive examination (NDE) requirements, including technique, extent of coverage, procedures, personnel qualification and acceptance criteria, shall be in accordance with the original code of construction used for construction of the pressure-retaining item. Weld repairs and alterations shall be subjected to the same nondestructive examination re-quirements as the original welds. Where this is not possible or practicable, alternative NDE methods acceptable to the Inspector and the jurisdiction where the pressure-retaining item is installed, where required, may be used.

NDE personnel shall be qualified and certi-fied in accordance with the requirements of the original code of construction. When this is not possible or practicable, NDE personnel may be qualified and certified in accordance with their employer’s written practice. ASNT SNT-TC-1A, Recommended Practice for Non-destructive Testing Personnel Qualification and Certification (2001 edition), or ASNTCP-189, Standard for Qualification and Certification of Nondestructive Testing Personnel (2001 edition), shall be used as a guideline for employers to establish their written practice. The ASNT Central Certification Program (ACCP, Rev. 3, Nov. 1997) may be used to fulfill the examina-tion and demonstration requirements of SNT-TC-1A and the employer’s written practice. Provisions for qualification and certification of NDE personnel shall be described in the “R” Certificate Holder’s written quality system.

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RC-1120 PRESSURE GAGES, MEASUREMENT, EXAMINATION AND TEST EQUIPMENT

The calibration of pressure gages, measure-ment, examination and test equipment and documentation of calibration shall be per-formed as required by the applicable standard used for construction.

RC-1130 ACCEPTANCE INSPECTION

The Inspector making the acceptance inspec-tion shall be the same inspector who autho-rized the repair or alteration. Where this is not possible or practicable, another Inspector may perform the acceptance inspection; however, in all cases, the Inspector who performs the acceptance inspection shall be an employee of the same organization as the Inspector who authorized the repair or alteration.

Before signing the appropriate NBIC Report Form, the Inspector shall review the drawings, assure the repair or alteration was performed in accordance with the acceptable code of construction or standard, witness any pres-sure test or any acceptable alternative test method applied, assure that the required nondestructive examinations have been performed satisfactorily and that the other functions necessary to assure compliance with the requirements of this Code have been performed.

RC-1140 STAMPING

The stamping of or attaching of a nameplate to, a pressure-retaining item shall indicate that the work was performed in accordance with the requirements of this Code. Such stamping or attaching of a nameplate shall be done only with the knowledge and authorization of the Inspector. The “R” Certificate Holder responsible for the repair

or the construction portion of the alteration shall apply the stamping. For a re-rating where no physical changes are made to the pressure-retaining item, the “R” Certificate Holder responsible for design shall apply the stamping. Required stamping and nameplate information is shown in Appendix 2.

RC-1141 REMOVAL OF ORIGINAL STAMPING OR NAMEPLATE

If it becomes necessary to remove the original stamping, the Inspector shall, subject to the approval of the Jurisdiction, witness the making of a facsimile of the stamping, the obliteration of the old stamping and the transfer of the stamping to the new item. When the stamping is on a nameplate, the Inspector shall witness the transfer of the nameplate to the new location. Any relocation shall be described on the applicable NBIC “R” Form. ASME Code items shall not be restamped with the ASME Code Symbol.

RC-1150 REGISTRATION OF “R” FORMS

Organizations performing repairs or alterations under an “R” stamp program may register such repairs or alterations with the National Board.

It should be noted that some jurisdictions may require registration of repairs and alterations with the National Board.

For those “R” Forms not registered with the National Board, the organization performing repairs or alterations shall retain a copy of the “R” Form on file for a minimum period of five years.

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RC-1151 FORM R LOG

The “R” Certificate Holder shall maintain a single, sequential log of “R” Form numbers assigned for NBIC Report Forms (i.e., R-1, R-2 and R-3) that are registered with the National Board.

RC-2000 ADDITIONAL REQUIREMENTS FOR REPAIRS

RC-2010 SCOPE This section provides additional require-ments for repairs to pressure-retaining items and shall be used in conjunction with RC-1000.

RC-2020 DEFECT REPAIRS

Before a repair is made to a defect in a welded joint or base metal, care should be taken to in-vestigate its cause and to determine its extent and likelihood of recurrance.

RC-2021 DRAWINGS

As appropriate, drawings shall be prepared to describe the repair. Drawings shall in-clude sufficient information to satisfactorily perform the repair.

RC-2030 AUTHORIZATION

Repairs to pressure-retaining items shall not be initiated without the authorization of the Inspector, who shall determine that the repair methods are acceptable.

Subject to acceptance of the Jurisdiction, the Inspector may give prior approval for routine

repairs provided the Inspector assures that the “R” Certificate Holder has acceptable procedures covering the repairs.

RC-2031 ROUTINE REPAIRS

Prior to performing routine repairs, the “R” Certificate Holder should determine that routine repairs are acceptable to the jurisdiction where the pressure-retaining item is installed.

a. The four categories of routine repairs are:

1. Welded repairs or replacements of tubes or pipes NPS 5 (DN 125) and smaller, or sections thereof, where neither postweld heat treatment nor NDE other than visual examination is required by the original code of construction.

2. The addition or repair of non-load bearing attachments to pressure retaining items where postweld heat treatment is not required.

3. Weld buildup of wasted areas in shells and heads not exceeding 100 sq. in. (65,000 sq. mm) or 25% of nominal wall thickness or 1/2 in. (13 mm), whichever is less.

4. Corrosion resistance weld overlay not exceeding 100 sq. in. (65,000 sq.mm).

b. Routine repairs shall be performed un-der the “R” Certificate Holder’s quality system program; however, the require-ment for in-process involvement of the Inspector and stamping may be waived. See RC-2060.

c. The process of identifying, controlling and implementing routine repairs shall

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be documented in the “R” Certificate Holder’s quality system program.

d. Routine repairs shall be documented on a Form R-1 with a statement on line 10, Remarks: “Routine Repair”.

RC-2032 WELD REPAIRS TO PRESSURE RELIEF VALVE PARTS

Prior to performing weld repairs to pressure relief valve (PRV) parts, the “R” Certificate Holder shall receive repair information re-quired by RA-2255(j) from the “VR” Certifi-cate Holder responsible for the pressure relief valve repair.

a. PRV part weld repairs shall be performed under the “R” Certificate Holder’s qual-ity system; however, the requirements for in-process involvement of the Inspector (RC-1130) may be waived. The require-ment for stamping is waived.

b. The process of identifying and controlling repairs shall be documented in the “R” Certificate Holder’s quality system.

c. PRV part repairs shall be documented on a Form R-1 with a statement under Remarks “PRV Part Repair.” The owner’s name and location of installation shall be that of the “VR” Certificate Holder. The information received from the “VR” Certificate Holder (RA-2255(j)) shall be noted under Descrip-tion of Work.

d. Upon completion of the repair, the re-paired part and completed Form R-1 shall be returned to the “VR” Certificate Holder responsible for completing the PRV repair.

RC-2050 EXAMINATION AND TEST

The following requirements shall apply to all repairs to pressure-retaining items:

a. The integrity of repairs and replacement parts used in repairs shall be verified by examination or test.

b. The “R” Certificate Holder is responsible for all activities relating to examination and test of repairs.

c. Examinations and tests to be used shall be subject to acceptance of the Inspector and where required, acceptance of the jurisdiction.

RC-2051 METHODS

Based on the nature and scope of the repair activity, one or a combination of the follow-ing examination and test methods shall be applied to repairs and replacement parts used in repairs.

a. Liquid Pressure Test Pressure testing of repairs shall meet the

following requirements:

1. Pressure tests shall be conducted us-ing water or other liquid medium. The test pressure shall be the minimum required to verify the leak tightness integrity of the repair, but not more than 150% of the maximum allowable working pressure (MAWP) stamped on the pressure-retaining items, as ad-justed for temperature. When original test pressure included consideration of corrosion allowance, the test pres-sure may be further adjusted based on the remaining corrosion allowance.

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2. During a pressure test where the test pressure will exceed 90% of the set pressure of the pressure relief device, the device shall be removed whenever posssible. If not possible, a test gag may be used following the valve manufacturer’s instructions and recommendations. Extreme caution should be employed to ensure only enough force is applied to contain pressure. Excessive mechanical force applied to the test gag may result in damage to the seat and/or spindle and may interfere with the proper opera-tion of the valve. The test gag shall be removed following the test.

3. The metal temperature for the pres-sure test shall be in accordance with the original code of construction, but not less than 60°F (16°C) unless the owner provides information on the toughness characteristics of the mate-rial to indicate the acceptability of a lower test temperature. During close examination the metal temperature shall not exceed 120°F (50°C) unless the owner specified requirements for a higher test temperature and it is ac-ceptable to the Inspector.

4. Hold-time for the pressure test shall be a minimum of 10 minutes prior to examination by the Inspector. Where the test pressure exceeds the MAWP of the item, the test pressure shall be reduced to the MAWP for close examination by the Inspector. Hold-time for close examination shall be as necessary for the Inspector to conduct the examination.

b. Pneumatic Test A pneumatic test may be conducted. Con-

currence of the owner shall be obtained in addition to that of the Inspector and juris-diction where required. The test pressure

shall be the minimum required to verify leak tightness integrity of the repair, but shall not exceed the maximum pneumatic test pressure of the original code of con-struction. Precautionary requirements of the original code of construction shall be followed.

c. Initial Service Leak Test When an initial service leak test is

permitted by the original code of con-struction, such testing may also be used to verify the leak tightness integrity of repairs.

d. Vacuum Test A vacuum test may be conducted. Vacuum

test methods used shall be suit-able to verify the leak tightness integrity of the repair.

e. Nondestructive Examination Nondestructive examination (NDE) may

be conducted. NDE methods used shall be suitable for providing meaningful results to verify the integrity of the repair.

RC-2060 STAMPING

Pressure-retaining items repaired in accordance with the NBIC shall be stamped as required by Appendix 2.

Subject to the acceptance of the jurisdiction and the concurrence of the Inspector, name-plates and stamping may not be required for routine repairs (RC-2031). In all cases, the type and extent of repairs necessary shall be considered prior to waiving the require-ment.

RC-2070 DOCUMENTATION

Repairs that have been performed in accor-dance with the NBIC shall be documented


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on Form R-1 Report of Repair, as shown in Appendix 5. Form R-4 Report Supplementary Sheet shall be used to record additional data when space is insufficient on Form R-1.

RC-2071 PREPARATION OF FORM R-1

Preparation of Form R-1 shall be the responsibility of the “R” Certificate Holder performing the repair.

An Inspector shall indicate acceptance by signing the Form R-1.

The Form R-3 and the manufacturer’s data reports described in RC-1050 shall be a part of the completed Form R-1 and shall be at-tached thereto.

RC-2072 DISTRIBUTION

Legible copies of the completed Form R-1, together with attachments, shall be distributed to the owner or user, the Inspec-tor, the jurisdiction, if required, and the Au-thorized Inspection Agency responsible for inservice inspection.

Distribution of Form R-1 and attachments shall be the responsibility of the organization performing the repair.

RC-2073 REGISTRATION

Form R-1 may be registered with the National Board as noted in RC-1150.

RC-2080 REPAIR OF ASME CODE SECTION VIII, DIVISION 2 OR 3, PRES-SURE VESSELS

RC-2081 SCOPE

The following requirements shall apply for the repair of pressure vessels constructed to the requirements of Section VIII, Division 2 or 3, of the ASME Code.

RC-2082 REPAIR PLAN

The user shall prepare or cause to have prepared a detailed plan covering the scope of the repair.

a. Professional Engineer Review The repair plan shall be reviewed and

certified by a Professional Engineer who is registered in one or more of the states of the United States of America or the provinces of Canada is experienced in pressure ves-sel design and is knowledgeable in ASME Section VIII, Div. 2 or 3 as applicable. The review and certification shall be such as to ensure the work involved in the repair is compatible with the user ’s design specification and the manufacturer ’s design report.

b. Authorized Inspection Agency Acceptance Following review and certification,

the repair plan shall be submitted for acceptance to the Authorized Inspection Agency/Owner-User Inspection Orga-nization whose Inspector will make the acceptance inspection and sign the Form R-1.

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RC-3000 ADDITIONAL REQUIREMENTS FOR ALTERATIONS

RC-3010 SCOPE

This section provides additional requirements for alterations to pressure-retaining items and shall be used in conjunction with RC-1000.

RC-3020 DESIGN

The “R” Certificate Holder performing alterations shall establish controls to en-sure that all required design information, applicable drawings, design calculations, specifications and instructions are prepared, obtained, controlled and interpreted to provide the basis for an alteration in accordance with the original code of con-struction. When a Manufacturer’s Data Re-port is required by the original construction standard, a copy of the original Data Report shall be obtained for use in the design of the alteration. When the original Manufacturer’s Data Report cannot be obtained, agreements on the method of establishing design basis for the alteration shall be obtained from the Inspector and the jurisdiction.

RC-3021 CALCULATIONS

A set of calculations shall be completed prior to the start of any physical work. All design work shall be completed by an organization experienced in the design portion of the standard used for construction of the item. All calculations shall be made available for review by the Inspector accepting the design.

RC-3022 RE-RATING 7

Re-rating of a pressure-retaining item by increasing the maximum allowable working pressure (internal or external) or tempera-ture or decreasing the minimum tempera-ture shall be done only after the following requirements have been met to the satisfaction of the jurisdiction at the location of the installation:

a. Revised calculations verifying the new service conditions shall be prepared in ac-cordance with the “R” Certificate Holder’s Quality Control System. Establishing a higher joint efficiency to re-rate a pres-sure-retaining item is not permitted.

b. All re-ratings shall be established in accordance with the requirements of the construction standard to which the pressure-retaining item was built.

c. Current inspection records verify that the pressure-retaining item is satisfactory for the proposed service conditions.

d. The pressure-retaining item has been pressure tested, as required, for the new service conditions.

RC-3023 DRAWINGS

As appropriate, drawings shall be prepared to describe the alteration. Drawings shall include sufficient information to satisfactorily perform the alteration.

7 Re-rating: Except as provided for Yankee Dryers in Appendix K, this code does not provide rules for derating boilers or pressure vessels; however, when the MAWP and/or allowable temperature of a boiler or pressure vessel is reduced, the jurisdiction wherein the object is installed should be contacted to determine if specific procedures should be fol-lowed.


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RC-3024 ALLOWABLE STRESSES

For re-rating or re-calculating a new minimum wall thickness for a pressure-retaining item using a later edition/addenda of the original code of construction that permits use of higher allowable material stress values than were used in the original construction, the addi-tional requirements of RD-3000 shall apply.

RC-3025 ALTERATION OF ASME CODE SECTION VIII, DIVISION 2 OR 3 PRESSURE VESSELS

RC-3026 SCOPE

The following shall apply for the alteration of pressure vessels constructed to the require-ments of Section VIII, Division 2 or 3 of the ASME Code.

RC-3027 ALTERATION PLAN

Professional Engineer ReviewThe alteration plan shall be reviewed and certified by a Professional Engineer who is registered in one or more of the states of the United States of America or the provinces of Canada, is experienced in pressure vessel design and is knowledgeable in ASME Sec-tion VIII, Div. 2 or 3 as applicable. The review and certification shall be such as to ensure the work involved in alteration is compatible with the user’s design specification and the manufacturer’s design report.

User’s Design SpecificationIf the alteration is such that the work is not compatible with or changes one or more requirement(s) of the original user’s design specification, the user’s design specification shall be revised by the user with the new parameters or changes. The revisions shall

be certified by a Professional Engineer who is registered in one or more of the states of the United States of America or the provinces of Canada, is experienced in pressure vessel design and is knowledgeable in ASME Section VIII, Div. 2 or 3 as applicable.

Manufacturer’s Design ReportThe “R” Certificate Holder shall prepare or cause to have prepared a supplement to the manufacturer’s design report to reconcile the new parameters or changes with the user’s design specification.

The supplement to the manufacturers design report shall be certified by a Professional En-gineer who is registered in one or more of the states of the United States of America or the provinces of Canada, is experienced in pres-sure vessel design and is knowledgeable in ASME Section VIII, Div. 2 or 3 as applicable.

Authorized Inspection Agency AcceptanceFollowing review and certification, the altera-tion plan shall be submitted for acceptance to the Authorized Inspection Agency/Owner-User Inspection Organization whose inspector will make the acceptance inspection and sign the Form R-2.

RC-3030 EXAMINATION AND TEST

The following requirements shall apply to all alterations to pressure-retaining items:

a. The integrity of alterations and replace-ment parts used in alterations shall be verified by examination or test.

b. The “R” Certificate Holder is responsible for all activities relating to examination and test of alterations.

c. Examinations and tests to be used shall be subject to acceptance of the Inspector, and where required, acceptance of the Jurisdiction.

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RC-3031 METHODS

Based on the nature and scope of the alterations activity, one or a combination of the following examination and test meth-ods shall be applied to alterations and replacement parts used in alterations.

a. Liquid Pressure Test Pressure testing of alterations shall meet

the following requirements:

1. A pressure test as required by the original code of construction shall be conducted. The test pressure shall not exceed 150% of the maximum al-lowable working pressure (MAWP) stamped on the pressure-retain-ing item, as adjusted for tempera-ture. When the original test pressure included consideration of corrosion allowance, the test pressure may be further adjusted based on the remaining corrosion allowance. The pressure test for replacement parts may be performed at the point of manufacture or point of installation.

2. As an alternative to pressure testing connecting welds in accordance with the original code of construction, connecting welds may be tested or examined in accordance with the rules for repairs (see RC-2051). Connecting welds are defined as welds attaching the replacement part to the pressure-retaining item.

3. During a pressure test where the test pressure will exceed 90% of the set pressure of the pressure relief device, the device shall be removed whenever possible. If not possible, a test gag may be used following the valve manufacturer’s instructions and recommendations. Extreme caution should be employed to ensure only enough force is applied to contain pressure. Excessive mechanical force applied to the test gag may result in

damage to the seat and/or spindle and may interfere with the proper opera-tion of the valve. The test gag shall be removed following the test.

4. The metal temperature for the pres-sure test shall be in accordance with the original code of construction, but not less than 60°F (16°C) unless the owner provides information on the toughness characteristics of the material to indicate the acceptability of a lower test temperature. During close examination the metal temperature shall not exceed 120°F (50°C) unless the owner specifies requirements for a higher test temperature and it is ac-ceptable to the Inspector.

5. Hold-time for the pressure test shall be a minimum of 10 minutes prior to examination by the Inspector. The test pressure shall be reduced to the MAWP for close examination by the Inspector. Hold-time for close exami-nation shall be as necessary for the In-spector to conduct the examination.

b. Pneumatic Test A pneumatic test may be conducted when

contamination of the pressure-retaining item by liquids is possible or when liq-uid pressure testing is not practicable. Concurrence of the owner shall be ob-tained in addition to the Inspector and jurisdiction where required. Pneumatic test requirements and precautions shall be in accordance with the original code of construction.

c. Nondestructive Examination Nondestructive examination (NDE) may

be conducted when contamination of the pressure-retaining item by liquids is possible or when pressure testing is not practicable. Concurrence of the owner shall be obtained in addition to the Inspector and jurisdiction where required. NDE methods used shall be suitable for providing meaningful results to verify the integrity of the alteration.


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RC-3040 STAMPING

Pressure-retaining items altered in accor-dance with this code shall have a nameplate or stamping applied adjacent to the original manufacturer’s stamping or nameplate in ac-cordance with Appendix 2. For an alteration where physical changes are made to the pres-sure-retaining item, the “R” Certificate Holder responsible for the construction portion of the alteration shall apply the stamping or nameplate. For an alteration where no physi-cal changes are made to the pressure-retain-ing item (e.g., a re-rating) the “R” Certificate Holder, assuming responsiblity for the design, shall apply the stamping or nameplate.

RC-3050 DOCUMENTATION

Alterations performed in accordance with the NBIC shall be documented on Form R-2, Report of Alteration, as shown in Appendix 5. Form R-4 Report Supplementary Sheet shall be used to record additional data when space is insufficient on Form R-2.

RC-3051 PREPARATION

Initial preparation of Form R-2 shall be the responsibility of the “R” Certificate Holder responsible for the design portion of the alteration. The design organization shall complete and sign the “Design Certificate” section of the Form R-2. An inspector shall indicate acceptance of the design by signing the “Certificate of Design Change Review” section of the Form R-2.

Final preparation of Form R-2, including the gathering and attaching of supporting reports, shall be the responsibility of the “R” Certifi-cate Holder that performed the construction portion of the alteration. The construction organization shall complete the Form R-2 provided by the design organization, includ-ing the Construction Certificate section. An

inspector shall indicate that the work complies with the applicable requirements of this code by completing and signing the Certificate of Inspection section of the form. When no con-struction work is performed (e.g., a re-rating with no physical changes), the “R” Certificate Holder responsible for the design shall pre-pare the Form R-2, including the gathering and attaching of supporting reports.

The following shall be attached to and become a part of the completed Form R-2:

a. For ASME boilers and pressure vessels, a copy of the original Manufacturer’s Data Report, when available;

b. Form R-3, Report of Parts Fabricated by Welding or Manufacturer’s Partial Data Reports, and;

c. For other than ASME, the manufacturer’s reports (i.e., reports required by the original code of construction), when avail-able.

RC-3052 DISTRIBUTION

Distribution of the completed Form R-2 shall be the responsibility of the “R” Certificate Holder that performed the construction por-tion of the alteration. When no construction work is performed, (e.g., a re-rating with no physical changes), the “R” Certificate Holder responsible for the design shall distribute the form.

Legible copies of the completed Form R-2, to-gether with attachments, shall be distributed to the inspector, the authorized inspection agency responsible for the inservice inspec-tion of the pressure-retaining item, the owner-user, the “R” Certificate Holder responsible for design and the jurisdiction if required.

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RC-3053 REGISTRATION

If the pressure-retaining item is registered with the National Board, an original Form R-2 together with attachments shall be registered with the National Board.

If the item is not registered with the National Board, one original Form R-2 together with attachments may be registered with the National Board or retained as required by RC-1150(b).

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Repair/Alteration Methods

Part RD

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PART RD — REPAIR/ALTERATION METHODS

TABLE OF CONTENTS

RD-1000 Alternatives to Postweld Heat Treatment ..................................................... 107 RD-1010 Scope ................................................................................................................... 107 RD-1020 Nondestructive Examination of Welds .......................................................... 107 RD-1030 Welding Method 1 ............................................................................................ 107 RD-1040 Welding Method 2 ............................................................................................ 108 RD-1050 Welding Method 3 ........................................................................................... 110 RD-1060 Welding Method 4 ........................................................................................... 111 RD-1070 Wedling Method 5 .............................................................................................113

RD-1100 Alternative Local Post Weld Heat Treatment Method .................................115

RD-2000 Repair Methods ................................................................................................. 115 RD-2010 Scope ................................................................................................................... 115 RD-2020 Defect Repairs ................................................................................................... 116 RD-2030 Wasted Areas ..................................................................................................... 117 RD-2040 Seal Welding ...................................................................................................... 117 RD-2050 Re-Ending or Piecing Pipes or Tubes ............................................................. 117 RD-2060 Patches ................................................................................................................ 117 RD-2070 Stays .................................................................................................................... 123

RD-3000 Alterations Based on Allowable Stress Values ..............................................123 RD-3010 Re-rating ..............................................................................................................123 RD-3020 Minimum Wall Thickness .................................................................................124

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RD-1000 ALTERNATIVES TO POSTWELD HEAT

TREATMENT

RD-1010 SCOPE

Under certain conditions, postweld heat treatment in accordance with the original code of construction may be inadvisable or impractical. In such instances, the following alternative methods may be used.

Competent technical advice shall be obtained from the manufacturer of the pres-sure-retaining item or from another qualified source, such advice being especially neces-sary if the alternative is to be used in highly stressed areas, if service conditions are con-ducive to stress corrosion cracking, if materi-als are subject to hydrogen embrittlement or are operating at temperatures in the creep range or if the alternative is being considered for “on-stream” repairs or “hot tapping” on piping systems. Selection of the weld-ing method used shall be based on the rules of the original code of construction together with the above mentioned advice concerning the adequacy of the weld in the as-welded condition at operating and pres-sure test conditions.

When reference is made in this part to materials by the ASME designation, P-Num-ber and Group Number, the requirements of this part apply to the applicable materials of the original code of construction, either ASME or other, which conform by chemical composition and mechanical properties to the ASME P-Number and Group Number designations.

RD-1020 NONDESTRUCTIVE EXAMINATION OF WELDS

Prior to welding, the area prepared for welding shall be examined using either the magnetic particle (MT) or the liquid penetrant (PT) examination method to determine that no defects exist. After the finished weld has reached ambient temperature, the weld shall be examined again by either of the above methods to determine that no defects exist using acceptance standards acceptable to the Inspector or original code of construction. In addition, welds greater than 3/8 in. (10 mm) deep or welds in a boiler, pressure vessel or piping systems that were originally required to be radiographed by the rules of the original code of construction, shall be radiographi-cally examined. In situations where it is not practical to perform radiography, the acces-sible surfaces of each nonradiographed repair weld shall be fully examined using the MT or PT method to determine that no defects exist and the maximum allowable working pres-sure and/or allowable temperature shall be reevaluated to the satisfaction of the jurisdic-tion at the location of installation.

RD-1030 WELDING METHOD 1

When using this method the following is required:

a. This method may be used when the applicable rules of the original code of construction did not require notch tough-ness testing.

b. The materials shall be limited to P-No. 1, Group 1, 2, and 3 and to P-No. 3, Group 1 and 2 (excluding Mn-Mo steels in Group 2), as permitted for welded construction by the applicable rules of the original code of construction.

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c. The welding shall be limited to the shielded metal-arc welding (SMAW), gas metal-arc welding (GMAW), fl uxcored arc welding (FCAW) and gas tungsten-arc welding (GTAW) processes.

d. The welders and welding procedures (WPS) shall be qualifi ed in accordance with the applicable rules of the original code of construction, except that the post-weld heat treatment of the test coupon used to qualify the weld procedure shall be omitted.

e. The weld area shall be preheated and maintained at a minimum temperature of 300˚F (150˚C) during welding. The 300˚F (150˚C) temperature should be checked to assure that 4 in. (100 mm) of the mate-rial or four times the material thickness (whichever is greater) on each side of the groove (or full thickness of joint for a groove weld) is maintained at the mini-mum temperature during welding. The maximum interpass temperature shall not exceed 450˚F (230˚C). When the weld does not penetrate through the full thickness of the material, the minimum preheat and maximum interpass temperatures need only be maintained at a distance of 4 in. (100 mm) or four times the depth of the repair weld, whichever is greater on each side of the joint.



a. This method shall be used when the applicable rules of the original code of con-struction required notch toughness testing or shall be used when the applicable rules of the original code of construction did not require notch toughness testing provided the adequacy of the notch toughness of the

weld, including the heat-affected zone, in the as-welded condition at operating and pressure test conditions is verifi ed.

b. The materials shall be limited to carbon and low alloy steels permitted for welded construction by the applicable rules of the original code of construction, includ-ing those materials conforming to any of the following ASME P-No. designations: P-No. 1, Group 1, 2 and 3, P-No. 3, Group 1, 2 and 3, P-No. 4, P-No. 5A, P-No. 9A, P-No. 10A, P-No. 10B, P-No. 10C, P-No. 11A or P-No. 11B.

c. The welding shall be limited to the shielded metal-arc welding (SMAW), gas metal-arc welding (GMAW), fl uxcored arc welding (FCAW) and gas tungsten-arc welding (GTAW) processes.

d. The welders and welding procedures (WPS) shall be qualifi ed in accordance with the applicable rules of the original code of construction, except that the post-weld heat treatment of the test coupon used to qualify the weld procedure shall be omitted. The WPS shall be qualifi ed for this repair method using the requirements in RD-1040(i). The qualifi cation thickness for the test plates and repair grooves shall be in accordance with Table RD-1040-1.

e. As shown in Table RD-1040-1, the depth of the repair groove (or full thickness of a joint for a groove weld) in base metal or in weld metal is not limited provided the test material thickness for the weld-ing procedure qualifi cation is at least fi ve times the depth of the repair but need not exceed the thickness of the material to be repaired, provided the required test speci-mens can be removed. When the thickness of the base metal to be repaired is greater than 2 in. (50 mm), the procedure qualifi -cation test material need not exceed 2 in. (50 mm); however, the depth of the groove

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in the test material shall be the greater of 1 in. (25 mm) or the depth of the groove to be repaired.

f. The test material for the welding proce-dure qualification shall be of the same material specification (including specifi-cation type, grade, class and condition of heat treatment) as the original material specification for the repair. In the event that the notch toughness of the material to be repaired is unknown, evidence from tests of that material or from another ac-ceptable source (see RD-1010) may be used for the base metal notch toughness when qualifying the WPS as required in (g). In the event that the original material specification is obsolete, the test material used should conform as close as possible to the original material used for construc-tion, but in no case shall the material be lower in strength.

g. The organization making the repair shall include, when qualifying its WPS, suffi-cient tests to determine that the toughness of the weld metal and the heat-affected zone of the base metal in the as-welded condition is adequate at the minimum operating and pressure test temperatures (including start-up and shutdown). When these conditions are met, any original code of construction credit for PWHT may be continued. If for reasons of corrosion resistance, special hardness limits are necessary, such limits shall be included when qualifying the WPS.

h. Notch toughness shall be determined and evaluated by Charpy impact tests in accordance with the provisions of the original code of construction.

i. The WPS shall include the following additional requirements:

1. The supplemental essential variable of ASME Code, Section IX, paragraph QW-250, shall apply;

2. The maximum weld heat input for each layer shall not exceed that used in the procedure qualification test;

3. The minimum preheat temperature for welding shall not be less than that used in the procedure qualification test;

4. The maximum interpass temperature for welding shall not be greater than that used in the procedure qualifica-tion test;

5. The preheat temperature shall be checked to assure that 4 in. (100 mm) of the material or four times the material thickness (whichever is greater) on each side of the weld joint will be maintained at the minimum temperature during welding. When the weld does not penetrate through the full thickness of the material, the minimum preheat temperature need only be maintained at a distance of 4 in. (100 mm) or four times the depth of the repair weld, whichever is greater on each side of the joint;

6. For the welding process in (c) above, use only filler metals which are clas-sified by the filler metal specification with an optional supplemental dif-fusible-hydrogen designator of H8 or lower. When shielding gases are used with a process, the gas shall exhibit a dew point that is below -60°F (-50°C). Surfaces on which welding will be done shall be main-tained in a dry condition during welding and be free of rust, mill scale and hydrogen producing con-taminents such as oil, grease and other organic materials.

7. The welding technique shall be a controlled-deposition temper bead or half bead technique. The specific technique or specific combinations of

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techniques shall be that used in the procedure qualification test;

8. After completion of welding and without allowing the weldment to cool below the minimum preheat temperature, the temperature of the weldment shall be raised to a tempera-ture of 450°F (230°C) minimum for a minimum period of two hours. This hydrogen bake-out treatment may be omitted provided the electrode used is classified by the filler metal specifi-cation with an optional supplemental diffusible-hydrogen designator of H4 (e.g., E7018-H4); and

9. After the finished repair weld has cooled to ambient temperature, the final temper bead reinforcement layer shall be removed substantially flush with the surface of the base material.



a. This method may be used when the applicable rules of the original code of construction did not require notch tough-ness testing.

b. The materials shall be limited to any P-No. 1 or P-No. 3 material as permitted for welded construction by the applicable rules of the original code of construc-tion.

c. The welding shall be limited to the shielded metal-arc welding (SMAW) and gas tungsten-arc welding (GTAW) pro-cesses.

d. The welders and welding procedures (WPS) shall be qualified in accordance with the applicable rules of the original code of construction, except that the post-weld heat treatment of the test coupon used to qualify the weld procedure shall be omitted. The WPS shall be qualified for this repair method using the require-ments in RD-1050(h). The qualification thicknesses for the test plates and repair grooves shall be in accordance with Table RD-1040-1.

e. As shown in Table RD-1040-1, the depth of the repair groove (or full thickness of a joint for a groove weld) in base metal or in weld metal is not limited provided the test material thickness for the weld-ing procedure qualification is at least five times the depth of the repair but need not exceed the thickness of the material to be repaired, provided the required test speci-mens can be removed. When the thickness of the base metal to be repaired is greater than 2 in. (50 mm), the procedure qualifi-cation test material need not exceed 2 in. (50 mm); however, the depth of the groove in the test material shall be the greater of 1 in. (25 mm) or the depth of the groove to be repaired.

f. The test material for the welding proce-dure qualification shall be of the same P-No. and Group No. as the original material specification for the repair. In the event that the original material specifica-tion is obsolete, the test material used should conform to the nominal composi-tion and carbon equivalent (IIW formula) as the original material used for construc-tion, but in no case shall the material be lower in strength.

g. If for reasons of corrosion resistance, special hardness limits are necessary, such limits shall be included when qualifying the WPS.

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h. The WPS shall include the following additional requirements:

1. The maximum weld heat input for each layer shall not exceed that used in the procedure qualification test;

2. The minimum preheat temperature for welding shall be 350°F (175°C) and the maximum interpass temperature shall be 450°F (230°C);

3. For the welding process in (c) above, use only filler metals which are clas-sified by the filler metal specification with an optional supplemental dif-fusible-hydrogen designator of H8 or lower. When shielding gases are used with a process, the gas shall ex-hibit a dew point that is below -60°F (-50°C). Surfaces on which welding will be done shall be maintained in a dry condition during welding and be free of rust, mill scale and hydrogen producing contaminents such as oil, grease and other organic materials.

4. The welding technique shall be a controlled-deposition temper bead or half bead technique. The specific technique or specific combinations of techniques shall be that used in the procedure qualification test;

5. For SMAW the electrode size shall not exceed 1/8 in. (3 mm) and for GTAW the electrode size and the filler metal size shall not exceed 3/32 in. (2.5 mm);

6. For welds made by SMAW, after completion of welding and without allowing the weldment to cool below the minimum preheat temperature, the temperature of the weldment shall be raised to a temperature of 450°F (230°C) minimum for a minimum

period of two hours. This hydrogen bake-out treatment may be omitted provided the electrodes used are clas-sified by the filler metal specification with an optional supplemental diffus-ible-hydrogen designator of H4 (e.g., E7018-H4); and

7. After the finished repair weld has cooled to ambient temperature, the final temper bead reinforcement layer shall be removed substantially flush with the surface of the base material.



a. This method is limited to boilers for which the applicable rules of the original code of construction did not require notch tough-ness testing.

b. The materials shall be limited to P-No. 4, Groups 1 and 2 and P-No. 5A steels as permitted for welded construction by the applicable rules of the original code of construction.

c. The welding shall be limited to the shielded metal-arc welding (SMAW) fluxcored-arc welding (FCAW) and gas tungsten-arc welding (GTAW) processes using low-hydrogren filler metals clas-sified by the filler metal specification with an optional supplemental diffus-able-hydrogen designator of H8 or lower and suitably controlled by maintenance procedures to avoid contamination by hydrogen producing sources. The surface of the metal prepared for welding shall be free of contaminants.

d. The welders and welding procedures (WPS) shall be qualified in accordance

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with the applicable rules of the original code of construction, except that the post-weld heat treatment of the test coupon used to qualify the weld procedure shall be omitted. The WPS shall be qualifi ed for this repair method using the requirements in RD-1060 (h). The qualifi cation thickness for the test plates and repair grooves shall be in accordance with Table RD-1040-1.

e. As shown in Table RD-1040-1, the depth of the repair groove (or full thickness of a joint for a groove weld) in the base metal or in weld metal is not limited provided the test material thickness for the weld-ing procedure qualifi cation is at least fi ve times the depth of the repair, but need not exceed the thickness of the material to be repaired, provided the required test specimens can be removed. When the thickness of the base metal to be repaired is greater than 2 in. (50 mm), the proce-dure qualifi cation test material need not exceed 2 in. (50 mm); however, the depth of the groove in the test material shall be the greater of 1 in. (25 mm) or the depth of the groove to be repaired.

f. The test material for the welding proce-dure qualifi cation shall be of the same P-No. and Group No. as the original ma-terial specifi cation for the repair. In the event that the original material specifi ca-tion is obsolete, the test material used shall conform to the nominal composition and carbon equivalent (IIW formula) as the original material used for construction, and in no case shall the material be lower in strength.

g. If for reasons of corrosion resistance, spe-cial hardness limits are necessary, such limits shall be included when qualifying the WPS.

h. The WPS shall include the following ad-ditional requirements:

1. The minimum preheat temperature for welding shall be 300°F (150°C) for P-No. 4 material and 400°F (205°C) for P-No. 5A material. The preheat temperature shall be checked to as-sure that 4 in. (100 mm) of the material or four times the material thickness (whichever is greater) on each side of the groove (or full thickness of joint for a groove weld) is maintained at the minimum temperature during welding. The maximum interpass temperature shall not exceed 800°F (425°C). When the weld does not pen-etrate through the full thickness of the material, the minimum preheat and maximum interpass temperature need only be maintained for 4 in. (100 mm) or four times the depth of the repair weld (whichever is greater) on each side of the joint.

2. The welding technique shall be a controlled-deposition temper bead technique and shall include a butter-ing layer deposited over the entire groove faces (or fi llet leg faces) using a 3/32 in. (2.5 mm) diameter electrode. The buttering layer shall be deposited using stringer beads with an overlap of approximately 50%. The second and remaining layers shall be deposited over the buttering layer using a 3/32 in. (2.5 mm) or 1/8 in. (3 mm) diameter electrode for SMAW, 0.045 in. (1.1 mm) for FCAW, or 1/16 in. (1.5 mm) or 3/32 in. (2.5 mm) for GTAW fi ller metal. The second and remaining layers shall not contact the base material and shall be deposited using stringer beads. After the groove is fi lled (or fi llet size is achieved), a 3/32 in. (2.5 mm) or 1/8 in. (3 mm) thick reinforcement layer

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TABLE RD-1040-1 —Welding Methods as Alternatives to Postweld Heat Treatment Qualification Thicknesses for Test Plates and Repair Grooves

BASE METALTHICKNESS

REPAIRGROOVEDEPTH

PQR TEST MATERIALTHICKNESS

PQR GROOVEDEPTHNote (2)

THICKNESSQUALIFIEDNote (1)

< 2” (50 mm) < 1” (25 mm) 5 times the repair cavity depth, but need not exceed the thickness of the base metal to be repaired.

< 1” (25 mm) See PQR test material thickness column and ≤ PQR groove depth.

≤ 2” (50 mm) > 1” (25 mm) Thickness of the base metal to be repaired.

> 1” (25 mm) ≤ PQR test material thickness and ≤ PQR groove depth.

> 2” (50 mm) 1” (25 mm) 2” (50 mm) 1” (25 mm) All base metal thick-ness and ≤ 1” (25 mm) repair groove depth.

> 2” (50 mm) > 1” (25 mm) 2” (50 mm) > 1” (25 mm) All base metal thick-ness and ≤ PQR groove depth.

Note 1. Repair groove depth is limited to the maximum depth qualified.

Note 2. The depth of the groove used for procedure qualification must be deep enough to remove test specimens.

shall be deposited to temper the prior weld layer. This temper layer shall be deposited to within 1/8 in. (3 mm) of the toe of the weld, but shall not contact the base metal.

3. After completion of welding and without allowing the weldment to cool below the minimum preheat temperature, the temperature of the weldment shall be raised to a tempera-ture of 450°F (230°C) minimum for a minimum period of two hours. This hydrogen bake-out treatment may be omitted provided the filler metal used is classified by the filler metal specifi-cation with an optional supplemental diffusable-hydrogen designator of H4 (e.g., E7018-H4).

4. After the finished repair weld has cooled to ambient temperature, the final temper bead reinforcement layer shall be removed substantially flush with the surface of the base metal (and for a fillet weld to the required size and suitable contour of the toes).



a. This method may be used when the appli-cable rules of the original code of construc-tion for which postweld heat treatment for one material joined to another material for which postweld heat treatment may be

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inadvisable, such as carbon or low-alloy steel joined to austenitic stainless steel or to nickel or nickel-based alloys.

b. The materials shall be limited to those ma-terials conforming to any of the following ASME designations: P-No. 1, Groups 1, 2, and 3, P-No. 3, Groups 1, 2, and 3, P-No. 4, P-No. 5A, P-No. 9A, P-No. 10A, P-No. 10B, P-No. 10C, P-No. 11A, or P-No. 11B joined to either P-No. 8, P-No. 41, P-No. 42, P-No. 43, P-No. 44, P-No. 45, P-No. 46, or P-No. 47 as permitted for welded construction by the applicable rules of the original code of construction.

c. The welding shall be limited to the shielded metal-arc welding (SMAW), flux-cored-arc welding (FCAW), gas metal-arc welding (GMAW), and gas tungsten-arc welding (GTAW) processes. The surface of the metal prepared for welding shall be free of contaminants. It is cautioned to determine if the dissimilar metal joint will be exposed to elevated temperature service since significant differences in coefficient of thermal expansion of dis-similar metal-welded joints may result in excessive differences in relative deforma-tion and thermal fatigue at the joint. The electrodes/filler metals for dissimilar metal welded joint shall be either of those conforming to the ASME designations A-No. 8 or F-No. 43 as applicable. It is cautioned that using austenitic stainless steel electrodes/filler metals for joining P-No. 8 materials to carbon or low-alloy steels for weld joints exposed to service temperatures greater than 800°F (425°C) will exhibit reduced creep life along the fusion zone of the ferritic material due to carbon diffusion.

d. The welders and welding procedures (WPS) shall be qualified in accordance

with the applicable rules of the original code of construction, except that the postweld heat treatment of the test cou-pon used to qualifty the weld procedure shall be omitted in accordance with the following paragraphs (e) through (h), as applicable.

e. Qualification of welding procedures (WPS) for joining P-No. 1 Groups 1, 2, and 3, P-No. 3, Groups 1, 2 (excluding Mn-Mo steels in Group 2) ferritic materials to either P-No. 8, P-No. 41, P-No. 42, P-No. 43, P-No. 44, P-No. 45, P-No. 46 or P-No. 47 materials shall be in accordance with RD-1030 Welding Method 1 if the original code of construction did not require notch toughness testing.

f. Qualification of welding procedures (WPS) for joining ASME P-No. 1, Groups 1, 2, and 3, P-No. 3 Groups 1, 2, and 3, P-No. 4, P-No. 5A, P-No. 9A, P-No. 10A, P-No. 10B, P-No. 10C, P-No. 11A, P-No. 11B ferritic materials to either P-No. 8, P-No. 41, P-No. 42, P-No. 43, P-No. 44, P-No. 45, P-No. 46 or P-No. 47 materials shall be in accordance with RD-1040 Welding Meth-od 2 if the original code of construction required notch toughness testing or when the original code of construction did not require notch toughness testing provided the adequacy of the heat affected zone of the ferritic material in the as-welded condition at operating and pressure test conditions has been verified.

g. Qualification of welding procedures (WPS) for joining any P-No. 1 or P-No. 3 materials to P-No. 8, P-No. 41, P-No. 42, P-No. 43, P-No. 44, P-No. 45, P-No. 46 or P-No. 47 materials shall be in accordance with RD-1050 Welding Method 3 if the original code of construction did not require notch toughness testing and the


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welding is limited to the shielded metal-arc welding (SMAW) and the gas-tung-sten-arc welding (GTAW) processes.

h. Qualification of welding procedures (WPS) for joining P-No. 4 and P-No. 5A materials to either P-No. 8, P-No. 41, P-No. 42, P-No. 43, P-No. 44, P-No. 45, P-No. 46 or P-No. 47 materials shall be in ac-cordance with RD-1060 Welding Method 4 if the original code of construction did not require notch toughness testing.

i. The requirements of RD-1040(i)(6) and (i)(8), RD-1050 (h)(3) and RD-1060(c) and (h)(3) for low hydrogen electrodes/filler metals and for a hydrogen bake-out treat-ment may be omitted.

RD-1100 ALTERNATIVE LOCAL POST WELD HEAT TREATMENT METHOD

When it is impractical or detrimental to post weld heat treat the entire item or an entire band around the item, the following local (e.g., bulls eye) post weld heat treatment method may be performed on spherical or cylindrical pressure retaining items using the time and temperature parameters in the original code of construction and in accordance with a writ-ten procedure.

a. Heat a local area around the nozzle, welded attachment or repair area in such a manner that the area is brought up uni-formly to the required temperature. The application of local post weld heat treat-ment should be performed with controlled heating methods such as induction or electric resistance heaters with thermo-couples. The soak band, which is the band required to be heated to the minimum PWHT temperature, shall be a circle (e.g.,

bulls eye method) that extends beyond the entire nozzle, attachment weld and repair area in all directions by a minimum of the thickness of the shell, t or 2” (50 mm), whichever is less.

b. The temperature gradient extending outside the bulls eye post weld heat treat-ment band applied to repair welds or attachment welds shall be kept as low as possible in all directions to avoid harmful temperature gradients adjacent to nozzles or geometric discontinuities.

c. For bulls eye post weld heat treatment of nozzle welds, repair welds and external attachment welds on smooth spherical shells, heads and cylindrical shells the thermal gradients outside the circumfer-ential heat band should not exceed 250°F (120°C) per foot (0.3 m).

d. The term t, or definition of thickness for calculating the holding time, for local post weld heat treatment shall be the nominal thickness of either a full penetration weld, the groove weld depth of a partial pen-etration repair weld or if a fillet weld is used in combination with a groove weld the nominal thickness is the depth of the groove or the throat dimensions, which-ever is greater.

RD-2000 REPAIR METHODS

RD-2010 SCOPE

A repair of a defect, such as a crack in a welded joint or base material, shall not be made un-til the defect has been removed. A suitable nondestructive examination method such as magnetic particle (MT) or liquid penetrant (PT) may be necessary to assure complete

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removal of the defect. If the defect penetrates the full thickness of the material, the repair shall be made with a complete penetration weld such as a double butt weld or a single butt weld with or without backing. Where cir-cumstances indicate that the defect is likely to recur, consideration should be given to remov-ing the defective area and installing a fl ush patch or taking other acceptable, corrective measures. A repair of a bulge or blister shall be made if a bulge or blister will affect the pres-sure-retaining capability of the plate or tube or when evidence of leakage is noted.

RD-2020 DEFECT REPAIRS

Unstayed Boiler Furnace Cracks Cracks at the knuckle or at the turn of the fl ange of the furnace opening require immedi-ate replacement of the affected area or specifi c approval of repairs by the jurisdiction. See Figure RD-2020-a.

Rivet or Staybolt Hole CracksCracks radiating from rivet or staybolt holes may be repaired if the plate is not seriously damaged. If the plate is seriously damaged, it shall be replaced. For suggested methods of repair. See Figure RD-2020-b.

Minor DefectsMinor cracks, isolated pits and small plate imperfections should be examined to deter-mine the extent of the defect and whether repair by welding is required. Prior to repair by welding, the defects shall be removed to sound metal. Liquid penetrant or magnetic particle examination may be used before or after welding.

Defective Bolting Defective bolting material shall not be re-paired but shall be replaced with suitable material which meets the specifi cations of the original code of construction.

A bulge on a water tube shall be investigated to determine the cause and extent of dam-age to the tube prior to repair. If the bulge has resulted in metallurgical changes to the original tube material as determined by fi eld metallography, installation of a new length of tubing or tube patch (RD-2060) is required. If the bulge has cracks as determined by NDE, installation of a new length of tubing or a tube patch is required. If the bulge does not exhibit cracks and has not resulted in metal-lurgical changes to the original tube mate-rial, a mechanical repair may be considered subject to the concurrence of the inspector or jurisdiction.

A bulge on a plate shall be investigated to de-termine the cause and extent of damage to the plate prior to repair. If the bulge has resulted in metallurgical changes to the original plate material as determined by fi eld metallogra-phy, installation of a fl ush patch (RD-2060) is required. If the plate has cracks as determined by NDE, installation of a fl ush patch is re-quired. If the bulge does not exhibit cracks and has not resulted in metallurgical changes to the original plate material, a mechanical repair may be considered, subject to the concurrence of the inspector or jurisdiction.

A blister may be caused by a defect in the metal such as lamination where one side ex-posed to the fi re overheats but the other side retains its strength due to the cooling effect of the water. After the blistered material has been removed, the remaining wall thickness shall be determined by ultrasonic thickness testing. A surface examination using liquid penetrant testing or magnetic particle testing shall be made to assure the remaining mate-rial contains no defects. If the remaining wall thickness is adequate, in the judgement of the inspector, the area may be repaired by weld-ing as covered in RD-2030, Wasted Areas. If the remaining wall thickness is not adequate,

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a plate will require a fl ush patch (RD-2060) and a tube will require a new length of tube or tube patch (RD-2060).

RD-2030 WASTED AREAS

Shells, Drums, HeadersWasted areas in stayed and unstayed shells, drums and headers may be built up by welding provided that in the judgement of the Inspector the strength of the struc-ture has not been impaired. Where ex-tensive weld buildup is employed, the Inspector may require an appropriate method of NDE for the completed surface of the repair. For suggested methods of building up wasted areas by welding. See Figure RD-2030-a.

Access OpeningWasted areas around access openings may be built up by welding or they may be repaired as described in Figure RD-2030-b.

FlangesWasted fl ange faces may be cleaned thorough-ly and built up with weld metal. They should be machined in place if possible to a thickness not less than that of the original fl ange or that required by calculations in accordance with the provisions of the original code of construc-tion. Wasted fl anges may also be remachined in place without building up with weld metal provided that metal removed in the process does not reduce the thickness of the fl ange to a measurement below that calculated above. Flanges which leak because of warpage or distortion and which cannot be remachined shall be replaced with new fl anges which have at least the dimensions conforming to the original code of construction.

TubesWasted areas on tubes may be repaired by welding provided that in the judgement of the Inspector the strength of the tube has not been

impaired. Where deemed necessary, compe-tent technical advice should be obtained from the manufacturer or from another qualifi ed source. This may be necessary when consider-ing such items as size limitations of repaired areas, minimum tube thickness to be repaired, tube environment, location of the tube in the boiler and other similar conditions.

RD-2040 SEAL WELDING

Seal Welding of TubesTubes may be seal welded provided the ends of the tubes have suffi cient wall thickness to prevent burn through and the requirements of the original code of construction are satisfi ed. See Figure RD-2040-a.

Seal Welding of Riveted JointsEdges of buttstraps, plate laps and noz-zles, or of connections attached by riv-e t ing may be res tored to or ig ina l dimensions by welding. Seal welding of riv-eted joints, buttstraps or rivets shall require the approval of the jurisdiction. If seal welding is approved, suggested methods and precau-tions are shown in Figure RD-2040-b.

RD-2050 RE-ENDING OR PIECING PIPES OR TUBES

Re-ending or piecing pipes or tubes is per-mitted provided the thickness of the remain-ing pipe or tube is not less than 90% of that required by the original code of construc-tion.

RD-2060 PATCHES

Flush PatchesThe weld around a flush patch shall bea full penetration weld and the accessible surfaces shall be ground fl ush where required

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FIGURE RD-2020-a — UNSTAYED BOILER FURNACESCracks at the knuckle or at the turn of the flange of the furnace opening require immediate replacement of the affected area. If repairs are attempted, specific approval of the jurisdiction is required.

FIGURE RD-2020-b — RIVET AND STAYBOLTHOLE CRACKSCracks radiating from rivet or staybolt holes may be repaired if the plate is not seriously damaged. If the plate is seriously damaged, it shall be replaced. A suggested repair method is described below:

a. Prior to welding, the rivets or staybolts from which the cracks extend and the adjacent rivets (or staybolts if appropriate) should be removed.

b. In riveted joints, tack bolts should be placed in alternate holes to hold the plate laps firmly.

c. The cracks should then be prepared for welding by chipping, grinding or gouging.

d. In riveted joints, cracks which extend past the inner edge of the plate lap should be welded from both sides.

e. Rivet holes should be reamed before new rivets are driven.

CIRCUMFERENTIAL CRACKS AT GIRTH SEAMS

FIRE CRACKS AT GIRTH SEAMS

CRACKS IN STAYED PLATES


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f. Threaded staybolt holes should be retapped and new staybolts properly driven and headed.

FIGURE RD-2030-a — WELD BUILDUP OF WASTED AREARivet and Stayboltsa. Prior to welding, the rivets or staybolts in the wasted area should be removed.

b. Threaded staybolt holes should be retapped after welding.

c. Rivet holes should be reamed after welding.

d. Welding should not cover rivet or staybolt heads.

Tubesheeta. Prior to welding, the tubes in the wasted area should be removed.

b. After welding, the tube holes may be reamed before new tubes are installed.

Wasted areas in stayed and unstayed surfaces may be repaired by weld build-up, provided that in the judgment of the Inspector the strength of the structure will not be impaired. Where extensive weld buildup is employed, the Inspector may require an appropriate method of NDE for the complete surface of the repair.

FIRE CRACKS AT DOOR OPENINGS

TUBESHEET

rivet and staybolt

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FIGURE RD-2030-b — REPAIRS FOR ACCESS OPENINGSA badly wasted manhole flange may be removed and replaced with a ring-type frame as shown at right. The requirements for flush patches shall be met. A full penetration weld is required. May be either double or welded from one side with or without a back-ing ring.

A badly wasted area around a handhole opening may be repaired by adding a ring, as shown at right, on the inside of the object.

FIGURE RD-2040-a — TYPICAL EXAMPLES OF SEAL WELDING TUBESTubes may be seal welded provided the ends of the tubes have sufficient wall thickness to prevent burn-through. Seal welding shall be applied with a maximum of three light layers in lieu of one or two heavy layers. Seal welding shall not be considered a strength weld.

In watertube boilers, tubes may be seal welded on the inside or outside of the tubesheet.

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FIGURE RD-2040-b — SEAL WELDING OFRIVETED JOINTSSeal welding of riveted joints requires the approval of the jurisdiction. Seal welding shall not be consid-ered a strength weld.Prior to welding, the area should be examined by an appropriate method of NDE to assure that there are no cracks radiating from the rivet holes. If necessary, the rivets should be removed to assure complete examina-tion of the area. Seal welding should not be performed if cracks are present in riveted areas.

FIGURE RD-2060-a — FLUSH PATCHESBefore installing a flush patch, the defective material should be removed until sound material is reached. The patch should be rolled or pressed to the proper shape or curvature. The edges should align without overlap.

In stayed areas, the weld seams should come between staybolt rows or riveted seams.Patches should be made from a material that is at least equal in quality and thickness to the original material.

Patches may be of any shape or size. If the patch is rectangular, an adequate radius should be provided at the corners. Square corners should be avoided.

TYPICAL RIVET JOINT SHOWING SEAL WELD

FLUSH PATCHES IN UNSTAYED AREAS

FLUSH PATCHES IN STAYED AREAS

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FIGURE RD-2060-b —TUBE WINDOW PATCHING METHODIt may be necessary to weld a flush patch on a tube since, in some situations, accessibility around the complete circumfer-ence of the tube is restricted. Listed below are the suggested methods for making window patches:

a. The patch should be made from tube material of the same type, diameter and thickness as the one being repaired.

b. Fit-up of the patch is important to weld integrity. The root open-ing should be uniform around the patch.

c. The gas tungsten-arc welding process should be used for the ini-tial pass on the inside of the tube and for the initial pass joining the patch to the tube.

d. The balance of the weld may be completed by any appropriate welding process.

SIDE VIEW SHOWING PATCH FIT AND WELDING

FRONT AND SIDE VIEW OF TUBE

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by the applicable original code of construc-tion. Examples of fl ush welded patches are shown in Figure RD-2060-a. The welds shall be subjected to the non-destructive exami-nation method used in the original code of construction or an alternative acceptable to the Inspector.

Tube PatchesIn some situations it is necessary to weld a flush patch on a tube, such as when replacing tube sections and accessibil-ity around the complete circumference of the tube is restricted or when it is necessary to repair a small bulge. This is referred to as a window patch. Suggested methods for window patches are shown in Figure RD-2060-b.

RD-2070 STAYS

Threaded stays may be replaced by welded-in stays provided that, in the judgement of the Inspector, the material adjacent to the staybolt has not been materially weakened by deterio-ration or wasting away. All requirements of the original code of construction governing welded-in stays shall be met.

RD-3000 ALTERATIONS BASED ON ALLOWABLE STRESS

VALUES

RD-3010 RE-RATING

The following requirements shall apply for re-rating a pressure retaining item by using a later edition/addendum of the original code of construction which permits higher allow-able stress values for the material than was used in the original construction.

a. The “R” Certifi cate Holder shall verify, by calculations and other means, that the re-rated item can be satisfactorily operated at the new service condition (e.g., stiffness, buckling, external mechanical loadings, etc.).

b. The pressure-retaining item shall not be used in lethal service.

c. The pressure-retaining item shall not be used in high-cycle operation or fatigue service (i.e., loadings other than primary membrane stress are controlling design considerations).

d. The pressure-retaining item shall have been constructed to the 1968 Edition or later edition/addenda of the original code of construction.

e. The pressure-retaining item shall be shown to comply with all relevant require-ments of the edition/addenda of the code of construction which permits the higher allowable stress values (e.g., reinforce-ment, toughness, examination, pressure testing, etc.).

f. The pressure-retaining item shall have a satisfactory operating history and cur-rent inspection of the pressure retaining item shall verify the item exhibits no un-repaired damage (e.g., cracks, corrosion, erosion, etc.).

g. The re-rating shall be acceptable to the Inspector and, where required, the juris-diction.

h. All other requirements of Part RC shall be met.

i. Use of this paragraph shall be documented in the Remarks Section of Form R-2.

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RD-3020 MINIMUM WALL THICKNESS

The following requirements shall apply for recalculating a new minimum wall thickness for a pressure-retaining item by using a later edition/addendum of the original code of construction which permits higher allowable stress values for the material than was used in the original construction.

a. The “R” Certificate Holder shall verify, by calculations and other means, that the affected portions of the pressure-retaining item can be satisfactorily operated (e.g., stiffness, buckling, external mechanical loadings, etc.).

b. The pressure-retaining item shall not be used in lethal service.

c. The pressure-retaining item shall not be used in high-cycle operation or fatigue service (i.e., loadings other than primary membrane stress are controlling design considerations).

d. The pressure-retaining item shall have been constructed to the 1968 Edition or later edition/addenda of the original code of construction.

e. The pressure-retaining item shall be shown to comply with all relevant require-ments of the edition/addenda of the code of construction which permits the higher allowable stress values (e.g., reinforce-ment, toughness, examination, pressure testing, etc.).

f. The pressure-retaining item shall have a satisfactory operating history and current inspection of the pressure-retaining item shall verify the item exhibits no unre-paired damage (e.g., cracks, etc.). Areas of corrosion or erosion may be left in place provided the remaining wall thickness is greater than the new minimum thick-ness.

g. The design shall be acceptable to the In-spector and, where required the jurisdic-tion.

h. All other requirements of Part RC shall be met.

i. Use of this paragraph shall be documented in the Remarks Section of Form R-2.

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Repairs of Pressure Relief Valves

Part RE

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PART RE — REPAIRS OF PRESSURE RELIEF VALVES

TABLE OF CONTENTS

RE-1000 General ............................................................................................................... 127 RE-1010 Scope ................................................................................................................... 127 RE-1020 Defi nition of Repair .......................................................................................... 127 RE-1030 Accreditation ......................................................................................................128 RE-1040 Materials .............................................................................................................128 RE-1050 Replacement Parts .............................................................................................128 RE-1060 Nameplates .........................................................................................................128 RE-1070 Field Repair ........................................................................................................130

RE-1000 Welding for Pressure Relief Valves ................................................................ 131 RE-1110 Welding Procedure Specifi cations .................................................................. 131 RE-1120 Standard Welding Procedure Specifi cations ..................................................131 RE-1130 Performance Qualifi cation ...............................................................................131 RE-1140 Welding Records ................................................................................................131 RE-1150 Welders’ Identifi cation ......................................................................................131 RE-1160 Welders’ Continuity ..........................................................................................132

RE-1200 Heat Treatment ...................................................................................................132 RE-1210 Preheating .......................................................................................................... 132 RE-1220 Postweld Heat Treatment .................................................................................132

RE-2000 Performance Testing and Testing Equipment ................................................132 RE-2010 Test Medium and Testing Equipment .............................................................132 RE-2020 Owner-User Section VIII Steam Testing .........................................................133 RE-2030 Lift Assist Testing ...............................................................................................133

RE-3000 Training and Qualifi cation of Personnel ........................................................134 RE-3010 General ................................................................................................................134 RE-3020 Contents of Training Program .........................................................................134 RE-3030 Qualifi cation of Personnel ................................................................................134 RE-3040 Annual Review of Qualifi cation ......................................................................134


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RE-1000 GENERAL REQUIREMENTS

RE-1010 SCOPE

This part provides general requirements that apply to repairs to pressure relief valves. Repairs may be required because of defects found during periodic inspections because testing has identified that valve performance does not meet the original Code of Construc-tion requirements, failure during operation, or for routine preventative maintenance.

RE-1020 DEFINITION OF REPAIR

Repair of a pressure relief valve is considered to be the disassembly, replacement, remachin-ing, or cleaning of any critical part, lapping of a seat and disc, reassembly, adjustment, testing, or any other operation that may affect the flow passage, capacity, function or pres-sure-retaining integrity.

Conversions, changes or adjustments affecting critical parts are also considered repairs. The scope of conversions may include changes in service fluid and changes such as bellows, soft seats and other changes that may affect type/model number provided such changes are recorded on the document required by RA-2255(i) and the repair nameplate. See RE-1060.

The scope of repair activities shall not include changes in ASME Code status.

When a repair is being performed under the administrative requirements of Part RA-2200, a repair shall consist of the following opera-tions as a minimum:

a. Complete disassembly, cleaning and in-spection of all parts, repair or replacement

of parts found to be defective, reassembly, testing as required by RE-2000, sealing and application of a repair nameplate. When completed, the valve’s condition and performance shall be equivalent to the standards for new valves.

b. The administrative requirements of RA-2200 apply only to valves which are stamped with an ASME “V”, “UV”, or “NV” Code symbol or marked with an ASME “HV” symbol and have been capac-ity certified on the applicable fluid by the National Board.

RE-1021 CONSTRUCTION STANDARDS

The applicable standard for new valves to be used for reference during repairs is the ASME Code. ASME Code Cases shall be used for repairs when they were used in the original construction of the valve. ASME Code Cases may be used when they have been accepted for use by revision or interpretation by the NBIC Committee.

The Code Case number shall be noted on the repair document specified in RA-2255(i)(1), and when required by the Code Case, stamped on the repair nameplate. The applicable juris-diction shall be consulted for any unique requirements it may have established.

RE-1022 INITIAL ADJUSTMENTS TO PRESSURE RELIEF VALVES

The initial installation testing and adjustments of a new pressure relief valve on a boiler or pressure vessel are not considered a repair if made by the manufacturer or assembler of the valve.

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RE-1050 REPLACEMENT PARTS

All critical parts shall be fabricated by the valve manufacturer or to his specifications. Critical parts are those that may affect the valve flow passage, capacity, function or pres-sure-retaining integrity.

All critical parts not fabricated by the valve manufacturer shall be received with mate-rial test certification for the material used to fabricate the part.

Parts fabricated by the valve manufacturer do not require material test certification if they have the manufacturer’s identification on the part or are accompanied by the manufactur-er’s identification label or tag.

Material for bolting shall meet the manufac-turer’s specification, but does not require ma-terial test certification if marked as required by the material specification.

RE-1060 NAMEPLATES

Proper marking and identification of tested or repaired valves is critical to ensuring a valves acceptance during subsequent inspections, and also provide for traceability and identifi-cation of any changes made to the valve. All operations which require the valve’s seals to be replaced shall be identified by a nameplate as described in RE-1061 or RE-1063.

RE-1061 REPAIR NAMEPLATE

When a pressure relief valve is repaired, a metal repair nameplate stamped with the information required by RE-106 shall be se-curely attached to the valve. If not mounted directly on the valve, the nameplate shall be securely attached so as not to interfere with valve operation and sealed in accordance with RA-2255(k).

RE-1023 JURISDICTIONAL AUTHORIZATION TO ADJUST PRESSURE RELIEF

VALVES

The jurisdiction may authorize properly trained and qualified employees of boiler or pressure vessel owners-users or their desig-nees to restore required set pressure and/or performance of pressure relief valves. All external adjustments shall be resealed with a seal identifying the responsible organization and a metal tag that identifies the organiza-tion and the date of the adjustment shall be installed (See RE-1063 for marking require-ments and Appendix J).

RE-1024 DEFINITIONS

Unless otherwise specified in these rules and procedures, the definitions relating to pressure relief devices in Section 2 of ANSI/ ASME PTC-25-2001 shall apply.

RE-1030 ACCREDITATION

Organizations performing repairs shall be accredited as described in Part RA-2200, as appropriate for the scope of work to be per-formed.

RE-1040 MATERIALS

The materials used in making repairs shall conform to the requirements of the original code of construction. The “VR” Certificate Holder is responsible for verifying identifica-tion of existing materials from original data, drawings, or unit records and identification of the materials to be installed. A04


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As a minimum, the information on the valve repair nameplate (see Appendix 2, Figure 2-1000-e) shall include:

a. The name of the repair organization pre-ceded by the words “repaired by”;

b. The “VR” repair symbol stamp and the “VR” Certificate Number;

c. Unique identifier (e.g., repair serial num-ber, shop order number, etc.);

d. Date of repair;

e. Set pressure;

f. Capacity and capacity units (if changed from original nameplate due to set pres-sure or service fluid change); and

g. Type/model number (if changed from original nameplate by a conversion, see RE-1020).

h. When an adjustment is made to correct for service conditions of superimposed back pressure and/or temperature or the differential between popping pressure between steam and air (See RE-2200), the information on the valve repair nameplate shall include the:

1. Cold Differential Test Pressure (CDTP), and

2. Superimposed Back Pressure (BP) (only when applicable)

RE-1062 CHANGES TO ORIGINAL PRESSURE RELIEF VALVE NAMEPLATE INFORMATION

If the set pressure is changed, the set pressure, capacity and blowdown, if applicable, on the original nameplate or stamping shall be

marked out but left legible. The new capacity shall be based on that for which the valve was originally certified.

If the service fluid is changed, the capacity, including units, on the original nameplate or stamping shall be marked out but left legible. The new capacity shall be based on that for which the valve was originally certified, or if a conversion has been made, as described in RE-1020 on the capacity certification for the valve as converted.

If the type/model number is changed, the type/model number on the original name-plate shall be marked out but left legible.

If the blowdown is changed, the blowdown on the original nameplate or stamping shall be marked out but left legible. The new blow-down may be based on the current ASME Code requirements.

RE-1063 TEST ONLY NAMEPLATE

Where a valve has been tested and adjusted as permitted by RE-1023 but not otherwise repaired, a “Test Only” nameplate shall be applied which contains the following infor-mation:

a. Name of responsible organization,

b. Date of test,

c. Set Pressure,

d. An identification such as “Test Only.”

A “test only” nameplate is also recommended when periodic testing has been performed, even when no adjustments have been made, for the purpose of identifying the date the valve was tested.

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RE-1064 ILLEGIBLE OR REPLACEMENT OF MISSING

NAMEPLATES

Illegible NameplatesWhen the information on the original manu-facturer’s or assembler’s nameplate or stamp-ing is illegible, the nameplate or stamping will be augmented or replaced by a nameplate furnished by the “VR” stamp holder stamped “duplicate”. It shall contain all information that originally appeared on the nameplate or valve, as required by the applicable section of the ASME Code, except the “V”, “HV” or “UV” symbol and the National Board mark. The repair organization’s nameplate, with the “VR” stamp and other required data specified in RE-1061, will make the repairer respon-sible to the owner and the jurisdiction that the information on the duplicate nameplate is correct.

Missing NameplatesWhen the original valve nameplate is missing, the repair organization is not authorized to perform repairs to the valve under the “VR” program, unless positive identification can be made to that specific valve and verification that the valve was originally stamped with an ASME “V” or “UV” symbol or marked with an ASME “HV” symbol. Valves that can be positively identified will be equipped with a duplicate nameplate, as described in RE-1064, in addition to the repairer’s “VR” stamped nameplate. The repairer’s responsibilities for accurate data, as defined in RE-1064 (Illegible Nameplates), shall apply.

Marking of Original Code StampWhen a duplicate nameplate is affixed to a valve, as required by RE-1064, it shall be marked “Sec. I”, “Sec. IV” or “Sec. VIII”, as applicable, to indicate the original ASME Code stamping.

RE-1070 FIELD REPAIR

Repair organizations may obtain a “VR” Cer-tificate of Authorization for field repair, either as an extension to their in-shop/plant scope or as a field-only scope, provided that:

a. Qualified technicians in the employ of the certificate holder perform such repairs;

b. An acceptable quality system covering field repairs, including field audits, is maintained;

c. All functions affecting the quality of the repaired valves are supervised from the address of record where the “VR” certifi-cation is issued.

RE-1071 AUDIT REQUIREMENTS

Upon issuance of a certificate of authorization, provided field repairs are performed, annual audits of the work carried out in the field shall be performed to ensure that the requirements of the certificate holder’s quality system are met. The audit shall include, but not be limited to, performance testing, in accordance with RE-2000, of valve(s) that were repaired in the field. The audits shall be documented.

RE-1072 USE OF OWNER-USER PERSONNEL

For the repair of pressure relief valves at an owner-user’s facility for the owner-user’s own use, the “VR” Certificate Holder may utilize owner-user personnel to assist certifi-cate holder technician(s) in the performance of repairs provided:

a. The use of such personnel is addressed in the “VR” Certificate Holder’s quality system;


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b. The owner-user personnel are trained and qualified in accordance with RE-3000;

c. Owner-user personnel work under di-rect supervision and control of the “VR” Certificate Holder’s technician(s) during any stage of the repair when they are uti-lized;

d. The “VR” Certificate Holder shall have the authority to assign and remove owner-user personnel at its own discretion;

e. The names of the owner-user personnel utilized are recorded on the document required by RA-2255(i).

RE-1100 WELDING FOR PRESSURE RELIEF VALVES

Welding shall be performed in accordance with the requirements of the original code of construction used for the pressure relief valve.

Cast iron and carbon or alloy steel having a carbon content of more than 0.35%, shall not be welded.

Defects in pressure relief valve parts such as cracks, pits or corrosion that will be repaired by welding shall be completely removed be-fore the weld repair of the part is performed. Removal of the defect shall be verified by suitable NDE as required.

Consideration shall be given to the condition of the existing material, especially in the weld preparation area.

RE-1110 WELDING PROCEDURE SPECIFICATIONS

Welding shall be performed in accordance with Welding Procedure Specifications (WPS)

qualified in accordance with the original code of construction. When this is not possible or practicable, the WPS may be qualified in ac-cordance with Section IX of the ASME Code.

RE-1120 STANDARD WELDING PROCEDURE SPECIFICATIONS

A “VR” Certificate Holder may use one or more applicable Standard Welding Procedure Specifications shown in Appendix A.

RE-1130 PERFORMANCE QUALIFICATION

Welders or welding operators shall be quali-fied for the welding processes that are used. Such qualification shall be in accordance with the requirements of the original code of con-struction or Section IX of the ASME Code.

RE-1140 WELDING RECORDS

The “VR” Certificate Holder shall maintain a record of the results obtained in welding procedure qualifications, except for those qualifications for which the provisions of RE-1120 are used, and of the results obtained in welding performance qualifications. These records shall be certified by the “VR” Cer-tificate Holder and shall be available to the National Board.

RE-1150 WELDERS’ IDENTIFICATION

The “VR” Certificate Holder shall establish a system for the assignment of a unique identifi-cation mark to each welder/welding operator qualified in accordance with the requirements of the NBIC. The “VR” Certificate Holder shall also establish a written procedure whereby all welded joints can be identified as to the

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welder or welding operator who made them. This procedure shall use one or more of the following methods and shall be described in the quality control system written description. The welder’s or welding operator’s identi-fication mark may be stamped (low stress stamp) adjacent to all welded joints made by the individual or, in lieu of stamping, the “VR” Certificate Holder may keep a record of welded joints and the welders or welding operators used in making the joints.

RE-1160 WELDERS’ CONTINUITY

The performance qualification of a welder or welding operator shall be affected when one of the following conditions occur:

a. When the welder or welding operator has not welded using a specific process during a period of six (6) months or more, their qualifications for that process shall expire.

b. When there is specific reason to question their ability to make welds that meet the specification, the qualification which sup-ports the welding that is being performed shall be revoked. All other qualifications not questioned remain in effect.

RE-1200 HEAT TREATMENT

RE-1210 PREHEATING

Preheating may be employed during welding to assist in completion of the welded joint (Ap-pendix B). The need for and the temperature of preheat are dependent on a number of factors, such as chemical analysis, degree of restraint of the items being joined, material thickness, and mechanical properties. The welding procedure specification for the ma-terial being welded shall specify the preheat temperature requirements.

RE-1220 POSTWELD HEAT TREATMENT

Postweld heat treatment shall be performed as required by the original code of construc-tion in accordance with a written procedure. The procedure shall contain the parameters for postweld heat treatment.

RE-2000 PERFORMANCE TESTING AND TESTING EQUIPMENT

Each pressure relief valve to which the “VR” repair symbol stamp is to be applied shall be subjected to the following tests by the repair certificate holder.

RE-2010 TEST MEDIUM AND TESTING EQUIPMENT

Valves marked for steam service, or having special internal parts for steam service, shall be tested on steam. Valves marked for air, gas or vapor service shall be tested with air or gas. Valves marked for liquid service shall be tested with water or other suitable liquid. Section IV hot water valves shall be tested on water, steam or air.

a. Each valve shall be tested to demonstrate the following:

1. Set pressure (as defined by the valve manufacturer and as listed in NB-18);

2. Response to blowdown, when re-quired by the original Code of Con-struction;

3. Seat tightness;

4. For valve designed to discharge to a closed system, the tightness of the sec-ondary pressure zone shall be tested as required by the original Code of Construction.


133

b. The equipment used for the performance testing prescribed by RE-2010 shall meet the following requirements:

1. The performance testing equipment shall include a pressure vessel of ad-equate volume and pressure source capacity to ensure compliance with RE-2010(a)(1).

2. Prior to use, all performance testing equipment shall be qualified by the certificate holder to ensure that the equipment and testing procedures will provide accurate results when used within the ranges established for that equipment. This qualification may be accomplished by bench mark testing, comparisons to equipment used for verification testing (RA-2225) or comparisons to field performance. This qualification shall be docu-mented and provisions made to retain such documentation for a period of at least five years after the testing equip-ment is retired. Documentation of this qualification shall include but not be limited to:

a. Schematic of the performance test equipment;

b. Size and pressure ranges of valves to be tested;

c. Dimensions of test vessels;

d. Accuracy of pressure measuring equipment;

e. Size and design type of valves used to control flow; and

f. Method of qualifying.

3. Prior to the implementation of any addition or modification to the test-ing equipment which would alter the

contents of the document required in RE-2010(b)(2), the certificate holder shall requalify the performance test equipment in accordance with RE-2010(b)(2). If the equipment changed was used to satisfy the requirements of verification testing, the certificate holder shall notify the National Board and additional verification testing, in accordance with RA-2225, may be required.

RE-2020 OWNER-USER SECTION VIII STEAM TESTING

When ASME Section VIII valves are repaired by the owner for the owner’s own use, valves for steam service may be tested on air for set pressure and, if possible, blowdown adjust-ment provided manufacturer’s corrections for differential in set pressure between steam and air are applied to the set pressure.

RE-2030 LIFT ASSIST TESTING

A device may be used to apply an auxiliary lifting load on the spring of a repaired valve to establish the set pressure in lieu of the tests required in RE-2010(a)(1) when such testing at full pressure:

a. may cause damage to the valve being tested; or

b. is impractical when system design con-siderations preclude testing at full pres-sure.

While actual valve blowdown and valve per-formance characteristics cannot be verified, valve set pressure may be determined to an ac-ceptable degree of accuracy using this testing technique provided, as a minimum, that:

a. Equipment utilized is calibrated as re-quired in RA-2255(m);

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b. The device and test procedures which have proved to give accurate results are used and followed;

c. A static inlet pressure is applied with the test medium specified in RE-2010;

d. Adjustments are made in accordance with the valve manufacturer’s recom-mendations as to ensure proper lift and blowdown.

RE-3000 TRAINING AND QUALIFICATION OF PERSONNEL

RE-3010 GENERAL

It is essential that valve repair organizations ensure that their personnel engaged in repairs to pressure relief valves are knowledgeable and qualified within the scope of the repairs to be conducted.

The National Board offers coordinated train-ing courses for valve repair organization per-sonnel to further their skills and knowledge in the repair of pressure relief valves. Many relief valve manufacturers also sponsor training courses on the repair and maintenance of their respective valve types and series. Pressure re-lief valve repair organizations are encouraged to have their personnel participate in these courses. It is also recommended that valve repair organizations cooperate and establish working relationships with valve manufac-turers to help ensure the proper repair of the manufacturer’s specific valves.

RE-3020 CONTENTS OF TRAINING PROGRAM

The repair organization shall establish a documented in-house training program. This program shall establish training objectives

and provide a method of evaluating training effectiveness. As a minimum, training objec-tives for knowledge level shall include:

a. Applicable ASME Code and NBIC re-quirements;

b. Responsibilities within the organization’s quality system; and

c. Knowledge of the technical aspects and mechanical skills for the applicable posi-tion held.

RE-3030 QUALIFICATION OF PERSONNEL

Each repair organization shall establish minimum qualification requirements for those positions within the organization as they directly relate to pressure relief valve repair. Each repair organization shall document the evaluation and acceptance of an individual’s qualification for the applicable position.

RE-3040 ANNUAL REVIEW OF QUALIFICATION

The repair organization shall annually review the qualifications of repair personnel to verify proficiency as well as compliance with the cer-tificate holder’s quality system. This review shall include training records, documented evidence of work performed and, when neces-sary, monitoring job performance. The review shall be documented.

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Preparation of Technical Inquiries to the National Board Inspection Code Committee

Appendix 1

136


APPENDIX 1 — PREPARATION OF TECHNICAL INQUIRIES TO THENATIONAL BOARD INSPECTION CODE COMMITTEE

1-1000 INTRODUCTION

The NBIC Committee meets regularly to consider written requests for interpretations and revisions to the Code rules and to de-velop new rules, as dictated by technological development. The Committee’s activities in this regard are limited strictly to interpreta-tions of the rules or to the consideration of revisions to the present rules on the basis of new data or technology. As a matter of published policy, the National Board does not approve, certify or endorse any item, construction, proprietary device or activity and, accordingly, inquiries requiring such consideration will be returned. Moreover, the National Board does not act as a consultant on specific engineering problems or on the general application or understanding of the Code rules. If, based on the inqui-ry information submitted, it is the opin-ion of the Committee that the inquirer should seek assistance, the inquiry will be returned with the recommendation that such assistance be obtained.

All inquiries that do not provide the information needed for the Committee’s full understanding will be returned.

1-2000 INQUIRY FORMAT

Inquiries shall be limited strictly to interpre-tations of the rules or to the consideration of revision to the present rules on the basis of new data or technology. Inquiries shall be submitted in the following format:

a. Scope Involve a single rule or closely relat-

ed rules. An inquiry letter concerning unrelated subjects will be returned.

b. Background State the purpose of the inquiry, which

would be either to obtain an interpre-ta-tion of Code rules or to propose consid-eration of a revision to the present rules. Provide concisely the information needed for the Committee’s understanding of the inquiry, being sure to include reference to the applicable Code Edition, Addenda, paragraphs and figures. If sketches are provided, they shall be limited to the scope of the inquiry.

c. Inquiry Structure Prepare statements in a condensed

and precise question format, omitting superfluous background information, and, where appropriate, composed in such a way that “yes” or “no” (perhaps with provisos) would be an acceptable reply. This inquiry statement should be technically and editorially correct.

d. Proposed Reply State what it is believed the Code

requires. If, in the inquirer’s opinion, a revis ion to the Code is needed, recommended wording shall be pro-vided.

1-3000 SUBMITTAL

Inquiries shall preferably be submitted in typewritten form; however, legible hand-written inquiries will also be considered. They shall include the name, email address and mailing address of the inquirer and be mailed to the following address:

Secretary, NBIC Committee 1055 Crupper Avenue Columbus, OH 43229

614.847.1828 — Fax 614.888.8320 ext. 240 — Phone

[email protected] — Email

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Stamping and Nameplate Information

Appendix 2

138


APPENDIX 2 — STAMPING AND NAMEPLATE INFORMATION

2-1000 SCOPE

When a pressure-retaining item is repaired or altered, the Certifi cate Holder shall attach a nameplate or stamp the item, except when otherwise permitted by these rules. Similarly, when pressure relief devices are repaired, the attachment of a nameplate is required. The specifi c requirements for nameplates/stamp-ing are described in this Appendix. See Fig-ures 2-1000-a thru 2-1000-g.

2-2000 GENERAL REQUIREMENTS FOR STAMPING AND NAMEPLATES

Required data shall be in characters at least 5/32 in. (4 mm) high, except that characters for pressure relief valve repair nameplates may be smaller. Markings may be produced by cast-ing, etching, embossing, debossing, stamp-ing or engraving. The selected method shall not result in any harmful contamination of or sharp discontinuities to the pressure retaining item.

The National Board code symbols (“R”, “VR”, and “NR”) are to be stamped; do not emboss.

S tamping d i rec t ly on i t ems , when used, shall be done with blunt-nose continu-ous or blunt-nose interrupted dot die stamps. If direct stamping would be detrimental to the item, required markings may appear on a nameplate affi xed to the item.

The Certifi cate Holder shall use its full name as shown on the Certifi cate of Authorization or an abbreviation acceptable to the National Board.

Stamping or nameplate shall be applied ad-jacent to the original manufacturer’s stamp-

ing or nameplate. A single repair nameplate or stamping may be used for more than one repair to a pressure retaining item provided it is carried out by the same Certifi cate Holder. The date of each repair, corresponding with the date on the associated Form R-1, shall be stamped on the nameplate.

The letters “RP” shall be stamped below the “R” symbol stamp to indicate organizations accredited for performing repairs or altera-tions to Fiber Reinforced Plastic items.

The letter “G” shall be stamped below the “R” symbol stamp to indicate organizations accredited for performing repairs or altera-tions to Graphite Pressure vessels.

2-2100 ADDITIONAL STAMPING REQUIREMENTS FOR

REPAIRS

Stamping or nameplate shall be applied ad-jacent to the original manufacturer’s stamp-ing or nameplate. A single repair nameplate or stamping may be used for more than one repair to a pressure retaining item provided it is carried out by the same Certifi cate Holder. The date of each repair, corresponding with the date on the associated Form R-1, shall be stamped on the namepate.


ALTERATIONS AND RE-RATINGS

Stamping or nameplate shall be applied adja-cent to the original manufacturer’s stamping or nameplate.

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APPENDIX 2 — STAMPING AND NAMEPLATE INFORMATION

2-2300 ADDITIONAL STAMPING REQUIREMENTS FOR PARTS

Stamping or nameplate shall be applied in a conspicuous location on the part.


PRESSURE RELIEF VALVES

Pressure relief valve repair stamping or name-plate shall be applied adjacent to the original manufacturer’s stamping or nameplate.

Note(2): To be indicated only when changed.

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Figure 2-1000-b — Required Markings for Altera-tions, with use of National Board Form R-2

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Figure 2-1000-c — Required Markings for Re-rat-ings, with use of National Board Form R-2

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Figure 2-1000-d — Required Markings for PartsFabricated by Welding, with use of National Board Form R-3

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Figure 2-1000-e — Required Markings for Repair of ASME/National Board “V”, “UV”, and “HV” Stamped Pressure Relief Valves

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Figure 2-1000-f — Required Markings for Nuclear Repairs or Replacements

Figure 2-1000-g — Required Markings for Repair or Replacement of Nuclear Pressure Relief Valves

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Steam Locomotive Firetube Boiler Inspection, Repair and Storage

Appendix 3

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FIGURE 3-1010-FIGURE 3-1010-aa — — Locomotive Boiler General ArrangementLocomotive Boiler General Arrangement

CombustionChamber

SideSheet

RoofSheet

Throat Sheet

Inside Throat Sheet

Dome Course

Crown SheetCrown Sheet

FIGURE 3-1010-b — Arrangement of Firebox Sheets (Staybolts Deleted for Clarity)

APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILERINSPECTION, REPAIR, AND STORAGEA04

3-1000 GENERAL REQUIREMENTS

3-1010 SCOPE

This appendix is provided as a guide for in-spection, repairs and alterations and storage

of steam locomotive fi retube boilers. These rules for the repair and alteration of steam locomotive boilers shall be used in conjunc-tion with the applicable rules of this code. See general fi gures 3-1010-a and 3-1010-b.

A04

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APPENDIX 3 — STEAM LOCOMOTIVE FIRETUBE BOILER INSPECTION AND REPAIR

3-1100 SPECIAL JURISDICTIONAL REQUIREMENTS

Many jurisdictions have special requirements for locomotive boilers. Such requirements shall be considered in addition to those in this appendix.

3-1200 FEDERAL RAILROAD ADMINISTRATION (FRA)

The FRA rules for steam locomotive boil-ers are published in the Code of Federal Regulations (CFR) 49CFR Part 230 Dated November 17,1999.8 All locomotives under FRA jurisdiction are documented on FRA Form 4 as defined in 49CFR Part 230. This document is the formal documentation of the steam locomotive boiler and is required to be completed prior to the boiler being placed in service. This document shall be used as the Data Report for the boiler, applicable to all repairs and alterations performed. National Board “R” Certificate Holders shall document their repairs and/or alterations on National Board Forms R-1 or R-2. These reports shall be distributed to the owner/user of the boiler who is required to incorporate them into a FRA Form 19 which becomes an attachment to the FRA Form 4. The design margin for all such repairs or alterations shall not be less than 4 based on ultimate tensile strength of the material.

3-1300 REQUIREMENTS FOR WELDING ACTIVITIES

Before performing any welding activities, consideration shall be given to ensure the weldability of locomotive boiler materials.

Special jurisdictional approval may be re-quired prior to starting welding activity on locomotive boilers.

3-1400 FORMULA AND CALCULATIONS FOR STEAM

LOCOMOTIVE BOILERS

Most steam locomotive boilers were manu-factured in the first half of the 20th century or before. The calculations, formula and shop practices used are now distant history and quite difficult to obtain. The rules for riveted construction were last published by ASME in Section I Code, 1971 Edition. Appendix C, herein, provides a copy of the 1971 riveting rules from Parts PR and PFT.

Appendix 3, herein, is based in part on the ASME Code, Section III, 1952 Edition9 which was the last published edition of the Steam Locomotive Code. The railroad industry has attempted to collect the old formula and some shop practices. These have been published by The Engineering Standards Committee for Steam Locomotives, Inc. (ESC) as Compendi-um, Volume 1, Compilation of Calculations.10

3-2000 LOCOMOTIVE FIRETUBE BOILER INSPECTION

3-2010 INSPECTION METHODS

Plate thickness and depth of corrosion may be determined by use of the ultrasonic thickness testing process.

Where access is possible, the depth of pitting may be determined by use of a depth microm-eter or a pit gage.

On stayed sections, the plate thickness read-ings should be taken on a grid not exceeding the maximum staybolt pitch at the center of each section of four staybolts. Additional

9 This Code is available from the National Board10 Copies of The Engineering Standards Committee for

Steam Locomotives, Inc., Compendium, Volume 1, Compilation of Calculations may be obtained from the Strasburg Rail Road, P.O. Box 96, Strasburg, PA 17579, phone 717.687.8421.

8 Steam locomotive inspection and maintenance stan-dards, which is now codified at 49CFR Part 230 may be obtained at the FRA Web site. The final rule at www.fra.dot.gov/downloads/counsel/fr/slfr.pdf

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readings may be taken close to each staybolt to determine if localized thinning has occurred. Particular attention should be given to the joint between the staybolt and the plate.

On unstayed sections, the plate thickness read-ings should be taken on a grid not exceeding 12 inch (300 mm) centers. Additional readings should be taken if conditions warrant.

Cracks in plates may be located by the use of appropriate Nondestructive Examination (NDE) methods.

Separation of plates at riveted seams may be detected by use of a feeler gage and magnify-ing glass or other applicable method.

Varying the intensity of inspection lights may facilitate discovery of defects. Placement of the light to shine parallel to the surface is one method of detecting pits and surface ir-regularities.

When inspecting internal stayed surfaces, placement of a light source within the stayed zone will aid the inspection.

Broken staybolts may be detected by leakage through telltale holes and by hammer testing. Both methods are most effective when the boiler is under hydrostatic pressure of at least 95% MAWP. If a hydrostatic test can not be applied, the hammer test may be performed alone with the boiler drained.

Visual inspection shall be performed as a supplement to all of the above.

3-2020 INSPECTION ZONES

Riveted Seams and Rivet HeadsRiveted seams and rivet heads shall be in-spected for:

• Grooving• Corrosion• Cracks• Pitting

• Leakage • Separation of the plates • Excessive or deep caulking of the plate

edges and rivet head• Seal welding of the plate edges and rivet

heads • Rivet heads that have been built up by or

covered over completely by welding • Rivets replaced by patch bolts • Defective components of the seam

Notes: 1. Broken rivet heads or cracked plates may

result from sodium hydroxide cracking (caustic embitterment).

2. Riveted longitudinal lap seams should be given careful examination, using NDE if necessary, because this type of construc-tion is prone to cracking.

3. When determining the extent of corrosion to rivet heads, it is important to know the rivet size and the type of rivet head used for the original construction. Corrosion can alter the appearance of these items and disguise the full extent of the dam-age.

4. Fire cracks extending to the rivet holes in riveted lap seams of firebox sheets may be acceptable under NBIC RB-4480.

Welded & Riveted RepairsWelded and riveted repairs shall be inspected for:

• Correct application of welded patches or weld application

• Correct application of riveting • Cracks • Separation of the plates • Dents or other mechanical damage • Leakage

Boiler Shell CourseThe boiler shell course shall be inspected for:

• Grooving or cuts• Corrosion• Cracks• Pitting

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• Separation of the plates • Dents or other mechanical damage • Leakage

Note: 1. An accurate inspection often cannot be

performed until the interior has been cleaned since mud and scale make it dif-ficult to detect defects.

Dome & Dome LidThe dome and dome lid shall be inspected for:

• Grooving • Corrosion, especially at the interior section

attached to the boiler course • Cracks • Pitting • Separation of plates • Dents or other mechanical damage • Leakage • Stretched, bent or corroded dome studs • Damage to the steam dome cover sealing

surfaces

Notes: 1. Close inspection should be made to the

interior section at the joint attached to the boiler course.

2. If the dome studs are bent, a careful evalu-ation should be made of the lid for leakage and mechanical damage.

Mud RingThe mud ring and mud ring rivets shall be inspected for:

• Mud and scale on the waterside • Debris on the waterside • Corrosion • Grooving • Cracks• Separation of the firebox plates from the

mudring • Dents or other mechanical damage • Leakage

Flue SheetsFlue sheets shall be inspected for:

• Grooving around flue holes, rivet seams and braces

• Pitting• Fireside and waterside corrosion • Fire cracks at riveted lap seams • Cracks • Bulges • Leakage • Excessive or deep caulking of the plate

edges

Note: 1. Corrosion is common at the bottom section

of the front flue sheet. Close inspection of the joint between the front flue sheet and shell shall be made.

Flanged SheetsThe flanged section of all flanged sheets shall be inspected for:

• Pitting • Corrosion • Cracks • Grooving• Scale and mud deposits • Correct fit up and alignment of the flanged

sheet to the adjacent sheets

Notes: 1. Corrosion is common at the bottom sec-

tion of the front flue sheet. 2. The flanges should have a smooth uniform

curvature and should make a smooth transition to the flat sheets.

Stayed SheetsStayed sheet shall be examined for:

• Scale and mud deposits • Grooving around staybolt holes • Deterioration of the joint between the

staybolt and the sheet • Grooving on the waterside section • Pitting • Fireside and waterside corrosion

146


• Overheating • Fire cracks at riveted lap seams • Cracks • Bulges

Notes: 1. Close inspection for fireside corrosion

should be given to sections located behind refractory or grate bars.

2. Close inspection should be made for grooving on waterside surfaces of the stayed sheets just above the mudring.

3. Fire cracks extending to the rivet holes in riveted lap seam firebox sheets may be acceptable under RB-4480.

StayboltsStaybolts shall be inspected for:

• Cracks in or breakage of the body • Erosion of the driven head from corrosion

or combustion gases • Staybolt head flush with or below the

surface of the sheet • Plugging of telltale holes except as permit-

ted by 49 CFR Part 230.41 • Waterside corrosion • Staybolt heads that have been covered

over by welding • Correct application of seal welding to

staybolt heads

Notes: 1. An indicator of waterside corrosion on

threaded staybolts is the lack of threads on the section of the staybolt body just above the sheet.

2. Broken staybolts may be detected by leak-age through telltale holes and by hammer testing. Both methods are most effective when the boiler is under hydrostatic pres-sure of at least 95% MAWP. If a hydrostatic test can not be applied, the hammer test may be performed alone with the boiler drained.

3. When a broken stay is found, the stays adjacent to it should be examined closely

because these may have become over-stressed by addition of the load from the broken stay.

4. A telltale hole plugged by installation of a nail or pin may indicate the staybolt is broken and requires replacement.

5. The plugging of telltale holes by refractory to prevent build up of foreign matter in the telltale hole is permitted for locomo-tives operating under FRA jurisdiction per 49 CFR Section 230.41.

6. One indication that a threaded staybolt leaks during service is when the head of it is found to have been re-driven repeat-edly.

Flexible Staybolts & SleevesFlexible staybolt sleeves and caps shall be inspected for:

• Corrosion • Cracks • Dents or other mechanical damage• Leakage • Damaged threads or welds • Scale and mud accumulations inside the

sleeve that could restrict bolt movement• Correct application of welding to welded

sleeves and welded caps • Seal welding of threaded sleeves or

threaded caps


threaded staybolts is the lack of threads on the section of the staybolt body just above the sheet.

2. Broken staybolts may be detected by leak-age through telltale holes and by hammer testing. Both methods are most effective when the boiler is under hydrostatic pres-sure of at least 95% MAWP. If a hydrostatic test can not be applied, the hammer test may be performed alone with the boiler drained.

3. On ball head flexible staybolts, one method of testing the stay for cracks or

147


breakage is to strike the ball head using a pneumatic hammer or hand hammer. Another method is to twist the ball head using a long handle wrench. Access to the ball head is gained by removing the cap from the sleeve.

4. When a broken stay is found, the stays adjacent to it should be examined closely because these may have become over-stressed by addition of the load from the broken stay.

5. A telltale hole plugged by installation of a nail or pin may indicate the staybolt is broken and requires replacement.

6. The plugging of telltale holes by refractory to prevent build up of foreign matter in the telltale hole is permitted for locomo-tives operating under FRA jurisdiction per 49 CFR Section 230.41.

7. One indication that a threaded staybolt leaks during service is when the head of it is found to have been re-driven repeat-edly.

Girder Stay & Crown BarsGirder stays, crown bars and their associated fasteners including stays, rivets, pins, wash-ers, nuts, thimbles, spacers and the adjacent sections of the firebox plates shall be inspected for:

• Corrosion • Cracks • Mud and scale • Correct fit and alignment of the girder stay

or crown bar to the firebox plate surface, including flanged sections

• Correct fit and alignment of the thimbles, spacers and pins to the girder stay or crown bar and the firebox plates

• Dents or other mechanical damage • Stays or rivets built up by or covered over

completely by welding• Leakage from the stay heads • Seal welding of rivet heads

• Correct application of retainers to all nuts and fasteners

• Missing fasteners, nuts or retainers

Notes: 1. An accurate inspection often cannot be

performed until the girder stay or crown bar has been cleaned since mud and scale will make it difficult to detect defects.

2. When a broken stay is found, the stays adjacent to it should be examined closely because these may have become over-stressed by addition of the load from the broken stay.

Sling StaysSling stays and their associated fasteners including the pins, retainers, washers, nuts and their associated attachment at eyes, girder stays or crown stays shall be inspected for:

• Corrosion • Cracks • Dents, wear or other mechanical dam-

age • Mud and scale • Wear to the pin hole or expansion slot of

the sling stay and mating component• Correct application of retainers to the

pins • Missing fasteners, nuts or retainers • Any of the above that would restrict

movement of the sling stays

Notes: 1. An accurate inspection often cannot be

performed until the sling stay has been cleaned since mud and scale will make it difficult to detect defects.

2. When a broken or loose stay is found, the stays adjacent to it should be examined closely because these may have become overstressed by addition of the load from defective stay.

3. Special attention should be given to the row of sling stays adjacent to the flue sheet to ensure that these stays are not loose.

148


Crown Stays & Expansion StaysCrown stays and expansion stays shall be inspected for:

• Cracks in or breakage of the body • Dents, wear or other mechanical dam-

age• Erosion of the driven head from corrosion

or combustion gases • Stay head flush with or below the surface

of the sheet • Plugging of telltale holes, except as per-

mitted by 49 CFR Part 230.41 • Waterside corrosion • Stay heads that have been covered over

by welding • Correct application of seal welding to stay

heads • Correct application of retainers to the

pins • Missing fasteners, nuts or retainers • Correct fit and alignment of the stay as-

sembly • Any of the above that would restrict

movement of the stay


threaded stays is the lack of threads on the section of the stay body just above the sheet.

2. Broken stays may be detected by leakage through telltale holes and by hammer testing. Both methods are most effective when the boiler is under hydrostatic pres-sure of at least 95% MAWP. If a hydrostatic test can not be applied, the hammer test may be performed alone with the boiler drained.

3. When a broken stay is found, the stays adjacent to it should be examined closely because these may have become over-stressed by addition of the load from broken stay.

4. A telltale hole plugged by installation of a nail or pin may indicate the stay is broken and requires replacement.

5. The plugging of telltale holes by refractory to prevent build up of foreign matter in the telltale hole is permitted for locomotives operating under FRA jurisdiction per 49 CFR Part 230.41.

6. One indication that a threaded stay leaks during service is when the head of it is found to have been re-driven repeatedly.

7. Special attention should be given to the row of stays adjacent to the flue sheet to ensure that these stays are not loose.

Diagonal & Gusset BracesDiagonal and gusset braces, and their attach-ments, shall be inspected for:

• Looseness • Corrosion • Cracks • Welded repairs • Missing pins or pin retainers • Defective rivets • Scale and mud deposits

Notes: 1. Diagonal and gusset braces should be

under tension. 2. The brace pins should fit the brace clevis

and eye securely and be retained from coming out by some type of fixed or keyed retainer.

3. Diagonal braces having loop-type ends should be given close inspection for cracks and corrosion. The loop-type end is formed by the brace body being split, looped around and forged to the body. Some versions of it have a low mar-gin of material to provide the required strength.

FluesAll boiler and superheater flues shall be in-spected for:

• Fire cracks • Pitting • Corrosion • Erosion

149


• Obstructions in the flue interior • Mud or scale buildup on the waterside • Erosion or cracking of the flue ends, flue

beads and/or seal welds • Leakage • Number of circumferential welded joints

on flues repaired by re-ending • Correct application including expand-

ing/rolling and belling, beading or seal welding of the flue end

Notes: 1. Erosion (cinder cutting) generally occurs

to the firebox end of the flue. 2. Galvanic corrosion of the flue in the flue

sheet may occur if flues are installed with copper ferrules.

Superheater Units & HeaderSuperheater units and the superheater header shall be inspected for:

• Pitting• Cracks • Erosion • Corrosion • Bulges • Leakage • Missing shields • Missing or broken bands or supports on

the superheater units • Missing, damaged or welded attachment

bolts, nuts, clamps, studs and washers • Adequate structural bracing and support

of the superheater header

Arch Tubes, Water Bar Tubes & CirculatorsArch tubes, water bar tubes and circulators shall be inspected for:

• Erosion • Corrosion • Fire cracks • Pitting • Cracking of tube ends • Overheating and blistering • Bulges

• Mud and scale buildup in the waterside • Welded repairs • Correct application including expand-

ing/rolling and belling, beading or seal welding of the tube end

Note: 1. Weld build up or welded patches are not

permitted on arch tubes and water bar tubes of locomotives operating under FRA jurisdiction per 49 CFR Section 230.61. The defective tubes must be replaced.

Thermic SyphonsThermic syphons shall be inspected for: • Erosion • Corrosion • Fire cracks • Pitting • Cracking of the syphon neck • Overheating and blistering • Bulges• Mud and scale blockage in the wateside • Broken or damaged staybolts

Note: 1. Refer to sections Staybolts, Stayed Sheets

and Flanged Sheets for additional inspec-tion procedures.

Fire Box RefractoryFirebox refractory shall be inspected to en-sure it is properly applied and maintained to prevent undesired flame impingement on the firebox sheets.

Dry PipeThe dry pipe of boilers having dome mounted (internal) throttle valves shall be inspected for:

• Erosion • Corrosion • Cracks • Adequate structural bracing, support and

attachment to the boiler and dome • Loose, bent or damaged rivets, nuts, bolts

and studs

150


Note: 1. A steam leak into the dry pipe of a dome

mounted (internal) throttle valve will send an unregulated flow of steam to the cylinders.

Throttle & Throttle ValveThe throttle handle and its mechanism shall be inspected for:

• Proper operation • Lost motion or looseness • Adequate structural bracing, support

and attachment to the boiler, dome and firebox

• Loose, bent or damaged nuts, bolts and studs

Note: 1. The throttle handle shall be equipped

with some type of locking mechanism to prevent the throttle from being opened by the steam pressure.

Screw Type Washout Plugs, Holes & SleevesScrew type washout plugs, holes and sleeves, especially those having square or Acme thread, shall be inspected for:

• Damaged or cracked threads on the plug, hole or sleeve.

• Corrosion • Cracks • Distortion • Looseness • Leakage • Steam cuts to threads and sealing sur-

faces • Twisting of the plug head or body

Note: 1. When washout plugs are threaded with

USF or NPT thread, the minimum num-ber of threads in good condition in the threaded hole shall be adequate for the service.

Handhole Washout DoorsHandhole washout doors and their mating surfaces shall be inspected for:

• Damaged or cracked threads on the door studs

• Corrosion of door sealing surfaces and stud

• Cracks • Stretching or bending of the door stud or

handhole door • Looseness • Leakage and steam cuts • Damage to the clamp• Damage to the clamp seating surface on

the sheet • Confirmation that the handhole door

makes unbroken line contact along the entire circumference of the sheet at the opening

• Material of the handhole door gaskets • Correct repairs

Notes: 1. Confirmation that the handhole door has

unbroken line contact against sheet can be determined by performing a “blue check”. This requires applying a light coating of “contact blue” or “Prussian Blue” to the handhole door sealing surfaces. The door then is held against the sheet and removed. The transfer of the bluing will show the areas that contact the sheet sur-faces.

2. The material of the handhole door gaskets should be reviewed with the operator to confirm that it meets the pressure and temperature requirements of the boiler.

Threaded & Welded Attachment StudsThreaded and welded attachment studs shall be inspected for:

• Corrosion, especially at the sheet • Cracks • Damaged threads • Stretching or bending • Looseness • Leakage

151


Fusible PlugsFusible plugs shall be inspected for:

• Corrosion• Scale build up on the waterside • Damage • Tampering • Leakage from the threads • Height of the plug above waterside of

crown sheet • Evidence of melting or overheating • Proper marking

Water Glass, Water Column & Gage CocksThe water glass, water column and gage cock boiler connections and piping shall be inspected for:

• Mud and scale blockage • Kinks or sharp, restricted or flattened

bends in the piping • Sags in the piping horizontal runs • Condition of tubular or reflex water

glass • Correct type and material of piping and

fittings • Correct location, size and installation of

the connections to the sheets • Correct installation of the safety shield (if

used) • Correct installation of the viewing light (if

used) • Correct installation of the test and drain

valves• Proper installation• Proper bracing to prevent vibration • Loose, bent or damaged nuts, bolts and

studs

Steam Pressure GageThe steam pressure gauge, gauge cock boiler connections and piping shall be inspected for: • Kinks or sharp, restricted or flattened

bends in the piping • Correct installation of the shutoff valve

and syphon

• Proper size, type and material of piping and fittings

• Proper installation • Proper lighting for viewing • Proper bracing to prevent vibration • Calibration

Boiler Fittings & PipingThe boiler fittings and associated piping shall be inspected for:

• Cracks • Corrosion • Pitting • Leakage • Looseness • Loose, bent or damaged nuts, bolts and

studs • Adequate structural bracing, support, at-

tachment and provision for expansion • Proper size, type and material

Boiler Attachment BracketsThe boiler attachment brackets and associated components and fasteners used to secure the boiler to the frame shall be inspected for:

• Correct installation • Damaged or missing components • Looseness • Leakage • Loose, bent or damaged rivets, nuts, bolts

and studs • Defective rivets • Provision for expansion

Fire DoorThe fire door, the locking mechanism and the operating mechanism shall be inspected for:

• Safe and suitable operation • Cracked, damaged or burned parts • Loose, damaged or bent rivets, nuts, bolts

and studs

Note: 1. The locking mechanism should be in-

spected for correct operation to confirm

152


it will not allow the door to open in the event the firebox becomes pressurized.

Grates & Grate Operating MechanismThe grates shall be inspected for:

• Cracked, damaged, burned or missing segments.

The grate operating mechanism of rocking grates shall be checked for:

• Uniform operation of all segments • Corrosion • Worn or cracked linkage • Correct fit of the shaker bar on the link-

age• Missing pins or pin retainers • Loose, bent or damaged nuts, bolts and

studs

SmokeboxThe smokebox shall be inspected for:

• Erosion • Corrosion • Leakage • Holes • Looseness • Loose, bent or damaged nuts, bolts and

studs

Smokebox Steam PipesThe smokebox steam pipes shall be inspected for:

• Erosion • Corrosion• Pitting • Leakage • Looseness • Loose, bent or damaged nuts, bolts and

studs

Note: 1. Pitting from the casting process may be

evident on cast thick wall steam pipes but may not constitute a defect.

Ash Pan & Fire PanThe ash pan or fire pan shall be inspected for:

• Corrosion • Holes • Looseness • Loose or damaged rivets, nuts, bolt and

studs • Secure attachment to the frame or fire-

box • Proper operation of the slides, clean out

doors, dumping mechanism and damp-ers

• Proper sealing of the slides, clean out doors and dampers

3-2030 STEAM TESTING

The following items shall be inspected during a steam test or when the boiler is in opera-tion:

• Test injectors and all other boiler feeding devices to confirm these operate cor-rectly

• Confirm all water glasses or other water level indicating devices are operating properly

• Test operation of all test valves and drain valves of water glasses or other water level indicating devices

• Confirm all boiler controls operate cor-rectly

• Test set and reseating pressure of safety valves as required

• Inspect boiler shell and rivet seams for leakage, cracks and bulges

• Inspect firebox plates for leakage, cracks and bulges

• Verify firebox refractory is satisfactory • If boiler tube ends can be seen, inspect

these for leakage and application of tube plugs

• If fusible plug can be seen, inspect it for leakage

153


• Inspect staybolts for leakage at the head and telltale hole

• Inspect boiler fi ttings, controls and associ-ated piping for leakage

• Inspect water tanks, fuel tanks and associ-ated piping for leakage

• Inspect fi rebox door for proper operation and locking

3-3000 LOCOMOTIVE FIRETUBE BOILER REPAIRS

3-3010 REPAIR OF STAYBOLT HOLES

Staybolt holes may be repaired by welding, reaming or retapping to a larger size or by installing a fl ush patch.

If the staybolt hole was threaded and is to be repaired by welding, the threads shall be removed prior to welding.

3-3020 THREADED STAYBOLTS (See Figure 3-3020)

All threaded staybolts shall have either 11- or 12-thread pitch. Staybolt threads shall have a good close fi t in sheets. Changing the staybolt thread pitch from 11 to 12 or the reverse shall be considered a repair.

All staybolts shorter than 8 in.(200 mm) in length shall have telltale holes. Staybolt tell-tale holes in existing bolts shall be 3/16 in. (5 mm) to 7/32 in. (5.5 mm) in diameter and at least 1-1/4 in. (32 mm) deep in the outer

Taper Head CrownBolt-Type Staybolts

Rigid Staybolt EquippedWith Telltale Holes

Bucking Bar For BallSocket Flexible Staybolts

Ball Socket-TypeFlexible Staybolt

TaperHeadType

ButtonHeadType

ReducedSection

FIGURE 3-3020 — Threaded Staybolts

A04

154


end. When staybolts 8 in. (200 mm) or less in length are replaced, they shall be replaced with staybolts that have a telltale hole 3/16 in. (5 mm) to 7/32 in. (5.5 mm) in diameter their entire length or with ones that have a 3/16 in. (5 mm) to 7/32 in. (5.5 mm) diameter hole in each end, drilled a minimum of 1-1/4 in. (31 mm) deep. On reduced body staybolts the telltale hole shall extend beyond the fi llet and into the reduced section of the staybolt. Ball socket-type fl exible staybolts may have telltale holes that extend from the threaded end of the bolt into the bolt head for a distance of 1/3 the spherical bolt head diameter.

Telltale holes shall be reopened after driv-ing.

Staybolt length shall be sized so the length of bolt projecting through the sheet is not less than 1/8 in. (3 mm) and is suffi cient to produce a full head after driving.

The thread lead of both bolt ends and both fi rebox sheets shall be synchronized to permit the bolt to be installed without stripping the threads.

When driving staybolt heads, the bolt’s oppo-site end shall be bucked or braced to prevent damaging the bolt’s threads. Bracing can be done several ways, such as using a pneumatic holder-on or a heavy steel bucking bar. Driv-ing the heads on both ends of the staybolt simultaneously using two pneumatic rivet hammers (double gunning) is acceptable. Bolts are to be driven in such a manner as to expand radially the bolt body and threads into the sheet prior to forming the head. Merely driving over the head is not acceptable.

Ball socket-type fl exible staybolts shall not be braced by inserting a spacer under the cap.

Installation of different diameter staybolts shall be considered a repair.

3-3030 BALL SOCKET-TYPE FLEXIBLE STAYBOLTS,

SLEEVES, AND CAPS

Welded fl exible staybolt sleeves shall be ap-plied as shown in Figures 3-3030-a through 3-3030-e. Sleeve axis shall be in alignment with centerline through holes in wrapper and fi rebox sheets.

Welded sleeves and welded caps that leak at the welds or the sleeve shall be repaired.

Wasted caps and sleeves shall not be repaired by weld buildup.

Welded sleeves that have damaged cap threads shall be repaired or replaced. If the sleeve has wasted to less than 60% of the original thickness at the threaded cap section, it may be repaired by cutting off the threaded section and welding on a replacement section using full penetra-tion welds.

Threaded or welded sleeves that are cracked or have wasted to less than 60% of the origi-nal thickness at any section other than the threaded cap section shall be replaced.

Threaded sleeves that leak where screwed into the boiler shell or wrapper sheet shall be re-paired. Seal welding of one pass not exceeding 3/16 in. (5 mm) leg size is permissible for caulk-ing purposes only. If seal welding is applied, the sleeve threads in the weld zone shall be removed prior to welding.

New threaded sleeves seal welded af-ter installation shall have the threads removed from the weld zone of the sleeve prior to welding.

Threaded staybolt caps that leak shall not be seal welded.

Substitution of one type of fl exible staybolt sleeve by another type shall be considered a repair.

155


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FIGURE 3-3030-a — Flexible Staybolts — Welded Sleeves, Caps, and Gaskets

threaded cover cap

threaded sleeve

ball socket staybolt consistingof a spherical nut on a threaded

rigid staybolt

ball socket staybolt

FIGURE 3-3030-b — Ball Socket-Type Flexible Staybolts

Welded Cover Cap Type

ball socket staybolt

welded cover cap

Welded Sleeve With Threaded Cover Cap Type

threaded cover capball socket stayboltwelded sleeve

Threaded Sleeve With Threaded Cover Cap Type

FIGURE 3-3030-c — Half Sleeve Repair Procedure for Damaged Ball Socket Flexible Staybolt Welded Sleeve

welded sleeve damaged at threaded sec-tion

remove threadedsection down togasket surface

do not remove existing flexible staybolt

156


Where necessary for boiler expansion, ball sock-et-type fl exible staybolts shall be positioned in such a manner as to not interfere with boiler expansion. Where individual bolts are re-placed, care should be taken to assure that the stress load of the new bolt is compatible to the loading on adjacent bolts.

Note: Some locomotive boiler designs po-sitioned the bolts by backing the bolt head away from the sleeve socket bottom a certain amount.

3-3040 SEAL WELDED STAYBOLTS(See Figure 3-3040)

Replacement threaded staybolts may be seal welded before or after driving.

Existing threaded staybolts that leak shall be repaired and may be seal welded. When used, seal welding shall not be the sole means of repair.

3-3050 WELDED INSTALLATION OF STAYBOLTS

The installation of unthreaded staybolts using full penetration welds is permissible.

this surface machined for this surface machined for full penetration weld jointfull penetration weld joint

thread for standard fl exible staybolt cap and gasket

FIGURE 3-3030-d — Half Sleeve Repair Procedure for Damaged Ball Socket Flexible Staybolt Welded Sleeve

half sleevehalf sleeve

FIGURE 3-3030-e — Half Sleeve Repair Proce-dure for Damaged Ball Socket Flexible Staybolt Welded Sleeve

half sleeve in-stalled with full penetration weld

FIGURE 3-3040 — Seal Welded Staybolts

staybolt head seal welded staybolt head seal welded before driving

staybolt head seal welded after driving

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157


All staybolts shorter than 8 in. (200 mm) in length shall have telltale holes. Telltale hole diameter shall be 3/16 in. (5 mm) to 7/32 in. (5.5 mm) in diameter and at least 1-1/4 in. (31 mm) deep in the outer end. On reduced body staybolts, the telltale hole shall ex-tend beyond the fillet and into the reduced section of the staybolt. Staybolts may have through telltale holes which are preferred. Ball socket-type flexible staybolts may have telltale holes that extend from the welded end of the bolt into the bolt head for a distance of 1/3 the spherical bolt head diameter.

Where necessary for boiler expansion, ball socket-type flexible staybolts shall be posi-tioned in such a manner as to not interfere with boiler expansion. Where individual bolts are replaced, care should be taken to assure that the stress load of the new bolt is compat-ible to the loading of adjacent bolts.

Note: Some locomotive boiler designs po-sitioned the bolts by backing the bolt head away from the sleeve socket bottom a certain amount.

Installation of different diameter staybolts shall be considered a repair.

3-3060 DIAGONAL BRACES, GUSSET BRACES AND

THROAT SHEET/TUBESHEET BRACES

Loose or damaged braces shall be repaired or replaced.

Only steel braces may be repaired by weld-ing. All such welds shall be full penetration. Wrought iron braces shall not be repaired by welding.

When repairs or alterations are completed, the tightness and condition of the braces and their staybolts, rivets, clevises, eyes and pins shall be verified.

3-3070 THREADED STUDS

Studs threaded into the boiler or firebox sheets shall not be seal welded.

FIGURE 3-3060 — Diagonal Braces, Gusset Braces and Throat Sheet / Tubesheet Braces

Diagonal Brace Solid-Type BracePin-Type Diagonal Brace

Gusset BraceThroat Sheet / Tubesheet Brace

158


3-3080 PATCH BOLTS(See Figure 3-3080)

Patch bolts may be replaced in kind.

Seal welding of bolts is permitted.

3-3100 FLUES, ARCH TUBES, CIRCULATORS, THERMIC

SYPHONS

3-3110 FLUE AND TUBE RE-ENDING

Each boiler tube or fl ue that is repaired by welding is limited to not more than three (3) circumferential welded joints.

Re-ending is permitted provided the thickness of the tube or fl ue to be re-ended is not less than 90% of that required by Table 3-3110.

Re-end pieces shall be new material and meet the thickness requirements of Table 3-3110.

3-3120 ARCH TUBES

Arch tubes that are damaged or reduced to less than minimum required wall thickness shall be replaced in entirety by new one-piece arch tubes. Welded repairs or partial replace-ment is not permitted. Damage includes de-fects such as bulging, burns and cracks.

When arch tubes are installed by rolling, the tube end shall project through the fi rebox sheet not less than 1/4 in. (6 mm) nor more than 3/4 in. (19 mm) before fl aring. At a mini-mum the tube shall be expanded and fl ared at least 1/8 in. (3 mm) greater than the diameter of the tube hole. Additionally, the tube may be beaded and/or seal welded provided the throat of the seal weld is not more than 3/8 in. (10 mm) and the tube is fi nished rolled after welding.

An arch tube installed by welding shall be considered a welded nozzle. Some acceptable weld joints are shown on Figure 3-3120. Ref. ASME Section I, Part PW 16.1

A change in tube attachment from rolled to welded or welded to rolled shall be consid-ered an alteration.

3-3121 TUBE WALL THICKNESS FOR ARCH TUBES

The minimum wall thickness of replacement arch tubes shall be as shown in Table 3-3121.

Table 3-3121Size Wall Thickness

Up to 3 in. (75 mm) OD 8 BWGMore than 3 in. (75 mm) OD to 4 in. (100 mm) OD

7 BWG

3-3130 THERMIC SYPHONS

For repairs to syphon knuckles see Repair of Firebox and Tubesheet Knuckles, and Figures 3-3130-a and 3-3130-b.

FIGURE 3-3080 — Patch Bolts

Typical Patch Bolts

Typical Patch Bolt Application

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159


TABLE 3-3110 MAXIMUM ALLOWABLE WORKING PRESSURES FOR STEEL TUBES OR FLUES FOR FIRETUBE BOILERS FOR DIFFERENT DIAMETERS AND GAGES OF TUBES CONFORMING TO THE REQUIREMENTS OF SPEC. SA-176, SA-192, SA-209, OR SA 210*

Outsidediameter oftube, inches

D

Minimum gage, BWG

13t = 0.095

12t = 0.109

11t = 0.120

10t = 0.134

9t = 0.148

8t = 0.165

7t = 0.180

6t = 0.203

5t = 0.220

4t = 0.238

1 470 690 — — — — — — — —

1-1/2 320 460 570 720 860 — — — — —

1-3/4 270 400 490 620 740 890 — — — —

2 240 350 430 540 650 780 900 — — —

2-1/4 210 310 380 480 580 690 800 960 — —

2-1/2 190 280 350 430 520 630 720 860 970 1080

3 160 230 290 360 430 520 600 720 810 900

3-1/4 — 210 270 330 400 480 550 660 750 830

3-1/2 — 200 250 310 370 450 520 620 690 770

4 — 180 220 270 330 390 450 540 610 680

4-1/2 — 160 190 240 290 350 400 480 540 600

5 — — 180 220 260 320 360 430 490 540

5-3/8 — — 160 200 240 290 340 400 450 500

5-1/2 — — — 200 240 290 330 390 440 490

6 — — — 180 220 260 300 360 410 450

P = {(t–0.065)/D} x 15.550 where P = maximum allowable working pressure, pounds per square inch, t = minimum wall thickness, inches, D = outside diameter of tubes, inches.

For pre given by the formulas.For pressures below those given in the table, the gage thickness shall be not less than the minimum given in the table.* These values have been rounded out to the next higher unit of 10.

Ref: 1952 ASME, Sec. III – Boilers of Locomotives

TABLE 3-3110M MAXIMUM ALLOWABLE WORKING PRESSURES FOR STEEL TUBES OR FLUES FOR FIRETUBE BOILERS FOR DIFFERENT DIAMETERS AND GAGES OF TUBES CONFORMING TO THE REQUIREMENTS OF SPEC. SA-176, SA-192, SA-209, OR SA 210*

Outsidediameter oftube, mm

D

Minimum gage, BWG, to mm

13t = 2.4

12t = 2.8

11t = 3.1

10t = 3.4

9t = 3.8

8t = 4.2

7t = 4.6

6t = 5.2

5t = 5.6

4t = 6.1

25 3220 4930 — — — — — — — —

40 2010 3080 3890 4690 5760 — — — — —

45 1790 2740 3460 4170 5120 6080 — — — —

50 1610 2470 3110 3750 4610 5470 6330 7610 — —

60 1340 2060 2590 3130 3840 4560 5270 6350 7060 7950

65 1240 1900 2390 2890 3550 4210 4870 5860 6520 7340

75 — 1650 2080 2500 3080 3650 4220 5080 5650 6360

85 — — 1830 2210 2710 3220 3720 4480 4990 5620

90 — — 1730 2090 2560 3040 3520 4230 4710 5300

100 — — 1560 1880 2310 2740 3170 3810 4240 4770

115 — — 1350 1630 2010 2380 2750 3310 3690 4150

125 — — — 1500 1850 2190 2530 3050 3390 3820

135 — — — 1390 1710 2030 2350 2820 3140 3540

140 — — — — 1650 1960 2260 2720 3030 3410

150 — — — — 1540 1830 2110 2540 2830 3180

P = {(t–1.651)/D} x 107510 where P = maximum allowable working pressure, kilopascals (kPa), t = minimum wall thickness, mm, D = outside diameter of tubes, mm.

For pre given by the formulas.For pressures below those given in the table, the gage thickness shall be not less than the minimum given in the table.* These values have been rounded out to the next higher unit of 10.

Ref: 1952 ASME, Sec. III – Boilers of Locomotives

160


FIGURE 3-3130-a — Locomotive Firebox Thermic Syphon Installation

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FIGURE 3-3130-b — Thermic Syphon Repair

full penetration welds

length to suit

section on w-w full penetration weld radiographically examined after welding

syphon neckrepair

flush patch on staybolt syphon body

FIGURE 3-3120 — Welded Installation of Arch Tube

t = thickness of vessel shell or head, in.tn = thickness of nozzle wall, in.tw = dimension of partial penetration attachment welds (fillet, single bevel, or single J), measured as shown in

Figure PW-16.1, in.tc = not less than the smaller of 1/4 in. (6 mm) or 0.7 tmin. (inside corner welds may be further limited by a

lesser length of projection of the nozzle wall beyond the inside face of the vessel wall)tmin = the smaller of 3/4 in. (19 mm) or the thickness of either of the weld parts joined by a fillet, single bevel, or

single J-weld, in.

1

1

tc

tn

tn but not less than1/4 in. (6 mm)

Section 1-1

tw

tc

(y)tn but not less than 1/4 in. (6 mm)

tw

tn

tc

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All weld repairs to the unstayed sections of the syphon neck and body shall be radiographically examined.

3-3140 CIRCULATORS

All butt welds on circulators shall be radio-graphically examined.

Welds applied to the circulator/firebox sheet joint shall be in accordance with the weld requirements for arch tubes. See Figure 3-3120.

3-3200 REPAIRS AND ALTERATIONS TO BOILER

BARREL UNSTAYED AREAS

Defects such as cracks and wastage may be repaired by weld buildup, a welded fl ush patch or a riveted patch. Installation of a riv-eted patch shall be considered an alteration. Prior to repairing cracks, the plate shall be examined for defects. Affected sections shall be repaired.

Weld buildup shall not be used if the affected section of plate has wasted below 60% of the minimum required thickness.

If the cracked section of plate is retained andis to be repaired by installation of a riveted patch, the crack may be stopped by drilling stop holes at each end or removed by a meth-od such as grinding, cutting or machining. Re-sults of stop drilling or crack removal shall be verifi ed by NDE.

Welded repairs at or near riveted seams requiring preheating or postweld heat treatment shall be carefully made in order to prevent loosening in the riveted seams, especially when localized heat-ing is used. Where necessary to control expansion or to gain access for weld-

ing, rivets at the defective section and to each side of it may be removed. Reuse of rivets and staybolts is prohibited.

All welded repairs to boiler barrel un-stayed areas shall be radiographically ex-amined in accordance with the ASME Code, Section I when the size of the repaired area is greater than the maximum size of an unreinforced opening as calculated in accordance with the latest edition of the ASME Code, Section I.

Riveted patches may be any shape or size provided the lowest patch effi ciency is equal to or greater than the lowest equivalent seam effi ciency of the boiler course to which it is applied. Ref: ASME Code, Section I.

The factor of safety of all riveted patches shall not be less than four (4) for locomotives oper-ating under Federal Railroad Administration regulations.

3-3300 REPAIRS AND ALTERATIONS TO BOILER

BARREL STAYED AREA

3-3310 FIREBOX SHEET REPAIR

Cracks in all stayed fi rebox sheets may be repaired by welding or the installation of a fl ush patch.

If the crack extends into a staybolt or rivet hole, the staybolt or rivet shall be removed prior to making the repair.

3-3320 FIREBOX PATCHES

Patches may be any shape provided they are adequately supported by staybolts, rivets, tubes or other forms of construction. Patches on stayed surfaces should be designed so

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weld seams pass between staybolt rows. See Figure 3-3320.

Patches are to be fl ush type, using full penetra-tion welds. If the load on the patch is carried by other forms of construction, such as stay-bolts, rivets or tubes, radiographic examina-tion of the welds is not required.

If the patch includes an existing riveted seam, the patch shall be riveted at that seam. Changing a riveted seam to a welded seam is considered an alteration.

All rectangular or angled patches shall have adequate radius at all corners. Minimum ra-dius to be not less than three (3) times plate thickness.

Patches shall fi t fl ush on the waterside of the sheet. Misalignment shall not exceed one quarter (1/4) plate thickness on edge align-ment with the sheet water side.

Staybolts and rivets should be installed after welding of patch is completed. Reuse of stay-bolts and rivets is prohibited.

Weld seams parallel to a knuckle shall be lo-cated no closer to the knuckle than the point of tangency of the knuckle unless the weld is radiographically examined. Weld seams not located in the knuckle are preferred. See Figure 3-3350-b.

Patches shall be made from material that is at least equal in quality and thickness to the original material.

FIGURE 3-3330 — Stayed Firebox Sheet Grooved or Wasted at Mudring

First Staybolt Row

MudringMudring Rivet

Sheet Wasted BelowMudring Waterside

Firebox Sheets

Figure 3-3320-b - Rectangular Shaped Patch

FIGURE 3-3320 —Figure 3-3320-a illustrates what would be consid-ered a saw-tooth patch. Its advantage is that a maxi-mum amount of welding is obtained for securing a given patch and by zig-zagging the weld, the weld is supported by three (3) rows of staybolts instead of two (2). Its disadvantage is its irregular shape which causes greater diffi culty in fi tting and applying.

Figure 3-3320-a - Saw-Tooth Patch

Figure 3-3320-c - Diamond Shaped Patch

WELD

WELD

WELD

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FIGURE 3-3340 — Mudring Repair

mudring

remove fi rebox sheets for access

full penetration weldfull penetration weld

3-3330 REPAIR OF STAYED FIREBOX SHEETS GROOVED

OR WASTED AT THE MUDRING

(See Figure 3-3330)

Grooved or wasted firebox sheets having greater than 60% of the minimum required thickness remaining may be repaired by weld buildup provided the wastage does not extend below the waterside surface of the mudring and the strength of the structure will not be impaired. If extensive welding is required, the affected area shall be removed and replaced with a fl ush patch.

If the sheet thickness has been reduced to less than 60% of the minimum required thickness, the affected section shall be removed and replaced with a fl ush patch.

If wastage and grooving extends be-low the mudring waterside surface and if the plate thickness remaining has been reduced to less than the minimum required thickness, the affected section shall be removed and replaced with a fl ush patch.

Flush patches shall be arranged to include the mudring rivets and at least the fi rst row of staybolts above the mudring.

3-3340 MUDRING REPAIRS(See Figure 3-3340)

Pitted and wasted sections of mudrings may be built up by welding provided the strength of the mudring will not be impaired. Where extensive weld build-up is employed, the In-spector may require an appropriate method of NDE for the repair.

Cracked or broken mudrings may be repaired by welding or installation of fl ush patches using full penetration welds. Patches shall be made from material that is at least equal in

quality and thickness to the original material. Patches shall fi t fl ush on waterside surfaces. Where necessary, fi rebox sheets on both sides of the defect may be removed to provide ac-cess for inspection and welding.

3-3350 REPAIR OF FIREBOX AND TUBESHEET KNUCKLES

Welds within the points of tangency of a knuckle are permitted. Welds with angles of less than 45 degrees to the longitudinal axis of the knuckle shall be radiographically exam-ined. See Figures 3-3350-a through 3-3350-f.

Any patch not supported by means other than the weld, such as rivets, staybolts, tubes or other forms of construction, shall have all weld seams radiographically examined.

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FIGURE 3-3350-a — Firebox Tubesheet Knuckle Repair

knuckle patch welded around tube holes

knuckle patch welded through tube holes

top flue

fluesheet

line of weld is to be as nearlyhorizontal as conditioning will permit

knuckle

staybolts transverse crack in tubesheet knuckle

parallel crack in tubesheet knuckle

tubesheet

point of tan-gencyof knuckle

FIGURE 3-3350-b — Repair of Firebox and Tubesheet Knuckles

knuckle radius

welds located no closer to knuckle than point of tangency do not require radiographic examination

see layout method in Figure 15A

FIGURE 3-3350-b1 — Layout Method of Determining Knuckle Weld Angle

��

�

�

Illustrations are of inside surface of knuckle.

longitudinal axis point PT

b

bPT

R

To find the points of tangency (PT) of the knuckle:b = R - (R * cos )

Where:R = inside knuckle radius

ß = Angle of weld relative to the Reference Longitudinal Axis of Knuckle.

ß

weld

Reference Longitudinal Axis of Knuckle Longitudinal Axis Point

True Longitudinal Axis

��

��

��

��

�

� ��

��

��

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staybolt rows point oftangency of knuckle

knuckle

tube orstaybolt rows

FIGURE 3-3350-c — Repair of Firebox and Tubesheet Knuckles

STAYED PATCH APPLIED TO BUTT WELDED SEAM

patch length

weld seams located between staybolt rows and above first tube row or staybolt row

STAYED PATCH APPLIED TO RIVETED SEAM

riveted seam

weld seams located be-tween tube rows below staybolt rows or tube rows

weld seam located above first tube row or staybolt row

REPAIRS REQUIRING RADIOGRAPHICEXAMINATION OF WELD SEAMS

weld seam locatedin knuckle

patch notsupported by tubes, stayboltsor rivets

if access for welding or riveting is required, remove section of exterior or interior sheets

FIGURE 3-3350-d — Firebox Throat Sheet Knuckle

typical flush patches installed with fullpenetration welds

FIGURE 3-3350-e — Backhead KnuckleRepair

if access for welding and riveting isre-quired, remove section of exterior or interior sheets

typical flush patch

patch lengthoriginal wrapper sheet

new rivets

weld located between staybolt rows

staybolts

transverse weld

FIGURE 3-3350-f — Fire Door Opening Repair

flush patchinstalled with full penetra-tion welds

patch installed with full penetration welds andeither patch bolts or rivets

SEC A-A

SEC A-A

patch bolts or rivets

patch length

patch lengthpatch length

weld seam located between tube rows or staybolt rows

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typical tubesheet fl ush patches

tubesheet welded around tube holes

tubesheet welded through ligaments and tube holes

FIGURE 3-3360 — Tubesheet Repairs

Caulking Tool

Caulked Edge of PlateCaulked Edge of Plate

Caulking Tool

FIGURE 3-3410

Patches shall be formed to proper shape and curvature.

Wasted sections of knuckles that have not wasted below 60% of the minimum required thickness may be repaired by weld buildup provided the strength of the structure will not be impaired. Where weld buildup is employed, the Inspector may require an ap-propriate method of NDE for the repair.

Wasted sections of knuckles that have wasted below 60% of the minimum required thickness shall be replaced.

3-3360 TUBESHEET REPAIRS(See Figure 3-3360)

Cracked tubesheet ligaments may be re-paired by welding using full penetration welds.

Damaged tubesheet holes may be repaired by welding.

Sections of tubesheets damaged or wasted to less than 60% minimum required thickness shall be repaired by installing a fl ush patch using full penetration welds.

Sections of tubesheets that have not wasted below 60% minimum required thickness may be repaired by weld buildup provided the strength of the structure will not be impaired. Where weld buildup is employed, the Inspec-tor may require an appropriate method of NDE for the repair.

3-3400 SEAMS AND JOINTS

3-3410 CAULKING RIVETED SEAMS AND RIVET HEADS(See Figure 3-3410)

Caulking refers to the sealing of plate seams and rivet heads by driving the edge of one surface onto the other by use of an impact tool.

Riveted seams and rivet heads may be caulked in accordance with ASME Section I, 1971.

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3-3500 THREADED OPENINGS IN VESSEL WALLS,

BUSHINGS AND WELDED NOZZLES (WASHOUT PLUG HOLES AND OTHER

CONNECTIONS)

Threaded openings in vessel walls and welded nozzles with damaged threads that cannot be repaired by retapping or rethreading may be repaired by welding a nozzle in the sheet. The nozzle shall be of such a size as to not interfere with proper washout and inspection.

Threaded bushings and nozzles found to be defective shall be replaced. Seal welding is not permitted.

New threaded bushings equipped with shoul-ders may be seal welded at the shoulder.

New threaded bushings without shoulders that are seal welded after installation shall have the threads removed from the weld zone of the bushing prior to welding.

Threaded holes with damaged threads may be repaired by weld buildup and retapping. The threads shall be removed prior to welding.

3-3600 FITTINGS AND GAGES

3-3610 WATER GAGE CONNECTION

Water gage glasses shall be applied so that the lowest water reading in the water gage glass of a horizontal fi retube boiler on level track shall be at least 3 in. (75 mm) above the highest point of the tubes, fl ues or crown sheet.

The bottom mounting for water gage glass (and for water column if used) must not extend less than 1-1/2 in. (38 mm) inside the boiler and beyond any obstacle immediately above it. The passage must be straight and

approximately horizontal. Connections must be applied without pockets, traps, sags or syphons. Tubular water gage glasses must be equipped with a protection shield.

Locomotive water gage glasses shall be pro-vided with one top and one bottom shutoff cock and a means to illuminate each glass. Each top and bottom shutoff cock or valve shall be of such through fl ow construction as to prevent stoppage by deposits of sediments. Straight run globe valve of the ordinary type shall not be used on such connections. See Figure 3-3610. The water gage glass connec-tion and pipe connection shall be fi tted with a drain cock or valve having an unrestricted opening of not less than 3/8 in. (10 mm) in diameter to facilitate cleaning.

The top and bottom water gage glass fi tting are to be aligned, supported and secured so as to maintain the alignment of the water gage glass.

FIGURE 3-3610 — Straight Run Globe Valve Not Permitted

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The lower edge of the steam connection to a water column or water gage glass in the boiler shall not be below the highest visible water level in the water gage glass. There shall be no pockets, traps, sags or syphons in the pip-ing which will permit the accumulation of sediments.

The upper edge of the water connection to a water gage glass and the boiler shall not be above the lowest visible water level in the water gage glass. There shall be no pockets, traps, sags or syphons in the connection.

3-3700 MATERIAL LIST FOR STEAM LOCOMOTIVE BOILERS

The following list is intended as a basic guide-line only and covers just the basic carbon steel and some alloy steel material specifications. Other alloy materials may be available for these applications if necessary.

Application Specification

Boiler Tubes & SA-178 Grade A,Flues, Arch Tubes SA-192, SA-210Superheater Units

Boiler & Firebox Plate SA-285 Grade C, SA-515, SA-516, SA-203, SA-204

Staybolts SA-675, SA-36, ASTM A-31

Staybolt Sleeves and SA-105 Forging, Caps SA-675

Boiler Braces SA-675, SA-36

Rivets SA-675, ASTM A-31

Forged Parts & Fittings SA-105, SA-181

Pressure Retaining SA-216, SA-217Steel Casings

Hollow Cylindrical SA-105 Forgings Pressure Retaining SA-675 Bar StockParts

Superheater Unit Bolts Bolts - SA-193, & Nuts Nuts -SA-194

Pipe Flanges SA-181, SA-105

Pipe SA-106, SA-53 seamless

Bronze Castings & SB-61, SB-62Washout Plugs

a. SA-516 steel is recommended for firebox repairs. It is a fine grain that accepts flanging and bending with less chance of cracking than course grain steels such as SA-515 or SA-285 Grade C. Course grain steels have, on occasion, been found to crack or split after complicated flanging, bending and forming.

b. SA-36 is not to be used to make any pres-sure retaining part such as shells, staybolt sleeves or caps.

c. When rivets are made from SA-675, the finished rivets must meet the physical and test requirements of the original ASME rivet specification ASTM A-31 Grade A or B.

d. When staybolt material tensile strength is stronger than that of the firebox sheets, the firebox sheets deflect instead of the staybolts, which can result in the sheets developing cracks and leaking staybolts. In addition, high tensile strength steels are difficult to drive.

3-4000 GUIDELINES FOR STEAM LOCOMOTIVE STORAGE

The steam locomotive guidelines published herein list the general recommendations for storage of locomotive boilers and locomotives.

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3-4020 WET STORAGE METHOD

When utilizing the “wet storage method” the boiler is completely filled with treated water to exclude all air.

NOTE: This method cannot be used if the locomotive is exposed to freezing weather during storage.

Chemicals may be added to the storage wa-ter to further inhibit corrosion. However, depending on the chemical used the treated water may have to be disposed of as a hazard-ous waste to prevent chemical contamination of the surrounding property.

The procedure applies only to the sections of the boiler that contain water. The firebox interior, cylinders, piping and auxiliary equip-ment of the locomotive still require draining, preservation and dry storage.

3-4030 DRY STORAGE METHOD

When utilitizing the “dry storage method” the boiler is completely emptied of water, dried out and allowed to stand empty. Several variations of the “dry method” may be used. These include but are not limited to:

• Air tight storage with moisture absorbent placed in trays in the boiler;

• Air tight storage with the boiler filled with inert gas to exclude all oxygen;

• Open air storage with the mud ring wash-out plugs removed to enable air circula-tion for evaporation of formed moisture.

Each variation has positive and negative points that must be taken into account before use. If the boiler is filled with inert gas such as nitrogen, care must be taken because this method can result in asphyxiation of person-nel if the gas escapes the boiler through a leaking valve or washout plug and enters a pit, sump or enclosed room. In addition, the

The exact procedures used by the owner/operator must be reviewed by the railroad mechanical officers/engineers and be based on the conditions and facilities at the railroad shop or storage facility.

3-4010 STORAGE METHODS

The methods for preparing a steam locomo-tive for storage depend upon several factors, including:

• The anticipated length of time the locomo-tive will be stored.

• Whether storage will be indoors or out-doors.

• Anticipated weather conditions during the storage period.

• The availability of climate-controlled stor-age.

• Type of fuel used.• Equipment available at the storage site.

Indoor storage can be broken into two types: Indoor with climate control and indoor with-out climate control.

Outdoor storage can also be broken into two types: outdoors during a warm time of year or in a geographic location where it can reason-ably be expected to be above freezing during storage and outdoors during a time period or in a geographic location where it can be expected that freezing temperatures will occur during storage.

Locomotive boilers may be stored using the “wet method” or the “dry method.”

Before any method of storage, the boiler must be thoroughly washed out with all mud and scale removed from the mudring, crownsheet, bottom of the barrel and the top of the firing door.

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boiler must be completely vented to remove all gas, then tested and declared gas free be-fore personnel may enter.

Although the use of dry storage with several washout plugs removed for air circulation is the most common method, there are some potential drawbacks. The boiler interior may be subject to moisture forming from conden-sation created from humidity changes in the ambient air. Small animals may take up resi-dence inside if screens are not used to cover handholes and washouts.

Before storage the boiler must be thoroughly washed out with all mud and scale removed from the mudring, crownsheet, bottom of the barrel and top of the firing door. Any mud or loose scale left in the boiler will retain mois-ture leading to corrosion. After washing, all water must be removed and the boiler dried before storage. A portable gas or electric heater placed in the firebox to aid evapora-tion and drying along with a vacuum used to siphon water out via the lower washout plugs is recommended.

NOTE: Use of the common railroad drying out procedure of building a small wood fire in the firebox is not recommended because of the danger of overheating the firebox sheets.

The typical railroad dry storage method re-quired blow down of the boiler until empty while steam pressure registered on the gauge and removal of the washout plugs while the shell plates were hot and there was no steam pressure. This allowed the heat remaining in the boiler plates to evaporate all remaining water in the boiler. However, this method may result in staybolt damage from temperature change and requires extreme care, if used.

Oil should not be applied to the interior surfaces of the boiler because it is difficult to remove. Further, all of the oil must be re-moved before steaming or it will form scale and contribute to foaming.

3-4040 RECOMMENDED GENERAL PRESERVATION

PROCEDURESWhen the locomotive is under steam, inspect all piping, fittings and appliances for steam and water leaks that may introduce moisture into the lagging. Repair all leaks as necessary and remove wet lagging. Wet lagging can ac-celerate corrosion of the boiler external sur-faces, especially staybolt sleeves and caps.

Thoroughly wash the boiler and firebox and remove all mud and scale from the mudring, crownsheet, bottom of the barrel and top of the firing door. Any mud or loose scale left in the boiler will retain moisture leading to cor-rosion. Wash out thermic siphons, arch tubes and circulators.

To protect the boiler interior during storage, dry the boiler by using compressed air to blow out as much water as possible. A portable heater placed in the firebox to warm the boiler to 200°F (95°C) along with a vacuum used to siphon water out via the lower washout plugs can aid evaporation and drying of any mois-ture that collects in low or impossible-to-drain locations without harming the sheets.

CAUTION: To prevent a build up of steam pressure during the drying process, the steam dome cover or top washout plugs should be removed to enable the moisture to escape. In addition, the driving wheels should be blocked and the throttle and cylinder cocks should be opened to permit any steam that forms in the superheater units to escape.

Superheater units, by nature of design, can be difficult to drain and dry out. Typical methods include:

a. Pressurize the boiler with compressed air with the locomotive stationary and blocked in place. Using the throttle to regulate the airflow, allow the air to blow through the entire bank of superheater units and dry pipe and discharge into the cylinders. The cylinder cocks must be open.

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b. Pressurize the boiler with compressed air then operate the locomotive under air pressure over a short distance of track. The cylinder cocks should be opened during the initial operation to prevent damaging the cylinders by hydraulic lock.

If the air pressure draining procedure is not practical or can not be accomplished correctly, the superheater units can be protected against trapped moisture by filling the entire super-heater bundle with a standard antifreeze/wa-ter mixture or with diesel fuel.

NOTE: The air pressure dryout methods “1” or “2” may have to be performed several times to discharge all of the moisture. Refer to Sec-tion 3-4050, “Use of Compressed Air To Drain Locomotive Components,” for additional information on compressed air drying.

NOTE: If the locomotive is operated under air pressure, the air brake system should be made operational to provide safe stopping or other steps taken to control and stop the locomotive.

After drying, it will be necessary to either vent the boiler or to place containers of desic-cant inside the boiler through the dome cap to absorb any condensation that may occur during storage. Venting the boiler to allow air circulation is accomplished by leaving two or more of the lower washout plugs out and opening the vent valve on the top of the boiler. A vent line consisting of two 90° elbows and pipe nipples should be installed in the vent valve to locate the opening to the downward direction in order to keep rain or snow from entering the open valve.

If the locomotive will be stored outdoors, the following should be completed:

a. Inspect the boiler jacket and confirm it is tight with no gaps leading into the lag-ging or shell. Pay close attention to areas at shell openings such as for studs, safety

valves, etc. Repair all gaps or damaged jacket sections as necessary. Consider-ation should be given to covering the entire locomotive and tender with a tarp. Otherwise, all jacket openings should be covered to prevent the entrance of rain or snow. Where necessary, apply a water-proof covering over the exposed or open sections.

b. The smokestack should be sealed by ap-plying a wood and sheet rubber cover held in place by clamps or a through bolt.

c. The safety valves should either be covered or removed, with plugs or caps installed in the holes if the valves are removed.

d. The dynamo, air pump and feedwater heater exhausts should also be covered.

e. Empty and clean the smokebox, front tube sheet, superheater units, steam pipes and front end plates of all coal, ash or burnt oil. This work is especially critical at the bottom section of the smokebox and front tubesheet rivet flange. The smokebox door should be sealed by applying a gasket or sealant and any other air openings in the smokebox sealed. The exhaust nozzle should be sealed by applying a wood and sheet rubber cover held in place by clamps.

f. The potential for corrosion of the smoke-box interior can be further minimized by applying coating of outdoor paint or primer. All inspection of the smokebox and front tubesheet must be accomplished before painting since it will cover up many types of defects. The coating will burn off quickly when the locomotive is returned to service.

g. Thoroughly clean the firebox sheets, flues and superheater return bends of all ash and clinker.

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h. On coal burners, empty and clean the grates and ash pan of all coal and ash completely. This work is especially critical at the sections between the grate bearers, the mud ring rivets and firebox sheets; and from the grate segment air openings. On oil burners, care should be taken to remove ash from between the flash wall refractory and the firebox sheets.

i. If the locomotive will be out of service for longer than 12 months, removal of the brick arch or flash wall refractory that extends above the mudring should be considered to prevent condensation and corrosion from occurring between the brick and the steel. Temporary removal of the brick arch or flash wall to permit application of a preservative to firebox sides, arch tubes or siphons should be considered for shorter storage periods.

j. All appliances and piping that might contain water or condensation should be drained and blown dry using dry compressed air. This includes the air and equalizing reservoirs, dirt collectors, injec-tors, cylinders, stoker engine cylinders, dynamos, the steam and water sides of feedwater heaters and pumps, the steam side of air pumps, the steam side of lubri-cators, atomizers, oil tank heaters, gauge siphons, tank hoses and cab heater piping. A small quantity of valve oil should be sprayed into the valve chambers, cylin-ders and the steam side of all appliances to protect against corrosion. Refer to the Section “Use of Compressed Air To Drain Locomotive Components” for details.

k. The cylinder castings, exhaust cavities and steam lines must be drained of all moisture and blown dry. Typical methods include:

1. Pressurize the boiler with compressed air with the locomotive stationary and

blocked in place. Using the throttle to regulate the airflow, allow the air to blow through the dry pipe and dis-charge into the cylinders. The cylinder cocks must be open.

2. Pressurize the boiler with compressed air then operate the locomotive under air pressure over a short distance of track. The cylinder cocks should be opened during the initial operation to prevent damaging the cylinders by hydraulic lock.

NOTE: Methods “1” or “2” may have to be performed several times to discharge all of the moisture from the cylinders and steam pipes. If the locomotive is operated under air pressure, the air brake system should be made operational to provide safe stopping or other steps taken to con-trol and stop the locomotive.

Refer to the Section “Use of Compressed Air To Drain Locomotive Components” for additional information.

l. Drain and wash tender water spaces. The tank should be inspected afterward and any remaining water removed by syphon or vacuum. When dry, spray the water space with outdoor paint or a commercial rust preventative. Drain and dry tender tank hoses and clean screens.

m. On coal or wood burners, spray any ex-posed surfaces of the tender fuel space with outdoor paint or a commercial rust preventative. If the locomotive is to be stored outdoors for long term, remove all coal and spray the surfaces as above or cover the coal space with a tarp or a roof.

n. On oil burners, drain and blow out all fuel lines, tank heater and blowback lines and the burner itself. Drain sludge and water

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from the bottom of the fuel tank. Insure that tank hatches are secure and the tank is vented to prevent condensation. Draining the oil tank is recommended if the fuel oil is known to lose its volatile content during storage.

o. After cleaning thoroughly, coat all side and main rods, cross heads, valve gear, guides, piston rods, brake pistons, feed-water pump pistons and air pump pis-tons with water-resistant grease or a rust preventative. Grease should be applied to the junction of each axle and driving box and journal box to prevent water enter-ing. Grease should be applied to junction of rod and pin in valve gear and rods to prevent water entering.

p. If the locomotive is moved after this is ap-plied, it will be necessary to reapply the coating to piston rods and guides.

NOTE: Heavy oil or unrefined oil such as any of the Bunker types (Bunker 6, etc.) should not be used for preservation of any components because the sulfur contained in it can accelerate corrosion. Standard motor oil or journal oil will not stick to and preserve wetted surfaces. All surfaces, to be so coated, must be dry. If moisture is a problem, steam cylinder oil should be applied.

q. Plain journal bearings should be inspected for water and repacked. Roller bearing boxes should have all moisture drained and the boxes filled with lubricant. Grease plugs should be screwed down so that the threads are not exposed.

r. If the locomotive is to be stored outdoors with questionable or no security, remove and store all cab gages, water glasses, lubricators, brass handles, seatboxes and any other items that thieves or vandals might attack. Remove the whistle, bell,

headlight and marker and/or classifica-tion lights. Remove tools, radios and spare parts. Secure wood or metal covers over all windows and doors and board up the back of the cab. Secure all manholes on the top of the tender.

s. Inspect stored locomotives regularly for signs of rust, corrosion, damage, deterio-ration or vandalism and immediately take any corrective measures necessary.

3-4050 USE OF COMPRESSED AIR TO DRAIN LOCOMOTIVE COMPONENTS

The process of using air pressure to drain and empty auxiliary components such as the cylinders, superheater units and piping completely of water offers several advantages over other methods.

The air compressor must be equipped with a suitable filter to enable it to supply oil-free air because the introduction of air that contains oil into the water/steam parts of the boiler and superheater will promote the formation of scale and water foaming when the locomotive is returned to service.

The air compressor must be large enough size to provide the volume and pressure of air required.

If the boiler is pressurized with compressed air, the air pressure must be raised slowly to prevent distorting or overstressing the firebox sheets or staybolts because the normal expan-sion of the boiler that occurs under steam pressure is not present when air pressure is used.

Auxiliary components such as the stokers, air compressors, turbogenerators, power reverse are drained by pressurizing the boiler to be-tween 1/2 to 3/4 of the rated boiler pressure

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with compressed air from the stationary air compressor then operating each component individually until the exhaust from it contains no moisture.

When necessary, specific pipe lines can be drained by breaking the line at each end, at-taching the air line to it directly then blowing the line out.

3-4060 RETURN TO SERVICE

When returning a locomotive to service, the boiler, firebox and tender tank shall be ventilated to remove potentially hazardous atmosphere from the boiler interior before personnel enter it. In addition, the atmosphere in the boiler shall be verified to be safe for human occupancy before personnel enter it. For the boiler this can be accomplished by removing the washout plugs and placing a fan or air blower on top of the steam dome opening to force air into the boiler. For the firebox this can be accomplished by opening the smokebox door and firebox door and placing a fan or air blower at either location to force air through. Failure to do this could result in asphyxiation of the first personnel to enter the boiler or firebox.

If possible, the locomotive should be moved into a heated engine house and the boiler al-lowed to warm up in the air for several days until it is the same temperature as the air.

The initial fire up should be done slowly to allow even heating of the boiler.

Before movement the cylinders should be warmed up by allowing a small quantity of steam to blow through them and out the cylinder cocks and exhaust passages. This is necessary to reduce the stress in the casting from thermal expansion of the metal.

Steam should be discharged through the cyl-inder cocks for several minutes to aid removal of any solvent, debris or rust that may have formed in the superheater units, steam pipes and dry pipe.

All appliances should be tested under steam pressure before the locomotive is moved.

175

Glossary of Terms

Appendix 4

176


APPENDIX 4 — GLOSSARY OF TERMS

For the purpose of applying the rules of the NBIC, the following definitions of the terms used herein shall apply:

Address of Record (applicable to RA-2200) – Complete address of the company to which the National Board Certificate of Authoriza-tion is issued (shop facility). For field only certificates of authorization, the address from where the work is controlled.

Alteration – Any change in the item described on the original Manufacturer’s Data Report which affects the pressure contain-ing capability of the pressure-retaining item. Non-physical changes such as an increase in the maximum allowable working pres-sure (internal or external), increase in design temperature, or a reduction in minimum temperature of a pressure-retaining item shall be considered an alteration.

ANSI – The American National Standards Institute

ASME Code – The American Society of Mechanical Engineers’ Boiler and Pressure Vessel Code published by that Society, includ-ing addenda and Code Cases, approved by its council.

Assembler (applicable to RA-2200) – An or-ganization who purchases or receives from a manufacturer the necessary component parts of valves and assembles, adjusts, tests, seals and ships safety or safety relief valves at a geographical location and using facilities other than those used by the manufacturer.

Audit (applicable to RA-2300) – A docu-mented activity performed to verify by examination and evaluation of objective evi-dence that applicable elements of the quality program have been developed, documented, and implemented in accordance with speci-fied requirements. An audit is separate from

inspection or examination for the purpose of process control or acceptance of materials or items.

Authorized Inspection Agency – An Authorized Inspection Agency shall be ei-ther:

a. A jurisdictional authority as defined in the National Board Constitution; or

b. An insurance company which has been licensed or registered by the appropriate authority of a state of the United States or province of Canada to write boiler and pressure vessel insurance in such a state or province.

Authorized Nuclear Inspection Agency (applicable to RA-2300) – An Authorized Inspection Agency which employs Autho-rized Nuclear Inspectors and provides nuclear inspection services in accordance with the NBIC and Section XI of the ASME Code.

Authorized Nuclear Inspector (ANI) (appli-cable to RA-2300) – An Authorized Inspector employed by an Authorized Nuclear Inspec-tion Agency, qualified in accordance with the National Board Rules for Commissioned Inspectors.

Authorized Nuclear Repair Organization (applicable to RA-2300) – See “NR” Certificate Holder.

Capacity Certification – The verification by the National Board that a particular valve design or model has successfully completed all capacity testing as required by the ASME Code.

Conversion – The change of a pressure relief valve from one capacity-certified configura-tion to another by use of manufacturer’s instructions.

177


Critical Parts (applicable to RA-2200) – Criti-cal Parts are those that may affect the valve flow passage, capacity, function or pressure-retaining integrity.

Demonstration – A program of making evi-dent by illustration, explanation and comple-tion of tasks documenting evaluation of an applicant’s ability to perform code activities including the adequacy of the applicant’s quality program and by a review of the imple-mentation of that program at the address of record and/or work location.

Field – A temporary location, under the con-trol of the Certificate Holder, that is used for repairs and/or alterations to pressure-retain-ing items at an address different from that shown on the Certificate Holder’s Certificate of Authorization.

Field Repairs (applicable to RA-2200) – Field repairs are any repair conducted outside of the Certificate Holder’s fixed repair shop location. Field repairs may be conducted with the aid of mobile facilities with repair capabili-ties and with or without testing capabilities. Field repairs may be conducted in user facili-ties without the use of mobile facilities as de-scribed above, or in any other “VR” Certificate Holder’s fixed repair shop location.

Inspector – See National Board Commis-sioned Inspector and National Board Owner-User Commissioned Inspector.

Jurisdiction – A governmental entity with the power, right or authority to interpret and enforce law, rules or ordinances pertaining to boilers, pressure vessels or other pressure-retaining items. It includes National Board member jurisdictions defined as “jurisdic-tional authorities”.

Jurisdictional Authority – A member of the National Board, as defined in the National Board Constitution.

Lift Assist Device – A device used to apply an auxiliary load to a pressure relief valve stem or spindle, used to determine the valve set pres-sure as an alternative to a full pressure test.

Manufacturer (applicable to RA-2200) – An organization holding an ASME Certificate of Authorization to apply the Code Symbol stamp responsible for design, material selec-tion, capacity certification, manufacture of all component parts, assembly, testing, seal-ing, stamping and shipping of pressure relief valves.

Manufacturer’s Documentation – The docu-mentation that includes technical information and certification required by the original code of construction.

Modification (applicable to RA-2300) – Any change to an item which affects the existing design requirements. Modifications include nonphysical changes (such as an increase in the MAWP or design temperature, or a re-duction in minimum temperature such that additional mechanical tests are required), design reconciliation and revision of design specifications, and the process of making physical changes to an item as required to meet revised design requirements.

“NR” Certificate Holder – An organization in possession of a valid “NR” Certificate of Authorization issued by the National Board.

NBIC – The National Board Inspection Code published by The National Board of Boiler and Pressure Vessel Inspectors.

National Board – National Board of Boiler and Pressure Vessel Inspectors.

National Board Commissioned Inspector – An individual who holds a valid and current National Board Commission.

Nuclear Items – Items constructed in accor-dance with recognized standards to be used in nuclear power plants.

178


Original Code of Construction – Documents promulgated by recognized national stan-dards writing bodies that contain technical requirements for construction of pressure-retaining items or equivalent to which the pressure-retaining item was certified by the original manufacturer.

Owner (applicable to RA-2300) – The organi-zation legally responsible for the operation, maintenance, safety, and power generation of the nuclear power plant, including the repair, modification, or replacement of items in the plant.

Owner or User – As referenced in lower case letters means any person, firm or corporation legally responsible for the safe operation of any pressure-retaining item.

Owner-User Inspection Organization – An owner or user of pressure-retaining items that maintains an established inspection program, whose organization and inspection proce-dures meet the requirements of the National Board rules and are acceptable to the jurisdic-tion or jurisdictional authority wherein the owner or user is located.

Owner-User Inspector – An individual who holds a valid and current National Board Owner-User Commission.

Pressure-retaining Items (PRI) – Any boiler, pressure vessel, piping, or material used for the containment of pressure, either internal or external. The pressure may be obtained from an external source, or by the application of heat from a direct source, or any combination thereof.

Quality System (applicable to RA-2200 and RA-2300) – Those planned and systematic actions necessary to provide adequate confidence that items repaired, modified, or replaced are in accordance with the requirements of the NBIC and Section XI of the ASME Code.

Repair (applicable to RA-2200 and Part RE) – Repair of a pressure relief valve is consid-ered to be the replacement, remachining or cleaning of any critical part, lapping of the seat or disk or any other operation which may affect the pressure relief valve function or pressure-retaining integrity. Disassembly, reassembly and/or adjustments which affect the pressure relief valve function are also considered a repair. The initial installation, testing and adjustments of a new pressure relief valve on a boiler or pressure vessel are not considered a repair if made by the manu-facturer or assembler of the valve.

Repair – The work necessary to restore pres-sure-retaining items to a safe and satisfactory operating condition.

Repair (applicable to RA-2300) – The process of restoring a component or system to a safe and satisfactory condition such that the exist-ing design requirements are met.

Replacement (applicable to RA-2300) – A type of repair completed by the fabrication and installation of spare or renewal components, appurtenances, and sub-assemblies, or parts of a component or system.

Re-rating – See alteration.

“R” Certificate Holder – An organization in possession of a valid “R” Certificate of Au-thorization issued by the National Board.

Safety Relief Valves – A safety relief valve is a pressure relief valve characterized by rapid opening or pop action, or by opening in proportion to the increase in pressure over the opening pressure, depending on applica-tion.

Shop – A permanent location, the address which is shown on the Certificate of Autho-rization, from which a Certificate Holder controls the repair and/or alteration of pres-sure-retaining items.

179


Testing Laboratory – National Board accepted laboratory which performs functional and capacity tests of pressure relief devices.

Unique Identifier (applicable to RA-2200) – Repair serial number, shop order number, etc., that appears on a valve repair nameplate such that traceability to the repair documenta-tion is established.

“VR” Certificate Holder – An organization in possession of a valid “VR” Certificate of Authorization issued by the National Board.

180


181

National Board Forms

Appendix 5

182


183

APPENDIX 5 — NATIONAL BOARD FORMS

FORM R-1 REPORT OF REPAIRin accordance with provisions of the National Board Inspection Code

1. Work performed by

2. Owner

3. Location of installation

4. Unit identification Name of original manufacturer

5. Identifying nos.:

6. NBIC Edition/Addenda:

Original Code of Construction for Item:

Construction Code Used for Repair Performed:

7. Repair Type: Welded Graphite Pressure Equipment FRP Pressure Equipment8. Description of work:

Pressure Test, if applied psi MAWP psi9. Replacement Parts. Attached are Manufacturer’s Partial Data Reports or Form R-3s properly completed for the following items of this report: 10. Remarks:

CERTIFICATE OF COMPLIANCE

I, , certify that to the best of my knowledge and belief the statements in this report are correct and that all material, construction, and workmanship on this Repair conforms to the National Board Inspection Code.National Board “R” Certificate of Authorization No. expires on , Date , Signed

CERTIFICATE OF INSPECTIONI, , holding a valid Commission issued by The National Board of Boiler and Pressure Vessel Inspectors and certificate of competency issued by the jurisdiction of and employed by of have inspected the work described in this report on , and state that to the best of my knowledge and belief this work complies with the applicable requirements of the National Board Inspection Code.By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerning the work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner for any personal injury, property damage or loss of any kind arising from or connected with this inspection.Date , Signed Commissions

1 2 (name of repair organization) (Form R No.)

53 (PO No., Job No., etc.)

3 (name)

4 (address)

4 (name)

(address)

5 6 (boiler, pressure vessel)

7 8 8 8 9 (mfg serial no.) (National Board No.) (jurisdiction No.) (other) (year built)

10 10 (edition) (addenda)

11 11 (name/section/division) (edition/addenda)


55

12 (use supplemental sheet, Form R-4, if necessary)

13 54

14 (name of part, item number, data report type, mfg’s name, and identifying stamp)

15

16

17 18 19 20 21 (name of repair organization) (authorized representative)

22

23 24 25 26

19 27 28 (inspector) (National Board and Jurisdiction No.)

This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 NB-66 Rev. 10

184


185


FORM R-2 REPORT OF ALTERATIONin accordance with provisions of the National Board Inspection Code

1a. Construction performed by ____________________________________________ _________________

__________________________________________________________________________________________

1b. Design performed by ___________________________________________________________________

__________________________________________________________________________________________

2. Owner _________________________________________________________________________________

__________________________________________________________________________________________

3. Location of installation ___________________________________________________________________

__________________________________________________________________________________________

4.Unit identification ________________ Name of original manufacturer _________________________

5. Identifying nos.: ___________ __________________ _______________ ____________ ___________

6. NBIC Edition/Addenda: ____________________________ ________________________________

Original Code of Construction for Item: _____________________ ___________________________

Construction Code Used for Alteration Performed: ___________________ ____________________

7a. Description of construction work: ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

7b. Description of design scope: ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Pressure Test, if applied psi MAWP psi

8. Replacement Parts. Attached are Manufacturer’s Partial Data Reports or Form R-3s properly completed for the following items of this report:________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

9. Remarks: _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 NB-229 Rev.4

1 2 (name of “R” organization responsible for construction) (Form “R” No.)

53 (address) (PO No., Job No., etc.)

1 2 (name of “R” organization responsible for design) (Form “R” No.)


3 (name)

(address)

4 (name)

(address)

5 6 (boiler, pressure vessel)

7 8 8 8 9 (mfg serial no.) (National Board No.) (jurisdiction no.) (other) (year built)

10 10 (edition) (addenda)





13 54

14 (name of part, item number, data report type, mfg’s name, and identifying mark)

15

186


Form R-2 (back)

DESIGN CERTIFICATION

I, , certify that to the best of my knowledge and belief the statements in this report are correct and that the Design Change described in this report conforms to the National Board Inspection Code.National Board “R” Certificate of Authorization No. expires on , Date , Signed

CERTIFICATE OF DESIGN CHANGE REVIEW

I, , holding a valid Commission issued by The National Board of Boiler and Pressure Vessel Inspectors and certificate of competency issued by the jurisdiction of and employed by of have reviewed the design change as described in this report and state that to the best of my knowledge and belief such change complies with the applicable requirements of the National Board Inspection Code.By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerning the work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner for any personal injury, property damage or loss of any kind arising from or connected with this inspection.Date , Signed Commissions

CONSTRUCTION CERTIFICATION

I, , certify that to the best of my knowledge and belief the statements in this report are correct and that all material, construction, and workmanship on this Alteration conforms to the National Board Inspection Code.National Board “R” Certificate of Authorization No. expires on , Date , Signed

CERTIFICATE OF INSPECTION

I, ,holding a valid Commission issued by The National Board of Boiler and Pressure Vessel Inspectors and certificate of competency issued by the jurisdiction of and em-ployed by of have inspected the work described in this report on , and state that to the best of my knowledge and belief this work complies with the applicable requirements of the National Board Inspection Code.By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerning the work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner for any personal injury, property damage or loss of any kind arising from or connected with this inspection.Date , Signed Commissions

2 (Form “R” No.)

16

17 18 19 20 21 (name of design organization) (authorized representative)

22

23 24 25

26 27 28 (inspector) (National Board and jurisdiction no.)

16

17 18 19 20 21 (name of construction organization) (authorized signature)

22

23 24 25 26

26 27 28 (inspector) (National Board and jurisdication no.)

187


FORM R-3 REPORT OF PARTS FABRICATED BY WELDINGin accordance with provisions of the National Board Inspection Code

1. Manufactured by

2. Manufactured for

3. Design Condition specified by Code design by

4. Design Code

5. Identification of Parts

Name of Part Qty.Line No.

Manufacturer’s Identifying No.

Manufacturer’s Drawing No. MAWP

ShopHydro PSI Year Built

6. Description of Parts(a) Connections other than tubes Heads or Ends (b) Tubes

Line No.

Size and Shape

Material Spec. No.

Thickness (in.) Shape

Thickness(in.)

Material Spec. No.

Diameter(in.)

Thickness(in.)

Material Spec. No.

7. Remarks


1 2 (name of manufacturer) (Form “R” No.)


29 (name of purchaser)

30 31 (name of organization) (name of organizations)

32 33 34 35 (code type and section) (code year) (addenda year) (formula on which MAWP is based)

36 37 38 39 40 41 13 9

38 42 43 44 45 46 43 47 48 43

15

188


Form R-3 (back)


I, , certify that to the best of my knowledge and belief the statements in this report are correct and that all material, fabrication, construction, and workmanship of the described parts conforms to the National Board Inspection Code and standards of construction cited.National Board “R” Certificate of Authorization No. expires on , Date , Signed


I, ,holding a valid Commission issued by The National Board of Boiler and Pressure Vessel Inspectors and certificate of competency issued by the jurisdiction of and employed by of have inspected the parts described in this report on , and state that to the best of my knowledge and belief the parts comply with the applicable requirements of the National Board Inspection Code.By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerning the work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner for any personal injury, property damage or loss of any kind arising from or connected with this inspection.Date , Signed Commissions

2 (Form “R” No.)

16

17 18 19 20 21 (name of “R” Certificate Holder) (authorized representative)

22 23 24 25 26


189


FORM R-4 REPORT SUPPLEMENTARY SHEETin accordance with provisions of the National Board Inspection Code


2. Owner


ReferenceLine No. Continued from Form R–

Date , Signed Name

Date , Signed Commissions


1 49 2 49 (name) (Form “R” referenced)

53 49 (address) (PO No., Job No., etc.)

3 or 29 49 (name)

(address)

(name)

(address)

50

51 52

19 21 20 49 (authorized representative) (authorized representative)

19 21 20 49 (inspector) (National Board and jurisdiction no.)

190


191


GUIDE FOR COMPLETING NATIONAL BOARD FORM R REPORTS

1. Name and address of the “R” Certificate organization that performed the construction work (Line 1a) or the design (Line 1b).

2. For NBIC Report Forms registered with the National Board, indicate the sequential Form R Number assigned by the “R” Certificate organization that is registering the form; otherwise indicate “N/A”. For rerating only, the Design Organization registers the Form R-2. Where physical work is also performed, the Construction Organization registers the Form R-2.

3. Name and address of the Owner of the pressure retaining item.

4. Name and address of plant or facility where the pressure retaining item is installed.

5. Description of the pressure retaining item, such as boiler or pressure vessel.

6. Name of original manufacturer of the pressure retaining item if a boiler or pressure vessel. If other than a boiler or pressure vessel, complete if known.

7. Serial number of the pressure retaining item as assigned by the original manufacturer.

8. Identification of the pressure retaining item by applicable registration number. If in-stalled in Canada, indicate the Canadian design registration number (CRN), and list the drawing number under “other.”

9. Identify the year in which fabrication/construction of the item was completed.

10. Indicate edition and addenda of the NBIC under which this work is being performed.

11. Indicate the name, section, division, edition, and addenda of the original code of construction for the pressure retaining item. Also indicate the name, section,

division, edition, and addenda of the construction code used for the work being per-formed. If code cases are used, they shall be identified in the “Remarks” section.

12. State exact scope of work, and attach additional data, sketch, Form R-4, etc. as neces-sary. If additional data is attached, so state.

13. Indicate test pressure applied.

14. To be completed for all welded pressure components added during the work. Indicate part, item number, manufacturer’s name, stamped identification, and data report type.

15. Indicate any additional information pertaining to the work involved (e.g. routine re-pairs, code cases). For Form R-3 the part manufacturer is to indicate the extent he has performed any or all of the design function. If only a portion of the design, state which portion.

192


16. Type or print name of authorized representative of the “R” Certificate Holder.

17. Indicate National Board “R” Certificate or Authorization number.

18. Indicate month, day, and year that the “R” certificate expires.

19. Enter date certified.

20. Name of “R” Certificate organization that performed the identified work.

21. Signature of authorized representative.

22. Type or print name of Inspector.

23. Indicate Inspector’s jurisdiction.

24. Indicate Inspector’s employer.

25. Indicate address of Inspector’s employer (city and state or province).

26. Indicate month, day, and year of inspection by Inspector. In case of Routine Repairs this shall be the month, day and year the Inspector reviews the completed Routine Repair package.

27. Signature of Inspector.

28. National Board commission number of Inspector, jurisdiction, and certificate of com-petency numbers.

29. Name and address of organization that purchased the parts for incorporation into the repair or alteration, if known. If built for stock, so state.

30. Name of organization responsible for specifying the code design conditions.

31. Name of organization responsible for performing the code design, if known.

32. Name, section, and division of the design code, if known. 33. Indicate code edition year used for fabrication.

34. Indicate code addenda date used for fabrication.

35. Indicate code paragraph reference for formula used to establish the MAWP, if known.

36. Identify name of part, such as “superheater header.”

37. Indicate quantity of named parts.

38. Match line number references for identification of parts and description of parts.

193


39. Indicate manufacturer’s serial number for the named part.

40. Indicate drawing number for the named part.

41. Indicate Maximum Allowable Working Pressure for the part, if known.

42. Use inside diameter for size; indicate shape as square, round, etc.

43. Indicate the complete material specification number and grade.

44. Indicate nominal thickness of plate and minimum thickness after forming.

45. Indicate shape as flat, dished, ellipsoidal, or hemispherical.

46. Indicate minimum thickness after forming.

47. Indicate outside diameter.

48. Indicate minimum thickness of tubes.

49. Complete information identical to that shown on the Form R to which this sheet is supplementary.

50. Indicate the Form R type. Example: Form R-1, Form R-2, Form R-3

51. Indicate the reference line number from the Form R to which this sheet is supplemen-tary.

52. Complete information for which there was insufficient space on the reference Form R.

53. If applicable, purchase order, job number, etc. assigned by the organization performing the work.

54. Indicate the maximum allowable working pressure of the pressure-retaining item.

55. Indicate the type of repair, i.e., welded (RC-2000), graphite pressure equipment (Ap-pendix 8), or fiber reinforced plastic pressure equipment (Appendix 9).

194


195


FORM NR–1 REPORT OF REPAIR MODIFICATION OR REPLACEMENT TO NUCLEAR COMPONENTS AND SYSTEMS IN NUCLEAR POWER PLANTS


2. Owner

3. Name, address and identification of nuclear power plant

4. System

5a. Items Which Required Repair, Modification, or Replacement Activities

Identification Construction Code Activitity

No.Type of Item

Mfg. Name

Mfg. SerialNo.

Nat’l Bd No.

Juris.No. Other

Year Built

Name/Section/Division

Edition/Addenda

Code Case(s)

Code Class

Repair/Mod/Replace

1

2

3

4

5

6

7

8

9

10

11

12

5b. Items Installed During Replacement Activities

Identification Construction Code

Type of Item

Installed or Replaced 5a Item No.

Mfg. Name

Mfg.Serial No.

Nat’l Bd No.

Juris.No. Other

Year Built

Name/Section/Division

Edition/Addenda

Code Case(s)

Code Class

6. ASME Code Section XI applicable for inservice inspection:

7. ASME Code Section XI used for repairs, modifications, or replacements:

8. Construction Code used for repairs, modifications, or replacements:

9. Design responsibilities

10. Tests conducted: hydrostatic pneumatic design pressure pressure psi Code Case(s)

This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 NB-81

1

2 3 (name of NR certificate holder) (PO No., Job No., etc.)

(address) 5 (name)

(address) 6

7

9 10 12 13 16 17 18 19 20 20 20 21

9 22 23 24 25 26 27 28 29 30 30 30

31 31 31 32 32 32

33 33 33

34

35 35

196


11. Description of work

12. Remarks


I, , certify that to the best of my knowledge and belief the statements made in this report are correct and the repair, modification or replacement activities described above conform to Section XI of the ASME Code and the National Board Inspection Code “NR” rules.National Board Certificate of Authorization No. to use the “NR stamp expires , NR Certificate Holder

Date , Signed


I, , holding a valid commission issued by The National Board of Boiler and Pressure Ves-sel Inspectors and certificate of competency issued by the jurisdiction of and employed by

of

have inspected the repair, modification or replacement described in this report on , and state that to the best of my knowledge and belief, this repair, modification or replacement activity has been completed in accordance with

Section XI of the ASME Code and the National Board Inspection Code “NR” rules.By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concerning the work described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner for any personal injury, property damage or a loss of any kind arising from or connected with this inspection.Date , Signed Commissions

40 (use of properly identified additional sheet(s) or sketch(es) is acceptable)

41

42

43 44 45 (name) 46 47 48 (authorized representative) (title)

49 50 51 52

53


197


GUIDE FOR COMPLETING NATIONAL BOARDFORM NR-1 AND NVR-1 REPORTS

1. Indicate whether the report is to cover repair, modification, or replacement activity.

2. Name and address of the organization, as shown on the Certificate of Authorization, which performed the repair, modification, or replacement activity.

3. Indicate the purchase order number, job number, etc., as applicable, assigned by the organization which performed the work.

4. Name and address of the organization for which the work was performed.

5. Name and address of the Owner of the nuclear power plant.

6. Name and address of the nuclear power plant and, if applicable, identification of the unit.

7. Identify the system (e.g. residual heat removal, reactor coolant, etc.) with which the repair, modification, or replacement activity is associated.

8. Describe the type of pressure relief device (e.g. safety valve, safety relief valve, pressure relief valve, etc.)

9. Indicate the type of component (e.g. vessel, line valve, pump, piping system, etc.)

10. Manufacturer’s name of the repaired, modified, or replaced item.

11. Indicate the pressure relief device by the manufacturer’s valve series or catalog num-ber.

12. Manufacturer’s serial number of the repaired, modified, or replaced item.

13. National Board number, if applicable, of the repaired, modified, or replaced item.

14. Indicate the service as steam, liquid, gas, air, etc.

15. Indicate the pressure relief device by inlet size, in inches.

16. Indicate Jurisdiction number, if applicable, of the repaired, modified, or replaced item.

17. Indicate plant tag or identification number, if applicable, of the repaired, modified, or replaced item.

18. Year the repaired, modified, or replaced item was manufactured.

19. Identify the name, section, and division of the original construction Code for the re-paired, modified, or replaced item.

198


20. Identify the edition, addenda, and as applicable, Code Cases and class of the original construction Code for the repaired, modified, or replaced item.

21. Indicate the activity performed on this item, i.e. repair, modification, or replacement.

22. Indicate the Item No. from Section 5a with which this replacement item is associated. Attach the Manufacturer’s Data Report, as applicable.

23. Manufacturer’s name of this replacement item.

24. Manufacturer’s serial number of this replacement item.

25. National Board number, if applicable, of this replacement item.

26. Jurisdictional number, if applicable, of this replacement item.

27. Plant tag or identification number of this replacement item.

28. Year this replacement item was manufactured.

29. Name, section, and division of the construction Code for this replacement item.

30. Edition, addenda, and as applicable, Code Cases and class of the construction Code for this replacement item.

31. Identify the edition, addenda, and any applicable Code cases of the ASME Section XI Code used for inservice inspection.

32. Identify the edition, addenda, and any applicable Code Cases of the ASME Section XI Code for the repair, modification, or replacement activity.

33. Identify the edition, addenda, and any applicable Code Cases of the construction Code for the repair, modification, or replacement activity.

34. Identify the organization responsible for design or design reconciliation, if appli-cable.

35. Identify the type of pressure test (i.e. hydrostatic, pneumatic, or design) and applied test pressure. Also indicate any Code Cases used in connection with the pressure test.

36. Indicate the set pressure of the valve.

37. Indicate blowdown, if applicable, as a percentage of set pressure.

38. Indicate the repair organization’s name and address.

39. Indicate the medium (steam, air, etc.) used for the adjustment of set pressure and, if applicable, blowdown.

199


40. State exact scope of work for the repair, modification, or replacement activity. If nec-essary attach additional data, sketch, Form R-4, etc. If additional data is attached, so state.

41. Indicate any additional information pertaining to the work.

42. Type or print name of authorized representative from the certificate holder.

43. Indicate National Board Certificate of Authorization number.

44. Indicate month, day, and year the certificate expires.

45. Name of the certificate holder which performed the identified work.

46. Enter date certified.

47. Signature of authorized representative from the certificate holder.

48. Title of authorized representative.

49. Type or print name of Authorized Nuclear Inspector.

50. Indicate the jurisdiction where the work is performed.

51. Indicate Authorized Nuclear Inspector’s employer.

52. Indicate address of Authorized Nuclear Inspector’s employer (city and state or prov-ince).

53. Indicate month, day, and year of inspection by the Authorized Nuclear Inspector.

54. Signature of Authorized Nuclear Inspector.

55. National Board Commission number of the Authorized Nuclear Inspector, including endorsements, jurisdiction, and certificate of competency numbers.

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201


FORM NVR–1 REPORT OF REPAIR MODIFICATION OR REPLACEMENT OF NUCLEAR PRESSURE RELIEF DEVICES


2. Work performed for

3. Owner

4. Name, address and identification of nuclear power plant

5. a: Repaired pressure relief device:

b: Name of manufacturer

c: Identifying nos.

d: Construction Code

6. ASME Code Section XI applicable for inservice inspection:

7. ASME Code Section XI used for repairs, modifications, or replacements:

8. Construction Code used for repairs, modifications, or replacements:

9. Design responsibility

10. Opening pressure: Blowdown (if applicable) %. Set pressure and blowdown adjustment

made at: using

11. Description of work: (include name and identifying number of replacement parts)

12. Remarks:

CERTIFICATE OF COMPLIANCEI, , certify that to the best of my knowledge and belief the statements made in this report are correct and the repair, modification or replacement of the pressure relief devices described above conforms to Section XI of the ASME Code and the National Board Inspection Code “VR” and “NR” rules.National Board Certificate of Authorization No. to use the “VR” stamp expires , National Board Certificate of Authorization No. to use the “NR” stamp expires , Date , Signed

CERTIFICATE OF INSPECTIONI, , holding a valid commission issued by The National Board of Boiler and Pressure Vessel Inspectors and certificate of competency issued by the jurisdiction of andemployed by of have inspected the repair, modification or replacement described in this report on , and state that to the best of my knowledge and belief, this repair, modification or replacement has been completed in accordance with Section XI of the ASME Code and the National Board Inspection Code “VR” and “NR” rules.By signing this certificate, neither the undersigned nor my employer makes any warranty, expressed or implied, concern-ing the repair, modification or replacement described in this report. Furthermore, neither the undersigned nor my employer shall be liable in any manner for any personal injury, property damage or loss of any kind arising from or connected with this inspection.Date , Signed Commissions

This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 NB-160

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2 3 (name of certificate holder) (PO No., Job No., etc.)

(address)

4 (name)

5 (name)

(address)

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11 12 13 14 15 18 (type) (mfg’s serial no.) (Nat’l Bd no.) (service) (size) (year built)

19 20 20 20 20 (name/section/division) (edition) (addenda) (Code Case(s)) (code class)

31 31 31 (edition) (addenda) (Code Case(s))



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46 45 47 48

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REPLACEMENT OF STAMPED DATA FORMin accordance with provisions of the National Board Inspection Code

Submitted to Submitted by

1. Manufactured by

2. Manufactured for


4. Date installed

5. Previously installed at

6. Manufacturer’s Data Report attached No Yes

7. Item registered with National Board No Yes, NB Number

8. Item identification Year built

Type Dimensions

Mfg. serial no. Jurisdiction no.

MAWP psi Safety relief valve set at psi

9. Complete the reverse side of this report with a true facsimile of the legible portion of the nameplate.

10. If nameplate is lost or illegible, documentation shall be attached identifying the object to the Manufacturer’s Data report referenced on this form.

11. I request authorization to replace the stamped data and/or nameplate on the above describe pressure-retaining item in accordance with the rules of the National Board Inspection Code (NBIC),

Part RB-1030.

Owner’s name

Signature Date

Title

12. Authorization is granted to replace the stamped data or to replace the nameplate of the above described pressure-retaining item.

Signature Date

Jurisdiction

This form may be obtained from The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Ave., Columbus, OH 43229 NB-136 Rev.5

(name of jurisdiction) (name of owner.)

(address) (address)

(telephone no.) (telephone no.)

(name and address)

(name and address)

(address)

(chief inspector or authorized representative)

204


The following is a true facsimile of the legible portion of the item’s nameplate. (Please print. Where possible, also attach a rubbing of the nameplate.)

I certify that to the best of my knowledge and belief, the statements in this report are correct, and that the replacement information, data, and identification numbers are correct and in accordance with provisions of the National Board Inspection Code, Part RB-1030. Attached is a facsimile or rubbing of the stamping or nameplate.

Name of Original Manufacturer

Signature Date

Certificate of Authorization No. Expires

Witnessed by Employer

Signature Date Commissions

(authorized representative)

(name of inspector)

(inspector)

205


FORM NB-4NEW BUSINESS OR DISCONTINUANCE

USED BY AUTHORIZED INSPECTION AGENCIES

To: JURISDICTION 1. DATE OF SERVICE

New insurance business High pressure boiler2. Notice of: Discontinuance or cancellation 3. Effectve date 4. Type of object: Low pressure boiler Refusal to insure Pressure vessel

5. OBJECT 6. OWNER’S NO. 7. JURISDICTION NO. 8. NATIONALBOARD NO, 9. NAME OF MANUFACTURER

10. NAME OF OWNER

11. NAME OF OWNER INCLUDING COUNTY

12. LOCATION OF OBJECT INCLUDING COUNTY

13. USER OF OBJECT (IF SAME AS OWNER SHOW “SAME”)

14. DATE OF LAST CERTIFICATE INSPECT., IF ANY 15. CERTIFICATE ISSUED 16. REASON FOR DISCONTINUANCE OR CANCELLATION Yes No Phys. condition Out of use Other

17. REMARKS (USE REVERSE SIDE)

18. By: CHIEF INSPECTOR BRANCH OFFICE


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207


FORM NB-5 BOILER OR PRESSURE VESSEL DATA REPORTFIRST INTERNAL INSPECTION

Standard Form for Jurisdications Operating Under the ASME Code

DATE INSPECTED CERT EXP DATE CERTIFICATE POSTED OWNER NO. JURISDICTION NUMBER NAT’L BD NO. OTHER NO. MO | DAY | YEAR MO | YEAR Yes No

OWNER NATURE OF BUSINESS KIND OF INSPECTION CERTIFICATE INSPECTION Int Ext Yes No

OWNER STREET ADDRESS OWNERS CITY STATE ZIP NUMBER

USER’S NAME - OBJECT LOCATION SPECIFIC LOCATION IN PLANT OBJECT LOCATION - COUNTY

USER’S STREET ADDRESS USER’S CITY STATE ZIP NUMBER

TYPE FT WT CI AIR TANK WATER TANK YEAR BUILT MANUFACTURER YEAR INST New Other Second Hand

USE Power Process Steam Htg HWH HWS FUEL (BOILER) METHOD OF FIRING (BOILER) PRESSURE GAGE TESTED

Storage Heat Exchange Other Yes No

PRESSURE SAFETY-RELIEF VALVES EXPLAIN IF PRESSURE CHANGED

This Inspection Prev. Inspection Set at

IS CONDITION OF OBJECT SUCH THAT A CERTIFICATE MAY BE ISSUED? HYDRO TEST

Yes No (If no, explain fully on back of form - listing code violation) Yes psi Date No

SHELL DIAMETER ID OVERALL LENGTH THICKNESS TOTAL HTG SURFACE (BOILER) MATERIAL

No. in. OD ft. in. in. Sq Ft ASME Spec Nos

ALLOWABLE STRESS BUTT STRAP Single HEADERS - WT BOILERS TYPE

psi Thks in Double Thickness in. Box Sinuous Wtr Wall Other

TYPE LONGITUDINAL SEAM RIVITED PITCH SEAM EFF

Lap Butt Welded Brazed Rivited Dia Hole in. in. X in. X in. %

HEAD THICKNESS HEAD TYPE Fixed Movable RADIUS DISH ELLIP RATIO BOLTING

in. Plus Minus Flat Quick Opening in. No. Dia. in. Material

TUBE SHEET THICKNESS TUBES PITCH (WT BLRS) LIGAMENT EFF

in. No. Dia. in. Length ft. in. in. X in. %

FIRE TUBE DISTANCE UPPER TUBES TO SHELL STAYED AREA Above Tubes Above Tubes

BOILERS Front in. Rear in. FRONT HEAD Below Tubes REAR HEAD Below Tubes

STAYS ABOVE TUBES TYPE AREA OF STAYS

Front No. Rear No. Head to Head Diagonal Welded Weldless Front Rear

STAYS BELOWTUBES TYPE AREA OF STAYS

Front No. Rear No. Head to Head Diagonal Welded Weldless Front Rear

FURNACE - TYPE THICKNESS TOTAL LENGTH TYPE LONG. SEAM

Adamson (No. Sect .) Corrugated Plain Other in. ft. in. Welded Riveted Seamless

STAYBOLTS - TYPE DIAMETER PITCH NET AREA

Threaded Welded Hollow Drilled (Size Hole in.) in. in. X in. sq. in.

SAFETY-RELIEF VALVES TOTAL CAPACITY Cfm OUTLETS PROPERLY DRAINED

No. Size Lb/Hr Btu/Hr No. Size Yes No (If no, explain on back of form)

STOP ON STEAM LINE ON RETURN LINES OTHER CONNECTIONS STEAM LINES PROPERLY DRAINED

VALVES Yes No Yes No Yes No Yes No (If no, explain on back of form)

FEED PIPE FEED APPLIANCES TYPE DRIVE CHECK FEED LINE RETURN LINE

Size in. No. Steam Motor VALVES Yes No Yes No

WATER GAGE GLASS TRY COOKS BLOWOFF PIPE INSPECTION OPENINGS COMPLY WTH CODE

No. No. Size in. Location Yes No (If no, explain on back of form)

CAST-IRON BOILERS SECTIONS DOES WELDING ON STEAM, FEED BLOWOFF AND OTHER PIPING COMPLY WITH CODE

Length in. Width in. Height in. No. Yes No (If no, explain on back of form)

SHOW ALL CODE STAMPING ON BACK OF FORM. Give details (use sketch) for DOES ALL MATERIAL OTHER THAN AS INDICATED ABOVE COMPLY WITH CODE

special objects NOT covered above - such as Double wall vessels etc. Yes No (If no, explain on back of form)

NAME AND TITLE OF PERSON TO WHOM REQUIREMENTS WERE EXPLAINED:

I HEREBY CERTIFY THIS IS A TRUE REPORT OF MY INSPECTION IDENT NO. EMPLOYED BY IDENT NO. Signature of Inspector


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{ {

Com

plet

e W

hen

Not

Reg

iste

red

Nat

iona

l Boa

rdC

omplete W

hen Not R

egistered National Board

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OTHER CONDITIONS AND REQUIREMENTS

CODE STAMPING

(BACK)

209


FORM NB-6 BOILER-FIRED PRESSURE VESSELREPORT OF INSPECTION







TYPE YEAR BUILT MANUFACTURER

FT WT CI Other

USE FUEL METHOD OF FIRING PRESSURE GAGE TESTED

Power Process Steam Htg HWH HWS Other Yes No

PRESSURE ALLOWED SAFETY-RELIEF VALVES HEATING SURFACE OR BTU

This Inspection Prev. Inspection Set at Total Capacity


Yes No (If no, explain fully under conditions) Yes psi Date No

CONDITIONS: With respect to the internal surface, describe and state locat location and extent of any erosion, grooving, bulging, warping, c ends, coils, nipples, etc. Describe any adverse conditions baffles, supports, etc. Describe any major changes or repairs made since last inspection.

REQUIREMENTS: (List Code Violations)


I HEREBY CERTIFY THIS IS A TRUE REPORT OF MY INSPECTION

SIGNATURE OF INSPECTOR IDENT NO. EMPLOYED BY IDENT NO.


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3

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211


FORM NB-7 PRESSURE VESSELSREPORT OF INSPECTION







TYPE YEAR BUILT MANUFACTURER

AIR TANK WATER TANK Other

USE SIZE PRESSURE GAGE TESTED

Storage Process Heat Exchange Other Yes No

PRESSURE ALLOWED SAFETY-RELIEF VALVES EXPLAIN IF PRESSURE CHANGED

This Inspection Prev. Inspection Set at Total Capacity


Yes No (If no, explain fully under conditions) Yes psi Date No

CONDITIONS: With respect to the internal surface, describe and state locat location and extent of any erosion, grooving, bulging, warping, c ends, coils, nipples, etc. Describe any adverse conditions baffles, supports, etc. Describe any major changes or repairs made since last inspection.

REQUIREMENTS: (List Code Violations)


I HEREBY CERTIFY THIS IS A TRUE REPORT OF MY INSPECTION

SIGNATURE OF INSPECTOR IDENT NO. EMPLOYED BY IDENT NO.


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2

3

4

5

6

7

8

9

10

212


PRESSURE VESSEL — REPORT OF INSPECTION — (EXTENSION SHEET)

DATE OF INSPECTED OWNER-USER LOCATION

N.B. *CERT – OWNER’S JURISDICTION ASME OR NO. OF YEAR ALLOW. TEMP R.V.S.V. NO. NUMBER STD. NO. INT EXT YEARS TYPE OF OBJECT BUILT MADE BY PRESS. OF SETTING

* In this column show the number of years for which the inspector authorizes the issuance of the certificate.

213

Examples of Repairs and Alterations

Appendix 6

214


APPENDIX 6 — EXAMPLES OF REPAIRS AND ALTERATIONS

6-1000 INTRODUCTION

The purpose of this appendix is to provide owners, users, repair organizations and Inspectors with assistance in evaluating whether contemplated work on a pressure retaining item should be categorized as a repair or alteration. The significance of this categorization affects the qualifications of the organization performing the work as well as the resultant documentation.

6-2000 EXAMPLES OF REPAIRS

Repairs are defined in the Glossary. Examples of repairs are:

a. weld repairs or replacement of pressure parts or attachments that have failed in a weld or in the base material;

b. the addition of welded attachments to pressure parts, such as:

1. studs for insulation or refractory lining

2. hex steel or expanded metal for refractory lining

3. ladder clips

4. brackets, having loadings which do not affect the design of the pressure retaining item to which they are at-tached

5. tray support rings

c. corrosion resistant strip lining or weld overlay;

d. weld buildup of wasted areas;

e. replacement of heat exchanger tube sheets in accordance with the original design;

f. replacement of boiler and heat exchanger tubes where welding is involved;

g. in a boiler, a change in the arrangement of tubes in furnace walls, economizer or super heater sections;

h. replacement of pressure retaining parts identical to those existing on the pres-sure retaining item and described on the original Manufacturer’s Data Report. For example:

1. replacement of furnace floor tubes and/or sidewall tubes in a boiler

2. replacement of a shell or head in accordance with the original design

3. rewelding a circumferential or longi-tudinal seam in a shell or head

4. replacement of nozzles of a size where reinforcement is not a consideration

i. installation of new nozzles or openings of such a size and connection type that reinforcement and strength calculations are not a consideration required by the original code of construction;

j. the addition of a nozzle where reinforce-ment is a consideration may be considered to be a repair provided the nozzle is identi-cal to one in the original design, located in a similar part of the vessel, and not closer than three times its diameter from another nozzle. The addition of such a nozzle shall be restricted by any service requirements;

k. the installation of a flush patch to a pressure-retaining item;

l. the replacement of a shell course in a cylindrical pressure vessel;

A04

215

APPENDIX 6 — EXAMPLES OF REPAIRS AND ALTERATIONS

m. welding of gage holes;

n. welding of wasted or distorted flange faces;

o. replacement of slip-on flanges with weld neck flanges or vice-versa;

p. seal welding of buttstraps and rivets;

q. subject to the administrative procedures of the jurisdiction and approval of the Inspector, the replacement of a riveted section or part by welding;

r. the repair or replacement of a pressure part with a Code accepted material that has a nominal composition and strength that is equivalent to the original material, and is suitable for the intended service;

s. replacement of a pressure retaining part with a material of different nominal com-position, equal to or greater in allowable stress from that used in the original de-sign, provided the replacement material satisfies the material and design require-ments of the original code of construction under which the vessel was built.

6-3000 EXAMPLES OF ALTERATIONS

Alterations are defined in the Glossary. Examples are:

a. an increase in the maximum allowable working pressure (internal or external) or

temperature of a pressure retaining item regardless of whether or not a physical change was made to the pressure retaining item;

b. a decrease in the minimum temperature;

c. the addition of new nozzles or openings in a boiler or pressure vessel except those classified as repairs;

d. a change in the dimensions or contour of a pressure-retaining item;

e. in a boiler, an increase in the heating surface or steaming capacity such that an increase in the relieving capacity is required;

f. the addition of a pressurized jacket to a pressure vessel;

g. except as permitted in 6-2000(s), replace-ment of a pressure-retaining part in a pressure-retaining item with a material of different allowable stress or nominal composition from that used in the original design.

h. The addition of a bracket or an increase in loading on an existing bracket which affects the design of the pressure-retaining item to which it is attached.

216


217

Appendix 7

Procedures to Extend the “VR” Certificate of Authorization Stamp to ASME “NV” Stamped Pressure Relief Devices

218


APPENDIX 7 — PROCEDURES TO EXTEND THE “VR” CERTIFICATE OF AUTHORIZATION AND STAMP TO ASME “NV” STAMPED

PRESSURE RELIEF DEVICES

7-1000 INTRODUCTION

Approval to extend the scope of the National Board “VR” Certificate of Authorization to the Certificate Holder to use the “VR” stamp on ASME Code “NV” Class 1, 2 or 3 stamped pressure relief devices, which have been capacity certified by the National Board, may be given subject to the following provisions:

7-2000 ADMINISTRATIVE PROCEDURES

The repair organization shall hold a valid “VR” Certificate of Authorization.

The repair organization shall obtain a Na-tional Board “NR” Certificate of Authoriza-tion and stamp to repair, modify or replace nuclear components. The requirements for said certificate and stamp include, but are not limited to, the following. The repair organiza-tion shall:

a. Maintain a documented quality assur-ance program which meets the applicable requirements of RA-2300 of the NBIC. This program shall also include all the applicable requirements for the use of the “VR” stamp;

b. Have a contract or agreement with an Inspection Agency to provide inspection of repaired “NV” stamped pressure relief devices by Inspectors who have been qualified in accordance with the require-ments of ASME QAI-1, Qualifications for Authorized Inspection;

c. Successfully complete a survey of the qual-ity assurance program and its implemen-tation. This survey shall be conducted by representatives of the National Board, the

jurisdiction wherein the applicant’s repair facilities are located, and the applicant’s Authorized Inspection Agency. Further verification of such implementation by the survey team may not be necessary if the applicant holds a valid ASME “NV” certificate and can verify by documenta-tion the capability of implementing the quality assurance program for repair of “NV” stamped pressure relief devices, covered by the applicant’s ASME “NV” certificate.

The application of the “NR” Certificate of Authorization and stamp shall clearly define the scope of intended activities with respect to the repair of Section III “NV” stamped pres-sure relief devices.

Revisions to the quality assurance pro-gram shall be acceptable to the Authorized Nuclear Inspector Supervisor and the National Board before being implemented.

E n d o r s e m e n t o f t h e “ V R ” C e r t i f i -cate of Authorization for the repair of “NV” stamped pressure relief devices shall be granted upon acceptance by the National Board Accreditation Commit-tee on Nuclear Repair, Modification and Replacement.

Verification testing of valves repaired by the applicant shall not be required provided such testing has been successfully completed under the applicant’s “VR” certification program.

A survey of the applicant for the “VR” Certificate of Authorization and endorsement of the repair of “NV” stamped pressure relief devices may be made concurrently.

219

APPENDIX 7 — PROCEDURES TO EXTEND THE “VR” CERTIFICATE OF AUTHORIZATION STAMP TO ASME “NV” STAMPED PRESSURE RELIEF DEVICES

7-3000 GENERAL RULES

ASME Code Section III “NV” stamped pressure relief devices, which have been repaired in accordance with these rules, shall be stamped with both the “VR” and “NR” stamps.

The “VR” and “NR” stamps shall be ap-plied only to “NV” stamped (Class 1, 2 or 3) National Board capacity certified pressure relief devices which have been disassembled, inspected and repaired as necessary, such that the valves’ condition and performance are equivalent to the standards for new valves.

All measuring and test equipment used in the repair of pressure relief devices shall be calibrated against certified equipment hav-ing known valid relationships to nationally recognized standards.

Documentation of the repair of “NV” stamped pressure relief devices shall be recorded on the National Board Form NVR-1, Report of Re-pair, Modification or Replacement of Nuclear Pressure Relief Devices in accordance with the requirements of RA-2300 of the NBIC.

When an ASME “NV” Stamped Pressure Relief Device requires a duplicate name-plate because the original nameplate is illegible or missing, it may be applied using the procedures of RE-1064 provided concurrence is obtained from the Authorized Nuclear Inspector and jurisdiction. In this case the nameplate shall be marked “SEC. III” to indicate the original ASME Code stamping.

220


221

Appendix 8

Inspection, Repair and Alteration of Graphite Pressure Equipment

222


APPENDIX 8 — INSPECTION, REPAIR AND ALTERATION OF GRAPHITEPRESSURE EQUIPMENT

8-1000 SCOPE

a. The purpose of this Appendix is to provide requirements for inservice inspection, re-pair, and alteration of pressure equipment manufactured from impervious graphite materials.

b. Repair or alteration of metallic compo-nents shall comply with Part RC.

c. The impervious graphite (carbon, graph-ite, or graphite compound) used for the construction of graphite pressure ves-sels is a composite material, consisting of “raw” carbon or graphite which is impregnated with a resin using a tightly controlled pressure/heat cycle(s). The interaction between the raw material and the resin is the determining factor when considering the design characteristics of the material. The design characteristics include the strengths (flexural, compres-sive, and tensile), permeability, coefficient of thermal expansion, thermal conductiv-ity, and ultimately, the safe operating life of the vessel.

d. The process used in the manufacturing of the raw material is well documented. The expertise developed in this field allows for many different grades to be manufactured to meet the specific needs of various industries, including corrosive chemical processing pressure vessels. In the chemical processing industry the properties of the raw material are dictated by the Manufacturer of the impregnated material, based on the pressure/tempera-ture cycle and the type of resin used for impregnation. The raw material require-ments are defined and communicated to the manufacturer of the raw material. The cycle and resin type may vary from Manufacturer to Manufacturer, and also for each “grade” of impregnated material a Manufacturer produces.

e. Repairs to graphite pressure equipment require the use of certified impregnated graphite and cement. The determining factor in establishing the desired mate-rial properties is the resin impregnation cycle. If the resin impregnation cycle is not controlled, it is not possible to meet the minimum design values.

f. With over a century of experience with graphite pressure equipment, the essen-tial variables of the process have been defined and apply universally to all Manufacturers of impervious graphite equipment. Therefore, by requiring the essential variables of the resin impregna-tion cycle to be identified and verified, it is possible to assign a “lot” number to all certified materials at completion of the resin impregnation process. This can be done with the assurance of meaningful and consistent test results.

8-1010 APPLICATION

Due to inherent resistance to chemical attack, graphite pressure equipment is often used in corrosive applications, which may include lethal service.

8-1020 OPERATIONS

The owner should maintain controlled condi-tions for use of graphite pressure equipment, including the use of temperature and pressure recorders and/or operating logs. The owner should maintain operating procedures, and ensure that pressure and temperature are controlled. A thermal or pressure spike may damage the graphite or metal components.

223

APPENDIX 8 — INSPECTION, REPAIR, AND ALTERATION OF GRAPHITE PRESSURE EQUIPMENT

8-2000 INSERVICE INSPECTION

The guidelines provided in Part RB shall ap-ply to graphite pressure equipment, except as modified herein.

a. Graphite pressure vessels, pressure parts, and vessel components should receive an external visual examination biennially. All accessible surfaces should be chemi-cally cleaned. Cleaning fluids containing strong oxidants should not be used.

b. Typical indicators which may necessitate graphite pressure equipment inspection, evaluation, and repair include:

1. Cross contamination of either process or service fluids

2. External leakage is observed

3. Flow rate is reduced or excessive pres-sure drop is observed

4. Heat transfer performance is re-duced

c. Cracks, bulges, blisters, delaminations, spalling conditions, and excessive erosion are cause for repair or replacement. Any surface discoloration should be re-cleaned and examined more closely to determine if a delamination or spalling condition exists.

d. Other typical discontinuities include chipping, erosion, baffle cutting due to vibration, and cement deterioration. All passage ways are susceptible to fouling.

8-3000 REPAIRS

The requirements provided in Part RC-1020(i), RC-1060, RC-1070, RC-1110, RC-1120, RC-1140, RC-1141, RC-2020, RC-2030 and RC-2031 except (a) shall apply, insofar as they are

applicable to graphite pressure equipment. Graphite specific requirements include:

a. Organizations performing repairs shall be accredited as described in Part RA, as appropriate for the scope of work to be performed.

b. When the standard governing the origi-nal construction is not the ASME Code, repairs or alterations shall conform to the edition of the original construction standard or specification most applicable to the work. Where the original code of construction is unknown, the edition and addenda of the ASME Code most appropriate for the work shall be used, provided the “R” Certificate Holder has the concurrence of the Inspector and the jurisdiction where the pressure-retaining item is installed.

c. The materials used in making repairs or alterations shall conform to the require-ments of the original code of construction except as provided in subparagraph (j). The “R” Certificate Holder is responsible for verifying identification of existing materials from original data, drawings, or unit records and identification of the materials to be installed.

d. When ASME is the original code of con-struction, replacement parts subject to in-ternal or external pressure, which require shop inspection by an Authorized Inspec-tor, shall be fabricated by an organization having an appropriate ASME Certificate of Authorization. The item shall be inspected and stamped as required by the applicable section of the ASME Code. A completed ASME Manufacturer’s Partial Data Report shall be supplied by the manufacturer.

e. When the original code of construction is other than ASME, replacement parts subject to internal or external pressure shall be manufactured by an organization certified as required by the original code of

224


j. Graphite parts which have previously been in service in one pressure vessel should not be used in a second vessel without prior approval of the owner. Con-sideration should be given to the service condition of the previous process and possible contamination of the subsequent process.

k. Blind cracks and delaminations may not be repaired by cement injection only.

l. Cracks and porosity in tubes may not be repaired. Cracked and porous sections may be removed so that the remainder of the tube may be used. Individual tube sec-tions shall not be less than 24 in. (600 mm) in length, and the number of segments in a tube shall not exceed the quantity listed in Table 8-3000.

m. Cementing procedure specifi cations shall be qualifi ed by the repair organization. The specifi cations shall be qualifi ed as required by the code of construction. Ce-menting procedure qualifi cation shall be verifi ed by the Inspector.

TABLE 8-3000 — Permitted Quantity of Tube Segments

Total Tube Number of Number Length, ft. (m) Tube Segments Length, ft. (m) Tube Segments of JointsJoints 6 (1.8) 1 0 9 (2.7) 2 1 12 (3.7) 3 2 14 (4.3) 3 2 14 (4.3) 3 2 16 (4.9) 4 3 18 (5.5) 4 3 20 (6.1) 4 3 22 (6.7) 4 3 24 (7.3) 5 4 27 (8.3) 5 4

construction. The item shall be inspected and stamped as required by the original code of construction. Certifi cation to the original code of construction as required by the original code of construction or equivalent shall be supplied with the item. When this is not possible or practicable, the organization fabricating the part may have a National Board Certifi cate of Au-thorization; replacement parts shall be documented on Form R-3 and the “R” symbol stamp applied as described in Appendix 2.

f. Organizations performing repairs under an “R” stamp program shall register such repairs with the National Board.

g. Before signing the appropriate NBIC Form, the Inspector shall review the drawings, witness any required pressure test, assure that the required nondestructive examina-tions have been performed satisfactorily, and that the other functions necessary to assure compliance with the requirement of this Code have been performed.

h. Pressure-retaining items repaired in ac-cordance with the NBIC shall be marked as required by Appendix 2. The letter “G” shall be applied to the nameplate under the “R” stamp when graphite repairs are made. The procedure defi ned in 8-6000 may be used in lieu of the stamping and nameplate attachment requirements of Appendix 2.

i. Legible copies of the completed Form R-1, together with attachments, shall be distributed to the owner or user, the Inspector, the jurisdiction if required, and the Authorized Inspection Agency responsible for inservice inspection. Form R-1 shall be registered with the National Board. Distribution of Form R-1 and at-tachments shall be the responsibility of the organization performing the repair.

225


n. Cementing technicians shall be qualified by the repair organization. The technicians shall be qualified as required by the code of construction. A cementing technician is any individual who is responsible for proper joint preparation, cleaning parts to be joined, mixing cement, applying cement, securing the joint during the cur-ing process, and controlling the curing process.

o. All records shall be made available to the Inspector.

p. Completed repairs shall be subjected to a pressure test. The test pressure shall not be less than the maximum allowable working pressure or twice the operating pressure, whichever is lower. The hydrostatic test pressure shall be maintained for 30 min-utes.

q. Reimpregnation may be used to enhance the performance and extend the life of graphite components. Reimpregnation of graphite shall not be considered a means to restore original strength, nor shall it be considered a means to restore the original depth of impregnation.

8-3010 REPAIRS OF A ROUTINE NATURE

The following repairs shall be considered routine, and shall comply with RC-2031.

a. Machining — routine repair shall not in-clude the machining of pressure retaining parts with the exception of minor machin-ing for cleaning and joint preparation not to exceed 1/32 in. (0.8 mm) of material thickness.

b. Repair of Gasket Sufaces — remachining of gasket surfaces, reserrating, or flatten-ing is permitted if the design thickness is maintained.

c. Replacing Individual Tubes — drilling out and replacing tubes with new

tubes or repaired tubes. Only certified materials shall be used for this repair.

d. Nozzle Replacement — replacement of nozzles by removing the old nozzle and cementing a new nozzle in place. This is applicable for nozzles with inside diam-eters not exceeding 18 in. (450 mm).

e. Plugging Tubes — plugging individual tubes using accepted procedures.

f. Surface Repair — surface repair by instal-lation of plugs or inlay material shall not exceed 1 cu. in. (16 cu. cm) of total volume. Connected repairs are not to be considered routine.

g. Replacement or Addition of Non-Load Bear-ing Attachments to Pressure-Retaining Item — For attachment of non-load bearing attachments to pressure-retaining items, the cementing procedure specification need only be qualified for the pressure part and cement to be used.

Complete records of these routine repairs shall be kept for review by the Inspector. The records shall include the number of tubes re-placed or plugged and their location within the tube bundle.

8-4000 ALTERATIONS

The requirements provided in Part RC-3010, RC-3020, RC-3050, RC-3051, and RC-3052 shall apply, insofar as they are applicable to the materials discussed herein. Completed alterations shall be subjected to a pressure test not less than that required by the code of con-struction. The hydrostatic test pressure shall be maintained for a minimum of 30 minutes. The pressure shall be reduced to MAWP and maintained for inspection.

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FIGURE 8-5010-a — Typical tube-tubesheet joints

The nameplate shall be applied in accordance with Appendix 2. The letter “G” shall be ap-plied to the nameplate under the “R” stamp when graphite alterations are made. The pro-cedure defi ned in 8-6000 may be used in lieu of the stamping and nameplate attachment requirements of Appendix 2.

Organizations performing alterations under an “R” stamp program shall register such alterations with the National Board.

8-5000 REPAIR GUIDE FOR IMPERVIOUS GRAPHITE

8-5010 INTRODUCTION(See Figures 8-5010-a thru f)

This section is intended to provide suggested process and technique details for repairs. This section is nonmandatory, but should be used as a guide by the repair organization in developing specifi c repair procedures.

Damage to domes (heads), tubesheets, or nozzles is invariably a sign of improper in-stallation, operation, or maintenance. Because such damage is random in nature, each case must be analyzed separately to determine the appropriate repair procedure, and the economics of repair versus replacement.

Impervious graphite is a machinable material. Parts can be modifi ed or repaired in the fi eld, or in a repair shop.

Machining operations may be handled with high-speed steel tools. Extensive machining requires tungsten carbide or diamond tooling. No cooling or fl ushing fl uid is required, nor should either be used.

Cleanliness is important. Dusty, dirty, and chemically contaminated surfaces prevent proper cement adhesion. Poor cement adhe-sion will result in a low strength joint or a joint

which leaks. All surfaces should be neutral-ized to a pH of 7. Graphite parts should be cleaned and washed with acetone to remove all moisture.

All damage should be examined and evalu-ated to determine the cause. Identifi cation and elimination of the cause is essential in helping to prevent a recurrence.

An acetone wash on the surface of the dam-aged part is useful in identifying the full extent of the cracks. The acetone will quickly evaporate from the surface, leaving the cracks damp and clearly visible.

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FIGURE 8-5010-d — Typical tube-tube joints

FIGURE 8-5010-e — Typical edge repairmaterial inlay

FIGURE 8-5010-f — Typical nozzle connection

FIGURE 8-5010-b — Typical tube replace-ment using sleeve and insert at tubesheet joint.

FIGURE 8-5010-c — Typical Tube Replacement Using Sleeve at Tubesheet Joint

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8-5020 TYPICAL GRAPHITE FRACTURES

8-5021 MAJOR FRACTURE

An extensive fracture, such as shown inFigure 8-5021, is best repaired by completing the break and re-cementing the two pieces. Temporary steel banding around the circum-ference is a method of clamping the repair until the cement is cured.

8-5022 INTERMEDIATE FRACTURE

The break is too minor to warrant completing the fracture. A pie-shaped cut may be made and the segment re-cemented in place.

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11 plug: An undersized plug will allow the use of common size tooling.

FIGURE 8-5023 — Examples of minorfracture repair

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FIGURE 8-5022 — Example of intermedi-ate fracture repair

8-5023 MINOR FRACTURE

For minor fractures, such as those shown in Figure 8-5021, plug stitching can be used. The crack is removed by drilling and plugging a continuous chain of overlapping holes along the length and depth of fracture.

8-5030 GRAPHITE REPAIR BY PLUG STITCHING(See Figure 8-5030)

Plug stitching is a form of repair by material inlaying. In this case, the inlays are small cylindrical impervious graphite plugs. The crack or fracture is removed by drilling and plugging a continuous series of overlapping holes along its length and depth.

Most plug stitching is done with 7/8 in. (22 mm) diameter plugs. The plugs are laid out along the fracture line on a pitch of 5/8 in. (16 mm) centers. The overlap of plug material is 1/4 in. (6 mm) along the fracture line. A number of plug sizes are available and are used in repair, and the amount of overlap-ping is proportional to their diameters.

8-5031 PLUG STITCHING PROCEDURE (See Figure 8-5030)

The following procedure is defi ned for 7/8 in. (22 mm) diameter plugs11. Dimensions for other size plugs shall be adjusted propor-tionally to the diameter.

Trace the line of fracture with acetone and mark its length and direction.

Beyond the end points of the fracture (crack), one additional plug shall be installed.

FIGURE 8-5021 — Example of extensive fracture repair

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FIGURE 8-5030

Starting 5/8 in. (16 mm) beyond the end point of the crack, mark drilling centers every 5/8 in. (16 mm) along its length. Make sure there is a plug to be installed outside both end points of the line of fracture.

Drill a 1/4 in. (6 mm) pilot hole at each loca-tion.

Redrill a 7/8 in. (22 mm) hole at every other pilot hole. Holes must be drilled the full depth of the crack. The depth and direction of the crack can be checked with acetone.

A 7/8 in. (22 mm) diameter reamer may be used to true the drilled holes.

Dry fit a plug into the holes. There should be 0.005 in. to 0.010 in. (0.1 mm to 0.3 mm) clear-ance for the cement joint. At no time should there be a force fit of plugs into any drilled hole. Provisions shall be provided for venting trapped air.

Sand the O.D. surface of the plugs. Thor-oughly clean all the surfaces of the repair with acetone; plugs and drilled holes.

Apply graphite cement to both plugs and holes. All surfaces of plugs and holes to be joined are to be wetted with cement.

Insert the cemented plugs into the holes al-lowing 1/16 in. (1.5 mm) of the plug to extend beyond the surface of the graphite part.

Cure the graphite cement according to the cement Manufacturer’s instruction.

At this point, half of the plug stitch repair is completed. A row of plugs has been installed with 1/4 in. (6 mm) pilot holes between them.

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Redrill the remaining pilot holes to 7/8 in. (22 mm) diameter. The drill will remove part of the plugs which were installed. It is important to have the plugs replace all of the fracture. If the new holes do not cut into the installed plugs, it will be necessary to repeat the procedure between these holes and plug locations, to ensure that all of the crack has been repaired. The line of fracture is com-pletely removed by the overlapping effect of the graphite plugs.

After the second set of holes have been drilled, repeat the plug cementing procedures.

Contour the plugs to provide a smooth tran-sition into the adjoining surface area. The fi nished repair may be coated with a wash coat for appearance.

8-5040 FIGURES – TYPICAL PLUG STITCHING PROCEDURE(See Figure 8-5030)

Step one: Layout hole centers.Step two: Drilling pilot holes.Step three: Drilling the fi rst set of holes.Step four: Cementing and curing the fi rst set of plugs.Step fi ve: Drilling the second set of holes.Step six: Plug stitching repair completed.

8-5050 REIMPREGNATION OF GRAPHITE PARTS (TUBESHEETS, HEADS, AND BLOCKS)

As a function of time, temperature, and chemi-cal exposure, the resin used to impregnate graphite may shrink and/or degrade. As such, it is possible for voids to develop in impregnated graphite that has been in chemi-cal service for a period of time. The resin loss can vary from slight to almost complete loss of impregnation. There is no practical way to determine the amount of resin remaining

in the pores. However, a hydrostatic test will determine if the graphite has continuous porosity.

Reimpregnation of the graphite may be used to enhance the performance and extend the life of graphite components. A written reimpregnation procedure acceptable to the Inspector is required. The reimpregnation procedure shall include as a minimum:

• Decontamination and drying of the graphite component

• Subjecting the component to a vacuum• Introducing resin under pressure• Curing the resin at a specifi ed temperature

and time• Leak test

8-5060 CONTROL OF IMPREGNATION MATERIAL

Impregnation material shall be the same as that specifi ed in the Reimpregnation Proce-dure. Each impregnation material shall be traceable by the name of its manufacturer and the trade name or number of that manu-facturer.

The impregnation material manufacturer shall supply the Certifi cate Holder a Certifi cate of Analysis for each material. It shall include the following:

• Impregnation material identifi cation• Batch number(s)• Date of manufacture• Shelf life• Viscosity per ASTM D 2393• Specifi c gravity

Prior to reimpregnation, and at subsequent intervals not to exceed 14 days, the Certifi cate Holder shall test each batch of impregnation material to assure that the characteristics of the material have not changed from values specifi ed in the Reimpregnation Procedure.

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The values obtained for viscosity and specific gravity for the impregnation material shall be within the limits specified by the manu-facturer and as listed in the Reimpregnation Procedure. The test values shall be made available to the Inspector.

8-5070 FINISHING THE REPAIR

The parts should be held in place to prevent movement while curing the cemented joint to achieve a proper repair. The repair firm should take care to ensure that the cement joint thick-ness is within the range recommended by the cement Manufacturer. Care spent in precisely aligning the parts while clamping will avoid many finishing and machining operations later. Particular attention should be given to gasket and other bearing surfaces.

Gasket and bearing surfaces may have to be machined, filed, or sanded before the job is completed. Gasket serrations must be clean and continuous. Serrations can be easily re-cut into graphite and any repair plugs that cross the gasket surface.

8-6000 ALTERNATIVE MARKING AND STAMPING

General Requirementsa. This procedure may be used in lieu of the

stamping and nameplate requirements defined in Appendix 2.

b. The required data as defined in Appendix 2 shall be 5/32 in. (4 mm) high, mini-mum.

c. The National Board code symbol (“R”) shall be used to make the impression in the cement.

Application of the “R” Code Symbola. The graphite surface shall be clean and

smooth.

b. Apply a thin coating of cement onto the Code part. The cement should have the consistency of toothpaste.

c. Apply sufficient heat to the cement so that it begins to form a skin.

d. Apply a coating of a thinned release agent, such as “ANTISIEZE” to the tip of the “R” stamp with a brush.

e. Press the coated stamp all the way to the bottom of the cement and remove by pulling straight out before the cement hardens.

f. Cure or heat the impression as required.

g. When cured, the part may be washed to remove any excess release agent.

Application of characters directly to graphitea. Use a very thin template of a flexible ma-

terial (stainless steel; flexible and easily cleaned).

b. Place the template over a clean smooth surface.

c. Hold the template securely and trowel over with approved cement to fill all of the template area.

d. Carefully lift the template from the graph-ite part and examine the detail of the characters.

e. If acceptable, cure the cement.

f. If the characters are incorrect or damaged, wipe off the cement with a compatible solvent and reapply.

Note: The preceding methods can be applied jointly to identify the graphite part and to transfer the “R” stamp.

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233

Repair, Alteration and Inspection of Fiber-Re-inforced Thermosetting Plastic Pressure Equip-ment

Appendix 9Table 1 Visual Inspection Acceptance Criteria Reprinted from ASME B5.54-1992 by permission of the American Society of Mechanical Engineers. All rights reserved.

234


APPENDIX 9 — FIBER-REINFORCED THERMOSETTINGPLASTIC PRESSURE EQUIPMENT


9-1010 SCOPE

This appendix provides general requirements that apply to repairs and alterations to fiber -reinforced pressure retaining items.

The letters “RP” shall be included on the “R” Certificate of Authorization for those orga-nizations authorized to perform repairs/al-terations of fiber reinforced plastic pressure equipment.

9-1020 LIMITATIONS

All field work shall be limited to secondary bonding.

9-1030 REPAIR LIMITATIONS FOR FILAMENT WOUND VESSELS

When the MAWP is greater than 200 psig, field repair of filament wound ASME Code Section X, Class I vessels shall be limited to corrosion barrier or liner repairs only, provided there is access to the vessel interior. No structural repairs, re-rating, or alterations are allowed for filament wound ASME Code Section X, Class 1 vessels, that have an MAWP greater than 200 psig.

9-1031 VESSELS FABRICATED USING ELEVATED TEMPERATURE CURED

RESIN SYSTEMS

Repair of vessels fabricated using elevated temperature cured resin systems shall be lim-

ited to the corrosion barrier or liners only, pro-viding there is adequate access to the vessel surface that requires the repair. No structural repairs, rerating or alterations are permitted with the following exceptions:

a. Repair of vessels fabricated using elevated temperature cured material is permitted only if the following provisions are met.

1. Calculations must be submitted by a Registered Professional Engineer (P.E.) experienced in the field of FRP vessels (See 9-3022).

2. The original fabricator must provide its approval showing that the damage does not compromise the pressure rating of the vessel and that the safety factor required by the ASME Code or the original code of construction is maintained.

b. Repair that results in a revision to the pres-

sure rating of a vessel covered as a part of this section is permitted providing the new rating is less than the original rating and as long as the safety factor required by the ASME Code or the safety factor used as a design basis from the original code of construction is met in its entirety and all the requirements under 9-3000, Additional Requirements for Alterations are met.

9-1040 CODE OF CONSTRUCTION

When the standard governing the original construction is the ASME Code Section X or ASME RTP-1, repairs and alterations shall conform, insofar as possible, to the section and edition of ASME Code Section X or ASME RTP-1 most applicable to the work planned.

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APPENDIX 9 — REPAIR, ALTERATION AND INSPECTION OFFIBER-REINFORCED THERMOSETTING PLASTIC PRESSURE EQUIPMENT

When the standard governing the original construction is not the ASME Code Section X or ASME RTP-1, repairs and alterations shall conform to the original code of construction or standard. Where this is not possible, it is permissible to use other codes, standards, or specifications, including the ASME Code (Section X or RTP-1), provided the “RP” desig-nated “R” Certificate Holder (hereafter called the Certificate Holder) has the concurrence of the Inspector and the jurisdiction where the pressure retaining item is installed.

9-1050 MATERIALS

The materials used in making repairs or al-terations shall conform to the requirements of the original code of construction. All resins and reinforcements must be properly stored and prevented from being contaminated by water, soil or other impurities. The Certificate Holder is responsible for verifying identifica-tion of existing materials from original data, drawings, or units records and identification of the materials to be installed. Consideration shall be given to the condition of the existing laminate, especially in the secondary bond preparation area.

9-1060 REPLACEMENT PARTS

Replacement parts which will be subject to internal or external pressure including liquid head that are pre-assembled with or without secondary bonds shall have the fabrication performed in accordance with the original code of construction. The fabricator shall certify that the material and fabrication are in accordance with the original code of construc-tion. This certification shall be supplied in the form of bills of material and drawings with statements of certification. Examples include shell and head sections, or flanged nozzles.

When ASME is the original code of construc-tion, replacement parts subject to internal or external pressure which require shop inspection by an Authorized Inspector or by a Certified Individual as defined by ASME RTP shall be fabricated by an organization having an appropriate ASME Certificate of Authorization. The item shall be inspected and stamped or marked as required by the original code of construction. A completed ASME Fabricator’s Partial Data Report shall be supplied by the fabricator.

When the original code of construction is other than ASME, replacement parts subject to internal or external pressure shall be manufac-tured by an organization certified as required by the original code of construction. The item shall be inspected and stamped as required by the original code of construction. Certifi-cation to the original code of construction as required by the original code of construction or equivalent shall be supplied with the item. When this is not possible or practicable, the organization fabricating the part may have a National Board Certificate of Authorization. Replacement parts shall be documented on Form R-3 and the “R” symbol stamp applied as described in Appendix 2.

9-1070 SECONDARY BONDING

Secondary bonding shall be performed in accordance with the requirements of the original code of construction used for the pressure-retaining item.

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9-1071 SECONDARY BONDING PROCEDURE

SPECIFICATIONS

Secondary bonding shall be performed in accordance with the lamination procedure qualified in accordance with the original code of construction.

9-1072 PERFORMANCE QUALIFICATIONS

Secondary bonders shall be qualified for the lamination process that is used. Such qualifications shall be in accordance with the requirements of the original code of construc-tion.

9-1073 RECORDS

The Certificate Holder shall maintain a record of the results obtained in secondary bonder procedure qualifications. These records shall be certified by the Certificate Holder and shall be available to the Inspector.

9-1074 SECONDARY BONDER’S IDENTIFICATION

The Certificate Holder shall establish a system for the assignment of a unique identification mark for each secondary bonder qualified in accordance with the requirements of the NBIC. The Certificate Holder shall also estab-lish a written procedure whereby all second-ary bonds can be identified as to the secondary bonder who made them. The procedure shall be acceptable to the Inspector. The Certificate Holder shall keep a record of all secondary bonded joints and the secondary bonders who made the joints.

9-1075 SECONDARY BONDER’S CONTINUITY

The performance qualification of a secondary bonder shall be affected when one of the fol-lowing conditions occur:

a. When the secondary bonder has not made joints using a specific qualified lamination procedure during a period of eighteen (18) months or more, the bonder’s qualifica-tions for that procedure shall expire.

b. When there is specific reason to question the bonder’s ability to make secondary bonds that meet the specification, the qualification which supports the second-ary bonding that is being performed shall be revoked. All other qualifications not questioned remain in effect.

9-1080 CURING

Curing techniques shall be performed as required by the original code of construction or by the resin manufacturer’s recommenda-tions in accordance with a written procedure. The procedure shall contain the parameters for curing.

9-1090 NONDESTRUCTIVE EXAMINATION

Except as required by this appendix, the non-destructive examination (NDE) requirements, including technique, extent of coverage, procedures, personnel qualifications, and ac-ceptance criteria, shall be in accordance with the original code of construction used for the construction of the pressure-retaining item. Secondary bonded repairs and alterations shall be subjected to the same nondestructive

237


examination requirements as the original sec-ondary bonds. As a minimum, all secondary bonded joints made for repairs and alterations shall be subjected to a Barcol hardness test in accordance with ASTM D-2583 and an acetone wipe test for all polyester and vinyl ester res-ins. A visual inspection in accordance with Table 9-4100 is always required. The criteria for visual acceptance shall be the same as the original code of construction.

9-1100 PRESSURE AND ACOUSTIC EMISSION TESTS

All vessels subject to repairs other than those defined in 9-2040 shall be tested in accordance with the requirements of the original code of construction. In addition, all structural repairs and alterations shall be pressure tested. All vessels acoustic emission tested as required by the original code of construction shall be retested during the pressure test concentrating on the repaired or altered part of the vessel.

9-1110 PRESSURE GAGES, MEASUREMENT, AND EXAMINATION AND TEST

EQUIPMENT

The calibration of pressure gages, measure-ment, examination and test equipment and documentation of calibration shall be per-formed as required by the applicable standard used for construction.

9-1120 ACCEPTANCE INSPECTION

Before signing the appropriate NBIC report form, the inspector:

• shall review the drawings,

• assure the secondary bonding was per-formed in accordance with the original code of construction,

• witness any pressure or acoustic emission test,

• assure that the required nondestructive examinations have been performed sat-isfactorily, and

• that the other functions necessary to as-sure compliance with the requirements of this Code have been performed.

9-1130 STAMPING

The attaching of a nameplate to a repaired or altered vessel or tank shall indicate that the work was performed in accordance with the requirements of this Code. The attachment of a nameplate shall be done only with the knowledge and authorization of the Inspec-tor. The Certificate Holder responsible for the repair or alteration shall apply the stamping nameplate. Required stamping and nameplate information are shown in Appendix 2.

9-1140 REMOVAL OF ORIGINAL STAMPING OR

NAMEPLATE

If it becomes necessary to remove the original stamping, the Inspector shall, subject to the approval of the Jurisdiction, witness the mak-ing of a facsimile of the stamping, the oblit-eration of the old stamping, and the transfer of the stamping to the new item. When the stamping is on a nameplate, the Inspector shall witness the transfer of the nameplate to the new location. Any relocation shall be described on the applicable NBIC form. ASME Code items shall not be restamped with the ASME Code Symbol.

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9-1150 REGISTRATION OF DOCUMENTATION

Organizations performing repairs or alterations under an “R” stamp program shall register such repairs or alterations with the National Board.

9-2000 ADDITIONAL REQUIREMENTS FOR REPAIRS

9-2010 SCOPE

This section provides additional requirements for repairs to pressure-retaining items and shall be used in conjunction with 9-1000 and 9-4000.

9-2020 DRAWINGS

Drawings shall be prepared or modified to describe the repair. Drawings shall include sufficient information to satisfactorily per-form the repair.

9-2030 REPAIR PLAN

When repairs other than those defined in 9-2040 are being made to ASME Section X or RTP-1 stamped equipment, the user shall prepare or cause to have prepared a detailed plan covering the scope of the repair.

a. Professional Engineer Review The repair plan shall be reviewed and

certified by a Professional Engineer who is registered in one or more of the states of the United States of America or the provinces of Canada and is experienced in reinforced plastic vessel design. The review and certification shall be such to ensure that the work involved in the re-

pair is compatible with the User’s Design Specification or User’s Basic Requirements Specification and the Manufacturer’s De-sign Report. The certification shall also include any drawings and calculations prepared as part of the repair plan.

b. Authorized Acceptance Following review and certification, the

repair plan shall be submitted to the In-spector for his review and acceptance. Re-pairs to pressure-retaining items shall not be initiated without the authorization of the Inspector. Subject to acceptance of the Jurisdiction, the Inspector may give prior approval for routine repairs, provided the Inspector assures that the Certificate Holder has acceptable procedures cover-ing the repairs.

9-2040 ROUTINE REPAIRS

Prior to performing routine repairs, the Cer-tificate Holder should determine that routine repairs are acceptable to the jurisdiction where the work is to be performed.

a. Acceptable routine repairs are listed below:

1. The addition or repair of non-load bearing attachments to pressure-re-taining items where post curing is not required.

2. Replacement and repair of damaged corrosion liner areas in shells and heads shall not exceed 100 sq. in. (645 sq. cm.) and not exceed the original corrosion liner thickness.

b. Routine repairs may be performed under the Certificate Holder’s quality system program; however, the requirement for in-process involvement of the Inspector and stamping are waived. See 9-2070.

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c. The process of controlling and implement-ing routine repairs shall be documented in the Certificate Holder’s quality system program.

d. Routine repairs shall be documented on

a Form R-1 Repair form with a statement on line 9, Remarks: “Routine Repair”.

9-2050 REPAIR METHODS

The repair methods shall be acceptable to the inspector. Some methods of repair are contained in 9-4000.

9-2060 PRESSURE TESTING

Except as permitted in (e) below, the following requirements apply to all repairs to pressure-retaining items:

a. Repairs shall be pressure tested to 110% of the maximum allowable working pressure stamped on the pressure-retaining item using water or other liquid medium. The Certificate Holder is responsible for all activities relating to pressure testing of repairs.

b. Replacement parts used in repairs shall be pressure tested at the maximum allowable working pressure indicated on the pres-sure-retaining item being repaired.

c. During a pressure test, where the test pressure will exceed the set pressure of the pressure relief device, the device shall be prepared as recommended by the device manufacturer.

d. Hold time for the examination by the In-

spector shall be the time necessary for the Inspector to conduct the examination.

e. When pressure testing using liquids is not practical, other methods shall be used as follows:

1. The pressure test may be a pneumatic test provided the Certificate Holder has the concurrence of the Inspector, the jurisdictional authority where re-quired, and the owner. Precautionary requirements of the applicable section of the original code of construction shall be followed. In addition, a pneu-matic test shall always be monitored by acoustic emission examination.

2. For vessels designed for vacuum, a vacuum test shall be carried out to the original test vacuum level of the vessel. During the vacuum test, the vacuum source may be left connected to the vessel to compensate for leakage at fittings. All vessels acoustic emis-sion tested, as required by the original code of construction, shall be retested during the vacuum test concentrating on the repaired or altered part of the vessel.

9-2070 STAMPING

Pressure-retaining items repaired in accor-dance with the NBIC shall have a nameplate as required by Appendix 2. Subject to the acceptance of the jurisdiction and the concur-rence of the Inspector, nameplates may not be required for routine repairs (see 9-2040). In all cases, the type and extent of repairs neces-sary shall be considered prior to waiving the requirement.

9-2080 DOCUMENTATION

Repairs that have been performed in accor-dance with the NBIC shall be documented on Form R-1 as shown in Appendix 5. Form R-4 shall be used to record additional data when space is insufficient on Form R-1.

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9-2081 PREPARATION OF FORM R-1

a. Preparation of Form R-1 shall be the responsibility of the Certificate Holder performing the repair.

b An Inspector shall indicate acceptance by signing the Form R-1.

c. The Form R-3 and the Fabricator’s Data Report described in 9-1050 shall be a part of the completed Form R-1 and shall be attached thereto.

9-2082 DISTRIBUTION

Legible copies of the completed Form R-1, together with attachments, shall be distrib-uted to the owner-user, the Inspector, the jurisdiction if required, and the Authorized Inspection Agency responsible for inservice inspection. Form R-1 shall be registered with the National Board as noted in 9-1150.

Distribution of Form R-1 and attachments shall be the responsibility of the organization performing the repair.

9-3000 ADDITIONAL REQUIREMENTS FOR

ALTERATIONS

9-3010 SCOPE

This section provides additional requirements for alterations to pressure-retaining items, and shall be used in accordance with 9-1000 and 9-4000.

9-3020 DESIGN

The Certificate Holder performing altera-tions shall establish controls to ensure that all required design information, applicable

drawings, design calculations, specifications and instructions are prepared, obtained, con-trolled and interpreted to provide the basis for an alteration in accordance with the original code of construction. When a Fabricator’s Data Report is required by the original code of construction, a copy of the original Data Re-port shall be obtained for use in the design of the alteration. When the original Fabricator’s Data Report cannot be obtained, agreements on the method of establishing design basis for the alteration shall be obtained from the Inspector and the jurisdiction.

9-3021 ALTERATION PLAN

The user shall prepare or cause to have pre-pared a detailed plan covering the scope of the alteration.

a. Professional Engineer Review The alteration plan shall be reviewed and

certified by a Professional Engineer (P.E.) who is registered in one or more of the states of the United States of America or the provinces of Canada and is experi-enced in reinforced plastic vessel design. The review and certification shall be such as to ensure that the work involved in the alteration is compatible with the user’s design specification and the Fabricator’s Data Report.

b. Authorized Acceptance Following review and certification, the

alteration plan shall be submitted to the Inspector for his review and acceptance. Alterations to pressure-retaining items shall not be initiated without the autho-rization of the Inspector.

9-3022 CALCULATIONS

A set of calculations shall be completed prior to the start of any physical work. All design work shall be completed by an organization experienced in the design portion of the stan-

241


dard used for the construction of the item. All calculations for ASME Code Section X and RTP-1 alterations shall be certified by a P.E. experienced in reinforced plastic vessel design (See 9-3030). All calculations shall be made available for review by the Inspector.

9-3023 RERATING

Rerating of a pressure-retaining item by in-creasing the maximum allowable working pressure (internal or external) or temperature , or decreasing the minimum temperature shall be done only after the following requirements have been met to the satisfaction of the juris-diction at the location of the installation:

a. Revised calculations verifying the new service conditions shall be prepared in accordance with the Certificate Holders Quality Control System. Rerating calcula-tions for ASME Code Section X and RTP-1 vessels shall be performed by a P.E. expe-rienced in the design of reinforced plastic pressure vessels.

b. All rerating shall be established in

accordance with the requirements of the construction standard to which the pres-sure-retaining item was built.

c. Current inspection records verify that the pressure-retaining item is satisfactory for the proposed service conditions.

d. The pressure-retaining item has been pressure tested, as required, for the new service conditions.

This code does not provide rules for de-rat-ing pressure retaining items; however, when the MAWP and or allowable temperature of a pressure retaining item is reduced, the jurisdiction wherein the object is installed should be contacted to determine if specific procedures should be followed.

9-3024 DRAWINGS

As appropriate, drawings shall be prepared to describe the alteration. Drawings shall in-clude sufficient information to satisfactorily perform the alteration.

9-3030 PRESSURE TESTING

Except as permitted in (g) below, the follow-ing requirements apply for pressure testing of alterations to pressure-retaining items:

a. When the alteration activity involves the installation of a replacement part and/or the alteration will impact the design pres-sure, the design temperature, or the design rated capacity, a pressure test, as required by the original code of construction, shall be conducted. An acoustic emission test is also required if the original vessel was so tested, unless a nozzle whose diameter is one tenth the vessel diameter or less is being added.

The Certificate Holder is responsible for all activities related to pressure testing of replacement parts. The pressure test may be performed at the point of manufacture or point of installation.

b. The pressure test of replacement parts and connecting secondary bonds shall be tested at 1.1 times the maximum allow-able working pressure or the original test pressure, whichever is greatest.

c. During the pressure test, where the test pressure will exceed the set pressure of the pressure relief device, the device shall be prepared as recommended by the device manufacturer.

d. The liquid temperature used for pressure testing shall not be less than 40°F (4°C) nor more than 120°F (49°C) unless the

242


original pressure test was conducted at a higher temperature. If an acoustic emis-sion examination is being conducted, the temperature of the test liquid shall not vary by more than plus 5°F (3°C) or minus 10°F (6°C).

e. Hold time for the pressure test shall be a minimum of 30 minutes with an acoustic emission examination or a minimum of 4 hours without an acoustic emission ex-amination. The following procedure shall be used to retest a vessel that has been tested under the provisions of Article 6 of ASME Section X and has subsequently been repaired.

1. Load the vessel as specified in Article 6 of ASME Section X without monitor-ing for acoustic emission.

2. Hold the maximum load for at least 30 minutes.

3. Condition the vessel by holding at reduced load as required by Section V, Article 11, T-1121.

4. Retest the vessel as required by this appendix.

5. The vessel shall be judged against the evaluation criteria for subsequent loadings.

f. Hold time for the examination by the Inspector shall be the time necessary for the Inspector to conduct the inspection.

g. When pressure testing using liquids is not practical, other methods shall be used as follows:

1. The pressure test may be a pneumatic

test provided the Certificate Holder has the concurrence of the Inspector, the jurisdictional authority where re-quired, and the owner. Precautionary

requirements of the applicable section of the original code of construction shall be followed.

2. For vessels designed for vacuum, a vacuum test shall be carried out to as close as practical to the design vacuum level of the vessel. During the vacuum test the vacuum source may be left connected to the vessel to compen-sate for leakage at fittings. All vessels originally acoustic emission tested shall be retested during the vacuum test concentrating on the repaired or altered part of the vessel.

9-3040 STAMPING

The nameplate shall be applied in accordance with Appendix 2. The location of the name-plate shall be documented on the Form R-2.

9-3050 DOCUMENTATION

Alterations performed in accordance with the NBIC shall be documented on Form R-2, Report of Alteration, as shown in Appendix 5. Form R-2, Report Supplementary Sheet, shall be used to record additional data when space is insufficient on Form R-4.

9-3051 PREPARATION

The following items shall be attached to and become part of the R-2 report.

a. Preparation of Form R-2 shall be the re-sponsibility of the Certificate Holder per-forming the alteration. The Fabricator’s reports or Form R-3, as described in 9-1060, and for pressure vessels a copy of the original Fabricator’s Data Report, when available, shall be attached to and become a part of the completed Form R-2.

243


b. The Certificate Holder that certifies the “Design Change” shall complete and sign the “Design Certification” section of the Form R-2. An Inspector shall indicate acceptance of the design by signing the “Certification of Design Change Review” section of Form R-2.

c. The Certificate Holder performing the alteration shall complete and sign the “Construction Certification” section of the Form R-2. An Inspector shall indicate acceptance of the installation by signing the “Certificate of Inspection” section of Form R-2.

9-3052 DISTRIBUTION

Legible copies of the completed Form R-2, Re-port of Alteration, together with attachments, shall be distributed by the Certificate Holder performing the alteration, to the Inspector, the owner-user, and the jurisdiction, if required.

One original shall be submitted to the Na-tional Board.

9-4000 REPAIR/ALTERATION METHODS


In general, when a defective or damaged ves-sel wall is to be repaired, the total structural laminate sequence of laminate construction removed as part of the repair shall be replaced. The replacement laminate shall provide structural properties meeting or exceeding the requirement of the original construction standard. Moreover, when damage includes the corrosion barrier, a corrosion barrier of the same type, which shall meet or exceed the barrier properties of the original construction, shall replace the corrosion barrier removed as part of the repair.

The repair shall meet the requirements of the original construction standard.

9-4020 CLASSIFICATION OF REPAIRS

Vessel repairs shall be classified into the fol-lowing types:

a. Type 1a – Corrosion barrier repairs Type 1b – Corrosion barriers with preci-

sion bores b. Type 2 – Corrosion barrier and interior

structural layer repairs

c. Type 3 – External structural layer repairs

d. Type 4 – Alterations

e. Type 5 – Miscellaneous general external repairs or alterations

f. Type 6 – Thermoplastic repairs

g. Type 7 – Gel coat repairs

Each type of repair shall have its own corre-sponding general repair procedure as given in the following paragraphs.

9-4021 TYPE 1 – REPAIR OF THE CORROSION BARRIER

A corrosion barrier that has been exposed to a process may be permeated to the point that in some cases the entire corrosion barrier laminate may need to be removed.

After the Inspector has verified that the repair procedure is acceptable, the repair shall be performed by the Certificate Holder as fol-lows:

a. Surface Preparation The surface area that is damaged must be

removed by abrasive blasting or grinding,

244


to remove contaminated laminate and expose sound laminate. The edge of the repaired area must have a bevel of 2 in. minimum.

Note that any cracks, delaminations, or permeated surface must be removed. An adequate size abrasive, or proper sand-ing disc must be used to obtain a 2-3 mil anchor pattern.

Preparation of any surface requires that basic rules, common to all substrates, be followed. These rules are as outlined below:

• Surface must be free of contami-nants.

• Surface must be structurally sound.• Surface must have adequate anchor

pattern.• Surface must be dry.• Surface must be primed with recom-

mended primer.

Note: After the surface has been properly prepared, it must be kept clean and dry until laminating can be started. Dust, moisture, or traces of oil that come in contact with the surface may act as a mold release or act to inhibit the cure and prevent a good second-ary bond.

b. Applying Test Patches to Verify Adequate Surface Preparation

Test patches should be applied to any substrate that will require a secondary bond to determine the integrity of the primer bond prior to the application of the laminate.

The subsequent steps shall be followed:

1. Apply the primer (3 to 5 mils) to the prepared surface, and allow primer to cure.

2. Coat the primed surface with the same resin to be used in the laminate repair. Apply 4 in. (100 mm) x 14 in. (350 mm) piece of polyester, such as My-lar®, strip to one edge of primed area. Allow the polyester film to protrude from beneath the patch.

3. Apply two layers of 1-1/2 oz. (40 g)/sq. ft. chopped strand mat saturated with the same resin that will be used for the repair. Mat shall be 12 in. (300 mm) x 12 in. (300 mm) square.

4. Allow the mat layers to cure complete-ly, this may be verified by checking the hardness of the laminate.

5. Pry patch from surface using a screw-driver, chisel, or pry bar.

6. A clean separation indicates a poor bond.

7. Torn patch laminate or pulled sub-strate indicates that the bond is ac-ceptable.

If the bond is not adequate, go back to step (a) and repeat the procedure.

Note: If the repair area is smaller than the test patch dimensions, decrease the test patch size accordingly.

As a last resort, if the previous procedure does not provide an adequate bond, the permeated laminate must be handled differently using the following procedure:

• Hot water wash the equipment.

• Abrasive blast with #3 sand or equal and allow to completely dry.

• Prime with the recommended primer, an area 12 in. (300 mm) x 12 in. (300 mm) and apply a test patch.

245


TABL

E 9-

4021

— V

isua

l Ins

pect

ion

Acc

epta

nce

Cri

teri

a

Max

imum

Siz

e an

d C

umul

ativ

e Su

m o

f Im

perf

ectio

ns A

llow

ed A

fter R

epai

r.(S

ee G

ener

al N

otes

(a) a

nd (b

). Im

perf

ectio

ns S

ubje

ct to

Cum

ulat

ive

Sum

Lim

itatio

ns a

re in

dica

ted

with

an

aste

risk)

.

Leve

l 1

NO

NE

*1/8

in.

(3 m

m) d

ia.

max

. by

30%

of

vei

l(s)

thic

knes

s m

ax.

NO

NE

NO

NE

NO

NE

Defi

nitio

n of

Vis

ual I

nspe

ctio

n Le

vels

(to b

e Sp

ecifi

ed U

ser o

r Use

r’s A

gent

):Le

vel 1

= C

ritic

ally

Cor

rosi

on R

esis

tant

Leve

l 2 =

Sta

ndar

d C

orro

sion

Res

ista

nt

Inne

r Sur

face

Veil(

s), S

urfa

cing

Mat

Impe

rfec

tion

Nam

e

Burn

ed

Are

as

Chi

ps(s

urfa

ce)

Cra

cks

Cra

zing

(sur

face

)

Del

amin

atio

n(in

tern

al)

Defi

nitio

n of

Impe

rfec

tion

Show

ing

evid

ence

of t

herm

alde

com

posi

tion

thro

ugh

disc

ol-

orat

ion

or h

eavy

dis

tort

ion

Smal

l pie

ces b

roke

n of

f an

edge

or s

urfa

ce

Act

ual r

uptu

res o

r deb

ond

of p

ortio

ns o

f the

stru

ctur

e

Fine

cra

cks a

t the

surf

ace

of a

lam

inat

e

Sepa

ratio

n of

the

laye

rs in

a

lam

inat

e

Leve

l 2

NO

NE

*1/8

in.

(3 m

m) d

ia.

max

. by

50%

of

vei

l(s)

thic

knes

s m

ax.

NO

NE

NO

NE

NO

NE

Inte

rior L

ayer

sTh

ick

Mat

or C

hopp

ed S

tran

dSp

ray

Laye

rs

Leve

l 1

NO

NE

NO

NE

NO

NE

Leve

l 2

NO

NE

NO

NE

NO

NE

Stru

ctur

al L

ayer

sBa

lanc

e of

Lam

inat

e(In

clud

ing

Out

er S

urfa

ce)

Leve

l 1

NO

NE

*1/4

in.

(6m

m) d

ia.

or 1

/2 in

. (1

3mm

) len

gth

max

. by

1/16

(1

.5m

m) i

n.

deep

NO

NE

Max

. 1 in

.

(2

5 m

m) l

ong

by 1

/64

in.

(.4

mm

) dee

p,

max

. den

sity

3

in. (

75 m

m)

any

sq. f

t.

NO

NE

Leve

l 2

Nev

er in

mor

e th

an o

ne p

ly

and

not t

o ex

-ce

ed 1

6 sq

. in.

(1

0,50

0 m

m2 )

in a

ny v

esse

l

*1/4

in. (

6mm

) di

a. o

r 1/2

in.

(13m

m) l

engt

h m

ax. b

y 1/

16

(1.5

mm

) in.

de

ep

NO

NE

Max

. 2 in

.

(5

0 m

m) l

ong

by 1

/64

in.

(.4 m

m) d

eep,

m

ax. d

ensi

ty

5 in

. (12

5 m

m)

any

sq. f

t.

*Non

e in

thre

e pl

ies a

djac

ent

to in

terio

r la

yer,

none

la

rger

than

1

sq. i

n. (6

50

mm

2 ) in

tota

l ar

ea

Not

es

Dis

colo

ratio

n on

ly, n

ever

de

lam

inat

ion

or

deco

mpo

sitio

n

Not

to in

clud

e ar

-ea

s to

be c

over

ed

by jo

ints

246


Refe

r to

Use

r’s S

peci

ficat

ion

for q

uant

ity li

mita

tions

TABL

E 9-

4021

— V

isua

l Ins

pect

ion

Acc

epta

nce

Cri

teri

a, continued

Max

imum

Siz

e an

d C

umul

ativ

e Su

m o

f Im

perf

ectio

ns A

llow

ed A

fter R

epai

r.(S

ee G

ener

al N

otes

(a) a

nd (b

). Im

perf

ectio

ns S

ubje

ct to

Cum

ulat

ive

Sum

Lim

itatio

ns a

re in

dica

ted

with

an

aste

risk.

)

Leve

l 1

NO

NE

NO

NE

*3/1

6 in

.

(5 m

m) l

ong

max

. by

dia.

or

thic

knes

s no

t mor

e th

an

30%

of v

eil(s

) th

ickn

ess

Max

. dia

. 1/

16 in

.

(1.5

mm

) by

30%

of v

eil(s

) th

ickn

ess d

eep

Defi

nitio

n of

Vis

ual I

nspe

ctio

n Le

vels

(to b

e Sp

ecifi

ed U

ser o

r Use

r’s A

gent

):Le

vel 1

= C

ritic

ally

Cor

rosi

on R

esis

tant

Leve

l 2 =

Sta

ndar

d C

orro

sion

Res

ista

nt

Inne

r Sur

face

Veil(

s), S

urfa

cing

Mat

Impe

rfec

tion

Nam

e

Dry

Spo

t(s

urfa

ce)

Edge

Expo

sure

Fore

ign

Incl

usio

n

Defi

nitio

n of

Impe

rfec

tion

Are

as o

f sur

face

whe

re th

ere

info

rcem

ents

hav

e no

t bee

nw

ette

d w

ith re

sin.

Expo

sure

of m

ultip

le la

yers

of th

e re

info

rcin

g m

atrix

to

the

vess

el c

onte

nts,

usua

lly a

s a

resu

lt of

shap

ing

or c

ut-

ting

a se

ctio

n to

be

seco

ndar

y bo

nded

(inte

rior o

f ves

sel o

nly)

Part

icle

s inc

lude

d in

a la

mi-

nate

whi

ch a

re fo

reig

n to

its

com

posi

tion

(not

a m

inut

e sp

eck

of d

ust)

Leve

l 2

NO

NE

NO

NE

* 1/4

in.

(6

mm

) lon

g m

ax. b

y di

a.

or th

ickn

ess

not m

ore

th

an 5

0% o

f ve

il(s)

thic

k-ne

ss

Max

. dia

. 1/

16 in

. (1.

5 m

m) b

y 50

%

of v

eil(s

) th

ickn

ess

deep

Inte

rior L

ayer

(-0.1

25 in

. (3

mm

) Thi

ck)

Mat

or C

hopp

ed S

tran

dSp

ray

Laye

rs

Leve

l 1

* 1/2

in.

(1

3 m

m) l

ong

max

. by

dia.

or

thic

knes

s no

t mor

e th

an

30%

of v

eil(s

) th

ickn

ess

Max

. dia

.

1/8

in.

(3

mm

)

Leve

l 2

* 1/2

in.

(1

3 m

m) l

ong

max

. by

dia.

or

thic

knes

s no

t mor

e th

an

50%

of v

eil(s

) th

ickn

ess.

Max

. dia

.

1/8

in.

(3 m

m)

Stru

ctur

al L

ayer

Bala

nce

of L

amin

ate

(Incl

udin

g O

uter

Sur

face

)

Leve

l 1

NO

NE

NO

NE

*Dim

e si

ze,

neve

r to

pene

trat

e la

min

atio

n to

la

min

atio

n.

Max

. dia

. 3/

16 in

.(5

mm

)

Leve

l 2

NO

NE

NO

NE

*Nic

kel s

ize,

ne

ver t

o pe

netr

ate

lam

inat

ion

to

lam

inat

ion.

Max

. dia

.

1/4

in.

(6 m

m)

Not

es

Edge

s exp

osed

to

con

tent

s mus

t be

cov

ered

with

sa

me

num

ber

of v

eils

as i

nner

su

rfac

e.

Mus

t be

fully

re

sin

wet

ted

and

enca

psul

ated

.

Mus

t not

be

brea

kabl

e w

ith a

sh

arp

poin

t

Gas

eous

Bub

bles

or B

liste

rs A

ir e

ntra

pmen

t w

ithin

, on,

or b

etw

een

plie

s of

rein

forc

emen

ts,

0.01

5 in

. dia

met

er a

nd la

rger

247


TABL

E 9-

4021

— V

isua

l Ins

pect

ion

Acc

epta

nce

Cri

teri

a, continued

Max

imum

Siz

e an

d C

umul

ativ

e Su

m o

f Im

perf

ectio

ns A

llow

ed A

fter R

epai

r.(S

ee G

ener

al N

otes

(a) a

nd (b

). Im

perf

ectio

ns S

ubje

ct to

Cum

ulat

ive

Sum

Lim

itatio

ns a

re in

dica

ted

with

an

aste

risk.

)

Leve

l 1

*Max

. hei

ght

or d

iam

eter

1/

64 in

.

(.4

mm

)

*1/8

in.

(3 m

m) d

ia.

max

. by

30%

of

vei

l(s)

thic

knes

s m

ax.

Non

e m

ore

than

30%

of

veil(

s) th

ick-

ness

NO

NE

*Non

e ov

er

3/16

in.

(5 m

m) d

ia.

by 1

/16

in.

(1.5

mm

) in

hei

ght

NO

NE

Defi

nitio

n of

Vis

ual I

nspe

ctio

n Le

vels

(to b

e Sp

ecifi

ed U

ser o

r Use

r’s A

gent

):Le

vel 1

= C

ritic

ally

Cor

rosi

on R

esis

tant

Leve

l 2 =

Sta

ndar

d C

orro

sion

Res

ista

nt

Inne

r Sur

face

Veil(

s), S

urfa

cing

Mat

Impe

rfec

tion

Nam

e

Pim

ples

(s

urfa

ce)

Pit

(sur

face

)

Poro

sity

(sur

face

)

Scra

tche

s(s

urfa

ce)

Wet

Blis

ters

(sur

face

)

Wet

-Out

Inad

equa

te

Defi

nitio

n of

Impe

rfec

tion

Smal

l, sh

arp,

con

ical

el

evat

ions

on

the

surf

ace

of a

lam

inat

e.

Smal

l cra

ter i

n th

e su

rfac

e of

a la

min

ate.

Pres

ence

of n

umer

ous v

isua

l tin

y pi

ts (p

inho

les)

, app

roxi

mat

e di

men

sion

0.0

05 in

. (0.

1 m

m)

(for e

xam

ple,

5 in

. any

sq. i

n.

[650

sq. m

m.])

Shal

low

mar

ks, g

roov

es, f

ur-

row

s, or

cha

nnel

s cau

sed

by im

prop

er h

andl

ing

Roun

ded

elev

atio

ns o

f the

sur-

face

, som

ewha

t res

embl

ing

a bl

iste

r on

the

hum

an sk

in;

not r

einf

orce

d

Resi

n ha

s fai

led

to sa

tura

te

rein

forc

ing

(par

ticul

arly

wov

en ro

ving

).

Leve

l 2

*Max

. hei

ght

or d

iam

eter

1/

64 in

.(.4

mm

)

*1/8

in.

(3 m

m) d

ia.

max

. by

30%

of

vei

l(s)

thic

knes

s m

ax.

Non

e m

ore

than

50%

of

veil(

s) th

ick-

ness

NO

NE

*Non

e ov

er

3/16

in.

(5 m

m) d

ia.

by 1

/16

in.

(1.5

mm

) in

hei

ght

NO

NE

Inte

rior L

ayer

(-0.1

25 in

. (3

mm

) Thi

ck)

Mat

or C

hopp

ed S

tran

dSp

ray

Laye

rs

Leve

l 1

NO

NE

Leve

l 2

NO

NE

Stru

ctur

al L

ayer

Bala

nce

of L

amin

ate

(Incl

udin

g O

uter

Sur

face

)

Leve

l 1

No

Lim

it

*1/4

in.

(6 m

m) d

ia.

max

. by

1/16

in

. (1.

5 m

m)

deep

max

.

Leve

l 2

No

Lim

it

*1/4

in.

(6 m

m) d

ia.

max

. by

3/32

in

. (2.

5 m

m)

deep

max

.

Not

es

Mus

t be

fully

re

sin

fille

d an

d w

ette

d; g

ener

ally

ca

ptur

ed sa

ndin

g du

st

No

fiber

s may

be

exp

osed

No

fiber

s may

be

exp

osed

.

No

fiber

s may

be

exp

osed

.

Mus

t be

fully

re

sin

fille

d; n

ot

drip

s loo

sely

gl

ued

to su

rfac

e,

whi

ch a

re to

be

rem

oved

Split

test

s on

cuto

uts m

ay b

eus

ed to

dis

cern

degr

ee o

f sa

tura

tion

on

rein

forc

ing

laye

rs.

Non

e to

fully

pen

etra

te th

e ex

terio

r get

coa

t or g

et c

oate

d ex

terio

r vei

l. N

o qu

antit

y lim

it.*N

one

mor

e th

an 6

in.

long

(1

50 m

m)

No

Lim

it

*Non

e m

ore

than

12

in.

long

(3

00 m

m)

No

Lim

it

Dry

mat

or p

rom

inen

t and

dr

y w

oven

rovi

ng p

atte

rn n

ot

acce

ptab

le; d

isce

rnib

le b

ut

fully

satu

rate

d w

oven

pat

tern

ac

cept

able

.

248


TABL

E 9-

4021

— V

isua

l Ins

pect

ion

Acc

epta

nce

Cri

teri

a, continued

Max

imum

Siz

e an

d C

umul

ativ

e Su

m o

f Im

perf

ectio

ns A

llow

ed A

fter R

epai

r.(S

ee G

ener

al N

otes

(a) a

nd (b

). Im

perf

ectio

ns S

ubje

ct to

Cum

ulat

ive

Sum

Lim

itatio

ns a

re in

dica

ted

with

an

aste

risk.

)

Leve

l 1

Max

. dev

ia-

tion

20%

of

wal

l or 1

/16

in. (

1.5

mm

), w

hich

ever

is

leas

t

3 16

Defi

nitio

n of

Vis

ual I

nspe

ctio

n Le

vels

(to b

e Sp

ecifi

ed U

ser o

r Use

r’s A

gent

):Le

vel 1

= C

ritic

ally

Cor

rosi

on R

esis

tant

Leve

l 2 =

Sta

ndar

d C

orro

sion

Res

ista

nt

Inne

r Sur

face

Veil(

s), S

urfa

cing

Mat

Impe

rfec

tion

Nam

e

Wri

nkle

s an

d C

reas

es

Allo

wab

le C

u-m

ulat

ive

Sum

of

Hig

hlig

hted

Im

perf

ectio

ns

Defi

nitio

n of

Impe

rfec

tion

Gen

eral

ly li

near

, abr

upt

chan

ges i

n su

rfac

e pl

ane

caus

ed b

y la

ps o

f rei

nfor

cing

la

yers

, irr

egul

ar m

old

shap

e,

or M

ylar

® o

verla

p.

Max

imum

allo

wab

le in

any

sq

uare

feet

(sq.

0.3

m)

Max

imum

allo

wab

le in

any

sq

uare

yar

d (s

q. m

)

Leve

l 2

Max

. de

viat

ion

20%

of

wal

l or 1

/8

in. (

3 m

m),

whi

chev

er is

le

ast

5 20

Inte

rior L

ayer

(-0.1

25 in

. (3

mm

) Thi

ck)

Mat

or C

hopp

ed S

tran

dSp

ray

Laye

rs

Leve

l 1

3 20

Leve

l 2

5 30

Stru

ctur

al L

ayer

Bala

nce

of L

amin

ate

(Incl

udin

g O

uter

Sur

face

)

Leve

l 1Le

vel 2

Not

es

Not

to c

ause

a

cum

ulat

ive

linea

r de

fect

(out

side

de

fect

add

ing

to

insi

de d

efec

t)

GEN

ERA

L N

OTE

S

a. A

bove

acc

epta

nce

crite

ria a

pply

to c

ondi

tion

of la

min

ate

afte

r rep

air a

nd h

ydro

test

.

b. N

on-c

atal

yzed

resi

n is

not

per

mis

sibl

e to

any

ext

ent i

n an

y ar

ea o

f the

lam

inat

e.

5 40

Max

imum

dev

iatio

n 20

%

of w

all o

r 1/8

in. (

3 m

m),

whi

chev

er is

leas

t

5 30

249


• Prime a second spot 12 in. (300 mm) x 12 in. (300 mm) and prime with a recom-mended epoxy resin primer.

• Allow this primer to cure.

• Water wash, dry, and lightly abrasive blast the epoxy primer.

• Apply the test patches to both areas.

Pull both test patches after they are fully cured.

If both test patches are good, prime the ves-sel with the preferred primer. If only one test patch is good, prime the vessel with the suc-cessful primer.

Note: if the repair area is smaller than the test patch dimensions, decrease the test patch size accordingly.

If neither patch bonds, the vessel is probably not capable of bonding a patch and shall not be repaired.

c. Laminate Repair Repairs can be accomplished by adding

back the correct corrosion barrier surface material as specified on the Fabricator’s design drawings.

All repairs shall be made with the same type of resin and reinforcement materials used to fabricate the original vessel cor-rosion barrier. Laminate quality shall be in accordance with Table 9-4021. The ac-ceptance criteria shall be as agreed by the certificate holder and owner or as required by the code of construction.

1. Apply the selected primer (3 to 5 mils) and allow to dry to the touch.

2. Continue with the specified laminate using the proper resin and cure. The first layer of chopped strand mat used in the repair shall extend a minimum of 1 in. (25 mm) past the damaged

area. The following chopped strand mat layer shall extend a minimum of 1 in. (25 mm) past the first layer, (in this manner, the entire area that was removed will now be filled with the mat layers. If additional layers are required to fill the removed surface, they must be applied), followed by the specified layer(s) of veil. The veil(s) shall extend a minimum of 1 in. (25 mm) past the last chopped strand mat layer.

3. Apply a final coat of resin over entire surfacing veil. This final coat should contain a small amount of wax to pre-vent air contact, which might inhibit the cure. Allow laminate to achieve the manufacturer’s recommended Barcol hardness before finalizing the repair. Note: Apply heat to finalize the cure if hardness is not achieved.

9-4022 TYPE 1B – REPAIR OF THE CORROSION BARRIER FOR VESSELS WITH PRECISION BORES

Vessels with precision bores are commonly used when a device is installed inside the vessel and a seal between the device and the inside diameter is required. A corrosion bar-rier of a precision bore vessel is (susceptible) to scratching and damage that may affect performance and service life of the vessel or the device placed inside the vessel. Many times this damage may extend into areas of the vessel that cannot be reached. Before starting, ensure that the damaged area can be reached. After the Inspector has verified that the repair procedure is acceptable, the repair shall be performed by the certificate Holder as follows:

a. Surface Preparation The surface area that is damaged must be

removed by abrasive blasting or grinding, to expose sound laminate. No more than 0.020 may be removed from the wall of the

250


vessel. The repaired area shall be beveled into the good areas surrounding the dam-age.

Note that any cracks, delaminations, or permeated surfaces must be removed. If the damage is deeper than the corrosion barrier and the material removed reaches the structural laminate, the vessel is not repairable. An adequate size abrasive, or proper sanding disc must be used to obtain a 2-3 mil anchor pattern to the area that requires the repair.


• Surface must be free of contaminants• Surface must be structurally sound• Surface must have adequate anchor

pattern• Surface must be dry• Surface must be primed with recom-

mended primer

Note: After the surface has been properly prepared, it must be kept clean and dry until laminating can be started. Dust, moisture, or traces of oil that come in contact with the surface may act as a mold release or act to inhibit the cure and pre-vent a good secondary bond. Laminating should be done within two hours of the surface preparation.


Test patches may be applied to any sub-strate that will require a secondary bond to determine the integrity of the bond prior to the application of the laminate.



2. Coat the surface with the same resin to be used in the laminate repair. Apply a small strip of polyester film, such as Mylar®, strip to one edge of primed area. Allow the polyester film to pro-trude from beneath the patch.

3. Apply two layers of 1-1/2 oz. (40 g)/ sq. ft. chopped strand mat saturated with the same resin that will be used for the repair.

4. Allow the mat layers to cure complete-ly, this may be verified by checking the hardness of the laminate. If required, heat may be used to cure the material providing it is compatible with the initial resin used in the fabrication of the vessel.




If the bond is not adequate, go back to step (a) and repeat the procedure again.

Note: if the repair area is smaller than the test patch dimensions, decrease the test patch size accordingly.

If neither patch bonds, the vessel is probably not capable of bonding a patch and shall not be repaired.

251


c. Laminate repair Repairs can be accomplished by adding

back the correct corrosion barrier surface material as specifi ed on the Fabricator’s design drawings.

When possible repairs shall be made with the same type of resin and reinforcement materials used to fabricate the original vessel corrosion barrier. Laminate qual-ity shall be in accordance with Table 9-4021, or the original code of construction. However, when the original material of construction was gelled and post cured at elevated temperatures, using the same resin may not be possible. In this case an alternate resin system may be used.

1. Apply the selected primer (3 to 5 mils) (as required for polyester and vinyl ester resins) and allow to dry to the touch.

2. Continue with the specifi ed laminate using the proper resin and cure. The first layer of non-woven polyester veil used in the repair shall extend to the exact edge of the damaged area. If additional layers are required to fi ll the removed surface, they must be applied, followed by the specifi ed layer(s) of veil.

3. Apply a fi nal coat of resin over entire surfacing veil. If this fi nal coat is a vinyl ester or polyester material, it should contain a small amount of wax to prevent air contact, which might inhibit the cure. Allow laminate to achieve the manufacturer’s recom-mended Barcol hardness before fi nal-izing the repair.

Note: Apply heat to fi nalize the cure if hardness is not achieved.

4. After the repair has been properly cured, remove any excess material with the appropriate sanding tools to obtain a smooth surface that blends into the surrounding area. Care should be take to ensure that the fi nal inside diameter of the repaired area matches that of the surrounding area and also conforms to the original suppliers specifi cations.

9-4023 TYPE 2 – CORROSION BARRIER AND INTERNAL

STRUCTURAL LAYER REPAIRS

The Procedure for the Type 1a repair must be followed with the exception of additional layers (structural layers) that must be re-moved if the structure is also damaged. The repair area must be tapered similar to the Type 1, and all of the structural layers must be replaced making sure that the mat layers increase in length and width by at least 1 in. The structural laminate sequence and thick-ness must be approved by the Inspector, and proper calculations and the repair plan must be reviewed and approved by a P.E. familiar with the work involved prior to the job.

Surface preparation, priming, and laminate repair must be done per Type 1 procedure.

9-4024 TYPE 3 – EXTERNAL STRUCTURAL LAYER REPAIRS

a. Surface Preparation The surface area that is damaged is to be

repaired by removing the damaged area either by abrasive blasting or grinding to expose sound laminate. The repair area must have a bevel of 2 in. (50 mm) mini-mum. The ground or blasted surface must extend a minimum of 4 in. (100 mm) past

252


the damaged area into the sound solid structural laminate, (making sure that no layers are removed in these four inches) or as calculated accordingly.

Note that any cracks, or delaminations must be removed. An adequate size abra-sive, or proper sanding disc must be used to obtain a 2-3 mil anchor pattern.


• Surface must be free of contaminants

• Surface must be structurally sound

• Surface must have adequate anchor pattern

• Surface must be dry

• Surface must be primed with recom-mended primer

Note: After the surface has been properly prepared, it must be kept clean and dry until laminating can be started. Dust, moisture, or traces of oil that come in contact with the surface may act as a mold release or act to inhibit the cure and pre-vent a good secondary bond. Laminating should be done within two hours of the surface preparation.


Test patches may be applied to any sub-strate that will require a secondary bond to determine the integrity of the primer bond prior to the application of the lami-nate.



2. Coat the primed surface with resin to be used in the repair. Apply 4 in. (100 mm) x 14 in. (350 mm) Mylar® strip to one edge of primed area. Allow poly-ester film to protrude from beneath the patch.

3. Apply two layers of 1-1/2 oz. (40 g)/sq. ft. chopped strand mat saturated with the specified resin that will be used for the repair. Mat shall be 12 in. (300 mm) x 12 in. (300 mm) square.

4. Allow to cure completely, this may be verified by checking the hardness of the laminate.




If the bond is not adequate, go back to step 1 and prepare the surface again.

Note: If the repair area is smaller than the test patch dimensions, decrease the test patch size accordingly.

c. Laminate Repair Repairs can be accomplished by add-

ing back the correct equivalent contact molded laminate material as specified on the Fabricator’s design drawings, or in the Repair Plan.

All repairs shall be made with the same type of resin and reinforcement materi-als used to fabricate the original vessel. Laminate quality shall be in accordance with the original construction code as specified in the vessel drawings and speci-fications.

253


1. Apply the selected primer (3 to 5 mils) and allow to dry to the touch.

2. Continue with the specified laminate using the proper resin and cure.

3. Fill the removed layers with the same sequence as the original structural thickness, making sure that the layers are increasingly larger as the laminate is applied (in the case of filament wound structure, an equivalent con-tact molded thickness must be used for the repair calculations). The first bond of the repair shall cover 1 degree times the width in the axial direction and shall be centered. The repair shall extend completely around the circumference using contact molded procedures as set forth in the code of construction.

4. After the area is completely filled with the proper laminate, a reinforcing laminate shall be applied over the en-tire surface with a minimum overlap of four inches over the original shell, or as shown in the calculations, which-ever is greater. This overlay thickness shall be calculated in the same way as the reinforcing pad of a nozzle with the diameter equal to the damaged area. The design shall be in accordance with the original construction code. Allow the laminate to achieve the manufacturer’s recommended Barcol hardness before finalizing the repair. Note: Apply heat to finalize the cure if hardness is not achieved.

5. A pressure test shall be performed per 9-3030.

9-4025 TYPE 4 – ALTERATIONS

Alterations, such as the addition of a nozzle or supports, must be designed according to the original construction standard. In the case

of nozzles, the internal overlay is required according to ASME RTP-1 Figure 4-8 or 4-9 (overlay “ti”). The procedure for preparing the inside surface is the same as the Type 1 repair. The external reinforcing pad shall be designed and installed according to the original con-struction standard. Surface preparation for the external overlay shall be according to the Type 3 repair procedure.

After the alteration is completed, a pressure test shall be performed in accordance with 9-3030. As an option, an Acoustic Emission test can be performed to monitor the repaired area during the pressure test.

9-4026 TYPE 5 – MISCELLANEOUS GENERAL EXTERNAL

REPAIRS OR ALTERATIONS

External repairs or alterations that are per-formed on non-pressure containing parts, shall be calculated according to the original construction standard. The Inspector and the P.E. must review and approve such modifica-tions. All repairs and alterations shall be done according to the Type 3 repair procedure, with the exception of removing damaged layers from the structure. Surface preparation shall be restricted to the external layer of the ves-sel.

9-4027 TYPE 6 – THERMOPLASTIC REPAIRS

The surface area that is damaged must be reconditioned so that the thermoplastic liner geometry matches that of its contacting lami-nate. Surfaces that are cut or torn or missing sections shall be repaired by plastic welding. Welding practice, including choice of welding equipment, weld surface preparation, and weld temperature shall conform to Appendix M-14 of ASME RTP-1. For materials not speci-fied in these documents, the best practice as recommended by the material supplier shall be used. Welding rod, pellets, powder, or


254

plates shall be made with plastic of an iden-tical type with properties such as melt index and specifi c gravity as close as possible to the original corrosion barrier plastic.

Thickness of the repaired barrier between the wetted surface and the original surface shall be equal to or greater than the original corro-sion barrier surface specifi cation.

The repaired surface shall be capable of sup-porting the full pressure rating of the vessel at the temperature rating of the vessel with no fl uid leakage.

9-4028 TYPE 7 – GEL COAT REPAIRS

Following restoration of the structural laminate layers, a gel coat shall be applied to replace the gel coat lost in the repair. The procedure for the Type 1 repair item (a) sur-face preparation shall be followed. Gel coat of the same type is then to be applied to the surface. Gel coat thickness is to be checked with a wet thickness gage at each 36 sq. in. area element. Thickness shall be equal to or greater than the original gel coat specifi cation in the “as manufactured” state of the vessel. The entire repair surface including all seams shall be coated. There shall be at least a 3 in. overlap of gel coat at the union of repaired surface and non-repaired surface.

9-5000 INSERVICE INSPECTION

Part RB shall apply to inspection of Fiber Re-inforced Plastic (FRP) equipment, except as modifi ed herein. This section covers vessels and tanks only and was not written to cover piping and ductwork, although some of the information contained herein may be used for the inspection of piping and ductwork.

9-5100 GENERAL

Typical FRP equipment consists of the struc-tural laminate (pressure retaining material) and a liner (corrosion barrier) to protect the structural laminate; Fig 9-5100-1. The structur-al laminate is defi ned as one or more layers of reinforced resin material bonded together. In addition to damage from mechanical sources, FRP material may be susceptible to damage from acids, alkalis, compounds containing fl uorine, solvents, and hot clean water.

For equipment fabricated with a liner, the primary purpose of a process side inspection is to assure the integrity of the liner to pre-vent chemical attack and degradation of the structural laminate. For equipment fabricated without a liner, the purpose of a process side inspection is to determine the condition of the structural laminate.

In addition to chemical attack, the laminate is also susceptible to damage from:

• excessive service temperatures,• mechanical or service abuse,• ultra-violet light (See 9-5520)

Note: the liner (a) and the corrosion layer (b) are optional.a = linerb = corrosion layerc = structural laminate

Figure 9-5100-1 — Typical vessel Shell

255


9-5200 VISUAL EXAMINATION

Exposed surfaces shall be visually examined for defects, and mechanical or environmental damage in the liner or the laminate. Classifi ca-tion and acceptance of any defects in the liner or laminate shall be according to Table 9-4021 in this Appendix.

Defects to look for include:

• Cracks• Separation of secondary edges• Leaks, especially around nozzles• Discolored areas• Areas of mechanical damage such as impacts or gouges.• Surface deterioration; fi ber exposure• Cracked or broken attachments• Damage due to dynamic loading• Defective supports• Delaminations• Blisters

9-5300 INSPECTOR QUALIFICATIONS

The inspector shall be familiar with FRP equipment and qualifi ed by experience for such inspections. The inspector shall be able to read a Jaeger Type No. 1 Standard Chart at a distance of not less than 12 in. (300 mm). The inspector shall be capable of distinguishing and differentiating contrast between colors. Visual acuity shall be checked annually to assure natural or corrected near distance acuity.

9-5400 ASSESSMENT OF INSTALLATION

9-5410 PREPARATION

An observation shall be made of the condition of the complete installation, including main-

tenance and operation, as a guide in forming an opinion of the care the equipment receives. The history of the equipment shall be estab-lished, and shall include: date built, service history, maintenance, and a review of previ-ous inspection records. Process conditions shall be reviewed to identify areas most likely to be attacked. Surface cleaning procedures and requirements shall also be reviewed.

9-5420 LEAKAGE

Any leak shall be thoroughly investigated and corrective action initiated. Repairs shall be in accordance with 9-2000.

9-5430 TOOLS

The following tools may be required by the inspector.

• Adequate lighting including overall light-ing and a portable lamp for close inspec-tions

• Hand held magnifying glass• Barcol hardness tester• Small pick or pen knife• Small quantity of acetone and cotton

swabs• Camera with fl ash capability• Liquid penetrant testing kit

9-5440 SAFETY

Inspectors shall take all safety precautions when examining equipment. Proper per-sonal protective equipment shall be worn, equipment shall be locked out, blanked off, decontaminated, and confi ned space entry permits obtained before internal inspections are conducted. In addition, inspectors shall comply with plant safety rules associated with the equipment and area in which they are inspecting. Inspectors are also cautioned that a thorough decontamination of the interior of

256


vessels is sometimes very hard to obtain and proper safety precautions must be adhered to prevent contact or inhalation injury with any extraneous substance which may remain in the tank or vessel.

9-5500 EXTERNAL INSPECTION

9-5510 INSULATION OR OTHER COVERINGS

It is not necessary to remove insulation and corrosion resistant covers for examination of the pressure equipment, if the coverings show no sign of mechanical impact, gouging, scratching, leaks, etc., and there is no reason to suspect any unsafe condition behind them. Where insulation coverings are impervious, such as a sealed fiberglass jacket, it is recom-mended that weep or drain holes be installed at the bottom of the insulation jacket as a means to detect leakage.

9-5520 EXPOSED SURFACES

Exposed surfaces of pressure equipment are subject to mechanical, thermal, and environ-mental damage. Exposed surfaces may show damage from impact, gouging, abrasion, scratching, temperature excursions, etc. Sunlit areas may be degraded by ultraviolet light with a resulting change in surface color and increased fiber prominence, but with no loss in physical properties. Overheating may also cause a change in color.

9-5530

Areas that should be closely examined are:

• Nozzle attachments • Gusset attachments• Flanges• Secondary joints• Hold down lugs • Lifting lugs• Attachments.

9-5540 STRUCTURAL ATTACHMENTS

Attachments of legs, saddles, skirts, or other components shall be examined for cracks where the component attaches to or contacts the vessel and the component itself. See Figure 9-5900-r.

9-5550

Piping loads on nozzles may be excessive. Therefore, all nozzles shall be closely exam-ined for cracks as shown in Fig. 9-5900-p and 9-5900-cc.

9-5560

The location of external damage should be noted so that the opposing internal surface at that location can be examined. For example, an impact load applied to the outer surface may be transmitted through the laminate causing a star crack in the inner surface. See Figure 9-5900-t.

9-5600 INTERNAL INSPECTION

9-5610

FRP surfaces shall be dry and clean for the inspection. Every effort shall be made to mini-mize damage to the liner during inspection. Defects to look for include:

• Indentations• Cracks• Porosity• Exposed fibers• Lack of resin• Delaminations• Thinning at points of fluid impingement• Blisters• Scratches• Gouges• Discolorations.

257


9-5620 GENERAL

All surfaces shall be examined with both direct and oblique illumination. Color differ-ences, opacity, stains, wetness, roughness, or any deviation from the original surface (origi-nal cutout sample) condition shall be noted and investigated. Liquid level lines shall be defined so the laminate condition in both the wet and dry zones can be determined. The following areas should be closely examined for cracks, porosity, or chemical attacks on the liner or laminate:

• Fittings• Changes in shape• Baffles• Secondary overlays• Nozzles• Cut edges• Supports/internal structures & areas of

attachment.

9-5630 EXAMINATION

The inspector shall look for cracks, porosity, and any indication of deterioration of the liner and/or laminate. Liquid penetrant examina-tion per RT-630 of ASME Section X may be used to locate and determine the extent of cracks. Deterioration of the surface may in-clude softening or fiber prominence.

A Barcol 934-1 hardness test (ASTM D-2583) shall be performed on areas of suspected laminate degeneration and areas that appear in good condition for comparison purposes. If the average Barcol test data indicates that the surface hardness of the laminate surfacing veil is below 70% of the minimum acceptable hardness specified by the resin manufacturer for a clear resin casting, then it is recommend-ed that the inspector consult with the resin manufacturer as to the integrity of the liner laminate. Note that resin hardness values may be lower than the initial value for new equip-ment. This should not be cause for concern if the complete veil portion of the corrosion

resistant barrier is still present; retention of resin hardness is dependent on the environ-ment to which resin laminates are exposed. Even if the veil is gone, there is generally another 80-mils of corrosion resistant barrier remaining consisting of resin and chopped strand glass mat. The resin hardness of a cor-rosion barrier without the veil may be higher since the glass content of that portion of the laminate is higher. The resin hardness values should be used to monitor the condition of the laminate over time as compared to the initial hardness value. If the corrosion resis-tant barrier shows severe attack (for example, loose chopped strand glass mat fibers) that penetration of the corrosion barrier appears imminent before the next scheduled inspec-tion, it should be repaired.

9-5700 RECORD KEEPING

A detailed record of external and internal in-spections shall be retained by the owner for the life of the FRP equipment.

9-5800 INSPECTION FREQUENCY

9-5810 NEWLY INSTALLED EQUIPMENT

a. The following factors should be consid-ered when determining the frequency of inspection of FRP equipment that is new and recently placed into service.

• The distance between the FRP equip-ment and personnel or critical equip-ment

• Substance contained in the vessel is of such a nature that if abruptly released it could threaten the health or safety of personnel

• Contains chemicals or is subject to con-ditions known to degrade or shorten the life of FRP laminates

258


• Past experience has shown that the service application warrants more frequent internal and external inspec-tions

• Insurance or jurisdictional require-ments

b. FRP equipment should be externally inspected

• Once every 2 to 3 years after introduc-tion of process fluid — all findings are to be documented in the equipment inspection file for comparison to fu-ture inspection.

• If upsets outside the vessel design conditions in the process occur, exter-nal inspections shall be performed to ensure equipment integrity.

• If prior experience (i.e. if equipment was recently replaced using same material/construction) dictates that inspection frequency other than that listed is acceptable (through previ-ous inspections and records) then the inspection frequency may be altered.

c. FRP equipment should be internally in-spected:

• One year after the introduction of process fluid to establish any changes due to service and chemical environ-ment.

• After the initial first year inspection, subsequent inspections are to be established based on those results. Subsequent inspection intervals shall be documented. It is suggested to document inspections using photo-graphs.

• Some conditions may exist where en-try is prohibited and alternate means of inspection considered.

• If prior experience (i.e. if equipment was recently replaced using same material/construction) dictates that inspection frequency other than that documented is acceptable, then the inspection frequency may be altered.

• If upsets outside the vessel design conditions in the process occur, inter-nal inspections shall be performed to ensure equipment integrity.

9-5820

Previously repaired or altered equipment:

a. The following factors should be consid-ered when determining the frequency of inspection for FRP equipment.

• The distance between the FRP equip-ment and personnel or critical equip-ment

• Substance contained in the vessel is of such a nature that if abruptly released it could threaten the health or safety of personnel

• Contains chemicals or is subject to con-ditions known to degrade or shorten the life of FRP laminates

• Past experience has shown that the service application warrants more frequent internal and external inspec-tions

• Insurance or jurisdictional require-ments

b. FRP equipment should be externally in-spected:

• Annually – all findings and non-findings are to be documented in the equipment inspection file for compari-son to future inspection.

259


• If upsets outside the vessel design conditions in the process occur, exter-nal inspections need be performed to ensure equipment integrity.

• If prior experience (i.e. if equipment was recently replaced using same material/construction) dictates that inspection frequency other than that listed is acceptable (through previ-ous inspections and records) then the inspection frequency may be altered

c. FRP equipment should be internally in-spected:

• One year after the introduction of pro-cess fl uid to establish any changes due to service and chemical environment

• If upsets outside the vessel design conditions in the process occur, inter-nal inspections need be performed to ensure equipment integrity

• Based on the initial fi rst year inspec-tion subsequent inspections are to be established based on those document-ed results and the results documented. It is suggested to document using pho-

tographs of the interior inspection

• If prior experience (i.e. if equipment was recently replaced using same material/construction) dictates that inspection frequency other than that listed is acceptable (through previ-ous inspections and records) then the inspection frequency may be altered

• Some conditions may exist where en-try is prohibited and alternate means of inspection must be considered

9-5900

The following pages contain photographs of typical conditions that may exist in inservice FRP vessels and piping.

Note: Figures 9-5900-j through 9-5900-u were reprinted with permission of the Copyright Owner. © MATERIALS TECHNOLOGY IN-STITUTE, INC. (2002). The captions of the fi g-ures were revised by the NBIC Committee.

260


261


Figure 9-5900-a — Excessive Heat

Figure 9-5900-b — Laminate Voids at Overlays

262


Figure 9-5900-c — HCL Attack

Figure 9-5900-d — Blisters

263


Figure 9-5900-e — Surface Erosion

Figure 9-5900-f — Corrosion/Erosion

264


Figure 9-5900-g — Cracks

Figure 9-5900-h — Corrosion (Loss of Veil)

265


Figure 9-5900-i — Shell Fracture

Figure 9-5900-j — Concentrated Sulfuric Acid Attack

266


Figure 9-5900-k — Small Blister and Cracked Veil

Figure 9-5900-l — Fiber Prominence

267


Figure 9-5900-m — Color Change

Figure 9-5900-n — Cut Edge Evaluation

268


Figure 9-5900-o — Erosion in the Liner

Figure 9-5900-p — Cracked Flange

269


Figure 9-5900-q — Gouge

Figure 9-5900-r — Gusset Crack

270


Figure 9-5900-s — Cracks at the Knuckle

Figure 9-5900-t — Star Craze in Corroded Liner

271


Figure 9-5900-u — Sulfuric Acid Attack and Theraml Shock

Figure 9-5900-v — Exposed Liner with Air Bubbles

272


Figure 9-5900-w — Deleminations and Blisters

Figure 9-5900-x — Flange Cracking

273


Figure 9-5900-y — EPDM Gasket (Over Tongue)

Figure 9-5900-z — Incorrect Gusset Attachment

274


Figure 9-5900-aa — Star Craze

Figure 9-5900-bb — Improper Use of Putty

275


Figure 9-5900-cc — Cracked Flange

276


277

Standard Welding Procedures

Appendix A

278


APPENDIX A — STANDARD WELDING PROCEDURES

One or more Standard Welding Procedure Specifications (WPSs) from the following list may be used as an alternative to one or more WPS documents qualified by the organization making the repair, or alteration provided the organization accepts by certification (contained therein) full responsibility for the application of the Standard WPS in conformance with the application as stated in the SWP. When using SWPs, all variables listed on the standard welding procedure are considered essential and, therefore, the repair organization cannot deviate, modify, amend or revise any SWP. Standard welding procedures shall not be used in the same product joint together with other standard welding procedures or other welding procedure specifications qualified by the organization.

CARBON STEEL — (P1 MATERIALS)

SMAW — Shielded Metal Arc WeldingStandard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel, (M-1/P-1, Group 1 or 2), 3/16 in. (5 mm) through 3/4 in. (19 mm), in the As-Welded Condition, With Backing.

B2.1.001-90

Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E7018, As-Welded or PWHT Condition.

B2.1-1-016-94

Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E6010, As-Welded or PWHT Condition.

B2.1-1-017-94

Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E6010 (Vertical Uphill) Followed by E7018, As-Welded or PWHT Condition.

B2.1-1-022-94

Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E6010 (Vertical Downhill) Followed by E7018, As-Welded or PWHT Condition.

B2.1-1-026-94

Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, E6010 (vertical uphill) followed by E7018, As-Welded Condition, Primarily Pipe Application.

B2.1-1-201-96

Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, E6010 (vertical uphill), As-Welded Condition, Primarily Pipe Ap-plication.

B2.1-1-203-96

A04

279

APPENDIX A - STANDARD WELDING PROCEDURES

Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, E6010 (vertical downhill root with balance vertical uphill), As-Welded Condition, Primarily Pipe Application.

B2.1-1-204-96

Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, E6010 (vertical uphill) followed by E7018, As-Welded or PWHT Condition, Primarily Pipe Application.

B2.1-1-205-96

Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, E6010 (vertical downhill) followed by E7018, As-Welded or PWHT Condition, Primarily Pipe Application.

B2.1-1-206-96

Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, E7018, As-Welded or PWHT Condition, Primarily Pipe Application.

B2.1-1-208-96

GTAW — Gas Tungsten Arc WeldingStandard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding of Carbon Steel, (M-1/P-1, Group 1 or 2), 3/16 in. (5 mm) through 7/8 in. (22 mm), in the As-Welded Condition, With or Without Backing.

B2.1.002-90

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, ER70S-2, As-Welded or PWHT Condition, Primarily Pipe Applica-tion.

B2.1-1-207-96

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding (Consumable Insert) of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, INMs1 and ER70S-2, As-Welded or PWHT Condition, Primarily Pipe Application.

B2.1-1-210-96

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding with Consumable Insert Root of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 1-1/2 in. Thick, INMs-1, ER70S-2, As-Welded or PWHT Condition, Primarily Pipe Applications.

B2.1-1-210:2001

280


FCAW — Flux Core Arc WeldingStandard Welding Procedure Specification (WPS) for Self-Shielded Flux Cored Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E71T-8, As-Welded Condition.

B2.1-1-018-94

Standard Welding Procedure Specification (WPS) for CO2 Shielded Flux Cored Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E70T-1 and E71T-1, As-Welded Condition.

B2.1-1-019-94

Standard Welding Procedure Specification (WPS) for 75% Ar/25% CO2 Shielded Flux Cored Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, E70T-1 and E71T-1, As-Welded or PWHT Condition.

B2.1-1-020-94

Standard Welding Procedure (SWP) for Self-Shielded Flux Cored Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1/2 in. Thick, E71T-11, As-Welded Condition.

B2.1-1-027-1998

Carbon Steel — Combination Processes GTAW/SMAWStandard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding Followed by Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2), 1/8 through 1-1/2 in. Thick, ER70S-2 and E7018, As-Welded or PWHT Condition.

B2.1-1-021-94

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding followed by Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, ER70S-2 and E7018, As-Welded or PWHT Condition, Primarily Pipe Application.

B2.1-1-209-96

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding (Consumable Insert) Followed by Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 3/4 in. thick, INMs1 and E7018, As-Welded or PWHT Condition, Primarily Pipe Ap-plication.

B2.1-1-211-96

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding with Consumable Insert Root Followed by Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Group 1 or 2) 1/8 through 1-1/2 in. Thick, INMs-1, ER70S-2 and E7018 As-Welded or PWHT Condition, Primarily Pipe Applications.

B2.1-1-211:2001

281


AUSTENITIC STAINLESS STEEL — (P8 MATERIALS)

SMAW — Shielded Metal Arc WeldingStandard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, As-Welded Condition.

B2.1-8-023-94

Standard Welding Procedure Specification (WPS) for Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 2-1/2 in. thick, E3XX-XX, As-Welded Condition, Primarily Pipe Application.

B2.1-8-213-97

GTAW — Gas Tungsten Arc WeldingStandard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, As-Welded Condition.

B2.1-8-024-94

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/16 through 1-1/2 in. Thick, ER3XX, As-Welded Condition, Primarily Plate and Structural Applications.

B2.1-8-024:2001

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 2-1/2 in. thick, ER3XX, As-Welded Condition, Primarily Pipe Application.

B2.1-8-212-97

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/16 through 1-1/2 in. Thick, ER3XX, As-Welded Condition, Primarily Pipe Applications.

B2.1-8-212:2001

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding With Consumable Insert Root of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, IN3XX and ER3XX As-Welded Condition, Primarily Pipe Application.

B2.1-8-215-2001

282


Carbon Steel — Combination Processes GTAW/SMAWStandard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding followed by Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, As-Welded Condition.

B2.1-8-025-94

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding followed by Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1) 1/8 through 1-1/2 in. Thick, ER3XX and E3XX-XX, As-Welded Condition, Primarily Plate and Structural Applications.

B2.1-8-025:2001

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding Followed by Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 2-1/2 in. thick, ER3XX and E3XX-XX, As-Welded Condition, Primarily Pipe Application.

B2.1-8-214-97

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding Followed by Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, ER3XX and E3XX-XX, As-Welded Condition, Primarily Pipe Applications.

B2.1-8-214:2001

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding With Consumable Insert Followed by Shielded Metal Arc Weld-ing of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, IN3XX, ER3XX, and E3XX-XX As-Welded Condition, Primarily Pipe Application.

B2.1-8-216-1998

Standard Welding Procedure Specification (WPS) for Gas Tungsten Arc Welding with Consumable Insert Root followed by Shielded Metal Arc Welding of Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 in. Thick, IN3XX, ER3XX and E3XX-XX As-Welded Condition, Primarily Pipe Applications.

B2.1-8-216-2001

COMBINATION CARBON STEEL TO AUSTENITIC STAINLESS STEEL

SMAW — Shielded Metal Arc WeldingStandard Welding Procedure Specifications (SWPS) for Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Groups 1 or 2) to Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 inch Thick, E309(L)-15, -16, or -17, As-Welded Condition, Primarily Pipe Applications.

B2.1-1/8-228:2002

283


GTAW — Gas Tungsten Arc WeldingStandard Welding Procedure Specification (SWPS) for Gas Tungsten Arc Welding of Carbon Steel (M-1/P-1/S-1, Groups 1 or 2) to Austentic Stainless Steel (M-8/P-8/S-8, Group 1), 1/16 through 1-1/2 inch Thick, ER309(L), As-Welded Condition, Primarily Pipe Applications.

B2.1-1/8-227:2002

Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding with Consumable Insert Root of Carbon Steel (M-1/P-1/S-1, Groups 1 or 2) to Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/16 through 1-1/2 inch Thick, IN309 and ER309(L), As-Welded Condition, Primarily Pipe Applications.

B2.1-1/8-230:2002

Carbon Steel — Combination Processes GTAW/SMAWStandard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding followed by Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1,Groups 1 or 2) to Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 inch Thick, ER309(L) and E309(L)-15, -16, or -17, As-Welded Condition, Primarily Pipe Applications.

B2.1-1/8-229:2002

Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding with Consumable Insert Root followed by Shielded Metal Arc Welding of Carbon Steel (M-1/P-1/S-1, Groups 1 or 2) to Austenitic Stainless Steel (M-8/P-8/S-8, Group 1), 1/8 through 1-1/2 inch Thick, IN3009, ER309, and E309-15, -16, or -17 or IN309, ER309(L) and ER309(L)-15, -16, or -17, As-Welded Condition, Primarily Pipe Applications.

B2.1-1/8-231:2002

CHROMIUM MOLYBDENUM STEEL (P4 AND P5A MATERIALS)SMAW — Shielded Metal Arc WeldingStandard Welding Procedure Specifications (SWPS) for Shielded Metal Arc Welding of Chromium-Molybdenum Steel (M-4/P-4, Group 1 or 2), E8018-B2, 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 1-1/2 in. Thick, PWHT Condition, Primarily Pipe Applications.

B2.1-4-218:1999

Standard Welding Procedure Specifications (SWPS) for Shielded Metal Arc Welding of Chromium-Molybdenum Steel (M-5A/P-5A), E9018-B3, 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 in. through 1-1/2 in. Thick, PWHT Condition, Primarily Pipe Applications.

B2.1-5A-223:1999

284


GTAW — Gas Tungsten Arc WeldingStandard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding of Chromium-Molybdenum Steel (M-4/P-4, Group 1 or 2), ER80S-B2, 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 3/4 in. Thick, PWHT Condition, Primarily Pipe Applications.

B2.1-4-217:1999

Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding (Consumable Insert Root) of Chromium-Molybdenum Steel (M-4/P-4, Group 1 or 2), E8018-B2, 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 3/4 in. Thick, PWHT Condition, IN515 and ER80S-B2, Primarily Pipe Applications.

B2.1-4-220:1999

Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding of Chromium-Molybdenum Steel (M-5A/P-5A), ER90S-B3, 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 3/4 in. Thick, PWHT Condition, Primarily Pipe Applications.

B2.1-5A-222:1999

Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding (Consumable Insert Root) of Chromium-Molybdenum Steel (M-5A/P-5A), 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 3/4 in. Thick, PWHT Condition, IN521 and ER90S-B3, Primarily Pipe Applications.

B2.1-5A-225:1999

Chromium-Molybdenum Steel Processes GTAW/SMAWStandard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding followed by Shielded Metal Arc Welding of Chromium-Molybdenum Steel (M-4/P-4, Group 1 or 2), 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 1-1/2 in Thick, PWHT Condition, ER80S-B2 and E8018-B2, Primarily Pipe Applications.

B2.1-4-219:1999

Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding (Consumable Insert Root) followed by Shielded Metal Arc Welding of Chromium-Molybdenum Steel (M-4/P-4, Group 1 or 2), 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 1-1/2 in. Thick, PWHT Condition, IN515, ER80S-B2, and E8018-B2, Primarily Pipe Applications.

B2.1-4-221:1999

Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welded followed by Shielded Metal Arc Welding of Chromium-Molybdenum Steel (M-5A/P-5A), 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 1-1/2 in. Thick, PWHT Condition, ER90S-B3 and E9018-B3, Primarily Pipe Applications.

B2.1-5A-224:1999

285


Standard Welding Procedure Specifications (SWPS) for Gas Tungsten Arc Welding (Consumable Insert Root) followed by Shielded Metal Arc Welding of Chromium-Molybdenum Steel (M-5A/P-5A), 1/8 through 1/2 in. Thick, As-Welded Condition, 1/8 through 1-1/2 in. Thick, PWHT Condition, IN521, ER90S-B3, and E9018-B3, Primarily Pipe Applications.

B2.1-5A-226:1999

286


287

Recommended Preheat Temperatures

Appendix B

288


APPENDIX B — RECOMMENDED PREHEAT TEMPERATURES

B-1000 SCOPE

Some minimum temperatures for preheat-ing are given below as a general guide. It is cautioned that the preheating temperatures listed do not necessarily ensure satisfactory completion of the welded joint. Require-ments for individual materials within the P-Number listing may have preheating requirements more or less restrictive than this general guide. When reference is made in this Appendix to materials by the ASME designation, P-Number and Group Num-ber, the suggestions of this Appendix apply to the applicable materials of the original code of construction, either ASME or other, which conform by chemical composition and mechanical properties to ASME materials hav-ing the ASME P-Number and Group Number designations. (See RC-1101)

B-2000 MINIMUM TEMPERATURES FOR PREHEATING

Thicknesses referenced to are nominal at the weld for the parts to be joined.

1. P-No. 1 Group Nos. 1, 2 and 3

a. 175˚F (79˚C) for material which has both a specified maximum carbon content in excess of 0.30% and a thick-ness at the joint in excess of 1 in.

b. 50˚F (10˚C) for all other materials in this P-Number.


a. 175˚F (79˚C) for material which has either a specified minimum tensile strength in excess of 70,000 psi (480 MPa) or a thickness at the joint in excess of 5/8 in. (16 mm).


3. P-No. 4 Group Nos. 1 and 2

a. 250˚F (120˚C) for material which has either a specified minimum tensile strength in excess of 60,000 psi (410 MPa) or a thickness at the joint in excess of 1/2 in. (13 mm).


4. P-No. 5A Group 1 and 5B, Group 1

a. 400˚F (205˚C) for material which has either a specified minimum ten-sile strength in excess of 60,000 psi (410 MPa) or has both a specified mini-mum chromium content above 6.0% and thickness at the joint in excess of 1/2 in. (13 mm).



400˚F (205˚C)


None


None

8. P-No. 9 Group

a. 250˚F (120˚C) for P-9A Gr. 1 materi-als

b. 300˚F (150˚C) for P-9B Gr. 1 materials

289

APPENDIX B — RECOMMENDED PREHEAT TEMPERATURES

9. P-No. 10 Group

a. 175˚F (79˚C) for P-10A Gr. 1 materi-als

b. 250˚F (120˚C) for P-10B Gr. 2 materi-als

c. 175˚F (79˚C) for P-10C Gr. 3 materi-als

d. 250˚F (120˚C) for P-10F Gr. 6 materi-als

e. For P-10C Gr. 3 materials, preheat is neither required nor prohibited, and consideration shall be given to the limitation of interpass temperature for various thicknesses to avoid det-rimental effects on the mechanical properties of heat treated material.

f. For P-10D Gr. 4 and P-10E Gr. 5 materials, 300˚F (150˚C) with interpass temperature maintained between 350˚F and 450˚F (175˚C and 230˚C).

10. P-No. 11 Group

a. P-11A Group Group 1 - None (Note 1) Group 2 - Same as for P-No. 5

(Note 1) Group 3 - Same as for P-No. 5

(Note 1) Group 4 - 250˚F (120˚C)

b. P-11B Group Group 1 - Same as for P-No. 3







(Note 1)

Note 1: Consideration shall be given to the limitation of interpass temperature for various thicknesses to avoid detrimental effects on the mechanical properties of heat treated materials.

290


291

Historical Boilers

Appendix CNote:Part PR and excerpts from Part PFT and Appendix A have been reprinted from ASME 1971 BPVC Section I, by permission of the American Society of Mechanical Engineers. All rights reserved.

292


APPENDIX C — HISTORICAL BOILERS

C-1000 PURPOSE

This section provides recommended require-ments for the inspection and repair of histori-cal steam boilers.

C-1010 SCOPE

Historical steam boilers of riveted construc-tion, preserved, restored, or maintained for hobby or demonstration use.

C-2000 PRE-INSPECTION REQUIREMENT

See RB-3120 Internal Inspection of Boilers.

C-2010 INITIAL INSPECTION

The results of examinations and tests shall be documented by an inspector, acceptable to the jurisdiction, who has demonstrated knowl-edge with historical boilers. The following examinations and tests shall be performed:

a. An internal and external visual inspection (See Boiler Inspection Guideline).

b. All threaded openings in the boiler shall be inspected.

c. Ultrasonic thickness testing and evalua-tion of all pressure retaining boundaries. Ultrasonic results in areas of generalized thinning (3 in. (75 mm) in diameter or greater) or where grooved thinning is noted (2 in. (50 mm) in length or greater) are to be used in calculating MAWP in accordance with C-8000.

d. A hydrostatic pressure test at 1.25 times MAWP, but in no case shall the test pres-sure be exceeded by more than 6%.

e. The inspector may require other examina-tions to be performed, including but not limited to:

1. An ultrasonic transverse wave exami-nation in two directions at 90° to each other of the longitudinal lap seam for cracks located between or adjacent to rivet holes.

2. A magnetic particle examination of 100% of the longitudinal seam riveted area, and an ultrasonic (longitudinal wave mode) examination of 10% of the rivets for shear failure.

3. An ultrasonic examination (longitudi-nal wave mode) of all firebox staybolts and rivets.

4. A liquid penetrant examination.

5. Drilling or treppaning of pressure-retaining components.

C-2020 RECURRING INSPECTION REQUIREMENTS

The following examinations and tests shall be performed:

a. Annual visual internal and external inspection (See Boiler Inspection Guide-line).

b. Annual visual inspection of the fusible plugs to determine the condition of the threads in the crown sheet and on the fusible plug. The fusible plugs shall be removed, inspected and confirmed as an ASME Std. plug.

c. Annual hydrostatic test at a pressure at least equal to MAWP up to 1.25 times MAWP, but in no case shall the test pres-sure exceed 1.25 times MAWP by more than 6%.

293


d. Every five years ultrasonic thickness test-ing.

e. Additional testing and examination as deemed necessary by the inspector.

C- 2030 SAFETY DEVICES AND CONTROLS

Each boiler shall be equipped with the fol-lowing safety devices and controls. Pressure relief valve(s), gage glasses, try-cocks, fusible plugs, and pressure gages shall be tested dur-ing each inspection.

C-2031 PRESSURE RELIEF VALVES

Pressure relief valve(s) shall be National Board capacity certified.

Pressure relief valve(s) shall be sealed by an ASME “V” Stamp assembler or NB “VR” repair firm.

The required pressure relief valve capacity in pounds per hour shall be calculated by boiler heating surface area and type of fuel used. Ex-cessive pressure relief valve capacity should be avoided. (Only heating surface area above the grates to be used.)

Minimum pounds of steam per hour per square foot of heating surface (kg/hr/sq. 0.3 m).

Boiler Heating Firetube Watertube Surface Boiler Boiler

hand fired 5 6

stoker fired 7 8

oil, gas or pulverized fuel fired 8 10

Pressure relief valve(s) shall have a test lever.

No valve of any description shall be placed between the required pressure relief valve or

valves and the boiler, nor on the discharge pipe between the valve and the atmosphere.

The piping connection between the boiler and the safety valve shall not be less than the inlet size of the safety valve, and the discharge pipe, if used, shall not be reduced between the safety valve and the point of discharge.

C-2032 GAGE GLASS

The gage glass shall be fit with a guard to protect the gage glass.

The gage glass shall indicate the minimum safe operating water level.

The gage glass shall be provided with a drain valve or petcock, piped to a safe location.

The gage glass shall be fully operational.

C-2030 TRY-COCKS

Try-cocks shall be correctly located in refer-ence to the minimum required water level.

Try-cocks shall be fully operational

C-2034 FUSIBLE PLUG

All boilers shall have a fusible plug unless equipped and operated with automatic con-trols.

All fusible plugs shall be constructed to meet the requirements of the ASME Code, and in-dicated as such by the ASME marking on the filler material.

Fireside fusible plugs must protrude a mini-mum of one inch into the water.

Waterside fusible plugs may not protrude into the fire area more than one inch.

Fusible plugs shall not be refilled.

294


C-2035 PRESSURE GAGE

Tested and proven accurate at the time of the annual pressure test.

Siphon, or water seal, shall be installed be-tween pressure gage and boiler.

If a valve is installed between the gage and the boiler, the valve shall indicate the open position or be wired open.

C-2040 APPURTENANCES

C-2041 PIPING AND FITTINGS All boiler piping and fittings shall meet the following requirements:

a. Threaded openings shall follow accepted standard piping practices.

b. Schedule 80, black pipe (SA-53 B or SA-106 B) shall be used from the boiler to the first valve.

c. All steam piping components shall be used in the manner for which they were designed and shall not exceed manufac-turer’s pressure rating.

d. The boiler shall be equipped with two means of supplying feedwater while the boiler is under pressure. Pumped water shall be heated.

e. The blowdown line shall be plugged off

during the time the boiler is operating on display, or piped to a safe point of dis-charge.

f. All piping shall be properly supported.

C-3000 REPLACEMENTS

The installation date should be stamped or stenciled on all replaced boiler piping. Alter-natively, the installation date may be docu-mented in permanent boiler records.

C-4000 MAXIMUM ALLOWABLE WORKING PRESSURE

The maximum allowable working pressure of a boiler shall be determined by computing the strength of each component to find the weakest point. The strength of the weakest component and the factor of safety allowed by these rules shall determine the maximum allowable working pressure. The following shall be used to compute the strength of each boiler component.

C-4010 STRENGTH

In calculating the MAWP, when the ten-sile strength of the steel or wrought iron is known, that value shall be used. When the tensile strength of the steel or wrought iron is not known, the values to be used are 55,000 psi (380 MPa) for steel and 45,000 psi (310 MPa) for wrought iron. Original steel stamp marks, original material certifications, or cur-rent laboratory tests are acceptable sources for verification of tensile strength. Catalogs and advertising literature are not acceptable sources for tensile strength values.

In computing the ultimate strength of rivets in shear, the following values in pounds per square inch of the cross-sectional area of the rivet shanks shall be used:

Iron rivets in single shear ...........38,000 (260 MPa)

Iron rivets in double shear .........76,000 (520 MPa)

Steel rivets in single shear ..........44,000 (300 MPa)

Steel rivets in double shear ........88,000 (600 MPa)

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The resistance to crushing of mild steel shall be taken as 95,000 psi (655 MPa) of cross-sec-tional area.

C-4020 RIVETS

When the diameter of the rivet holes in the longitudinal joints of a boiler is not known, the diameter of rivets, after driving, may be ascertained from the table below.

Sizes of Rivets Based on Plate Thickness

Thickness of 1/4 9/32 5/16 11/32 3/8 13/32Plate, inches (6) (7) (8) (9) (10) (10)(mm) Diameter of 11/16 11/16 3/4 3/4 13/16 13/16Rivet after (17) (17) (19) (19) (21) (21)Driving,inches (mm)

Thickness of 7/16 15/32 1/2 9/16 5/8Plate, inches (11) (12) (13) (14) (16)(mm) Diameter of 15/16 15/16 15/16 1-1/16 1-1/16Rivet after (24) (24) (24) (27) (27)Driving,inches (mm)

C-4030 CYLINDRICAL COMPONENTS

The maximum allowable working pressure of cylindrical components under internal pres-sure shall be determined by the strength of weakest course computed from the thickness of the plate, the tensile strength of the plate, the efficiency of the longitudinal joint, the inside diameter of weakest course, and the factor of safety allowed by these rules using the following formula:

TS x t x E = maximum allowable working pressure (MAWP), psi

R x FS

C-4040 STAYED SURFACES

The maximum allowable working pressure for stayed flat plates and those parts which, by these rules, require staying as flat plates with stays or staybolts of uniform diameter symmetrically spaced, shall be calculated using the following formulas:

t2 x TS x C = maximum allowable working pressure (MAWP), psi

FS x p2

C-4050 BRACED AND STAYED SURFACES (REQUIRED

BRACE OR STAYBOLT DIAMETER)

The MAWP based on the net minimum diam-eters of staybolts shall be computed using the following formula:

π x d2 x TS = maximum allowable working pressure (MAWP), psi

FS x 4 x p2

The “d” in the formula refers to the diameter of the staybolt at the base of the threads or the smallest diameter as specified in ASME Section I, Pg-49.2, and “TS” in the formula refers to the ultimate tensile strength of the staybolt material. For stayed curved plates, the ratio between TS/FS in the formula shall not exceed 7500 psi as referenced in ASME Section I, PFT 23.3.

C-4060 CONSTRUCTION CODE

In order to address the many pressure-related components and features of construction en-countered in firetube boilers, a reprint of the 1971 Edition of Section I of ASME Boiler Code, Part PFT is provided.

A04

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C-4070 NOMENCLATURE

The nomenclature for the terms used in the above equations is:

C = 2.1 for welded stays or stays screwed through plates not over 7/16 in. (11 mm) in thickness with ends riv-eted over

C = 2.2 for welded stays or stays screwed through plates over 7/16 in. (11 mm) in thickness with ends riveted over

C = 2.5 for stays screwed through plates and fitted with single nuts outside of plate, or with inside and outside nuts, omitting washers

C = 2.8 for stays with heads not less than 1.3 times the diameter of the stays screwed through plates, or made a taper fit and having the heads formed on the stays before install-ing them and not riveted over, said heads being made to have true bear-ing on the plate

C = 3.2 for stays fitted with inside and outside nuts and outside washers where the diameter of washers is not less than 0.4p and thickness not less than t.

Note: the ends of stays fitted with nuts shall not be exposed to the direct radiant heat of the fire.

d = diameter of staybolt over the threads, in.

E = efficiency of the longitudinal joint

The following is a table of efficiencies which are the average for the different types of joints.

Type of Riveting Lap Butt

single 58double 74 82triple 88quadruple 94

Note: The efficiency of a particular joint depends upon the strength of the plate and rivet, thickness of the plates and the diameter of the rivets. The 1971 Edition of Section I of the ASME Code, Appendix A-1 through A-7, provides a method for calculating a specific joint efficiency which may be used with the concurrence of the jurisdiction.

FS = 5 (A jurisdiction may mandate a higher factor of safety or permit a lower factor of safety, but in no case may the factor of safety be less than 4)

p = maximum pitch measured between straight lines passing through the centers of the staybolts in the dif-ferent rows, which lines may be horizontal, vertical or inclined, in.

R = inside radius of the weakest course of shell or drum, in.

TS = ultimate tensile strength of shell plates, psi (MPa)

t = minimum thickness of shell plate in the weakest course, in. (mm)

C-5000 LIMITATIONS

The maximum allowable working pressure shall be the lesser of that calculated by C-8000 or the MAWP established by the original manufacturer.

The shell or drum of a boiler in which a typi-cal “lap seam crack” extending parallel to the longitudinal joint and located either between or adjacent to rivet holes, is discovered along a longitudinal riveted joint for either butt or lap joint shall be permanently discontinued for use under steam pressure.

C-6000 REPAIRS

Repairs to boilers of historical nature should be performed with consideration towards preserving the authenticity of original design, while at the same time ensuring that the boiler is safe to operate at the pressure allowed by C-8000.

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C-6010 CONSTRUCTION STANDARDS

Repairs shall conform to the requirements of the original construction standard insofar as possible. If the original construction standard is unknown or unavailable, the boiler shall be considered a boiler of locomotive design as described in Appendix 3, and subject to the construction standard most applicable to the boiler design. The construction standard selected for the repair must meet the approval of the jurisdiction.

C-6020 ACCREDITATION

Organizations performing welded repairs shall be accredited as described in Part RA. Organizations performing non-welded repairs shall be otherwise acceptable to the jurisdic-tion by having demonstrated competency in the repair of boilers of locomotive design.

C-6030 MATERIALS

Materials used in making repairs shall con-form to the original construction standard, if known, or to a construction standard accept-able to the jurisdiction. Carbon or alloy steels having a carbon content greater than 0.35% shall not be welded. The repair organization is responsible for verifying identification of existing and replacement materials.

C-6040 REPLACEMENT PARTS

Replacement pressure parts formed by cast-ing, forging, or die forming, and on which no welding has been performed, shall be sup-plied as material. Such parts shall be marked with the material identification required by the construction standard used for the repair. Replacement pressure parts fabricated by welding shall be manufactured by an organi-zation certified as required by the construction

standard used for the repair. Where there is no manufacturer prepared to supply parts fabri-cated by welding, an organization accredited as described in Part RA may fabricate the part with the approval of the jurisdiction.

C-6050 WELDED REPAIR INSPECTION

Prior to commencing any welded repairs to the pressure boundaries of historic boil-ers, the repair organization shall obtain an Inspector’s approval of the proposed repair. The Inspector shall be an employee of either a jurisdiction, as defined in Appendix 4, or of the Authorized Inspection Agency contracted by the repair organization. The Inspector shall assure the repairs are performed in accordance with the approved construction standard, and shall witness any nondestructive or pressure testing of the completed repair.

C-6060 WELDING

Welding shall be performed in accordance with the requirements of the approved construction standard in consultation with the inspector identified in C-4000. A repair organization accredited as described in Part RA may use the Standard Welding Procedure Specifications shown in Appendix A, as ap-plicable. Welders shall be qualified for the welding processes used. Qualification shall be in accordance with the approved construction standard, or Section IX of the ASME Code.

C-6070 HEAT TREATMENT

Preheating may be used to assist in comple-tion of the welded joint. Consideration should be given to the percentage of carbon content and to the thickness of the original boiler materials. Preheat temperatures shall be speci-fied by the welding procedure specification being used.

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Postweld heat treatment shall be performed as required by the accepted construction standard, in accordance with written proce-dures.

Welded repairs at or near riveted seams re-quiring preheat or postweld heat treatment shall be carefully made in order to prevent loosening in the riveted seams, especially when localized heat treatment is used.

Alternative postweld heat treatment methods may be used with the inspector’s approval. Welding methods which may be used as alternatives to postweld heat treatment are described in Part RD.

C-6080 NONDESTRUCTIVE EXAMINATION

The Inspector may require nondestructive examination (RT, PT, MT, UT, VT) as necessary to ensure satisfactory welded repairs have been accomplished.

C-6090 DOCUMENTATION

Organizations performing repairs to historic boilers shall document the repair as required by the jurisdiction.

Permanent documentation detailing repairs, inspections, etc. should be retained by the owner.

BOILER INSPECTION GUIDELINE

Owner

Location

Make

Year Engine No.

Heating Surface Design Pressure Current Operating Pressure

Inspector

Smoke Box

1. Front Tube Sheet

a. Check condition of sheet and thickness around handhole openings.

b. Check condition of threaded openings and plugs.

c. Check condition of rivets between sheet and shell.

2. Tubes

a. Are tubes beaded?

b. Are there signs of leakage?

3. Check condition of smoke box shell (especially around lower surfaces).

4. Check inside condition of barrel and O.D. of tubes.

5. Check back side of tube sheet (especially area in contact with handhole gasket and area where tube sheet joins barrel).

6. Check tube sheet supports (through stays, supports or strong backs).

7. Check inside rivet heads on lap or butt-strap joints.

8. Check front bolster (front axle) attachment points inside shell.

Barrel (shell)

1. Check front bolster attachment points on outside of shell.

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2. Check condition of tube sheet rivets on outside of shell.

3. Check condition of threaded openings and plugs in openings.

4. Check radius rod attachment point.

5. Check attachment points of studs, cast-ings, brackets, accessories, etc.

6. Check plumbing openings on shell (feed-water nozzles, steam take off, water col-umn, etc.).

7. Check handhole openings in shell.

8. Lap seam or buttstrap

a. Check for leakage around seams or joint rivets.

b. Confirm joint efficiency based on number of rows of rivets and type of joint.

9. Identify and check any external contour that does not appear normal.

10. Jacket

a. Does jacket cover any critical areas or make them difficult to observe?

b. Is barrel pitted or corroded under jacket?

Wrapper Sheet

1. Check handhole openings (material thick-ness, gasket area, etc.).

2. Check for seepage around attachment points (wing sheets, axle supports, etc.).

3. Check condition of seams joining wrapper to throat sheet and rear head.

4. Check condition of seams joining throat sheet to barrel.

5. Check external shapes or contours that do not appear normal.

6. Check for seepage around staybolt heads.

7. Check condition of staybolt heads. 8. Check condition of threaded openings.

9. Check internal surfaces (cracks, pits, mate-rial thickness).

10. Check staybolt thickness and condition.

11. Check for scale and mud buildup in wa-terlegs.

12. Check for buildup of dirt and grease be-tween or behind attaching brackets such as wing sheets.

13. a. Dry bottom boilers

1. Check seams at bottom of waterlegs in ash pan area.

2. Do you need to remove ash pans and grates to observe above seams?

3. Check condition of grate support brackets.

b. Wet bottom boilers

1. Check ash pan area for pits and stay-bolt head condition.

2. Check inside bottom of wrapper and

staybolt condition. 3. Check condition of lap seam in wrap-

per. 4. Check condition of ash pan drain tube

if present.

14. Check for presence and condition of blowdown valve.

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Dome

1. Check for presence and condition of drain-back holes in shell.

2. Check condition of main line shutoff valve.

3. Check condition of plumbing on main-stream line and on dome.

4. Check condition of dome seams and seams between dome and boiler shell.

a. Is seepage present? b. Can interior seams be observed?

5. Check for presence and condition of pres-sure gage.

a. Is there a siphon and what is its condi-tion?

b. Is the gage readable from the opera-

tor’s position?

c. Has the gage been calibrated or checked against another gage?

d. If a shutoff valve is present, its handle shall indicate open position, or the handle shall be wired open.

6. Check for presence and condition of safety valve.

a. Does it have its own inlet/outlet pip-ing with no possibility of closure?

b. Check that the inlet pipe size is not smaller than the valve inlet size.

c. Check that the outlet pipe size is not smaller than the valve outlet size.

d. Is it a National Board capacity certi-fied, ASME “V”/NB “VR” stamped valve of proper pressure and capacity rating for the boiler heating surface?

e. Does it have a try lever?

f. Is it sealed with a factory seal?

Water Column and Water Glass

1. Is water glass calibrated to level of crown sheet?

2. Check condition of try-cock valves and blowdown valves on column and glass.

3. Check condition of glass (cracks or scratches).

4. Are there leaks around the water glass gaskets?

Firebox

1. Check for bulges or abnormal shapes (What caused them?).

2. Check seams around fire door.

3. Check for sediment buildup over fire door opening rear head.

4. Check for sediment buildup over peep-hole opening in wrapper sheet (where applicable).

5. Check condition of fusible plug. (Must be removed for observation.)

a. Is it an ASME plug?

b. Check condition of top surface. (May need to brush it off.)

6. When fusible plug is removed, check crown sheet thickness at that location and thread condition.

7. Fireside fusible plug must protrude a minimum of 1 in. (25 mm) into water.

8. Waterside fusible plug may not protrude into fire area of more than 1 in. (25 mm).

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9. Water glass calibration can only be done when crown sheet and fusible plug can be seen and measured. (A recommended minimum water level may be determined as follows: With engine sitting on level ground and water just observable at the bottom of the glass, the crown sheet should be covered by a minimum of at least 2-1/2 in. plus on a full-size boiler.

10. Check staybolt condition, especially near top surface of crown sheet.

11. Check through stays, strong backs, knee braces, etc. on rear head.

12. Check handhole openings, threaded open-ings and plugs in rear head.

13. Check condition of rear tube sheet, and check if rear end of tubes are beaded.

14. Check condition of staybolt heads inside fire box.

15. Check condition or design of crown sheet. Is it flat-topped or able to trap water?

External Plumbing

1. Is black pipe (as opposed to galvanized) used throughout?

2. Check for use of Schedule 80 black pipe required between boiler and first valve.

3. Are fittings of proper pressure rating for operating pressure?

4. Are isolation valves present to shut off individual system lines?

5. Are two separate feedwater systems pres-ent and operable?

6. Check plumbing for frost damage.

7. Are plumbing support brackets present where needed?

8. Fittings dates are to be stamped, stenciled or recorded on boiler records.

9. 20-year life on piping except for main steam line which shall be evaluated as to life.

Ultrasonic Testing (Every fifth year)

Hydrostatic Pressure Test (Annually)

1. Hydrostatic pressure test should be be-tween maximum allowable working pres-sure and 1.25 times maximum allowable working pressure with water temperature at 60° to 120° F (16° to 50° C).

2. An accurate gage with proven accuracy shall be used when hydrostatically pres-sure testing a boiler. The engine gage shall be calibrated at this time.

3. Safety valve may be checked against test gage and/or engine gage. (Test should only be performed at a pressure greater than 75% of the stamped set pressure of the valve or the safety valve or lifting lever may be damaged.)

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PART PR — REQUIREMENTS FOR BOILERS FABRICATED BY RIVETING

GENERAL

PR-1 SCOPE

The rules in Part PR are applicable to boilers and parts thereof that are fabricated by rivet-ing and shall be used in conjunction with the general requirements in Part PG as well as with the specifi c requirements in the appli-cable Parts of this Section that pertain to the type of boiler under construction.

MATERIALS

PR-5 GENERAL

Materials entering into the construction of riveted boilers shall comply with the require-ments for materials given in PG-5 through PG-14.

DESIGN

PR-9 GENERAL

The rules in the following paragraphs apply specifi cally to the design of boilers and parts thereof that are fabricated by riveting and shall be used in conjunction with the general requirements for Design in Part PG as well as with the specifi c requirements for Design in the applicable Parts of this Section that pertain to the type of boiler under consideration.

PR-10 STRENGTH OF PLATES

In determining the maximum allowable working pressure, the maximum allowable working stress in Table PG-23.1 shall be used in the computations.

PR-11 STRENGTH OF RIVETS

In computing the ultimate strength of rivets in shear, the values given in Table PG-23.4 in pounds per square inch of the cross-sectional area of the rivet shank shall be used.

PR-12 CRUSHING STRENGTH OF PLATES

The resistance to crushing of steel plate in pounds per square inch of cross-sectional area shall be taken from Table PG-23.5.

PR-14 THICKNESS OF BUTTSTRAPS

The minimum thickness of buttstraps for double-strap joints shall be as given in Table PR-14 in which the required thickness of the shell is that obtained by the rules given in PG-27.2 employing a value of E correspond-ing to the effi ciency of the buttstrap joint. Intermediate values shall be determined by interpolation. Where the required thickness of the plate exceeds 1-1/2 in., the thickness of the buttstraps shall be not less than two-thirds of the required thickness of the plate. In no case shall either of the buttstraps have a lesser thickness than one-half the actual thickness of the plate.

PR-15 JOINT EFFICIENCY

The effi ciency of a joint is the ratio which the strength of the joint bears to the strength of the solid plate. In the case of a riveted joint this is determined by calculating the breaking strength of a unit section of the joint, consider-ing each possible mode of failure separately, and dividing the lowest result by the breaking strength of the solid plate of a length equal to that of the section considered (see A-1 through A-7 for detailed methods and examples).

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PR-16 LONGITUDINAL JOINTS to resist the total longitudinal force acting on the joint with a factor of safety of 5. The total longitudinal force is determined by the fol-lowing formula:

F = 3.14R2P

where,F = total longitudinal force, poundsR = radius of the circular area acted on

by the pressure in producing the total longitudinal force on the joint, inches

P = pressure, pounds per square inch

17.2 When 50 percent or more of the total force as described in PR-17.1 is relieved by the effect of tubes or through stays, in consequence of the reduction of the area acted on by the pres-sure and the holding power of the tubes and stays, the strength of the circumferential joints shall be at least 70 percent of that required by PR-17.1.

PR-20 TRANSVERSE PITCH (BACK PITCH) OF ROWS OF RIVETS

20.1 For longitudinal joints the distance between the centerlines of any two adjacent rows of rivets, or the “back pitch” measured at right angles to the direction of the joint, shall have the following minimum values:

20.1.1 If P/d is 4 or less, the minimum value shall be 2d.

20.1.2 If P/d is over 4, the minimum value shall be:

2d + 0.1 (P - 4d)

where, P = pitch of rivets in outer row where a

rivet in the inner row comes midway between two rivets in the outer row, inches

16.1 The riveted longitudinal joints of a shell or drum which exceeds 36 in. in diameter shall be of butt- and double-strap construc-tion. This rule does not apply to the portion of a boiler shell which is staybolted to the firebox sheet.

16.2 The longitudinal joints of a shell or drum which does not exceed 36 in. in diameter may be of lap-riveted construction, but the maxi-mum allowable working pressure shall not exceed 100 psi.

TABLE PR-14 —Minimum Thickness Of Buttstraps

Required Thickness Minimum Thickness of Steel Plate, in. of Buttstraps, in.

1/4 1/4 9/32 1/4 5/16 1/4 11/32 1/4 3/8 5/16 13/32 5/16

7/16 3/8 15/32 3/8 1/2 7/16 17/32 7/16 9/16 7/16 5/8 1/2

3/4 1/2 7/8 5/8 1 11/16 1-1/8 3/4 1-1/4 7/8 1-1/2 1

PR-17 CIRCUMFERENTIAL JOINTS

17.1 The strength of a riveted circumferential joint of a boiler, the heads of which are not stayed by tubes or through-stays, shall be sufficient, considering all methods of failure,

304


P = pitch of rivets in the outer row less pitch of rivets in the inner row where two rivets in the inner row come between two rivets in the outer row, inches (it is here assumed that the joints are the usual construction where the rivets are symmetrically spaced)

d = diameter of the rivet holes, inches

20.2 The back pitch of rivets in circumferential joints may be less than that called for by the above formulas provided the ligaments be-tween rivets in a circumferential direction, as well as those in a diagonal direction as deter-mined by the rules in PG-52, are sufficient to withstand the stress due to pressure, together with any stress due to weight components in support of boiler structure, with a factor of safety of 5.

20.3 The back pitch of rivets shall be measured either on the flat plate before rolling, or on the median line after rolling, and the back pitch as there measured shall govern the locations of rivet holes in the buttstraps.

20.4 The distance between any two rows of rivets in a circumferential joint or back pitch shall be not less than 1.75d.

PR-21 PREPARATION OF PLATE EDGES

The plate edge shall be beveled to an angle not sharper than 70 deg. to the plane of the plate and as near thereto as practicable.

PR-22 EDGE DISTANCE

22.1 On longitudinal joints of all types of boilers and on circumferential joints of drums having heads which are not supported by tubes or through-stays, the distance from the centers of rivet holes to the edges of the plates, except rivet holes in the ends of buttstraps,

shall be not less than 1-1/2 and not more than 1-3/4 times the diameter of the rivet holes; this distance to be measured from the center of the rivet holes to the caulking edge of the plate before caulking.

22.2 The distance from the centers of rivet holes of circumferential joints to the edges of the plate in boilers having heads which are supported by tubes or through-stays shall be not less than 1-1/4 times the diameter of the rivet holes.

PR-23 RIVETED CONNECTIONS

Attachment by riveting shall be in accordance with the following requirements:

23.1 Openings for nozzles and other connec-tions shall be far enough away from any main riveted joint so that the joint and the opening reinforcement plates do not interfere with one another.

23.2 Welded connections which require post-weld heat treatment and which are attached to vessels having seams of riveted construction shall be fabricated and stress relieved prior to the making up or attachment of the courses by riveting. If they do not require postweld heat treatment and are attached after riveting, the welds shall be located at a distance from the riveted seam at least equal to the outside diameter of the attachment weld plus 4 times the thickness of the shell plate.

23.3 Openings for pipe connections to vessels having riveted joints may be made by insert-ing pipe couplings or similar devices, not exceeding 3 in. pipe size, in the shell or heads and securing them by welding, provided the welding is performed by welders or welding operators who have been qualified under the provisions of Section IX of the Code for the welding position and type of joint used.

23.4 For nozzle fittings having a bolting flange and an integral flange for riveting, the thick-

305


ness of the flange attached to the pressure vessel shall not be less than the thickness of the neck of the fitting.

23.5 The strength of rivets in tension in a flanged frame or ring riveted to the outside of a vessel shall be at least equal to that required to resist the load due to the maximum allow-able working pressure with a factor of safety of 5 computed as follows:

23.5.1 For outside caulking the load shall be equal to the area bounded by the out-side caulking multiplied by the maximum allowable working pressure.

23.5.2 For inside caulking (and with no outside caulking) the load shall be equal to the area bounded by the inside caulk-ing multiplied by the maximum allowable working pressure.

23.6 The rivets attaching nozzles shall be so spaced as to avoid the possibility of the shell plate or the nozzle flange failing by tearing around through the rivet holes. An example illustrating the method of calculations is given in A-70.

PR-25 REINFORCEMENT OF OPENINGS

25.1 The area of reinforcement shall be calcu-lated by the rules in PG-32 through PG-39.

25.2 In applying reinforcement plates to the drums of watertube boilers to strengthen the shell where the tubes enter, they shall be riv-eted to the shell, and where outside caulking is used, the tube shall be expanded into the inner and outer plates so that the rivets and tubes will hold the plates together in accordance with the rules for stayed surfaces. Where a reinforcing plate is inside the steam drum, it is the inner plate; where it is outside and there is no inner reinforcing plate, the unreinforced shell of the drum is the inner plate.

25.3 The spacing of the rivets with respect to the tubes shall conform to PG-46 for stayed surfaces, using a value of 2.5 for C, and shall be based on a unit pressure equal to the pres-sure that can be carried by the inner plate with a factor of safety of 5.

25.4 The tension in rivets and tubes shall conform to PFT-27 and PFT-38.

25.5 The combined drum shell and reinforc-ing plate or plates, and riveted connections, shall have a factor of safety of not less than 5 in the ligaments when calculated in accor-dance with PG-52. When reinforcing plates or buttstraps are exposed to flame or gas of the equivalent temperature, the joints shall be protected therefrom.

FABRICATION

PR-30 GENERAL

The rules in the following paragraphs apply specifically to the fabrication of the boilers and parts thereof that are fabricated by rivet-ing and shall be used in conjunction with the general requirements for Fabrication in Part PG as well as with the specific requirements for Fabrication in the applicable Parts of this Section that pertain to the type of boiler under construction.

PR-31 BUTTSTRAPS

31.1 Buttstraps shall be rolled or formed by pressure, not blows to the curvature of the shell with which they are to be used.

31.2 The ends of inner buttstraps of riveted buttstrap longitudinal joints may be fusion welded to the edges of heads or of the adjoin-ing shell plate, or to circumferential buttstraps for tightness, provided the carbon content in the steel does not exceed 0.35 percent. When the buttstrap of a longitudinal joint does not

306


WeldedWeldedW

max21”max1”max2

FIGURE PR-31 —Allowable Welding Of Plate Edges At Ends Of Buttstraps

extend the full length of the shell plates, as shown in Figure PR-31, the abutting edges of the shell plate may be welded provided the distance from the end of the buttstrap to the edge of the fl ange of the head or adjacent shell plate is not greater than 2-1/2 in.

PR-32 RIVET HOLES

All holes for rivets in plates, buttstraps, heads, stays and lugs shall be drilled; or they may be punched at least 1/8 in. less than full diameter for material not over 5/16 in. in thickness and at least 1/4 in. less than full diameter for material over 5/16 in.

Such holes shall not be punched in material more than 5/8 in. in thickness.

For fi nal drilling or reaming the hole to full diameter, the parts shall be fi rmly bolted in position by tack bolts.

The fi nished holes must be true, clean and concentric.

PR-37 ASSEMBLY OF JOINTS

After drilling or reaming rivet holes the plates and buttstraps of longitudinal joints shall be separated, the burrs and chips removed, the plates and buttstraps reassembled metal-to-metal with barrel pins fi tting the holes, and with tack bolts.

PR-39 RIVETING

39.1 Rivets shall be of suffi cient length to com-pletely fi ll the rivet holes and form heads at least equal in strength to the bodies of the riv-ets. Forms of fi nished rivet heads that will be acceptable are shown in ANSI B18.4-1966.

39.2 Rivets shall be so driven as to fi ll the holes preferably by a machine which main-tains the pressure until no part of the head

shows red in the daylight. Barrel pins fi tting the holes and tack bolts to hold the plates fi rmly together shall be used. A rivet shall be driven on each side of each tack bolt before removing the tack bolt.

PR-40 JOINT TIGHTNESS

40.1 The caulking edges of plates, buttstraps, and heads shall be beveled to an angle not sharper than 70 deg. to the plane of the plate, and as near thereof as practicable. Every por-tion of the unfi nished surfaces of the caulking edges of plates, buttstrap and heads shall be planed, milled, or chipped to a depth of not less than one-fourth of the thickness of the material, but in no case less than 1/8 in. Caulking shall be done with a tool of such form that there is no danger of scoring or damaging the plate underneath the caulking edge, or splitting the caulked sheet.

40.2 Fusion welding may be used to seal the calking edges of circumferential-riveted lap joints of power boilers provided the plates do not exceed 0.35 percent carbon and their thickness is at least 1/8 in. more than that required for a seamless shell of the same diameter, same working pressure, and same grade of material.

40.3 Seal welding may be used on nozzles and their reinforcing plates under the same conditions. On unstaying dished heads, seal welding shall not be applied closer than 1/2

307


in. to the point of tangency of the knuckle of the flange. Seal welding may be applied only when the weld metal is deposited in single layer having a throat thickness of not less than 3/16 in., nor more than 5/16 in. The heat from welding shall not distort the plate or loosen the rivets in such a manner as to break the initial bond effected in the riveted joint. After seal welding, the vessel shall be resub-jected to the prescribed hydrostatic test.

40.4 The inner buttstraps in locomotive-type boilers may be seal welded, provided the carbon content of the plates does not exceed 0.35 percent and the weld metal is deposited in a single layer having a weld size not greater than 3/8 in.

INSPECTION AND TESTS

PR-50 GENERAL

At least two inspections shall be made of riveted construction (one before reaming rivet holes and one at the hydrostatic test) and, at the option of the inspector, at such other stages of the work as he may designate.

308


PART PFT — REQUIREMENTS FOR FIRETUBE BOILERS

GENERAL

PFT -1 GENERAL

The rules in Part PFT are applicable to firetube boilers and parts thereof and shall be used in conjunction with the general requirements in Part PG as well as with the specific require-ments in the applicable Parts of this Section which apply to the method of fabrication used.

MATERIALS

PFT-5 GENERAL

5.1 Materials used in the construction of pres-sure parts for firetube boilers shall conform to one of the specifications given in Section II of the Code and shall be limited to those for which allowable stress values are given in Table PG-23 or as otherwise specifically permitted in Parts PG and PFT.

5.2 Waterleg and doorframe rings of vertical firetube boilers and of locomotive and other type boilers shall be of wrought iron or steel, or cast steel as designed in the Specification SA-216. The ogee or other flanged construc-tion may be used as a substitute in any case.

DESIGN

PFT-8 GENERAL

The rules in the following paragraphs apply specifically to the design of firetube boilers and parts thereof and shall be used in con-junction with the general requirements of Design in Part PG as well as with the specific requirements for Design in the applicable Parts of this Section which apply to the method of fabrication used.

PFT-9 MINIMUM THICKNESS

9.1 PlatesThe minimum thicknesses of shell plates, and dome plates after flanging, shall be as follows:

Diameter of Shell Minimum Thickness

36 in. or under 1/4 in.Over 36 to 54 in. 5/16 inOver 54 to 72 in. 3/8 in.Over 72 in. 1/2 in.

9.2.1 Except as otherwise provided in PFT-9.2.2, the minimum thickness of tube sheets for firetube boilers shall be as fol-lows:

Diameter of MinimumTube Sheet Thickness

42 in. or under 3/8 in.Over 42 to 54 in. 7/16 in.Over 54 to 72 in. 1/2 in.Over 72 in. 9/16 in.

9.2.2 Tube sheets with a straight flange longer than 1-1/2 times the tube sheet thickness, when butt-welded to the shell of a firetube boiler, shall have a minimum thickness as specified in PFT-9.2.1 but in no case shall be less than 0.75 times the required shell thickness, based on the maximum allowable working pressure.

PFT-10 SHELL JOINTS

10.1 Welded JointsWelded longitudinal and circumferential joints of a shell or drum shall comply with the rules in Part PW.

309


10.2 Riveted Longitudinal Joints

10.2.1 The longitudinal joints of horizon-tal-return tubular boilers shall be located above the fi re line of the setting.

10.2.2 In horizontal-return tubular boilers of riveted construction, no course shall be over 12 ft. long.

10.2.3 The inner buttstraps in locomotive-type boilers may be seal welded, provided the carbon content of the plates does not exceed 0.35% and the weld metal is depos-ited in a single layer having a weld size not greater than 3/8 in.

10.3 Riveted Circumferential Joints

10.3.1 In the portion of circumferential joints of horizontal-return tubular boilers ex-posed to the products of combustion, the shearing strength of the rivets shall be not less than 50% of the full strength of the plate corresponding to the thickness at the joint.

10.3.2 When shell plates exceed 5/8 in. in thickness in horizontal-return tubular boilers, the portion of the plates form-ing the laps of the circumferential joints, where exposed to the fi re or products of combustion, shall be planed or milled down as shown in Figure PFT-10 to a thickness of not over 9/16 in., provided the requirements in PR-17 are complied with. The entire circumference may be so planed or milled. The radius of the fi llet at the edge of the planing shall be not less than 1 in.

10.3.3 Where the circumferential joints of fi retube boilers are to be seal welded, the thickness of the plates at the calking edges of such seams shall be at least 1/8 in. more than 60% of that required for a seamless shell of the same diameter, the same working pressure, and the same grade of

material. Such seal welding shall not be applied until after the boiler is made tight as evidenced by the regular hydrostatic pressure test prescribed in PG-99.

PFT-11 ATTACHMENT OF HEADS AND TUBE SHEETS

Flat heads and tube sheets of fi retube boil-ers shall be attached by one of the following methods:

11.1 By fl anging and riveting in accordance with Part PR.

11.2 By fl anging and butt welding in accor-dance with Part PG and Part PW.

11.3 By attaching an outwardly or inwardly fl anged tube sheet to the shell by fi llet weld-ing provided the following requirements are met:

11.3.1 The tube sheet is supported by tubes, or stays, or both;

11.3.2 The joint attaching an outwardly fl anged tube sheet is wholly within the shell and forms no part thereof;

11.3.3 Inwardly fl anged tube sheets are full fi llet welded inside and outside;

11.3.4 The throat dimension of the full fi llet weld is equal to, not less than 0.7 of the thickness of the head;

11.3.5 The shell at the welds is not in contact with primary furnace gases; 12

11.3.6 The construction conforms in all other respects to the requirements of this Section, including welding and postweld heat treating, except that radiographic examination is not required;

12 Primary Furnace gases are those in a zone where the design temperature of those gases exceeds 850°F.

310


Not less than 1”Not less than 1”

Not less than 1”Not less than 1”

9”9” 1616

9” 1616

FIGURE PFT-10 — Circumferential Joint For Thick Plates Of Horizontal-Return Tubular Boilers

11.3.7 This construction shall not be used on the rear head of a horizontal-return tubular boiler and inwardly fl anged tube sheets shall not be used on a boiler with an extended shell;

11.3.8 On inwardly fl anged tube sheets, the length of fl ange shall conform to the requirements of PW-13 and the distance of the outside fi llet weld to the point of tangency of the knuckle radius shall be not less than 1/4 in.

11.4 By attaching an unfl anged tube sheet to the shell by welding provided the following requirements are met:

11.4.1 The tube sheet is supported by tubes, or stays or both;

11.4.2 The welded joint is wholly within the shell or wrapper sheet and forms no part thereof;

11.4.3 The weld is a full penetration weld equal at least to the full thickness of the tube sheet and applied from either or both sides;

11.4.4 The shell or wrapper sheet, where exposed to primary furnace gases6 and not water cooled does not extend more than 1/8 in. beyond the outside face of the tube sheet;

11.4.5 The weld attaching a furnace or a lower tube sheet of a vertical fi retube boiler to the furnace sheet is wholly within the furnace sheet and is ground fl ush with the upper or waterside of the tube sheet;

11.4.6 The construction conforms in all other aspects to the requirements of this Section including welding, and postweld heat treatment, except that radiographic examination is not required;

11.4.7 This construction shall not be used on the rear head of a horizontal-return tubular boiler.

PFT-12 TUBES

12.1 Allowable Working Pressure

12.1.1 The maximum allowable working pressure of tubes or fl ues of fi retube boil-ers shall be as given in Table PFT-12.1.

12.1.2 The maximum allowable work-ing pressure for copper tubes or nipples subjected to internal or external pressure shall be as given in Table PFT-12.2.

The maximum allowable working pres-sure for copper-clad tubes subjected to external pressure shall be determined by the formula in Table PFT 12.1, in which tmay be increased by one-half the thickness of the cladding.

12.2 Attachment of Tubes

12.2.1 A fi retube boiler shall have the ends of the tubes fi rmly rolled and beaded, or rolled and welded around the edge of the tube (see Figure PFT-12.1). Tube ends at-tached by rolling and welding are subject to the following provisions:

12.2.1.1 The tube sheet hole may be beveled or recessed to a depth at least equal to the thickness of the tubes. Where the hole is beveled or recessed, the projection of the tube beyond the tube sheet shall not exceed a distance equal to the tube thickness. The depth

311


of any bevel or recess shall not be less than the tube thickness or 1/8 in. whichever is greater, nor more than one-third of the tube sheet thickness [see Figure PFT-12.1(f) and (g)].

12.2.1.2 Where no bevel or recess is employed, the tube shall extend beyond the tube sheet not less than a distance equal to the tube thickness, nor more than twice the tube thickness [see Figure PFT-12.1 (e)].

12.2.1.3 On all types of welded attach-ments, the tubes shall be rolled before welding and again rolled lightly after the welding procedure.

12.2.2 Expanding of tubes by the Prosser method in lieu of rolling may be em-ployed in combination with any beaded or welded attachment method.

12.2.3 Seal welding is permissible on any type of beaded attachment. Where seal welding is employed, a single hydrostatic test of the boiler after seal welding shall suffi ce.

12.2.4 The inner surface of the tube hole in any form of attachment may be grooved or chamfered.

12.2.5 The sharp edges of tube holes shall be taken off on both sides of the plate with a fi le or other tool.

COMBUSTION CHAMBER AND FURNACES

PFT-13 COMBUSTION CHAMBER TUBE SHEET

13.1 The maximum allowable working pres-sure on a tube sheet of a combustion chamber, where the crown sheet is not suspended from

the shell of the boiler, shall be determined by the following formula:

t(D - d) P = 27,000 t(D - d) P = 27,000 t(D - d)

WDwhere, P = maximum allowable working pres-

sure, pounds per square inch D = least horizontal distance between

tube centers on a horizontal row, inches

d = inside diameter of tubes, inches t = thickness of tube plate, inches W = distance from the tube sheet to op-

posite combustion chamber sheet, inches

Where tubes are staggered the vertical dis-tance between the centerlines of tube in adja-cent rows must be not less than ��

Example: Required the minimum allowable working pressure of a tube sheet supporting a crown sheet stayed by crown bars. Horizontal distance between centers, 4-1/8 in.; inside diameter of tubes, 2.782 in.; thickness of tube sheets 11/16 in; distance from tube sheet to opposite combustion-chamber sheet, 34-1/4 in.; measured from outside of tube plate to outside of back plate; material, steel. Substitu-tion and solving:

��

��

13.2 Sling stays may be used in place of gird-ers in all cases covered in PFT-13.1, provided, however, that when such sling stays are used, girders or screw stays of the same section area shall be used for securing the bottom of the combustion chamber to the boiler shell.

13.3 When girders are dispensed with and the top and bottom of combustion chambers are secured by sling stays, the sectional area of such stays shall conform to the requirements of rules for stayed surfaces.

312


TABLE PFT-12.2 — Maximum Allowable Working Pressure For Copper Tubes For Firetube Boilers Conforming To The Requirements Of Specification SB-752 (For use at Pressures Not to Exceed 250 psi or Temperatures Not to Exceed 406° F)

Outside Gage — BwgDiameter of Tube in. 12 11 10 9 8 7 6 5 4

2 170 240 250 250 250 250 250 250 250 3-1/4 . . . . . . 110 150 220 250 250 250 250 4 . . . . . . . . . . . . 130 160 250 250 250 5 . . . . . . . . . . . . . . . . . . 150 190 230

2 These values have been rounded out to the next higher unit of 10.

where P = maximum allowable working pressure, pounds per square inch t = thickness of tube wall, inches D = outside diameter of tube, inches

TABLE PFT-12.1 — Maximum Allowable Working Pressure For Steel Tubes Or Flues For Firetube Boilers For Different Diameters And Gages Of Tubes Conforming To The Require-ments Of Specifications SA-178, SA-192, SA-209, SA-210, SA-226, OR SA-2501

Wall Nearest Size Outside Diameter, In.Thickness, Bwg in. No. 1 1-1/2 1-3/4 2 2-1/4 2-1/2 3 3-1/4 3-1/2 4 4-1/2 5 5-3/8 5-1/2 6

0.095 13 420 280 240 210 190 170 . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.105 12 560 380 320 280 250 230 190 180 160 . . . . . . . . . . . . . . . . . . 0.120 11 770 520 440 390 350 310 260 240 220 200 180 . . . . . . . . . . . .

0.135 10+ 980 660 570 490 430 400 330 310 280 250 220 200 . . . . . . . . . 0.150 9+ . . . 800 680 600 530 480 400 370 340 300 270 240 230 220 . . . 0.165 8 . . . 940 800 700 630 560 470 430 400 350 320 280 270 260 240

0.180 7 . . . . . . 920 810 720 650 540 500 460 410 360 330 300 300 270 0.200 6- . . . . . . 1090 950 840 760 630 590 540 480 420 380 360 350 320 0.220 5 . . . . . . 1240 1090 970 870 730 670 620 550 490 440 410 400 370 0.240 4+ . . . . . . 1410 1230 1090 990 820 760 700 620 550 490 460 450 410

1 These values have been increased to the next higher unit of 10 where the actual values exceed an even unit of 10.

where P = maximum allowable working pressure, pounds per square inch t = minimum wall thickness, inches D = outside diameter of tubes, inches

For pressures other than those given in the table, the allowable working pressures shall be the next higher unit of 10 above the values given by the formulas.

For pressures below those given in the table, the gage thickness shall be not less than the minimum given in the table.

��

�

��

��

313


(a)

(b)

(c) (d)

Not over 2 t nor lessthan t but in no casemore than 1/4 in. norless than 1/8 in.

Not less than tand in no caseless than 1/8 in.

Max t

t t(f)(e)

Max t and notmore than T/3 or1/8 in. whicheveris the greater

Not more than T/3nor less than t or1/8 in. whicheveris the greater

(g)

T

t

FIGURE PFT-12.1 — Acceptable Forms Of Tube Attachment On Firetube Boilers

PFT-14 PLAIN CIRCULAR FURNACES

14.1 The shells of unstayed circular furnaces may be of any length or height and of any of the following constructions:

14.1.1 Seamless Construction

14.1.2 Double-welded butt-type con-struction subject only to the require-ments that the welds are postweld heat treated in accordance with PW-39, and a bend test of a sample of the welding for each furnace meets the requirements of PW-53. Radiographic examination is

not required. When the longitudinal and circumferential joints have been subjected completely to radiographic examination, the individual bend test for each furnace is not required.

14.1.3 Riveted construction which meets the following requirements:

14.1.3.1 Circumferential and longi-tudinal joints shall have an efficiency not less than 50% nor less than PD/20,000t%,

where, P = maximum allowable working pres-

sure, pounds per square inch D = outside diameter, inches t = thickness of furnace walls, inches

14.1.3.2 Buttstrap seams shall be used only where they are protected from contact with the fire or flame.

14.2 The walls shall not be less than 5/16 in. in thickness.

14.3 The furnace may be of any length or height.

14.4 The following rules apply specifically to unstayed circular furnaces 12 in. in diameter and over:

14.4.1 Furnaces 12 to 18 in. in Outside Di-ameter, Inclusive. The maximum allowable working pressure for furnaces not more than 4-1/2 diameters in length or height shall be determined by formulas (1) and (2) as follows:

Where the length does not exceed 120 times the thickness of the plate:

��

�(1)

314


Where the length exceeds 120 times the thickness of the plate:

��

��(2)


sure, pounds per square inch D = outside diameter of furnace, inches L = total length of furnace between cen-

ters of head rivet seams (not length of a section), inches

T = thickness of furnace walls, sixteenths of an inch

14.4.2 The maximum allowable working pressure for furnaces over 4-1/2 diameters in length or height shall be determined in accordance with PFT-15.

14.4.3 Furnaces Over 18 in. in Outside Di-ameter to and Including 30 in. in Inside Di-ameter. The maximum allowable working pressure shall be determined by formulas (1) and (2); if over six diameters in length or height, L in the formula shall be taken as 6 times the diameter.

14.4.4 Furnaces Over 30 in. in Inside Diam-eter to and Including 36 in. in Inside Diameter. A riveted longitudinal joint may be of the lap type provided the furnace does not exceed 36 in. in length or height.

14.4.5 If the length of a horizontal furnace exceeds 36 in. and the joint is riveted, a butt- and single- or double-strap construc-tion shall be used and shall be located below the grate.

14.4.6 The maximum allowable working pressure shall be determined by formulas (1) and (2); if over six diameters in length, L in the formula shall be taken as 6 times the diameter.

14.4.7 Furnaces Over 36 in. in Inside Diam-eter to and Including 38 in. in Outside Diam-eter. When riveted the longitudinal joint of

a horizontal furnace shall be of butt- and single- or double-strap construction and shall be located below the grate.

14.4.8 The maximum allowable working pressure shall be determined by formulas (1) and (2); if over six diameters in length, L in the formula shall be taken as 6 times the diameter.

14.4.9 Furnaces Over 38 in. in Diameter. Furnaces over 38 in. in diameter shall be fully stayed as flat surfaces in accordance with requirements of PFT-23.4.

Where it is desired to apply staybolting to a furnace 38 in. or less in diameter, which is of proper thickness for the required working pressure under the above rules, the requirements of the Code for the stress allowed upon and the spacing of the stay-bolts may be disregarded.

PFT-15 CIRCULAR FLUES

The maximum allowable working pressure for seamless or welded flues over 5 in. in diameter, and including 18 in. in diameter shall be determined by one of the following formulas:

15.1 Where the thickness of the wall is not greater than 0.023 times the diameter:

10,000,000t3

P = D3

15.2 Where the thickness of the wall is greater than 0.023 times the diameter:

17,300t P = - 275 D


sure, pounds per square inch D = outside diameter of flue, inches t = thickness of wall of flue, inches

315


15.3 The above formulas may be applied to riveted flues of the size specified provided the sections are not over 3 ft. in length and the efficiency of the joint is not less than:

PD

20,000t

Example: Given a flue 14 in. in diameter and 5/16 in. in thickness. The thickness of the wall is less than 0.023 times the diameter, hence the formula in (1) applies. Substituting the values in this formula:

10,000,000 x 5/16 x 5/16 x 5/16P= =110 psi 14 x 14 x 14

PFT-16 ADAMSON TYPE

When plain horizontal flues are made in sec-tions not less than 18 in. in length and not less than 5/16 in. in thickness:

16.1 They shall be flanged with a radius mea-sured on the fireside of not less than 3 times the thickness of the plate, and the flat portion of the flange outside of the radius shall be at least 3 times the diameter of the rivet holes.

16.2 The distance from the edge of the rivet holes to the edge of the flange shall be not less than the diameter of the rivet hole, and the diameter of the rivets before driving shall be at least 1/4 in. larger than the thickness of the plate.

16.3 The depth of the Adamson ring between the flanges shall be not less than 3 times the diameter of the rivet holes, and the ring shall be substantially riveted to the flanges. The fire edge of the ring shall terminate at or about the point of tangency to the curve of the flange, and the thickness of the ring shall be not less than 1/2 in.

16.4 An Adamson furnace may be assembled by welding, provided the outside edges of the flue flanges are attached to Adamson rings by full fillet welds; inside edges of the rings are welded to the flat portions of the flue flanges by full fillet welds; and the welds are postweld heat treated in accordance with PW-39.

The maximum allowable working pressure shall be determined by the following for-mula:

57.6 (300t - 1.03L) P = D


sure, pounds per square inch D = outside diameter of furnace, inches L = length of furnace section, inches t = thickness of plate, inches

Example: Given a furnace 44 in. in diam-eter, 48 in. in length, and 1/2 in. in thick-ness. Substituting values in formula:

57.6 P = [(300 x 0.5) - (1.03 x 480] 44 = 1.309 (150 - 49.44) = 131 psi

The longitudinal and circumferential joints may be of the double-welded butt type, the only requirements being that the welds are postweld heat treated in accordance with PW-39 and a bend test of a sample of the welding for each furnace meets the require-ments of PW-53, no radiographic examination being required. When the longitudinal and circumferential joints have been subjected completely to radiographic examination, the individual bend test for each furnace is not required.

316


PFT-17 RING REINFORCED TYPE

Horizontal cylindrical fl ues or furnaces (Fig-ure PFT-17.2) may be constructed with com-pletely circular stiffening rings provided the following requirements are met:

17.1 The stiffening ring is rectangular in cross section and is fabricated from one piece of plate, or from plate sections or bars provided full penetration welds are used in assembling.

17.2 The stiffening ring after fabrication has a thickness of not less than 5/16 in. and not more than 13/16 in. and in no case thicker than 1-1/4 times the furnace wall thickness.

17.3 The ratio of the height of the stiffening ring to its thickness (Hr /Tr /Tr /T ) is not greater than 8 nor less than 3.

17.4 The stiffening ring is attached to the fur-nace by a full penetration weld on each side.

17.5 The thickness of the furnace wall or fl ue is a minimum of 5/16 in.

17.6 The spacing, L, of the rings on the furnace is not greater than 60t or 36 in., whichever is smaller.

17.7 The design temperature of the furnace is taken as 100° F higher than the water tem-perature.

17.8 The boiler design permits replacement of the furnace. A fl ared or welded OG ring is an acceptable type of assembly.

17.9 The completed furnace assembly is post-weld heat treated but radiographic examina-tion is not required.

17.10 The thickness of the furnace wall and design of stiffening rings are determined by the use of Figure PFT-17.1. The symbols de-fi ned below, and shown in Figures PFT-17.1and PFT-17.2 are used in the formulas of this paragraph:

t = minimum required wall thickness of furnace or fl ue, inches

L = design length of a furnace section, taken as the greatest center-to-center distance between any two adjacent stiffening rings, or the distance from the center of the fi rst stiffening ring to the center of the furnace weld attachment, inches. In case a fl ared end assembly is used, the distance shall be measured to the point of tangency of the fl are and the furnace and the adjacent stiffening ring.

Do = outside diameter of furnace or fl ue, inches

P = maximum allowable working pres-sure, pounds per square inch

The required wall thickness of a ring rein-forced furnace or fl ue shall not be less than that determined by the following procedure:

Step 1: Assume value for t and L. Deter-mine the ratios L/Do and Do/t;

Step 2: Enter left-hand side of Figure PFT 17.1 at the value of L/Do determined in Step 1;

Step 3: Move horizontally to the line rep-resenting the value of Do/t determined in Step 1;7

Step 4: From this intersection move ver-tically to the material line of the proper temperature; 13

Step 5: From this intersection move hori-zontally to the right and read the value of B;

Step 6: Compute the allowable working pressure, Pa , by the following formula:

��

��

13 For immediate temperatures and Do/t ratios, interpo-lations may be made between the lines on the chart in Figure PFT-17.1.

317


0.000012 3 4 5 6 78

0.00012 3 4 5 6 78 2 3 4 5 67 8

0.001 0.01 0.12 3 4 5 6 7 8

50

140

100

60708090

120

160180200

250

300

350400

500

600

7008009001,000

1,200

1,400

1,6001,8002,000

2,500

3,000

3,500

4,000

5,000

6,000

7,0008,0009,000

10,000

12,000

14,00016,00018,00020,000

25,000

40,000

50,000

35,000

30,000

0.05

0.06

0.07

0.080.090.10

0.12

0.140.16

0.20

0.25

0.30

0.18

0.35

0.50

0.60

0.70

0.40

0.901.0

0.80

1.2

1.4

1.82.0

1.6

2.5

3.0

3.5

4.0

5.0

6.0

7.0

9.08.0

10

12

14161820

25

30

35

40

50

FACTOR A

Leng

th /O

utsi

de D

iam

eter

= L

/D0

UP TO 300 FUP TO 500 F

UP TO 700 FUP TO 800 FUP TO 900 F

FA

CT

OR

B =

P(D

/t)

0

o

o

o

o

o

oD

/t=

300

oD

/t=

250

oD

/t=

200

oD

/t=

150

oD

/t=

60

oD

/t=

80

oD

/t=

100

oD

/t=

125

oD

/t=

50

oD

/t=

40

oD

/t=

30

oD

/t=

25

oD

/t=

20

oD

/t=

15

oD

/t=

10

oD

/t=300o

D /t=250

oD

/t=200

oD

/t=60o

D /t=80

oD

/t=100

oD

/t=125

oD

/t=50o

D /t=40

oD

/t=30o

D /t=25

oD

/t=20o

D /t=15

oD /t=10

oD

/t=150

oD

/t=400

oD

/t=500

oD

/t=600

oD

/t=800

oD

/t=1000

oD

/t=400

oD

/t=500o

D /t=600

oD

/t=800o

D /t=1000

FIGURE PFT-17.1 — Chart for Determining Wall Thickness of Ring Reinforced Furnaces When Constructed of Carbon Steel (Specified yield Strength 30,000 to 38,000 psi)

318


14 For immediate temperatures and Do/t ratios, interpolations may be made between the lines on the chart in Figure PFT-17.1.

Alternate End AssembliesHr

Tr

Hr

Tr

L

D

L

o

L

t

Full PenetrationContinuous WeldBoth Sides of Rings

FIGURE PFT 17.2 — Acceptable Type Of Ring Reinforced Furnace

Step 7: Compare Pa with P. If Pa is less than P, select greater value of t or a smaller value of L or some combination of both to increase Pa , so that it is equal to or greater than P. (An example shown in Appendix A-200.)

The required moment of inertia of a circum-ferential stiffening ring shall not be less than that determined by the formula:

��

��

��

��

��

where, Is = required moment of inertia of the

stiffening ring about its neutral axis parallel to the axis of the furnace, inches

As = cross-sectional area of the stiffening ring, square inches

A = factor determined from Figure PFT 17.1

P, Do , L, and t are as defined above

The moment of inertia for a stiffening ring shall be determined by the following proce-dure:

Step 1: Assuming that the furnace has been designed and Do , L and t are known, select a rectangular member to be used for a stiffening ring and determine its area, As , and its moment of inertia, I. Then calculate B by the formula:

��

��

�

where B = factor on the right-hand side of Fig-

ure PFT-17.1 and P, Do , t, As , and L are as defined above;

Step 2: Enter the right-hand side of Figure PFT-17.1 at the value of B determined in Step 1;

Step 3: Follow horizontally to the material line for the correct temperature; 14

Step 4: Move down vertically to the bot-tom of the chart and read the value of A;

Step 5: Compute the value of the required moment of inertia, Is , from the formula given above;

Step 6: If the required Is is greater than the moment of inertia, I for this section selected in Step 1, select a new section with a larger moment of inertia and determine a new value of Is .

If the required Is is smaller than I for the section selected in Step 1, that section should be satisfactory. (An ex-ample is shown in Appendix A-200.)

The longitudinal and circumferential joints may be of the double-welded butt type, the only requirements being

319


that the welds are postweld heat treated in accordance with PW-39 and a bend test of a sample of the welding for each furnace meets the requirements of PW-53, no radiographic examination being required. When the lon-gitudinal and circumferential joints have been subjected completely to radiographic examination, the individual bend test for each furnace is not required.

PFT-18 COMBINED PLAIN CIRCULAR AND CORRUGATED TYPE

Combination-type furnaces for external pressure may be constructed by combining a plain circular section and a corrugated section provided:

18.1 Each type of furnace is designed to be self-supporting, requiring no support from the other furnace at their point of connection.

18.2 Paragraphs PFT-14 and PFT-15 are used for calculating the maximum allowable work-ing pressure of the plain section. In applying the length in the text or L in the formulas, the value used shall always be twice the actual length of the plain section. The actual length of the plain section is the distance measured from the centerline of the head attachment weld to the centerline of the full penetration weld joining the two sections.

18.2.1 Furnaces 12 in. to 18 in. in outside diameter inclusive. A plain furnace section whose length is such that twice the actual length does not exceed 4-1/2 diameters shall have its maximum allowable work-ing pressure calculated by Equation (1) or (2) in PFT-14.4. If twice the actual length of the plain furnace section does not exceed 120 times the thickness of the plate, Equation (1) shall be used. If twice

the actual length of the plain furnace sec-tion exceeds 120 times the plate thickness, Equation (2) shall be used.

A plain furnace section whose length is such that twice the actual length exceeds 4-1/2 diameters shall have its maximum allowable working pressure determined in accordance with PFT-15.

18.2.2 Furnaces over 18 in. to and including 38 in. in outside diameter. The maximum allowable working pressure of a plain furnace section shall be determined by Equation (1) and (2) in PFT-14.4. When twice the actual length of the plain fur-nace section exceeds 6 times the furnace diameter, L in the formulas shall be taken as 6 times the diameter.

18.3 The maximum allowable working pres-sure of the corrugated section shall be deter-mined from PFT-19.

18.4 The full penetration weld joining a plain self-supporting section to a corrugated self-supporting section, shall be located as shown in Figure PFT-18.

18.5 The longitudinal and circumferential joints may be fusion welded of the double-welded butt type, the only requirements being that the welds are postweld heat treated in accordance with PW-39 and a bend test of a sample of the welding for each furnace meets the requirements of PW-53, no radiographic examination being required. When the lon-gitudinal and circumferential joints have been subjected completely to radiographic examination, the individual bend test for each furnace is not required.

320


Max 3 t or 1-1/2"(whichever is less)

c3

1

ct

Point of Tangency

FIGURE PFT-18 — Connection Between Plain And Corrugated Furnace

PFT-19 CORRUGATED FURNACES

19.1 The maximum allowable working pres-sure on corrugated furnaces, such as the Leeds suspension bulb, Morison, Fox, Purves, or Brown, having plain portions at the ends not exceeding 9 in. in length (except flues espe-cially provided for), when new and practically circular, shall be computed as follows:

Ct P = D


sure, pounds per square inch t = thickness, inches, not less than 5/16

in. for Leeds, Morison, Fox, and Brown, and not less than 7/16 in. for Purves and other furnaces cor-rugated by section not over 18 in. long

D = mean diameter, inches C = 17,300, a constant for Leeds furnaces,

when corrugations are not more than 8 in. from center to center and not less than 2-1/4 in. deep.

C = 15,600, a constant for Morison fur-naces, when corrugations are not more than 8 in. from center to center and the radius of the outer corruga-tion is not more than one-half of the suspension curve.

C = 14,000, a constant for Fox furnaces, when corrugations are not more than 8 in. from center to center and not less than 1-1/2 in. deep.

C = 14,000, a constant for Purves fur-naces, when rib projections are not more than 9 in. from center to center and not less than 1-5/8 in. deep.

C = 14,000 a constant for Brown furnac-es, when corrugations are not more than 9 in. from center to center and not less than 1-5/8 in. deep.

C = 10,000, a constant for furnaces cor-rugated by sections not more than 18 in. from center to center and not less than 1-1/2 in. deep, measured from the least inside to the greatest out-side diameter of the corrugations, and having the ends fitted one into the other and substantially riveted together, provided that the plain parts at the ends do not exceed 12 in. in length.

In calculating the mean diameter of the Mori-son furnace, the least inside diameter plus 2 in. may be taken as the mean diameter.

The longitudinal and circumferential joints may be fusion welded of the double-welded butt type, the only requirements being that the welds are postweld heat treated in accordance with PW-39 and a bend test of a sample of the welding for each furnace meets the require-ments of PW-53, no radiographic examination being required.

When the longitudinal and circumferential joints have been subjected completely to ra-diographic examination, the individual bend test for each furnace is not required.

19.2 The thickness of a corrugated or ribbed furnace shall be ascertained by actual mea-surement by the furnace manufacturer, by gaging the thickness of the corrugated por-tions. If a hole is used, the diameter of a hole drilled through the sheet to determine its thickness shall be 3/8 in. When the furnace is installed the hole shall be located beneath the bottom of the grate and closed by a plug. For the Brown and Purves furnaces, the holes shall be in the center of the second flat; for

321


the Morison, Fox and other similar types, in the center of the top corrugation, at least as far in as the fourth corrugation from the end of the furnace.

PFT-20 ATTACHMENT OF FURNACES

20.1 Riveted Construction. Furnaces may be attached to an inwardly or outwardly fl anged head or tube sheet by riveting in accordance with the rules of Part PR and applicable rules in Part PFT.

20.2 Fillet Welded Construction. In a scotch-type boiler, a furnace may be attached to an out-wardly fl anged opening in a front tube sheet by a circumferential fi llet weld, or a furnace may be attached to either tube sheet by fl ar-ing the end which extends beyond the outside face of the head to an angle of 20 to 30 deg. and using a circumferential fi llet weld, provided the following requirements are met:

20.2.1 The area of the head around the furnace is stayed by tubes, stays, or both in accordance with the requirements of this Section.

20.2.2 The joint is wholly outside the furnace.

20.2.3 The throat dimension of the full fi llet weld is not less than 0.7 times the thickness of the head.

20.2.4 Unless protected by refractory material, the furnace does not extend be-yond the outside face of the tube sheet, a distance greater than the thickness of the tube sheet. Any excess shall be removed before welding.

20.2.5 The construction conforms in all other respects to the requirements of this Section including welding and postweld heat treating, except that radiographic examination is not required.

20.3 Full Penetration Weld Construction. A furnace may be attached by a full penetra-tion weld, with the furnace extending at least through the full thickness of the tube sheet but not beyond the toe of the weld, and the toe shall not project beyond the face of the tube sheet by more than 3/8 in. unless protected from overheating by refractory material or other means.

20.4 Throat Sheets. Throat sheets and inside and outside front furnace sheets when fully stayed may be attached as required in PFT-11.4.

20.5 Furnace Sheets. Attached by WeldingVertical fi retube boilers may be constructed by welding the ogee bottom of the furnace sheet to the outside shell as shown in Figure PFT-20 provided the following requirements are met:

20.5.1 The tube or crown sheet is fully supported by tubes, or stays or both.

20.5.2 The joint is wholly within the shell and forms no part thereof.

20.5.3 The weld is not in contact with primary furnace gases.9

20.5.4 The throat dimension of the full fi llet weld is not less than 0.7 times the thickness of the furnace sheet.

20.5.5 The maximum depth of the water-leg does not exceed 4 in., and the radius

d (max = 4")d (max) (max)Pitch1

2

FIGURE PFT-20 — Welding Ogee Ring

9 Primary Furnace gases are those in a zone where the design temperature of those gases exceeds 850°F

322


of the ogee is not greater than the inside width of the waterleg.

20.5.6 The pitch of the lower row of stay-bolts meets the requirements of PFT-26.6.

20.5.7 The construction conforms in all other respects to Code requirements in-cluding welding and postweld heat treat-ing, except that radiographic examination is not required.

PFT-21 FIREBOXES AND WATERLEGS

21.1 Fireboxes and waterlegs may be of riv-eted construction provided the rules in Part PR and all applicable rules in Part PFT are followed.

21.2 Welded construction may be used in lieu of riveted joints in the fireboxes of internally fired boilers provided the welds are between two rows of staybolts, or in the case of flat surfaces the weld is not less than one-half of a staybolt pitch from the corner. In vertical tubular and firebox types of boilers the bottom edges of the plates may be attached by fusion welding, provided the load due to internal pressure is carried by staybolting and the inside width of the waterleg does not exceed 4 in. An acceptable construction is as shown in Figure PWT-12.2 with both plates flanged. As an alternative construction one plate only need be flanged, provided the weld joining the flanged plate to the straight plate is a groove weld having penetration for its full depth and the weld is outside of the header. The plates may be considered to be fully supported if stayed in accordance with the requirements of PFT 26.8.

The welds shall be postweld heat treated but radiographic examination is not required.

21.3 Mud rings of plate material permissible under this Section of the Code may be used in the construction of waterlegs of vertical firetube boilers and may be attached as shown

in Figure PG-31(g) in compliance with the requirements of Par. PG-31 provided:

21.3.1 The width of the waterleg does not exceed 4 in.

21.3.2 The thickness of the mud ring plate is at least 1/2 in.

The welds shall be postweld heat treated but radiographic examination is not required.

Any crevices between the mud ring and the sheets of the furnace section of a locomo-tive-type boiler may be made tight with seal welding when the mud ring is secured by rivets. The abutting ends of mud rings may be welded.

STAYED SURFACES

PFT-22 GENERAL

The rules of Part PG pertaining to stayed sur-faces which are applicable to firetube boilers shall be used in conjunction with the follow-ing requirements.

PFT-23 WORKING PRESSURE FOR CURVED SURFACES

23.1 The maximum allowable working pres-sure for curved stayed surfaces subject to internal pressure shall be obtained by the following two methods, and the minimum value obtained shall be used:

23.1.1 The maximum allowable work-ing pressure shall be computed without allowing for the holding power of the stays, due allowance being made for the weakening effect of the holes for the stays or riveted longitudinal joint or other construction. To this pressure there shall be added the pressure obtained by the formula for stayed surfaces given in PG-46 using 1.3 for the value of C.

323


23.1.2 The maximum allowable working pressure shall be computed without allow-ing for the holding power of the stays, due allowance being made for the weakening effect of the holes for the stays or riveted longitudinal joint or other construction. To this pressure there shall be added the pressure corresponding to the strength of the stays for the allowable stress values in Table PG-23.1, each stay being assumed to resist the pressure acting on the full area of the external surface supported by the stay.

23.2 The maximum allowable working pres-sure for a stayed wrapper sheet of a locomo-tive-type boiler shall be determined by the two methods given above and by the fol-lowing formula and the smallest of the three values obtained shall be used:

��

�� where, P = maximum allowable working pres-

sure, pounds per square inch t = thickness of wrapper sheet, inches E = minimum efficiency of wrapper

sheet through joints or stay holes R = radius of wrapper sheet, inches ∑(s x sin a) = summated value of transverse

spacing s x sin a for all crown stays considered in one transverse plane and on one side of the vertical axis of the boiler

s = transverse spacing of crown stays in the crown sheet, inches

a = angle any crown stay makes with the vertical axis of boiler

11,000 = allowable stress, pounds per square

inch

The above formula applies to the longitudinal center section of the wrapper sheet, and in cases where E is reduced at another section, the maximum allowable working pressure based on the strength at that section may be increased in the proportion that the distance

from the wrapper sheet to the top of the crown sheet at the center bears to the distance mea-sured on a radial line through the other sec-tion, from the wrapper sheet to a line tangent to the crown sheet and at right angles to the radial lines (see Figure PFT-23.1).

23.3 A furnace for a vertical fi retube boiler 38 in. or less in outside diameter which requires staying shall have the furnace sheet supported by one or more rows of staybolts, the circum-ferential pitch not to exceed 1.05 times that given by the formula in PG-46.

The longitudinal pitch between the staybolts, or between the nearest row of staybolts and the row of rivets at the joints between the fur-nace sheet and the tube sheet or the furnace sheet and mud ring, shall not exceed that given by the following formula:

��

��

�

where, L = longitudinal pitch of staybolts P = maximum allowable working pres-

sure, pounds per square inch t = thickness of furnace sheet, inches R = outside radius of furnace, inches

When values by this formula are less than the circumferential pitch, the longitudinal pitch may be as large as the allowable circumfer-ential pitch.

9090oo

90o

9090o

90

FIGURE PFT-23.1 — Stayed Wrapper Sheet of Locomotive-Type Boiler

324


The stress in the staybolts shall not exceed 7500 psi. and shall be determined as specifi ed in PFT-23.4.

23.4 In furnaces over 38 in. in outside diam-eter and combustion chambers not covered by special rules in this Section which have curved sheets subject to pressure on the convex side, neither the circumferential nor longitudinal pitches of the staybolts shall exceed 1.05 times that given by the rules in PG-46.

The stress in staybolts shall not exceed 7500 psi based on the total load obtained by mul-tiplying the product of the circumferential and longitudinal pitches less the minimum cross-sectional area, by the maximum allow-able working pressure.

23.5 Furnaces of Vertical Boilers. In a vertical fi retube boiler, the furnace length, for the pur-pose of calculating its strength and spacing staybolts over its surface, shall be measured from the center of rivets in the bottom of the waterleg to the center of rivets in the fl ange of the lower tubesheet.

23.6 When the longitudinal joint of the fur-nace sheet of a vertical fi retube boiler is of lap-riveted construction and staybolted, a staybolt in each circular row shall be located near the longitudinal joint, as shown in Figure PFT-23.2.

PFT-24 FLEXIBLE STAYBOLTS

Flexible-type staybolts having a cover cap welded under the provisions of PW-15 to the outer sheet may be used in the construction of locomotive-type boilers provided the bolts are hollow-drilled from the threaded end into and partly through the ball head to allow for proper inspection, and so that any breakage is disclosed by leakage at the inner end. These welded joints need not be postweld heat treated nor radiographed.

PFT-25 ATTACHMENT OF STAYS AND STAYBOLTS BY

WELDING

The attachment of stays and staybolts by welding shall meet the requirements of PW-19.

PFT-26 MAXIMUM SPACING

26.1 The maximum distance between cen-ters of rivets, or between the edges of tube holes and the centers of rivets attaching the crowfeet of stays to the stayed surface, shall be p as determined in PG-46 using 2.5 for the value of C.

26.2 The maximum distance between the edges of tube holes and the centers of other types of stays shall be p as determined by the formula in PG-46, using the value of C given for the thickness of plate and type of stay used.

26.3 For a fl anged head, riveted or welded to the shell, the maximum distance between the inner surface of the supporting fl ange and lines parallel to the surface of the shell passing through the center of the stay, or the rivets attaching crowfeet of stays shall be p as determined by the formula in PG-46, plus the inside radius of the supporting fl anges using the following C factors:

For riveted crowfoot stays—Use 2.1 for C factor.

FIGURE PFT-23.2 — Proper Location of Staybolts Adjacent to Longitudinal Joint in Furnance Sheet

325


For other types of stays—Use the C factor which applies to the thickness of the head plate and type of stay used [see Figure A-8(i) and (j)].

26.4 For unfl anged heads, the maximum distance between the inner surface of the shell and the centers of stays, or rivets attach-ing crowfeet of stays, shall not be more than one-half the maximum allowable pitch as determined by PG-46, using 2.5 for the value of C, plus 2 in. [see Figure A-8(k)].

26.5 The pitch of diagonal stays attached by welding between the shells and tube sheets of horizontal tubular and scotch boilers, and for other stays when supported plate is not exposed to radiant heat, as determined by PG-46, may be greater than 8-1/2 in., but shall not exceed 15 times the stay diameter.

26.6 The pitch of the lower row of staybolts of a vertical fi retube boiler, which is required to be stayed by the rules in this Section, and which is fabricated by welding the ogee bot-tom of the furnace sheet to the outside shell, shall not exceed one-half the maximum allow-able pitch as determined by PG-46, measured from the center of the staybolt to the tangent of the ogee (see Figure PFT-20).

26.7 The spacing of staybolts around door holes fabricated by fusion welding of the full penetration type of two-fl anged sheets, which are required to be stayed by the rules of this Section (see Figure PWT-12.2), shall not exceed one-half the maximum allowable pitch determined by PG-46, measured from the center of the staybolt to the points of tan-gency of the fl anges.

26.8 If the furnace sheets are required to be stayed by the rules of this Section, the spac-ing of staybolts around door holes and the spacing of the fi rst row of staybolts from the bottom of the mud ring fabricated by fusion welding of the full penetration type when ei-ther or both sheets are not fl anged [see Figure A-8(l), (m) and (n)] shall not exceed one-half the maximum pitch determined by PG-46, plus 2 in., measured from the center of the

staybolt to the root of the weld.

26.9 The maximum distance from the fi rst row of stays to a full penetration weld in com-pression applied from either or both sides of the tube sheet, attaching the crown sheet of a furnace or combustion chamber to a stayed head or tube sheet shall not exceed the pitch determined by PG-46, measured from the center of the stay to the furnace or combustion chamber side of the head or tube sheet [see Figures A-8(o) and (p)].

26.10 When a fl anged-in manhole opening with a fl ange depth of not less than 3 times the required thickness of the head, or when an unfl anged manhole ring meeting the require-ments of PG-32 through PG-39 is provided in a fl at stayed head of a fi retube boiler, as shown in Figures A-8(q) and (r), the area to be stayed as required by PFT-31 may be reduced by 100 sq. in. provided both the following require-ments are met:

26.10.1 The distance between the manhole opening and the inside of the shell does not exceed one-half the maximum allow-able pitch for an unfl anged manhole and one-half the maximum allowable pitch plus the radius of the head fl ange for a fl anged-in manhole in a fl anged head.

26.10.2 The distance between the centers of the fi rst rows of stays, or the edges of tube holes, and the manhole opening does not exceed one-half the maximum allow-able pitch as determined by PG-46.

26.11 In applying these rules and those in PG-46 to a head or plate having a manhole or reinforced opening, the spacing applies only to the plate around the opening and not across the opening.

26.12 For stays at the upper corners of fi re-boxes, the pitch from the staybolt next to the corner to the point of tangency to the corner curve shall be (see Figure PFT-26):

326


��

��

��

where T = thickness of plate in sixteenths of an

inch P = maximum allowable working pres-

sure, pounds per square inch C = factor for the thickness of plate and

type of stay used as required in Part PG-46.

PFT-27 AREA SUPPORTED BY STAY

27.1 The full pitch dimensions of the stays shall be employed in determining the area to be supported by a stay, and the area occupied by the stay shall be deducted therefrom to ob-tain the net area. The product of the net area in square inches by the maximum allowable working pressure in pounds per square inch gives the load to be supported by the stay.

27.2 Where stays come near the outer edge of the surfaces to be stayed and special allow-ances are made for the spacing, the load to be carried by such stays shall be determined by neglecting the added area provided for these special allowances.

Example: If the maximum pitch by PG-46 would make a staybolt come 6 in. from the edge of the plate and a special allowance

would make it come 7 in., the distance of 6 in. shall be used in computing the load to be carried.

PFT-28 STAYBOLTS AND STAYS

28.1 The required area at the point of least net cross section of staybolts and stays shall be as given in PG-49. The maximum allow-able stress per square inch at point of least net cross-sectional area of staybolts and stays shall be given as in Table PG-23.11. In deter-mining the net cross-sectional area of drilled or hollow staybolts, the cross-sectional area of the hole shall be deducted.

28.2 The length of the stay between supports shall be measured from the inner faces of the stayed plates. The stresses are based on ten-sion only. For computing stresses in diagonal stays, see PFT-32.

28.3 When stay rods are screwed through sheets and riveted over, they shall be sup-ported at intervals of not to exceed 6 ft. Stay rods over 6 ft. in length may be used without support if fitted with nuts and washers or attached by welding under PW-19, provided the least cross-sectional area of the stay rod is not less than that of a circle 1 in. in diameter.

PFT-29 STRUCTURAL REINFORCEMENTS

29.1 When channels or other structural shapes are riveted to the boiler heads for attaching through stays, the transverse stress on such members shall not exceed 12,500 psi. In computing the stress, the section modulus of the member shall be used without addition for the strength of the plate. The spacing of the rivets over the supported surface shall be determined by the formula in PG-46, using 2.5 for the value of C.

29.2 Provided the outstanding legs of the two members are fastened together so that they

MAX r = p AS CALULATED BY PAR. PFT-26.2

MIN r = 3 t

p

p

t

β

r

FIGURE PFT-26 — Pitch of Staybolts Adja-cent to Upper Corners of Fireboxs

327


act as one member in resisting the bending action produced by the load on the rivets attaching the members to the head of the boiler, and provided that the spacing of these rivets attaching the members to the head is approximately uniform, the members may be computed as a single beam uniformly loaded and supported at the points where the through stays are attached.

PFT-30 STAYING SEGMENTS OF HEADS

30.1 A segment of a head shall be stayed by head-to-head, through, diagonal, crowfoot, or gusset stays, except that a horizontal-return tubular boiler may be stayed as provided in PFT-35.

30.2 Stays shall be used in the tube sheets of a fi retube boiler if the distance between the edges of the tube holes exceeds the maximum pitch of staybolts for the corresponding plate thickness and pressure given in PG-46.

Any part of the tube sheet which comes be-tween the tube or cylindrical furnace and the shell need not be stayed if the greatest distance measured along a radial line from the inner surface of the shell to the center point of tan-gent to any two tube holes or tube hole and cylindrical furnace on the shell side of such holes does not exceed 1.5 times the value of p obtained by applying the formula of PG-46 with C equal to 2.1 or 2.2 depending upon the plate thickness. The tube holes, or tube hole and cylindrical furnace (see Figure PFT-30), to which a common tangent may be drawn in applying this rule, shall not be a greater distance from edge to edge than the maximum pitch referred to.

PFT-31 AREAS OF HEADS TO BE STAYED

31.1 The area of a segment of a fl anged head to be stayed shall be the area enclosed by lines drawn 2 in. from the tubes and a distance d

from the shell as shown in Figures PFT-31.1and PFT-31.2. The value of d used may be the larger of the following values:

d = the outer radius of the fl ange, not exceeding 8 times the thickness of the head

d = 80t/√Pwhere d = unstayed distance from shell, inches t = thickness of head in inches P = maximum allowable working pres-

sure, pounds per square inch

31.2 The area of a segment of an unfl anged head to be stayed shall be the area enclosed by the shell and a line drawn 2 in. from the tubes.

31.3 The rules on PFT-30.2 shall be used to determine if staying is required.

31.3.1 The net area to be stayed in a seg-ment of a fl anged head may be determined by the following formula:

��

�

� � ��

where, A = area to be stayed, square inches H = distance from tubes to shell, inches d = distance determined by formula in

PFT-31.1 for fl anged heads d = zero for unfl anged heads R = radius of boiler head, inches

31.3.2 The net area to be stayed in a seg-ment of an unfl anged head may be deter-mined by the following formula:

��

�

��

��

where, A = area to be stayed, square inches

328


1 p12

1 p121 p1

2

1 p12 1 p1

2

FIGURE PFT-30 — Example of Staying of Heads Adjacent to Cylindrical Furnaces

FIGURE PFT-31.1 — Method of Determining Net Area of Segment of a Head

FIGURE PFT-31.2 — Method of Determining Net Area of Irregular Segment of a Head

FIGURE PFT-32 — Measurements for Determining Stresses in Diagonal Stays

329


31.4 When stays are required, the portion of the heads below the tubes in a horizontal-return tubular boiler shall be supported by through stays attached by welding under PW-19 or with nuts inside and outside at the front head and by attachments which distribute the stress at the rear head.

The distance in the clear between the bodies of the stays or of the inside stays where more than two are used shall not be less than 10 in. at any point.

When horizontal firetube boilers are set so that the products of combustion do not come in contact with the lower part of the shell, tubes may be used instead of through stays at the sides of the manhole opening, if used.

PFT-32 STRESSES IN DIAGONAL AND GUSSET STAYS

32.1 To determine the required area of a di-agonal stay, multiply the area of a direct stay required to support the surface by the slant or diagonal length of the stay; and divide this product by the length of a line drawn at right angles to surface supported to center of palm of diagonal stay as follows:

��

�where, A = sectional area of diagonal stay,

square inches a = sectional area of direct stay, square

inches L = length of diagonal stay as indicated

in Figure PFT-32, inches l = length of line drawn at right angles

to boiler head or surface supported to center of palm of diagonal stay, as indicated in Figure PFT-32

Example: Given diameter of direct stay=1 in. a=0.7854 sq. in., L=60 in., l=48 in.; substituting and solving:

Diameter=1.11 in. = 1-1/8 in.

32.2 For staying segments of tube sheets such as in horizontal-return tubular boilers, where L is not more than 1.15 times l for any stay, the stays may be calculated as direct stays allow-ing 90 percent of the allowable stress value given in Table PG-23.1.

PFT-33 DESIGN OF STAYS AND STAY CONNECTIONS

All rivet holes and pinholes shall conform to the requirements of PR-32 and the pins shall be made a neat fit. To determine the sizes that shall be used, proceed as follows:

33.1 Determine the required cross-sectional area of the stay in accordance with PFT-29.

33.2 Design the body of the stay so that the cross-sectional area shall be at least equal to the required cross-sectional area of the stay for unwelded stays. Where the stays are forge welded, the cross-sectional area at the weld shall be at least as great as that computed for a stress of 6,000 psi (see Table PG-23.3).

33.3 Make the area of pins to resist double shear at least three-quarters of the required cross-sectional area of the stay.

33.4 Make the combined cross section of the eye at the side of the pin (in crowfoot stays) at least 25 percent greater than the required cross-sectional area of the stay.

33.5 Make the cross-sectional areas through the blades of diagonal stays where attached to the shell of the boiler at least equal to the required rivet section, that is, at least equal to 1-1/4 times the required cross-sectional area of the stay.

33.6 Design each branch of a crowfoot to carry two-thirds the total load on the stay.

33.7 Make the net sectional areas through the sides of the crowfoot, tee irons, or similar fastenings at the rivet holes at least equal to the required rivet section, that is, at least equal

330


to 1-1/4 times the required cross-sectional area of the stay.

33.8 Make the combined cross-sectional area of the rivets at each end of the stay at least 1-1/4 times the required cross-sectional area of the stay.

PFT-34 GUSSET STAYS

Gusset stays when constructed of triangular right-angled web plates secured to single- or double-angle bars along the two sides at right angles shall have a cross-sectional area (in a plane at right angles to the longest side and passing through the intersection of the two shorter sides) not less than 10 percent greater than would be required for a diagonal stay to support the same surface, calculated by the formula of PFT-32, assuming the diagonal stay is at the same angle as the longest side of the gusset plate.

PFT-35 STAYING OF UPPER SEGMENTS OF TUBE HEADS

BY STEEL STRUCTURAL SHAPES

35.1 When the shell of a boiler does not exceed 36 in. in diameter and is designed for a maximum allowable working pressure

Not over 3"

Not over 4"

Not over 8"3"

Not lessthan 2"

See

Tab

le

See

Tab

le

β

Α

FIGURE PFT-35 — Staying of Head with Steel Angles in Tubular Boiler

Height of Segment Dimension β in Fig. PFT-35 10 11 12 13 14 15 16 Thickness, In.

30-in. Boiler Angle 3 by 2-1/2 in. 3/8 7/16 9/16 ... ... ... ... Angle 3-1/2 by 3 in. 5/16 3/8 7/16 9/16 ... ... ... Angle 4 by 3 in. 5/16 5/16 3/8 7/16 1/2 ... ...

34-in. Boiler Angle 3-1/2 by 3 in. ... 7/16 1/2 11/16 ... ... ... Angle 4 by 3 in. ... 5/16 7/16 1/2 5/8 ... ... Angle 5 by 3 in. ... 5/16 5/16 5/16 3/8 1/2 ...

36-in. Boiler Angle 4 by 3 in. ... ... 7/16 9/16 5/8 3/4 ... Angle 5 by 3 in. ... ... 5/16 3/8 7/16 1/2 5/8 Angle 6 by 3 in. ... ... ... ... 3/8 3/8 7/16

Dimension A in. Fig. PFT-35 6-1/2 7 7-1/2 8 8-1/2 9 9-1/2

TABLE PFT-35Sizes of Angles Required for Staying Segments of Head(With the short legs of the angles attached to the head of the boiler.)

331


not exceeding 100 psi, the segment of heads above the tubes may be stayed by steel struc-tural shapes as specifi ed in Table PFT-35 and Figure PFT-35, except that structural shapes of equal thickness and greater depth of out-standing leg, or of greater thickness and the same or greater depth of outstanding leg, may be substituted for those specifi ed. The legs attached to heads may vary in depth 1/2 in. above or below the dimensions specifi ed in Table PFT-35.

35.2 When this form of staying is to be placed on a boiler, the diameter of which is inter-mediate to or below the diameters given in Table PFT-35, the tabular values for the next higher diameter shall govern. Rivets of the same diameter as used in the longitudinal joints of the boiler shall be used to attach the structural shapes to the head and to connect the outstanding legs.

35.3 The rivets attaching structural shapes to heads shall be spaced not over 4 in. apart. The centers of the end rivets shall be not over 3 in. from the ends of the structural shape. The rivets through the outstanding legs shall be spaced not over 8 in. apart; the centers of the end rivets shall be not more than 4 in. from the ends of the structural shapes. The ends of the structural shapes shall be considered those of the outstanding legs and the lengths shall be such that their ends overlap a circle 3 in. inside the inner surface of the shell as shown in Figure PFT-35.

35.4 The distance from the center of the struc-tural shapes to the shell of the boiler, marked A in Figure PFT-35, shall not exceed the values in Table PFT-35, but in no case shall the leg attached to the head of the lower angle come closer than 2 in. from the top of the tubes.

35.5 When segments are beyond the range specifi cation in Table PFT-35, the heads shall be stayed in accordance with the requirements in these rules.

PFT-36 CROWN BARS AND GIRDER STAYS

36.1 Crown bars and girder stays for tops of combustion chambers and back connections or wherever used, shall be proportional to conform to the following formula:

��

��

where, W = extreme distance between supports

of, in a scotch marine boiler, the distance from the fi reside of the tube sheet to the fi reside of the back con-nection plate, inches


p = pitch of supporting bolts, inches D1 = distance between girders from cen-

ter to center, inches d = depth of girder, inches C = 7,000 when girder is fi tted with one

supporting bolt C = 10,000 when the girder is fi tted with

two or three supporting bolts C = 11,000 when the girder is fi tted with

four or fi ve supporting bolts C = 11,500 when the girder is fi tted with

six or seven supporting bolts C = 12,000 when the girder is fi tted with

eight or more supporting bolts

Example: Given W=34 in., p=7.5 in., D1=7.75 in., d=7.5 in., t=2 in., three stays per girder, C=10,000; then substitute the formula:

��

��

Sling stays, if used between crown bars and boiler shell or wrapper sheet, shall be propor-tioned so as to carry the entire load without considering the strength of the crown bars.

36.2 In a form of reinforcement for crown sheets where the top sheet of the fi rebox is a

332


semicircle and the top part of the circle not exceeding 120 deg. in arc is reinforced by arch bars extending over the top and down below the top row of staybolts at the sides of the furnace beneath the semicircular crown sheet, these arch bars being riveted to the waterside through thimbles, the maximum allowable working pressure shall be deter-mined by adding to the maximum allowable working pressure for a plain circular furnace of the same thickness, diameter, and length determined by the formula in PFT-14, the pressure P1 determined from the following formula which is a modification of the first formula in PFT-15:

��

��

where, b = net width of crown bar, inches d = depth of crown bar, inches D1 = longitudinal spacing of crown bar

which shall not exceed twice the maximum allowable staybolt pitch, inches

D = two times the radius of the crown sheet, inches

provided that the maximum allowable work-ing pressure must not exceed that determined by the formula for furnaces of the Adamson type, in PFT-16 when L is made equal to D1 , and also provided that the diameter of the holes for the staybolts in the crown bars does not exceed 1/3 b, and the cross-sectional ar-eas of the crown bars is not less than 4 sq. in. PG-46 governs the spacing of the staybolts, rivets, or bolts attaching the sheet to the bars, and PFT-23.4, the size of the staybolts, rivets or bolts.

For constructions in which the crown sheet is not semicircular, or in which other features differ from those specified above, a test shall be made in accordance with PG-101 and the working pressure shall be based thereon.

36.3 Cast iron supporting lugs, legs, or ends shall not be used.

PFT-37 TRUNCATED CONE SHAPED COMBUSTION CHAMBERS OF VERTICAL TUBULAR BOILERS

37.1 Upper combustion chambers of verti-cal submerged tubular boilers made in the shape of a frustrum of a cone when not over 38 in. diameter at the large end may be used without stays if computed by the rule of plain cylindrical furnaces in PFT-14, making D in the formula equal to the diameter at the large end, provided that the longitudinal joint con-forms to the requirements of PFT-14.

37.2 When over 38 in. in diameter at the large end, that portion which is over 30 in. in diameter shall be fully supported by staybolts or gussets. If supported by staybolts, PFT-23.4 shall apply. If supported by gussets the spacing of the rivets attaching the gussets to the cone sheet shall not exceed the staybolt spacing given in PFT-23.4. The top row of staybolts or rivets shall be at a point where the cone top is 30 in. or less in diameter.

In calculating the pressure permissible on the unstayed portion of the cone, the vertical dis-tance between the horizontal planes passing through the centers of the rivets at the cone top and through the center of the top row of staybolts shall be as L in PFT-14.4 and D in that paragraph shall be the inside diameter at the center of the top row of staybolts.

PFT-38 STAY TUBES

38.1 When stay tubes are used in multitubu-lar boilers to give support to the tube plates, the sectional area of such stay tubes may be determined as follows:

Total section of stay tubes, sq. in. =

��

�

where, A = area of that portion of tube plate

containing the tubes, square inches a = aggregate area of holes in the tube

plate, square inches

333



S = maximum allowable stress value in the tubes, pounds per square inch (not to exceed 7,000 psi).

38.2 The pitch of stay tubes shall conform to the formula in PG-46, using the values of C as given in Table PFT-38.

When the ends of tubes are not shielded from the action of fl ame or radiant heat, the values of C shall be reduced 20%. The tubes shall project about 1/4 in. at each end and be slightly fl ared. Stay tubes when threaded shall be not less than 3/16 in. in thickness at bottom of thread; nuts on stay tubes are not advised. For nest of tubes, C shall be taken as 2.5 and p as the mean pitch of stay tubes. For spaces between nests of tubes, p shall be taken as the horizontal distance from center to center of the bounding rows of tubes and C as given in Table PFT-38.

DOORS AND OPENINGS

PFT-39 RIVETED DOOR OPENINGS

Doors in waterlegs may be attached by rivet-ing provided the rules for riveting in Part PR and the rules for stayed surfaces in this Part are complied with.

PFT-40 WELDED DOOR OPENINGS

Arc or gas welding may be used in the fabri-cation of door holes provided the sheets are stayed around the opening in accordance with the requirements of PFT-26.7 and 26.8.

The fi t-up of the several parts of an arc or gas welded door opening shall be such that the maximum gap between the two plates to be joined by welding does not exceed 1/8 in.

PFT-41 OPENINGS IN WRAPPER SHEETS

Openings located in the curved portion of the wrapper sheet of a locomotive-type boiler shall be designed in accordance with the rules in PG-32.

PFT-42 ACCESS AND FIRING DOORS

The minimum size of an access door to be placed in a boiler setting shall be 12 in. x 16 in., or equivalent area; 11 in. to be the least dimension in any case. The minimum size of a fi re door opening in an internally fi red boiler in which the minimum furnace dimension is 24 in. or over shall be not less than 11 in. x 15 in. or 10 in. x 16 in. in size. A circular opening shall be not less than 15 in. in diameter.

TABLE PFT-38 — Values of C For Determining Pitch of Stay Tubes

Pitch of Stay Tubes When Tubes Have No When Tubes Are Fitted Within the Bounding Rows Nuts Outside of Plates Nuts Outside of Plates

Where there are two plain tubes between two stay tubes 2.2 2.4

Where there is one plain tube between two stay tubes 2.6 2.8

Where every tube in the bounding rows is a stay tube and each alternate tube has a nut . . . 3.2

334


The bonnet or smoke hood of a vertical flue or tubular boiler shall be provided with an access opening at least 6 x 8 in. for the pur-pose of inspection and cleaning the top head of the boiler.

PFT-43 LOCATION OF MANHOLES AND HANDHOLES

43.1 The manhole shall be located in the front head below the tubes of a horizontal-return tubular boiler 48 in. or over in diameter. Smaller boilers shall have either a manhole or a handhole below the tubes. There shall be a manhole in the upper part of the shell or head of a firetube boiler over 40 in. in di-ameter, except on a vertical firetube boiler, or except on internally fired boilers not over 48 in. in diameter. The manhole may be placed in the head of the dome. Smaller boilers shall have either a manhole or a handhole above the tubes.

Where plugs are used the minimum size shall be 1-1/2 in. and the requirements of PG-32 through PG-44 shall apply.

43.2 A traction, portable, or stationary boiler of the locomotive type shall have not less than six handholes or washout plugs located as fol-lows: One in the rear head below the tubes; one in the front head at or about the line of the crown sheet; four in the lower part of the waterleg; also, where possible, one near the throat sheet. If the front head is obstructed by a smokebox, the handhole may be inserted in either side sheet at or about the line of the crown sheet.

43.3 A vertical boiler, except watertube type and boilers of steam fire engines and boilers less than 24 in. in diameter, shall have not less than four handhole openings in the shell located as follows: One at or about the water-line or opposite the fusible plug when used; three at or about the line of the crown sheet or lower tube sheet, and if internally fired not

less than three additional handhole openings at the lower part of the waterleg.

A submerged-tube type of vertical firetube boiler 24 in. or more in diameter shall have two or more additional handhole openings in the shell, in line with the underside of the upper tube sheet.

43.4 A vertical boiler, except of the watertube type, less than 24 in. in diameter, shall have in the shell a handhole opening at the waterline and two washout openings near the bottom in addition to the blowoff for washing out the boiler, except:

43.4.1 If of the internally fired type, it shall have a handhole opening in the shell in line with the crown sheet or lower tube sheet, in which case the handhole opening at the waterline may be omitted.

43.4.2 If of the submerged-tube type, it shall also have a handhole opening in the shell in line with the upper tube sheet in which case the handhole opening at the waterline may be omitted.

43.5 If a vertical-type boiler is equipped with manholes or other access openings, through which adequate inspection may be made, the required handhole and/or inspection open-ings at the waterline and for the tube sheets may be omitted.

43.6 A vertical firetube boiler of a steam fire engine shall have at least three washout open-ings located as follows: One at or about the line of the crown sheet, two at the lower part of the waterleg.

43.7 A boiler of the scotch type shall have a handhole or washout plug in the front head below or on each side of the furnace, or on each side of the shell near the front head, a handhole or a washout plug on the bottom of the shell, an opening to inspect the top of the furnace, and an inspection opening above

335


the top row of tubes. Scotch marine boilers (wet-back type) shall also have an opening for inspection of the water space at the rear of the combustion chamber.

PFT-44 OPENING BETWEEN BOILER AND SAFETY VALVE

The opening or connection between the boiler and the safety valve shall have at least the area of the valve inlet. In the case of fi retube boilers, the openings in the boilers for safety valves or safety relief valves shall be not less than given in Table PFT-44, except fi retube boilers used for waste heat purposes only, not equipped for direct fi ring, need not meet the requirements of Table PFT-44 provided the rated steaming capacity is stamped on the boiler and safety valves or safety relief valves of the required relieving capacity are supplied such that the provisions of PG-67.2 are satisfied. No valve of any description shall be placed between the required safety valve or safety relief valve or valves and the boiler, nor on the discharge pipe between the safety valve or safety relief valve and the atmosphere. When a discharge pipe is used, the cross-sectional area shall be not less than the full area of the valve outlet or of the total of the areas of the valve outlets discharging thereinto and shall be as short and straight as possible and so arranged as to avoid undue stresses on the valve or valves.

DOMES

PFT-45 REQUIREMENTS FOR DOMES

45.1 The longitudinal joint of a riveted dome 24 in. or over in inside diameter shall be of butt- and double-strap construction, or the dome may be made without a seam of one piece of steel pressed into shape; and its fl ange shall be double-riveted to the shell. In the case of a dome less than 24 in. in diameter, for

which the product of the inside diameter in inches and the maximum allowable working pressure in pounds per square inch does not exceed 4,000, its fl ange may be single-riveted to the shell and the longitudinal joint may be of the lap type, provided it is computed with a factor of safety of not less than 8.

The longitudinal joint of a dome may be butt-welded and the dome fl ange may be double full fi llet lap-welded to the shell, in place of riveting if the welding complies fully with the requirements for welding in Part PW. Radio-graphic examination of the fi llet welds may be omitted. The opening shall be reinforced in accordance with PG-32 through PG-44.

45.2 The joints of a dome may be welded and the dome welded to the shell if the welding complies fully with the requirements for welding in Part PW. The opening shall be reinforced in accordance with PG-32 through PG-44.

45.3 When a dome is located on the barrel of a locomotive-type boiler or on the shell of a horizontal-return tubular boiler, the diameter of the dome shall not exceed six-tenths the diameter of the shell or barrel of the boiler un-less the portion of the barrel or shell under the dome (the neutral sheet) is stayed to the head or shell of the dome by stays which conform in spacing and size to the requirements given in PG-46 and Table PG-23.1. With such stayed construction the diameter of a dome located on the barrel or shell of a boiler is limited to eight-tenths of the barrel or shell diameter.

45.4 All domes shall be so arranged that any water can drain back into the boiler.

45.5 Flanges of domes shall be formed with a corner radius, measured on the inside, of at least twice the thickness of the plate for plates 1 in. in thickness or less, and at least 3 times the thickness of the plate for plates over 1 in. in thickness.

336


TABL

E PF

T-44

— M

inim

um T

otal

Are

as o

f Ope

ning

s (S

quar

e In

ches

) in

Fire

tube

Boi

lers

for S

afet

y Va

lve

Con

nect

ions

Gag

e

Bo

iler H

eatin

g Su

rfac

e, sq

. ft.

Pres

sure

,

psi

100

200

300

400

500

600

800

1000

12

00

1400

16

00

1800

20

00

2500

30

00

V

16

3.17

4 6.

348

9.52

2 12

.695

15

.869

19

.043

25

.392

31

.739

38

.086

44

.435

50

.738

57

.130

63

.478

79

.347

95

.216

13

.330

25

2.50

0 5.

000

7.49

9 10

.000

12

.498

15

.000

20

.000

24

.996

30

.000

35

.000

40

.000

44

.992

49

.992

62

.489

74

.987

10

.498

50

1.58

4 3.

168

4.75

2 6.

338

7.92

0 9.

504

12.6

77

15.8

39

19.0

07

22.1

75

25.3

54

28.5

10

31.6

78

39.5

99

47.5

17

6.65

5

75

1.16

6 2.

331

3.49

7 4.

663

5.82

8 6.

995

9.32

6 11

.657

13

.989

16

.320

18

.652

20

.983

23

.314

29

.143

34

.972

4.

896

100

0.92

4 1.

849

2.77

3 3.

697

4.62

1 5.

546

7.39

4 9.

243

11.0

92

12.9

40

14.7

89

16.6

37

18.4

86

23.1

06

27.7

29

3.88

212

5 0.

767

1.53

3 2.

300

3.06

7 3.

834

4.60

0 6.

134

7.66

7 9.

201

10.7

34

12.2

67

13.8

00

15.3

34

19.1

16

23.0

00

3.22

0

150

0.65

5 1.

311

1.96

6 2.

621

3.27

6 3.

932

5.24

2 6.

553

7.86

3 9.

174

10.4

84

11.7

95

13.1

06

16.3

82

19.6

58

2.75

217

5 0.

572

1.14

5 1.

718

2.28

9 2.

862

3.43

5 4.

579

5.72

5 6.

870

8.01

5 9.

158

10.3

05

11.4

50

14.3

12

17.1

75

2.40

420

0 0.

508

1.01

6 1.

525

2.03

3 2.

541

3.04

9 4.

066

5.08

2 6.

099

7.11

5 8.

132

9.14

8 10

.164

12

.706

15

.247

2.

1345

225

0.45

7 0.

913

1.37

0 1.

827

2.28

4 2.

740

3.65

4 4.

567

5.48

1 6.

394

7.30

8 8.

221

9.13

4 11

.417

13

.702

1.

9183

250

0.41

5 0.

830

1.24

4 1.

659

2.07

4 2.

489

3.31

8 4.

148

4.97

8 5.

807

6.63

7 7.

466

8.29

6 10

.370

12

.444

1.

7422

base

d on

form

ula

�

��

�

��

whe

re

A

= to

tal a

rea

of o

peni

ngs,

squa

re in

ches

N

OTE

: num

ber a

nd si

ze o

f ope

ning

shal

l pro

vide

for n

ot le

ss th

an th

e ar

ea g

iven

.

H

= bo

iler h

eatin

g su

rfac

e, sq

uare

feet

In

term

edia

te v

alue

s may

be

inte

rpol

ated

. W

ith fl

ange

d op

enin

gs, u

se in

tern

al

V

=

spec

ific

volu

me

of st

eam

in c

ubic

feet

per

pou

nd

area

for d

eter

min

ing

diam

eter

.

at m

axim

um a

llow

able

wor

king

pre

ssur

e

Nom

inal

Pip

e In

tern

al

Inte

rnal

N

omin

al P

ipe

Inte

rnal

In

tern

al

Nom

inal

Pip

e In

tern

al

Inte

rnal

Size

, in.

D

iam

eter

A

rea,

sq. i

n.

Size

, in.

D

iam

eter

A

rea,

sq.,

in.

Size

, in.

D

iam

eter

A

rea,

sq. i

n.

1/2

0.62

2 0.

304

2 2.

067

3.35

5 4

4.02

6 12

.730

3/4

0.82

4 0.

533

2-1/

2 2.

469

4.78

8 5

5.04

7 20

.006

1 1.

049

0.86

4 3

3.06

8 7.

393

6 6.

065

28.8

911-

1/4

1.38

0 1.

495

3-1/

2 3.

548

9.88

6 8

8.07

1 51

.161

1-1/

2 1.

610

2.03

6

337


45.6 Domes and manhole frames attached to shells or heads of boilers shall be designed in accordance with PG-32 through PG-44, with the additional requirement that the maximum allowable stress value in tension of rivets in manhole frames having a thickness of 7/8 in. or less and of rivets in domes flanges shall not exceed 7,200 psi.

45.7 In a locomotive-type boiler with a dome on a tapered course, the maximum allowable diameter of the dome shall be based on that diameter of the tapered course which inter-sects the axis or centerline of the dome.

SETTING

PFT-46 METHOD OF SUPPORT

46.1 The design and attachment of lugs, hang-ers, saddles, and other supports shall meet the requirements of PG-22.1 and PG-55.

46.2 In applying the requirements of 46.1, localized stresses due to concentrated sup-port loads, temperature changes, and restraint against dilation of the boiler due to pressure shall be provided for. Lugs, brackets, saddles, and pads shall conform satisfactorily to the shape of the shell or surface to which they are attached or with which they are in contact.

46.3 A horizontal-return tubular boiler over 72 in. in diameter shall be supported from steel hangers by the outside-suspension type of setting, independent of the furnace side walls. The hangers shall be so designed that the load is properly distributed between the rivets attaching them to the shell and so that no more than two of these rivets come in the same longitudinal line on each hanger. The distance girthwise of the boiler from the cen-ters of the bottom rivets to the centers of the top rivets attaching the hangers shall be not less than 12 in. The other rivets used shall be spaced evenly between these points.

46.4 The horizontal-return tubular boiler, 14 ft. or more in length, or over 54 in. and up

2" Maximum

FIGURE PFT-46.1 — Spacing of Supporting Lugs in Pairs on Horizontal-Return Tubular Boiler

to and including 72 in. in diameter, shall be supported by the outside-suspension type of setting as specified in PFT-46.3, or at four points by not less than eight steel or cast iron lugs set in pairs. A horizontal-return tubular boiler up to and including 54 in. in diameter shall be supported by the outside-suspension type of setting as specified in PFT-46.3, or by not less than two steel or cast iron lugs on each side. The distance girthwise of the boiler from the centers of the bottom rivets to the centers of the top rivets attaching the hangers shall be not less than the square of the shell diameter divided by 675. If more than four lugs are used they shall be set in four pairs,

Section B-B

T T T34

34

34

122

“T” “T”min.

Dimension “T” notless than 1% ofBoiler Diameter

20m

ax.

20m

ax.

Dimension “R” not less than 1-1/2 x Diameter of Hole

“R”

B

B

FIGURE PFT-46.2 — Welded Bracket Connection for Horizontal-Return Tubular Boilers

338


the lugs of each pair to be spaced not over 2 in. apart and the load to be equalized between them (see Figure PFT-46.1). If the boiler is supported on structural steel work, the steel supporting members shall be so located or insulated that heat from the furnace cannot impair their strength.

46.5 Figure PFT-46.2 illustrates an acceptable design of hanger bracket for welded attach-ment to welded horizontal-return tubular boilers with the additional requirement that the hanger pin be located at the vertical cen-ter line over the center of a welded contact surface. The bracket plates shall be spaced at least 2-1/2 in. apart, but this dimension shall be increased if necessary to permit access for the welding operation.

46.6 Wet-bottom stationary boilers shall be supported so as to have a minimum clear-ance of 12 in. between the underside of the wet-bottom and the floor to facilitate in-spection. Other types of fi retube boilers set horizontally shall be supported so that they have a minimum clearance of 12 in. between the metal surface of the shell and the fl oor. Boiler insulation, saddles, or other supports shall be arranged so that inspection openings are readily accessible.

PIPING, FITTINGS, AND APPLIANCES

PFT-47 WATER GLASSES

Boilers of the horizontal fi retube type shall be so set that when the water is at the lowest reading in the water gage glass there shall be at least 3 in. of water over the highest point of the tubes, fl ues or crown sheet.

PFT-48 FEED PIPING

48.1 When a horizontal-return tubular boiler exceeds 40 in. in diameter, the feedwater shall

discharge at about three-fi fths the length from the end of the boiler which is subjected to the hottest gases of the furnace (except a horizon-tal-return tubular boiler equipped with an auxiliary feedwater heating and circulating device), above the central row of tubes. The feed pipe shall be carried through the head or shell farthest from the point of discharge of the feedwater in the manner specifi ed for a surface blowoff in PG-59.3.2, and be securely fastened inside the shell above the tubes.

48.2 In vertical tubular boilers having tubes 4 ft. or less in length, the feedwater shall be introduced at a point not less than 12 in. above the crown sheet. When the boiler is under pressure, feedwater shall not be introduced through the openings or connections used for the water column, the water gage glass, or the gage cocks. In closed systems the water may be introduced through any opening when the boiler is not under pressure.

PFT-49 BLOWOFF PIPING

49.1 Blowoff piping of fi retube boilers which are exposed to products of combustion shall be attached by screwing into a tapped open-ing with a screw fi tting or valve at the other end.

49.2 Blowoff piping of fi retube boilers which are not exposed to products of combustion may be attached by any method provided in this Section except by expanding into grooved holes.

49.3 The bottom blowoff pipes of traction and portable boilers shall have at least one slow or quick-opening blowoff valve or cock conform-ing to the requirements of PG-59.5.3.3.

339


APPENDIX — EXPLANATORY OF THE CODE AND CONTAINING MATTERWHICH IS NOT MANDATORY UNLESS SPECIFICALLY REFERRED

TO IN THE RULES OF THE CODE

A = strength of solid plate = P x t x TS B = strength of plate between rivet holes

(P - d) t x TS C = shearing strength of one rivet in

single shear = n x s x a D = crushing strength of plate in front of

a rivet = d x t x c

Divide B, C, or D (whichever is the least) by A, and the quotient will be the efficiency of a single-riveted lap joint as shown in Figure A-1.

TS = 55,000 psi t = 1/4 in. = 0.25 in. P = 1-5/8 in. = 1.625 in. d = 11/16 in. = 0.6875 in. a = 0.3712 sq. in. s = 44,000 psi c = 95,000 psi A = 1.625 x 0.25 x 55,000 = 22,343 B = (1.625–0.6875)0.25 x 55,000 = 12,890 C = 1 x 44,000 x 0.3712 = 16,332 D = 0.6875 x 0.25 x 95,000 = 16,328

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EFFICIENCY OF JOINTS

A-1 EFFICIENCY OF RIVETED JOINTS

The ratio which the strength of a unit length of a riveted joint has to the same unit length of the solid plate is known as the efficiency of the joint and shall be calculated by the general method illustrated in the following examples:

TS = tensile strength stamped on plate, pounds per square inch

t = thickness of plate, inches b = thickness of buttstrap, inches P = pitch of rivets, inches, on row having

greatest pitch d = diameter of rivet after driving,

inches = diameter of rivet hole a = cross-sectional area of rivet after

driving, square inches s = shearing strength of rivet in single

shear, pounds per square inch, as given in PG-23.2

S = shearing strength of rivet in double shear, pounds per square inch, as given in PG-23.2

c = crushing strength of mild steel, pounds per square inch, as given in PG-23.3

n = number of rivets in single shear in a unit length of joint

N = number of rivets in double shear in a unit length of joint

A-2 EXAMPLE

Lap joint, longitudinal or circumferential, single riveted.

P

FIGURE A-1 — Example of Lap Joint, Longitudinal, or Circumferential, Single Riveted

340


A-3 EXAMPLE

Lap joint, longitudinal or circumferential, double riveted.


(P–d) t x TS C = shearing strength of two rivets in

single shear = n x s x a D = crushing strength of plate in front of

two rivets = n x d x t x c

Divide B, C, or D (whichever is the least) by A, and the quotient will be the efficiency of a double-riveted lap joint as shown in Figure A-2.

TS = 55,000 psi t = 5/16 in. = 0.3125 in. P = 2 7/8 in. = 2.875 in. d = 3/4 in. = 0.75 in. a = 0.4418 sq. in. s = 44,000 psi c = 95,000 psi A = 2.875 x 0.3125 x 55,000 = 49,414 B = (2.875–0.75) 0.3125 x 55,000 =

36,523 C = 2 x 44,000 x 0.4418 = 38,878 D = 2 x 0.75 x 0.3125 x 95,000 = 44,531

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A-4 EXAMPLE

Butt- and double-strap joint, double riveted.


in the outer row = (P–d) t x TS C = shearing strength of two rivets in

double shear, plus the shearing strength of one rivet in single shear = N x S x a + n x s x a

D = strength of plate between rivet holes in the second row, plus the shearing strength of one rivet in single shear in the outer row = (P–2d) t x TS + n x s x a

E = strength of plate between rivet holes in the second row, plus the crushing strength of buttstrap in front of one rivet in the outer row = (P - 2d) t x TS + d x b x c

F = crushing strength of plate in front of two rivets, plus the crushing strength of buttstrap in front of one rivet = N x d x t x c + n x d x b x c

G = crushing strength of plate in front of two rivets, plus the shearing strength of one rivet in single shear = N x d x t x c + n x s x a

H = strength of buttstraps between rivet holes in the inner row = (P–2d) 2b x TS. This method of failure is not possible for thicknesses of buttstraps required by these rules and the

FIGURE A-2 — Example of Lap Joint, Longitudinal, or Circumferential, Double Riveted

P

FIGURE A-3 — Example of Butt- and Double-Strap Joint, Double Riveted

P

341


computation need only be made for old boilers in which thin buttstraps have been used. For this reason this method of failure will not be consid-ered in other joints.

Divide B, C, D, E, F, G, or H (whichever is the least) by A, and the quotient will be the effi ciency of a butt- and double-strap joint, double riveted, as shown in Figure A-3.

TS = 55,000 psi t = 3/8 in. = 0.375 in. b = 5/16 in. = 0.3125 in. P = 4-7/8 in. = 4.875 in. d = 7/8 in. = 0.875 in. a = 0.6013 sq. in. s = 44,000 psi S = 88,000 psi c = 95,000 psi

Number of rivets in single shear in a unit length of joint = 1.

Number of rivets in double shear in a unit length of joint = 2.

A = 4.875 x 0.375 x 55,000 = 100,547 B = (4.875–0.875)0.375 x 55,000 =

82,500 C = 2 x 88,000 x 0.6103 + 1 x 44,000 x

0.6013 = 132,286 D = (4.875–2 x 0.857) 0.375 x 55,000 + 1 x

44,000 x 0.6013 = 90,910 E = (4.875–2 x 0.875) 0.375 x 55,000 +

0.875 x 0.3125 x 95,000 = 90,499 F = 2 x 0.875 x 0.375 x 95,000 + 1 x 0.875

x 0.3125 x 95,000 = 88,320 G = 2 x 0.875 x 0.375 x 95,000 + 1 x 44,000

x 0.6013 = 88,800

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A-5 EXAMPLE

Butt- and double-strap joint, triple riveted.


in the outer row = (P–d)t x TS C = shearing strength of four rivets in

double shear, plus the shearing strength of one rivet in single shear = N x S x a + n x s x a

D = strength of plate between rivet holes in the second row, plus the shearing strength of one rivet in single shear in the outer row = (P–2d)t x TS + n x s x a

E = strength of plate between rivet holes in the second row, plus the crushing strength of buttstrap in front of one rivet in the outer row = (P–2d)t x TS + d x b x c

F = crushing strength of plate in front of four rivets, plus the crushing strength of buttstrap in front of one rivet = N x d x t x c + n x d x b x c

G = crushing strength of plate in front of four rivets, plus the shearing strength of one rivet in single shear = N x d x t x c + n x s x a

Divide B, C, D, E, F, or G (whichever is the least) by A, and the quotient will be the effi -ciency of a butt- and double-strap joint, triple riveted as shown in Figure A-4.

TS = 55,000 psi t = 3/8 in. = 0.375 in. b = 5/16 in. = 0.3125 in. P = 6-1/2 in. = 6.5 in. d = 13/16 in. = 0.8125 in. a = 0.5185 sq. in. s = 44,000 psi S = 88,000 psi c = 95,000 psi

342




A = 6.5 x 0.375 x 55,000 = 134,062 B = (6.5–0.8125) 0.375 x 55,000 =

117,304 C = 4 x 88,000 x 0.5185 + 1 x 44,000 x

0.5185 = 205,326 D = (6.5–2 x 0.8125) 0.375 x 55,000 + 1 x

44,000 x 0.5185 = 123,360 E = (6.5–2 x 0.8125)0.375 x 55,000 +

0.8125 x 0.3125 x 95,000 = 124,667 F = 4 x 0.8125 x 0.375 x 95,000 + 1 x 0.8125

x 0.3125 x 95,000 = 139,902 G = 4 x 0.8125 x 0.375 x 95,000 + 1 x 44,000

x 0.5185 = 138,595

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A-6 EXAMPLE

Butt- and double-strap joint, quadruple riv-eted.


in the outer row = (P–d)t x TS C = shearing strength of eight rivets

in double shear, plus the shearing strength of three rivets in single shear = N x S x a + n x s x a

D = strength of plate between rivet holes in the second row, plus the shearing strength of one rivet in single shear in the outer row = (P–2d)t x TS + 1 x s x a

E = strength of plate between rivet holes in the third row, plus the shearing strength of two rivets in the second row in single shear and one rivet in single shear in the outer row = (P–4d)t x TS + n x s x a

FIGURE A-4 — Example of Butt- and Double-Strap Joint, Triple Riveted

P

FIGURE A-5 — Example of Butt- and Double-Strap Joint, Quadruple Riveted

P

343


F = strength of plate between rivet holes in the second row, plus the crushing strength of buttstrap in front of one rivet in the outer row = (P–2d)t x TS + d x b x c

G = strength of plate between rivet holes in the third row, plus the crushing strength of buttstrap in front of two rivets in the second row and one rivet in the outer row = (P–4d)t x TS + n x d x b x c

H = crushing strength of plate in front of eight rivets, plus the crushing strength of buttstrap in front of three rivets = N x d x t x c + n x d x b x c

I = crushing strength of plate in front of eight rivets, plus the shearing strength of two rivets in the second row and one rivet in the outer row, in single shear = N x d x t x c + n x s x a

Divide B, C, D, E, F, G, H, or I (whichever is the least) by A, and the quotient will be the effi ciency of a butt- and double-strap joint, quadruple riveted, as shown in Figure A-5.

TS = 55,000 psi t = 1/2 in. = 0.5 in. b = 7/16 in. = 0.4375 in. P = 15 in. d = 15/16 in. = 0.9375 in. a = 0.6903 sq. in. s = 44,000 psi S = 88,000 psi c = 95,000 psi



A = 15 x 0.5 x 55,000 = 412,500 B = (15–0.9375)0.5 x 55,000 = 386,718 C = 8 x 88,000 x 0.6903 + 3 x 44,000 x

0.6903 = 577,090

D = (15–2 x 0.9375)0.5 x 55,000 + 1 x 44,000 x 0.6903 = 391,310

E = (15–4 x 0.9375)0.5 x 55,000 + 3 x 44,000 x 0.6903 = 400,494

F = (15–2 x 0.9375)0.5 x 55,000 + 0.9375 x 0.4375 x 95,000 = 399,902

G = (15–4 x 0.9375) 0.5 x 55,000 + 3 x 0.9375 x 0.4375 x 95,000 = 426,269

H = 8 x 0.9375 x 0.5 x 95,000 + 3 x 0.9375 x 0.4375 x 95,000 = 473,145

I = 8 x 0.9375 x 0.5 x 95,000 + 3 x 44,000 x 0.6903 = 447,369

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A-7

Figure A-6 and A-7 illustrate other joints that may be used in which eccentric stresses are avoided. The butt- and double-strap joint with straps of equal width shown in Figure A-6 may be so designed that it will have an effi ciency of from 82 to 84 percent and the sawtooth joint shown in Figure A-7 so that it will have an effi ciency of from 92 to 94 percent.

BRACED AND STAYED SURFACES

A-8

The allowable loads based on the net cross-sectional area of staybolts with V-threads are computed from the following formulas. The use of Whitworth threads with other pitches is permissible.

The formula for the diameter of a staybolt at the bottom of a V-thread is:

D–(P x 1.732) = d

344


where, D = diameter of staybolt over the

threads, inches P = pitch of threads, inches = 1/number of threads per inch d = diameter of staybolt at bottom of

threads, inches 1.732 = a constant

When ANSI Standard threads are used the formula becomes

D–(P x 1.732) = d

Tables A-1 and A-2 give the allowable loads on net cross-sectional areas for staybolts with V-threads having 12 and 10 threads per in.

FIGURE A-6 — Illustration of Butt- and Double-Strap Jint with Straps of Equal Width

FIGURE A-7 — Illustration of Butt- and Double-Strap Joint of the Sawtooth Type

A-9

Table A-3 shows the allowable loads on net cross-sectional areas of round stays or braces.

A-10

Table A-4 gives the net areas of segments of heads for use in computing stays.

345


TABLE A-1 — Allowable Loads on Staybolts with V Threads, 12 ThreadsPer Inch

Outside diameter Diameter at Net Cross-Sectional Allowable Load of Staybolts, in. Bottom of Area (at Bottom at 7500 lb Thread, in. of Thread). sq. in. Stress per sq. in.

3/4 0.7500 0.6057 0.288 216013/16 0.8125 0.6682 0.351 26327/8 0.8750 0.7307 0.419 3142

15/16 0.9375 0.7932 0.494 37051 1.0000 0.8557 0.575 43121-1/16 1.0625 0.9182 0.662 4965

1-1/8 1.1250 0.9807 0.755 56621-3/16 1.1875 1.0432 0.855 61421-1/4 1.2500 1.1057 0.960 7200

1-5/16 1.3125 1.1682 1.072 80401-3/8 1.3750 1.2307 1.190 89251-7/16 1.4375 1.2932 1.313 98491-1/2 1.5000 1.3557 1.444 10830

TABLE A-2 — Allowable Loads on Staybolts with V Threads, 10 ThreadsPer Inch

Outside diameter Diameter at Net Cross-Sectional Allowable Load of Staybolts, in. Bottom of Area (at Bottom at 7500 lb Thread, in. of Thread). sq. in. Stress per sq. in.

1-1/4 1.2500 1.0768 0.911 68321-5/16 1.3125 1.1393 1.019 76421-3/8 1.3750 1.2018 1.134 85051-7/16 1.4375 1.2643 1.255 94121-1/2 1.5000 1.3268 1.382 103651-9/16 1.5625 1.3893 1.515 113621-5/8 1.6250 1.4518 1.655 12412

346


TABLE A-3 — Allowable Loads on Round Braces or Stay Rods

Allowable stress, in psi, on Net Cross-Sectional Area Minimum Diameter of Net Cross-Sectional 6000 8500 9500Circular Stay, in. Area of Stay, sq. in. Allowable load, in lb., on Net Cross-Sectional Area

1 1.0000 0.7854 4712 6676 74621-1/16 1.0625 0.8866 5320 7536 84231-1/8 1.1250 0.9940 5964 8449 9443

1-3/16 1.1875 1.1075 6645 9414 105211-1/4 1.2500 1.2272 7363 10431 116581-5/16 1.3125 1.3530 8118 11501 12854

1-3/8 1.3750 1.4849 8909 12622 141071-7/16 1.4375 1.6230 9738 13796 154191-1/2 1.5000 1.7671 10603 15020 16787

1-9/16 1.5625 1.9175 11505 16298 182161-5/8 1.6250 2.0739 12443 17628 197021-11/16 1.6875 2.2365 13419 19010 21247

1-3/4 1.7500 2.4053 14432 20445 228521-13/16 1.8125 2.5802 15481 21932 245121-7/8 1.8750 2.7612 16567 23470 26231

1-15/16 1.9375 2.9483 17690 25061 280092 2.0000 3.1416 18850 26704 298452-1/8 2.1250 3.5466 21280 30147 33693

2-1/4 2.2500 3.9761 23857 33797 377732-3/8 2.3750 4.4301 26580 37656 420862-1/2 2.500 4.9087 29452 41724 46632

2-5/8 2.6250 5.4119 32471 46001 514132-3/4 2.7500 5.9396 35638 50487 564262-7/8 2.8750 6.4918 38951 55181 616733 3.0000 7.0686 42412 60083 67152

347


TABLE A-4 — Net Areas of Segments of Heads Where d, as Given in PFT-31.1 and PFT-31.3 is Equal t0o 3 inches

Height From Diameter of Boiler, in.Tubes to Shell, 24 30 36 42 48 54 60 66 72 78 84 90 96in. Area to Be Stayed, sq. in.

8 28 33 37 40 43 47 51 53 55 58 60 63 658-1/2 35 41 46 51 55 59 63 66 70 74 76 80 829 42 49 56 62 67 72 76 82 86 90 92 95 989-1/2 50 58 66 70 80 86 91 96 101 105 111 116 11910 57 68 77 85 93 99 106 112 117 123 129 132 137

10-1/2 66 78 89 98 107 114 123 131 135 142 147 153 16011 74 88 100 111 121 130 138 147 155 161 169 174 18311-1/2 83 99 112 124 137 146 156 165 173 181 189 196 20412 91 109 125 139 151 163 174 184 194 203 213 219 23012-1/2 ... 120 138 153 167 180 193 204 216 224 234 243 252

13 ... 132 151 168 183 197 211 224 235 247 256 267 27913-1/2 ... 143 164 183 200 216 230 246 258 270 282 293 30214 ... 155 178 199 217 234 250 266 280 294 305 319 33114-1/2 ... 167 192 215 235 254 271 287 303 318 333 345 36015 ... 178 206 231 252 273 291 309 326 343 357 372 386

15-1/2 ... ... 220 247 271 291 312 332 350 368 382 400 41716 ... ... 235 263 289 312 334 355 374 394 411 423 44316-1/2 ... ... 249 281 308 332 357 380 399 420 436 457 47517 ... ... 264 297 326 353 378 402 425 447 467 486 50217-1/2 ... ... ... 314 345 374 400 426 449 471 494 516 536

18 ... ... ... 331 365 396 424 450 476 500 520 543 56418-1/2 ... ... ... 349 384 417 448 476 501 526 552 577 59819 ... ... ... 366 404 439 470 500 529 555 580 604 63119-1/2 ... ... ... 384 424 461 496 528 558 584 613 641 66320 ... ... ... 401 444 483 519 552 583 613 642 667 699

20-1/2 ... ... ... ... 464 505 543 578 613 643 675 706 72921 ... ... ... ... 485 528 568 604 640 673 705 733 76621-1/2 ... ... ... ... 505 551 594 632 669 703 739 766 79722 ... ... ... ... 526 574 618 658 697 734 769 800 83522-1/2 ... ... ... ... ... 597 643 687 726 765 800 835 867

23 ... ... ... ... ... 620 668 713 754 796 830 869 90623-1/2 ... ... ... ... ... 642 695 740 784 827 866 904 94524 ... ... ... ... ... 667 719 768 814 859 897 939 97824-1/2 ... ... ... ... ... 689 745 797 843 892 934 975 101825 ... ... ... ... ... 714 771 825 875 922 966 1010 1051

25-1/2 ... ... ... ... ... 737 798 855 907 956 1003 1047 109226 ... ... ... ... ... 761 824 882 936 987 1035 1083 112626-1/2 ... ... ... ... ... ... 850 909 968 1024 1073 1120 116727 ... ... ... ... ... ... 877 939 998 1053 1106 1157 120227-1/2 ... ... ... ... ... ... 904 968 1030 1089 1145 1195 1243

28 ... ... ... ... ... ... 930 997 1060 1120 1177 1232 127928-1/2 ... ... ... ... ... ... ... 1028 1092 1157 1211 1270 132129 ... ... ... ... ... ... ... 1056 1123 1187 1248 1305 136029-1/2 ... ... ... ... ... ... ... 1084 1155 1221 1284 1347 140030 ... ... ... ... ... ... ... 1115 1187 1255 1321 1382 1442

30-1/2 ... ... ... ... ... ... ... ... 1218 1290 1358 1424 148031 ... ... ... ... ... ... ... ... 1252 1324 1394 1459 152331-1/2 ... ... ... ... ... ... ... ... 1286 1359 1433 1496 156132 ... ... ... ... ... ... ... ... 1317 1394 1467 1538 165032-1/2 ... ... ... ... ... ... ... ... ... 1430 1508 1575 1650

33 ... ... ... ... ... ... ... ... ... 1465 1542 1617 168733-1/2 ... ... ... ... ... ... ... ... ... 1500 1578 1655 173334 ... ... ... ... ... ... ... ... ... 1536 1617 1695 177034-1/2 ... ... ... ... ... ... ... ... ... ... 1654 1735 181635 ... ... ... ... ... ... ... ... ... ... 1692 1775 1856

35-1/2 ... ... ... ... ... ... ... ... ... ... ... 1810 190036 ... ... ... ... ... ... ... ... ... ... ... 1857 194136-1/2 ... ... ... ... ... ... ... ... ... ... ... ... 198437 ... ... ... ... ... ... ... ... ... ... ... ... 2026

348


349

Appendix D

Recommended Guide for the Design of a Test System for Pressure Relief Devices in Compressible Fluid Service

350


APPENDIX D — RECOMMENDED GUIDE FOR THE DESIGN OFA TEST SYSTEM FOR PRESSURE RELIEF DEVICES IN

COMPRESSIBLE FLUID SERVICE

D-1000 INTRODUCTION

This non-mandatory appendix provides guidance for the design of a test system using compressible fl uids (i.e., steam or air/gas) and permits the determination of pressure relief valve set pressure and valve operating characteristics such as blowdown. The size of the test vessel needed depends on the size of the valve, its set pressure, the design of the test system, and whether blowdown must be demonstrated. A repair organization may use the information provided in this appendix to determine the minimum size test vessel needed so that the measured performance is characteristic of the valve and not the test system.

D-1010 GENERAL

The National Board administrative rules and procedures for the “VR” Certifi cate of Authorization and symbol stamp require that pressure relief valves, after repair, be tested in accordance with the manufacturer’s recommendations and the applicable ASME Code. The purpose of this testing is to pro-vide reasonable assurance that valves will perform according to design when they are returned to service.

It is recognized that a full evaluation of the performance of some pressure relief valve de-signs requires testing at maximum allowable overpressure. However, it is beyond the scope of this appendix to defi ne test equipment or facilities for such testing.

D-1020 provides a glossary, D-2000 describes typical test equipment, and D-3000 provides data for estimating the size of test vessels required.

D-1020 GLOSSARY

Accumulator: A vessel in which the test me-dium is stored or accumulated prior to its use for testing.

Transient: A very short time, occurring over a brief time interval, maintained only for a short time interval as opposed to a steady state.

Velocity distortion: The pressure decrease that occurs when fl uid fl ows past the opening of a pressure sensing line. This is a distortion of the pressure that would be measured under the same conditions for a non or slowly mov-ing fl uid.

Intervening: Coming between or inserted between, as between the test vessel and the valve being tested.

Water head: The pressure adjustment that must be taken into account due to the weight of test media (in this case, steam) that is 0.433 psi per ft. (10 KPa per m.) added (subtracted) from the gage pressure for each foot the gage is below (above) the point at which the pres-sure is to be measured.

D-2000 TEST SYSTEM DESCRIPTION

An optimum configuration, particularly when the test medium source is of small capacity, is shown in Figure D-2000. The test medium flows from the pressure source, usually a compressor or boiler, to an accumulator. It then flows through a pressure-controlling valve into the test vessel, from which it is discharged, through the pressure relief valve mount-ed on the test vessel. The pressure-con-

351

APPENDIX D — RECOMMENDED GUIDE FOR THE DESIGN OF A TEST SYSTEM FORPRESSURE RELIEF DEVICES IN COMPRESSIBLE FLUID SERVICE

trolling valve is usually a globe valve, although any throttling valve is acceptable. If the pressure-controlling valve is of adequate size and can open quickly, large transient fl ows can be generated, increasing the pres-sure above the pressure relief valve set pres-sure, causing it to lift, and be sustained in its lifted condition.

Figure D-2000-a shows a simpler test sys-tem in which the test vessel is pressurized directly from the pressure source without the use of an accumulator. In this con-figuration, flow-rates through the pres-sure relief valve and any consequent over-pressure are dependent on the flow generating capacity of the pressure source.

In a test facility, the pressure relief valve is usually mounted on an isolating valve which should be of suffi cient size that it will not choke fl ow to the pressure relief valve. There should be no intervening piping between the two (2) valves to avoid any unnecessary pressure drop between the test vessel and the pressure relief valve.

The isolating valve and any adapter fl anges or valve test nozzles must be designed to sustain pressure relief valve discharge forces, and so secured that these forces cannot be transmit-ted to the test vessel. This is especially impor-tant for larger valves set at pressures greater than 100 psig (700 KPa).

The vessel should have a length-to-diameter ratio as low as is practical, and should be suit-ably anchored.

Pressure sensing lines should be connected to the test vessel well away from any inlet or outlet connections where transient fl ow velocity during testing could cause erroneous pressure readings. When testing with steam, any water head which develops in the gage line must be taken into consideration.

Any intervening piping between the test ves-sel and the pressure relief valve should be as short and as straight as possible and be of ad-equate size to minimize inlet pressure drop.

In the case of steam, the equipment should be insulated and steam traps should be installed, as appropriate, to ensure that the test steam is dry, saturated steam with a minimum quality of 98%.

Safety valves should be used to protect the test vessel and the accumulator.

D-3000 TEST VESSEL SIZING DATA

Recommended test vessel sizes are given in Fig-ures D-3000 and D-3000-a for a confi guration using one vessel fed directly from the source of the test medium. Figure D-3000 gives the test vessel size in cu. ft. vs. the valve orifi ce area in sq. in. for dry, saturated steam. Curves are shown for set pressures up to 500 psig (3.5 MPa) for three different blowdowns: 4%, 7% and 10%. The source is assumed to be capable of feeding the test vessel at 2500 lbs/hr. (1140 kg/hr) Figure D-3-000-a gives similar curves for air with a source capable of feeding the test vessel at 200 SCFM.

For smaller valves, with effective orifi ces less than 1.28 sq. in., the size of the test vessel needed becomes less dependent on the fl ow capacity of the source. For these valves, a 15 cu. ft. (0.4 cu. m.) minimum size test vessel is recommended. This should allow the accurate measurement and setting of blowdown for small valves. This minimum size should also be adequate for determining set pressures of larger valves; however, larger test vessels must be used if blowdown is to be set accu-rately. It is recognized that there are practical limits on the size and maximum pressure of a test vessel used to demonstrate pressure relief valve operational characteristics. In such cases, determination of valve set pressure

352


remains the only viable production and repair test option. The recommended minimum size test vessel (15 cu. ft. [0.4 cu. m.]) should be adequate for this purpose.

353

APPENDIX D — RECOMMENDED GUIDE FOR THE DESIGN OF A TEST SYSTEM FORPRESSURE RELIEF DEVICES IN COMPRESSIBLE FLUID SERVICE

FIGURE D-2000-a — Schematic of Test Equipment without Accumulator

FIGURE D-2000 — Schematic of Test Equipment with Accumulator

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354


300

250

200

150

100

50

0

0 5 10 15 20 25 30 35

VALVE FLOW AREA (SQ. IN.)

VALVE FLOW AREA (SQ. IN.)

250

200

150

100

50

0

0 5 10 15 20 25 30 35

VES

SEL

SIZE

(CU

. FT.

)V

ESSE

L SI

ZE (C

U. F

T.)

FIGURE D-3000 — Recommended Test Vessel Size, Test Medium: Steam

FIGURE D-3000-a — Recommended Test Vessel Size, Test Medium: Air or Gas

•■

4% Blowdown

10% Blowdown7% Blowdown

7% Blowdown

10% Blowdown

▼

■

•

▼

■

•

•■

Valve Flow Areas (sq. mm. x 104)

Valve Flow Areas (sq. mm. x 104)

– 8– 7– 6– 5

– 4

– 3

– 2

– 1

– 7– 8

– 5

– 4– 3

– 2

– 1

Vess

el S

ize

(m3 )

Vess

el S

ize

(m3 )

355

Recommended Procedures for Repairing Pressure Relief Valves

Appendix E

356


APPENDIX E — RECOMMENDED PROCEDURES FOR REPAIRINGPRESSURE RELIEF VALVES

E-1000 INTRODUCTION

It is essential that the repair organization establish basic, specific procedures for the repair of pressure relief valves. The purpose of these recommended procedures is to pro-vide the repair organization with guidelines for this important aspect of valve repair. It is realized that there are many various types of valves and conditions under which they are repaired and, for this reason, the specific items in these recommended procedures may not apply, or they may be inadequate for each of those types or to the detailed repairs which may be required for each valve. See RA-2255(i).

Part I contains recommended procedures for the repair of spring loaded pressure relief valves and Part II contains recommended procedures for the repair of pilot operated types of safety relief valves.

E-2000 SPRING LOADED PRESSURE RELIEF VALVES

Note 1: Prior to removal of a valve from a system for a repair or any disassembly, ensure that all sources of pressure have been removed from the valve.

1. Visual Inspection as Received This information is to be recorded:

a. Record user (customer) identification number.

b. Complete nameplate data, plus any important information received from customer.

c. Check external adjustment seals for warranty repair.

d. Check bonnet for venting on bellow type valves.

e. Check appearance for any unusu-al damage, missing or misapplied parts.

Note 2: If sufficient damage or other unusual conditions are detected that may pose a safety risk during preliminary testing, then proceed directly to step three.

Note 3: Valves which are to be repaired in place proceed to step 3, unless preliminary testing has been authorized by the owner.

2. Preliminary Test as Received Information from the recommended pre-

liminary performance test and subsequent disassembly and inspections will provide a basis for any repair interval change which may be necessary to ensure that the valve will function as intended.

a. Determine set pressure or Cold Dif-ferential Test Pressure (CDTP) in accordance with manufacturer ’s recommendations and appropriate ASME Code Section. Do not allow test pressure to exceed 116% of set pressure unless otherwise specified by the owner. A minimum of three tests is usually required to obtain consistent results.

Note 4: If results do not correlate with field performance, then steps to duplicate field conditions (fluid and temperature) may be necessary.

b. Record preliminary test results and test bench identification data.

357

APPENDIX E — RECOMMENDED PROCEDURES FOR REPAIRING PRESSURE RELIEF VALVES

3. Disassembly

a. Remove cap and lever assembly, if applicable.

b. Remove release nut assembly, if ap-plicable.

c. Loosen jam nut on adjusting (com-pression) screw.

d. Record measurement and remove adjusting (compression) screw.

e. Remove bonnet or yoke.

f. Remove spring and washers, and tag (identify) including upper and lower washers, as appropriate.

g. Remove spindle and disk assembly.

h. Remove ring pins.

i. Record measurement and remove adjusting rings, nozzle and guide, as applicable.

4. Cleaninga. Wire all small parts together and clean

by means of an abrasive (caution: do not use a cleaning method that will damage the parts.)

b. Do not clean in a chemical solution ex-cept under acceptable circumstances.

c. Protect seating surfaces and name-plates prior to cleaning.

5. Inspectiona. Check spring for damage such as

erosion, corrosion, cracking, breakage or compression below free height.

b. Check nozzle for cracks (NDE as applicable) or unusual wear.

c. Check disk assembly for cracks (NDE as applicable) or unusual wear.

d. Check spindle for trueness, bearing areas and thread condition.

e. Check guide for wear and galling.

f. Check adjusting ring(s) for worn threads and wear.

g. Check ring pins for bent or broken pin and thread condition.

h. Check bellows, if provided, for pin-holes and corrosion.

i. Check flange gasket facings for wear and cuts.

6. Machining Machine nozzle and disk as necessary

to the manufacturer’s critical dimension charts.

7. Lappinga. Machine or hand lap disk and nozzle

to be sure of flatness.

b. Lap bevel seats to a grey finish; then remachine disk or plug to the manu-facturer’s critical dimension.

8. Adjusting Rings Install lower ring and guide ring to the

same position they were when removed, or to manufacturer’s specifications.

9. Bearing Points Grind all bearing areas with grinding

compound to make sure they are round and true.

10. Testing All test data is to be recorded. Testing

will be done in accordance with manu-facturer’s recommendations and appro-

358


priate ASME Code section. To preclude unsafe and unstable valve operations or erroneous performance test results, it is recommended that low volume testing equipment (e.g., gas cylinders without a test vessel, hand pumps, tubing, etc.) should be avoided.

11. Sealing After final adjusting and acceptance by

quality control inspection, all external adjustments will be sealed with a safety seal providing a means of identification of the organization performing the repair.

12. Nameplate The repairer will place a repair nameplate

on each repaired valve. The nameplate shall, as a minimum, meet the require-ments of RE-1061.

E-3000 PILOT OPERATED SAFETY RELIEF VALVES

1. Visual Inspection as Received This information is to be recorded:

a. Complete nameplate data, plus any other important information received from the customer.

b. User identification number, if appli-cable.

c. Seals on external adjustment (yes/no).

d. Identification on seal.

e. Obvious damage and external condi-tion including missing or misapplied parts.

2. Disassemblya. Remove pilot and disassemble per

manufacturer’s maintenance instruc-tion.

b. Disassemble main valve. Where lift adjustments are provided, do not remove the locking device or change the lift unless it is required as part of conversion.

c. Remove the nozzle if recommended by the manufacturer’s maintenance instructions and/or when required as part of conversion.

3. Cleaninga. Pilot – Components of pilot are small

and must be handled carefully to prevent damage or loss. Clean parts and nameplates with solvents which will not affect the parent metal and/or polish with 500 grit paper.

b. Main Valve – Clean by appropriate means such as abrasive blast. Finishes of machined surfaces must not be affected. (Caution: Do not use a clean-ing method that will damage the parts or nameplates.)

4. Inspectiona. Pilot

1. Check spring for damage such as corrosion, cracks, out of square ends, etc.

2. Inspect all parts for damage. Small burrs or scratches may be removed by polishing. Severely damaged parts should be replaced. (Internal components or pilots should not be repaired by machining as the functions of the pilot could easily be impaired.)

3. Check strainers on inlet and outlet lines.

4. Replace all soft goods per manu-facturer’s recommendation.

359

APPENDIX E — RECOMMENDED PROCEDURES FOR REPAIRING PRESSURE RELIEF VALVES

b. Main Valve

1. Check nozzle seating surface for nicks. These can be removed by machining or lapping as re-quired.

2. Check the piston and liner (or other moving member) for gall-ing or excessive wear. The piston should move freely in the liner.

3. Replace soft goods or relap disk as required.

4. Where lift adjustments are pro-vided, measure the lift per the manufacturer’s specifications.

5. Testing All test data is to be recorded. Testing

will be done in accordance with the manufacturer’s recommendation and in accordance with the applicable ASME Code section. To preclude unsafe and un-stable valve operations or erroneous per-formance test results, it is recommended that low volume testing equipment (e.g., gas cylinders without a test vessel, hand pumps, tubing, etc.) should be avoided.

6. Sealing After final adjustment and acceptance by

quality control, all external adjustments will be sealed by means assuring positive identification of the organization perform-ing the repair.

7. Nameplate The repairer will place a repair nameplate

on each repaired valve. The nameplate, as a minimum, shall meet the requirements of RE-1061.

360


361

Appendix F

Pressure Differential Between Safety or Safety Relief Valve Setting and Boiler or Pressure Vessel Operating Pressure

362


APPENDIX F — PRESSURE DIFFERENTIAL BETWEEN SAFETY ORSAFETY RELIEF VALVE SETTING AND BOILER OR

PRESSURE VESSEL OPERATING PRESSURE

F-1000 SCOPE

If a safety valve or safety relief valve is subjected to pressure at or near its set pres-sure, it will tend to weep or simmer, and deposits may accumulate in the seat and disk area. Eventually, this can cause the valve to freeze close and thereafter the valve could fail to open at the set pressure. Unless the source of pressure to the boiler or pressure vessel is interrupted, the pressure could exceed the rupture pressure of the vessel.

It is important that the pressure differential between the valve set pressure and the boiler or pressure vessel operating pressure is suf-ficiently large to prevent the valve from weep-ing or simmering.

F-2000 HOT WATER HEATING BOILERS

For hot water heating boilers, the recom-mended pressure differential between the pressure relief valve set pressure and the boiler operating pressure should be at least 10 psi (70 KPa), or 25% of the boiler operating pressure, whichever is greater.

Two examples follow:a. If the safety relief valve of a hot-water-

heating boiler is set to open at 30 psi (210 KPa), the boiler operating pressure should not exceed 20 psi (140 KPa).

b. If the safety relief valve of a hot water heating boiler is set to open at 100 psi (690

KPa), the boiler operating pressure should not exceed 75 psi (520 KPa).

Section IV of the ASME Code does not require that safety relief valves used on hot water heating boilers have a specified blowdown. Therefore, to help ensure that the safety re-lief valve will close tightly after opening and when the boiler pressure is reduced to the normal operating pressure, the pressure at which the valve closes should be well above the operating pressure of the boiler.

F-3000 STEAM HEATING BOILERS

For steam heating boilers, the recommended pressure differential between the safety valve set pressure and boiler operating pressure should be at least 5 psi (35 KPa), i.e., the boiler operating pressure should not exceed 10 psi (70 KPa).

Since some absorption-type refrigeration systems use the steam heating boiler for their operation, the boiler operating pressure may exceed 10 psi (70 KPa). If, the boiler operat-ing pressure is greater than 10 psi (70 KPa), it should not exceed 15 psi (100 KPa), minus the blowdown pressure of the safety valve.

This recommendation can be verified by increasing the steam pressure in the boiler until the safety valve pops, then slowly reducing the pressure until it closes, to ensure that this closing pressure is above the operat-ing pressure.

363

APPENDIX F — PRESSURE DIFFERENTIAL BETWEEN SAFETY OR SAFETY RELIEF VALVE SETTING AND BOILER OR PRESSURE VESSEL OPERATING PRESSURE

F-4000 POWER BOILERS

For power boilers (steam), the recommended pressure differentials between the safety valve set pressure and the boiler operating pressure are as follows:

MINIMUM PRESSURE DIFFERENTIAL ASPERCENTAGE OF BOILER DESIGN PRESSURE

DESIGN PRESSURE: over 15 psi to 300 psi (100 KPa to 2100 KPa) 10% but not less than 7 psi (50 KPa)

over 300 psi to 1000 psi (2100 KPa to 6900 KPa) 7% but not less than 30 psi (210 KPa)

over 1000 psi to 2000 psi (6900 KPa to 13.8 MPa) 5% but not less than 70 psi (500 KPa)

over 2000 psi (13.8 MPa) per designer’s judgement

Notes: 1. Above 2000 psi (13.8 MPa) the pressure differential between operating pressure and the maximum allowable working pressure is a matter for the designer’s judge-ment, taking into consideration such factors as satisfactory operating experience and the intended service conditions .

2. Safety relief valves in hot water service are more susceptible to damage and sub-

sequent leakage, than safety valves relieving steam. It is recommended that the maximum allowable working pressure of the boiler and safety relief valve set-ting for high-temperature hot water boilers be selected substantially higher than the desired operating pressure, so as to minimize the times the safety relief valve must lift.

F-5000 PRESSURE VESSELS

Due to the variety of service conditions and the various designs of pressure relief valves, only general guidelines can be given regard-ing differentials between the set pressure of the valve and the operating pressure of the vessel. Operating difficulty will be mini-mized by providing an adequate differential for the application. The following is general advisory information on the characteristics of the intended service and of the pressure relief valves which may bear on the proper pressure differential selection for a given

application. These considerations should be reviewed early in the system design since they may dictate the maximum allowable working pressure of the system.

To minimize operational problems it is imperative that the user consider not only normal operating conditions of the fluids (liquids or gases), pressures, and tempera-tures but also start-up and shutdown condi-tions, process upsets, anticipated ambient conditions, instrument response time, pres-sure surges due to quick-closing valves, etc. When such conditions are not considered, the pressure relief devices may become, in effect, a

364


pressure controller, a duty for which it was not designed. Additional consideration should be given to the hazard and pollution associated with the release of the fluid. Larger differen-tials may be appropriate for fluids which are toxic, corrosive, or exceptionally valuable.

The blowdown characteristics and capabil-ity are the first consideration in selecting a compatible valve and operating margin. After a self-actuated release of pressure, the valve must be capable of reclosing above the normal operating pressure. For example: if the valve is set at 100 psi (690 KPa) with a 7% blowdown, it will close at 93 psi (640 KPa). The operating pressure must be maintained below 93 psi (640 KPa) in order to prevent leakage or flow from a partially open valve. Users should exercise caution regarding the blowdown adjustment of large, spring-loaded valves. Test facilities, whether owned by the manufacturer, repair house, or user, may not have sufficient capacity to accurately verify the blowdown setting. The setting cannot be considered accurate unless made in the field on an actual installation.

Pilot operated valves represent a special case from the standpoint of both blowdown and tightness. The pilot portion of some pilot operated valves can be set at blowdowns as short as 2%. This characteristic is not, how-ever, reflected in the operation of the main valve in all cases. The main valve can vary considerably from the pilot depending on the location of the two components in the system. If the pilot is installed remotely from the main valve, significant time and pressure lags can occur, but reseating of the pilot assures reseat-ing of the main valve. The pressure drop in connecting piping between the pilot and the main valve must not be excessive, otherwise the operation of the main valve will be ad-versely affected.

Tightness capability is another factor affect-ing valve selection, whether spring-loaded or pilot operated. Tightness varies somewhat depending on whether metal or resilient seats

are specified and also on such factors as corro-sion and temperature. The required tightness and test method should be specified to comply at a pressure not lower than the normal op-erating pressure of the process. It should be remembered that any degree of tightness ob-tained should not be considered permanent. Service operation of a valve almost invariably reduces the degree of tightness.

The following minimum pressure differentials are recommended unless the safety or safety relief valve has been designed or tested in a specific or similar service and a smaller differential has been recommended by the manufacturer:

a. for set pressures up to 70 psi (480 KPa), the recommended pressure differential is 5 psi (35 KPa);

b. for set pressure between 70 and 1000 psi (480 KPa and 6900 KPa), the recom-mended pressure differential is 10% of set pressure;

c. for set pressures above 1000 psi (6900 KPa), the recommended pressure differ-ential is 7% of set pressure.

365

Safety Valves on the Low-Pressure Side of Steam Pressure-Reducing Valves

Appendix G

366


APPENDIX G — SAFETY VALVES ON THE LOW-PRESSURE SIDEOF STEAM PRESSURE-REDUCING VALVES

G-1000 SCOPE

The subject of protection of vessels in steam service connected to the low pressure side of a steam pressure-reducing valve is of con-siderable importance to proper operation of auxiliary equipment such as pressure cookers, hot water heating systems, etc., operating at pressures below that which the primary boiler generating unit is operating.

To automatically reduce the primary boiler pressure for such processing equipment, pressure-reducing valves are used. The manufacturers of such equipment have data available listing the volume of flow through reducing valves manufactured by them, but such data are not compiled in a form that the results can be deduced readily. To protect the equipment operating on the low pressure side of a pressure-reducing valve, safety valves of a relieving capacity sufficient to prevent an unsafe pressure rise in case of failure of the pressure-reducing valve, should be in-stalled.

The pressure-reducing valve is a throttling device, the design of which is based on certain diaphragm pressures opposed by spring pressure which, in turn, controls the opening through the valve. If the spring, the diaphragm, or any part of the pressure-re-ducing valve fails, steam will flow directly through the valve and the low pressure equip-ment will be subjected to the boiler pressure. To protect the equipment operating on the low pressure side of the pressure-reducing valve, safety valve(s) should be installed on the low pressure side of the pressure-reducing valve which will provide a relieving capacity sufficient to prevent the pressure from rising above the system design pressure.

In most cases pressure-reducing valves used for the reduction of steam pressures have the same pipe size on the inlet and outlet. In case

of failure of a pressure-reducing valve, the safety valve on the low pressure side must have a capacity to take care of the volume of steam determined by the high pressure side and the area of the pipe.

G-2000 INSTALLATION OF SAFETY VALVES

In most cases it is necessary to install more than one safety valve on the low pressure side of the pressure-reducing valve. It is advisable, if the safety valves are connected to the pipe attached to the pressure-reducing valve, that each safety valve have a separate connection to the pipe. It is not important that all the safety valves be mounted on the pipeline connecting the pressure-reducing valve to the auxiliaries. Safety valves will be equally effective if they are attached to some of the auxiliaries provided the piping between the pressure-reducing valve and the safety valve is of a size adequate for the maximum pressure, and there are no intervening stop valves.

G-3000 SAFETY VALVE CAPACITY

The capacity of the safety valve(s) on the low pressure side of the pressure-reducing valve should be based on the capacity of the pressure-reducing valve when wide open or under maximum flow conditions or the flow capacity through the bypass valve.

By using the formula in G-4000 below, In-spectors may calculate the required relieving capacities of the safety valve(s) installed on the low pressure side of the pressure-reduc-ing valve.

Usually a pressure-reducing valve has a by-pass arrangement so that in case of failure of the pressure-reducing valve the boiler pres-

367

APPENDIX G — SAFETY VALVES ON THE LOW-PRESSURE SIDE OF STEAM PRESSURE REDUCING VALVES

sure may be short circuited into the low pres-sure line without passing through the pres-sure-reducing valve. When determining the required relieving capacity of safety valves for the low pressure side of the pressure-reducing valve, the steam fl ow through the bypass must be taken into consideration.

G-4000 CALCULATION OF SAFETY VALVE RELIEVING

CAPACITY

When a pressure-reducing valve is installed, there are two possibilities of introducing boiler pressure into the low pressure system:

a. the failure of the pressure-reducing valve so that it remains wide open;

b. the possibility of the bypass valve being open.

It is necessary therefore, to determine the fl ow under both circumstances (a) and (b) and check that the size of the safety valve under either condition will be adequate. The follow-ing formula should be used:

a. steam flow, W in lbs/hr through the pressure-reducing valve

W = AKCwhere, A = internal area in sq. in. of the inlet

pipe size of the pressure-reducing valve (ref. Table 2)

K = flow coefficient for the pressure reducing valve (see G-5000)

C = fl ow of saturated steam through a 1 sq. in. pipe at various pressure differ entials from Table G-4000.

b. steam fl ow, W in lbs/hr through the by-pass valve

W = A1 K1 C1where, A1 = internal area in sq. in. of the pipe size

of the bypass around the pressure-reducing valve

K1 = fl ow coeffi cient for the bypass valves (see V)

C1 = fl ow of saturated steam through a 1 sq. in. pipe at various pressure differ entials from Table G-4000.

G-5000 STEAM FLOW WHEN FLOW COEFFICIENTS ARE NOT KNOWN

It is possible that the fl ow coeffi cients K and K1may not be known and in such instances for approximating the fl ow, a factor of 1/3 may be substituted for K and 1/2 for K1.

The formulas in G-4000 then become:

W = 1/3 AC for the capacity through the pressure-reducing valve and

W = 1/2 A1 C1 for the capacity through the bypass valve.

Caution should be exercised when substitut-ing these factors for the actual coeffi cients since this method will provide approximate values only and the capacities so obtained may in fact be lower than actual. It is recom-mended that the actual fl ow coeffi cient be obtained from the pressure-reducing valve manufacturer and reference books be con-sulted for the fl ow coeffi cient of the bypass valve.

G-6000 TWO-STAGE PRESSURE- REDUCING VALVE

STATIONS

The safety relief valve for two-stage pressure-reducing valve stations shall be sized on the basis of the high side pressure and the inlet size of the fi rst pressure-reducing valve in the line. If an intermediate pressure line is taken off between the pressure-reducing valves then this line and the fi nal low side shall be protected by safety relief valves sized on the basis of the high side pressure and the inlet size of the fi rst pressure-reducing valve. See Table G-6000.

368


TABLE G-4000 — Capacity of Saturated Steam, in lb./hr., per sq. in. of Pipe Area

850 800 750 700 650 600 550 500 450 400 350 300 250 1000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 950 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 900 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 850 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800 22550 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 750 30600 21800 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 700 35730 29420 21020 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650 39200 34250 28260 20190 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 600 41500 37470 32800 27090 19480 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 550 42840 39850 35730 31310 25940 18620 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500 43330 40530 37610 33880 29760 24630 17720 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450 43330 40730 38150 35260 31980 28080 23290 16680 . . . . . . . . . . . . . . . . . . . . . . . . . 400 . . . . . 40760 38220 35680 33050 29980 26380 21870 15760 . . . . . . . . . . . . . . . . . . . . 350 . . . . . . . . . . . . . . . . . . . . 33120 30690 27910 24570 20460 14790 . . . . . . . . . . . . . . . 300 . . . . . . . . . . . . . . . . . . . . 33240 . . . . . 28140 25610 22620 18860 13630 . . . . . . . . . . 250 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28150 25650 23200 21000 17100 10800 . . . . . 200 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21350 18250 15350 10900 175 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18250 16000 12600 150 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18250 16200 13400 125 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18780 . . . . . 13600 110 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13600 100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13600 85 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13600 75 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13600 60 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13630 50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Outletpres.,psi

Pressure reducing valve inlet pressure, psi

Where capacities are not shown for inlet and outlet conditions, use the highest capacity shown under the applicable inlet pressure column.Metric equivalents will appear in the 2005 Addendum.


1500 1450 1400 1350 1300 1250 1200 1150 1100 1050 1000 950 900 1000 76560 72970 69170 64950 60540 55570 49930 43930 35230 25500 . . . . . . . . . . . . . . . 950 77430 74180 70760 67000 63100 58770 53920 48610 42380 34890 24910 . . . . . . . . . . 900 77750 74810 71720 68340 64870 61040 56820 52260 47050 41050 33490 23960 . . . . . 850 77830 74950 72160 69130 66020 62610 58900 54930 50480 45470 39660 29080 23190 800 . . . . . 75070 72330 69490 66700 63680 60390 56910 53060 48800 43980 38340 31610 750 . . . . . . . . . . . . . . . 69610 66880 64270 61260 58200 54840 51170 47080 42420 37110 700 . . . . . . . . . . . . . . . . . . . . 66900 64270 61520 58820 55870 52670 49170 45230 40860 650 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61550 58860 56260 53480 50440 47070 43400 600 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58980 56270 53660 51020 48470 45010 550 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53810 51040 48470 45800 500 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45850 450 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45870 400 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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369

APPENDIX G — SAFETY VALVES ON THE LOW-PRESSURE SIDE OF STEAM PRESSURE REDUCING VALVES

TABLE G-6000 — Pipe Data

Nominal Approx. pipe size, Actual external Approx. internal internal area in. (DN) diameter, in. (mm) diameter, in. (mm) sq. in. (sq. mm)

3/8 (10) 0.675 (17) 0.49 (12) 0.19 (123) 1/2 (15) 0.840 (21) 0.62 (16) 0.30 (194) 3/4 (20) 1.050 (27) 0.82 (21) 0.53 (342) 1 (25) 1.315 (33) 1.05 (27) 0.86 (555) 1-1/4 (32) 1.660 (42) 1.38 (35) 1.50 (968) 1-1/2 (40) 1.900 (48) 1.61 (41) 2.04 (1,316) 2 (50) 2.375 (60) 2.07 (53) 3.36 (2,168) 2-1/2 (65) 2.875 (73) 2.47 (63) 4.78 (3,084) 3 (80) 3.500 (89) 3.07 (78) 7.39 (4,768) 3-1/3 (90) 4.000 (102) 3.55 (90) 9.89 (6,381) 4 (100) 4.500 (114) 4.03 (102) 12.73 (8,213) 5 (125) 5.563 (141) 5.05 (128) 19.99 (12,897) 6 (150) 6.625 (168) 6.07 (154) 28.89 (18,639) 8 (200) 8.625 (219) 8.07 (205) 51.15 (33,000) 10 (250) 10.750 (273) 10.19 (259) 81.55 (52,613) 12 (300) 12.750 (324) 12.09 (307) 114.80 (74,064)

Note: In applying these rules, the area of the pipe is always based upon standard weight pipe and the inlet size of the pressure reducing valve.

200 175 150 125 100 85 75 60 50 40 30 25 1000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 950 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 900 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 850 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 750 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 700 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 600 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 550 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 450 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 7250 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 9540 6750 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 10800 8780 6220 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 11000 9460 7420 4550 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 11000 9760 7970 5630 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 11000 . . . . . 8480 6640 4070 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 11000 . . . . . . . . . . 7050 4980 3150 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 11000 . . . . . . . . . . 7200 5750 4540 3520 . . . . . . . . . . . . . . . . . . . . . . . . . 50 11000 . . . . . . . . . . . . . . . 5920 5000 4230 2680 . . . . . . . . . . . . . . . . . . . . 40 11000 . . . . . . . . . . . . . . . . . . . . 5140 4630 3480 2470 . . . . . . . . . . . . . . . 30 11050 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3860 3140 2210 . . . . . . . . . . 25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3340 2580 1485 . . . . . 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2830 2320 1800 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2060 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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370


371

Recommended Guide for the Inspection of Pressure Vessels in LP Gas Service —Nonmandatory

Appendix H

372


APPENDIX H — RECOMMENDED GUIDE FOR THE INSPECTION OF PRESSURE VESSELS IN LP GAS SERVICE

H-1000 GENERAL CONDITIONS

Pressure vessels designed for storing LP gas can be stationary or can be mounted on skids. LP gases are generally considered to be noncorrosive to the interior of the vessel. This part is provided for guidance of a general nature for the owner, user, or jurisdictional authority. There may be occasions where more detailed procedures will be required.

The application of this section to underground vessels will only be necessary when evidence of structural damage to the vessel has been observed, leakage has been determined, or the tank has been dug up and is to be reinstalled.

H-2000 PRE-INSPECTION ACTIVITIES

A review of the known history of the pressure vessel should be performed. This should include a review of information, such as:

a. Operating conditions

b. Normal contents of the vessel

c. Results of any previous inspection

d. Current jurisdictional inspection certificate, if required

e. ASME Code symbol stamping or mark of code of construction, if required

f. National Board and/or jurisdictional registration number, if required

The vessel should be sufficiently cleaned to allow for visual inspection.

H-3000 ASSESSMENT OF INSTALLATION

The type of inspection given to pressure vessels should take into consideration the condition of the vessel and the environment in which it operates. The inspection may be external or internal, and use a variety of nondestructive examination methods. Where there is no reason to suspect an unsafe condition or where there are no inspection openings, internal inspections need not be performed. The external inspection may be performed when the vessel is pressurized or depressurized, but shall provide the necessary information that the essential sections of the vessel are of a condition to operate.

H-3100 DEFINITIONS

Dents — Deformations caused by a blunt object coming in contact with the vessel in such a way that the thickness of the metal is not materially reduced.

Cuts or Gouges — Deformations caused by a sharp object coming in contact with the vessel in such a way as to cut into or upset the metal reducing the thickness of the metal at that point.

Corrosion or Pitting — The loss of wall thickness by corrosive media, for example:

Isolated Pitting — Small diameter voids separated from other pits or corrosion that do not effectively weaken the vessel.

Line Corrosion — A loss of wall thickness (corrosion) in a continuous pattern or pitting connected in a narrow band or line.

Crevice Corrosion — A loss of metal in the area of the intersection of skirts (footrings), collars (headrings), saddle bands and other attachments with the vessel.

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APPENDIX H — RECOMMENDED GXUIDE FOR THE INSPECTION OF PRESSURE VESSELS IN LP GAS SERVICE

General Corrosion — A loss of metal over a considerable surface area of the vessel.

Crack — Any surface or subsurface separation of base metal or weld material whose extent must be determined by nondestructive examination methods. See H-3510.

Distortion — Any change in the original shape of the vessel, for example:

Bulges — Permanent deformations caused by excessive internal pressure that results in the pressure vessel’s surface being outside its original symmetry.

H-3200 EXTERNAL INSPECTION

All parts of the vessel shall be inspected for corrosion, distortion, cracking or other conditions as described in this section. In addition, the following should be reviewed, where applicable:

a. Insulation If the insulation is in good condition and

there is no reason to suspect an unsafe condition behind it, then it is not necessary to remove the insulation in order to inspect the vessel. However, it may be advisable to remove a small portion of the insulation in order to determine its condition and the condition of the vessel surface.

b. Evidence of Leakage Any leakage of vapor or liquid shall be

investigated. Leakage coming from behind insulation, supports, or evidence of past leakage shall be thoroughly investigated by removing any insulation necessary until the source is established.

c. Structural Attachments The pressure vessel mountings should

be checked for adequate allowance for expansion and contraction, such as provided by slotted bolt holes or unobstructed saddle mountings. Attachments of legs, saddles, skirts or

other supports should be examined for distortion or cracks at welds.

d. Vessel Connections Components which are exterior to

the vessel and are accessible without disassembly shall be inspected as described in this paragraph. Manholes, reinforcing plates, nozzles, or other connections shall be examined for cracks, deformation or other defects. Bolts or nuts should be examined for corrosion or defects. Weep holes in reinforcing plates shall remain open to provide visual evidence of leakage as well as to prevent pressure build up between the vessel and the reinforcing plate. Accessible flange faces should be examined for distortion. It is not intended that flanges or other connections be opened unless there is evidence of corrosion to justify opening the connection.

e. Fire Damage Pressure vessels shall be carefully inspected

for evidence of fire damage. The extent of fire damage determines the repair that is necessary, if any.

H-3300 INTERNAL INSPECTION

When there is a reason to suspect an unsafe condition, the suspect parts of the vessel shall be inspected and evaluated. See RB-6230.

H-3400 NONDESTRUCTIVE EXAMINATION (NDE)

Listed below are a variety of methods that may be employed to assess the condition of the pressure vessel. These examination methods should be implemented by experienced and qualified individuals. Generally, some form of surface preparation will be required prior to the use of these examination methods: visual, magnetic particle, liquid penetrant, ultrasonic, radiography, radioscopy, eddy current, metallographic examination, and

374


acoustic emission. When there is doubt as to the extent of a defect or detrimental condition found in a pressure vessel, additional NDE may be required.

H-3500 ACCEPTANCE CRITERIA

H-3510 CRACKS

Cracks in the pressure boundary (heads, shells, nozzles, welds joining parts, and attachment welds) are unacceptable. When a crack is identified, the vessel shall be removed from service until the crack is repaired by a qualified repair organization or permanently retired from service. See Part RC.

H-3520 DENTS

Dents may be evaluated as follows:

a. Shells The maximum mean dent diameter in

shells shall not exceed 10% of the shell diameter, and the maximum depth of the dent shall not exceed 10% of the mean dent diameter. The mean dent diameter is defined as the average of the maximum dent diameter and the minimum dent diameter. If any portion of the dent is closer to a weld than 5% of the shell diameter, the dent shall be treated as a dent in a weld area, see paragraph H-3520(b).

b. Welds The maximum mean dent diameter

on welds (i.e., part of the deformation includes a weld) shall not exceed 10% of the shell diameter. The maximum depth shall not exceed one twentieth of the mean dent diameter.

c. Heads The maximum mean dent diameter on

heads shall not exceed 10% of the shell

diameter. The maximum depth shall not exceed one twentieth of the mean dent diameter. The use of a template may be required to measure dents on heads.

When dents are identified which exceed the limits set forth in these paragraphs, the vessel shall be removed from service until the dents are repaired by a qualified repair organization or permanently retired from service.

H-3530 BULGES

Bulges may be evaluated as follows:

a. Shells If a bulge is suspected, the circumference

shall be measured at the suspect location and several places remote from the suspect location. The variation between measurements shall not exceed 1%.

b. Heads If a bulge is suspected, the radius of

curvature shall be measured by the use of templates. At any point the radius of curvature shall not exceed 1.25% of the diameter for the specified shape of the head.

When bulges are identified which exceed the limits set forth in these paragraphs, the vessel shall be removed from service until the bulges are repaired by a qualified repair organization or permanently retired from service.

H-3540 CUTS OR GOUGES

When a cut or a gouge exceeds 1/4 of the thickness of the vessel, the vessel shall be removed from service until it is repaired by a qualified repair organization or permanently retired from service.

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APPENDIX H — RECOMMENDED GXUIDE FOR THE INSPECTION OF PRESSURE VESSELS IN LP GAS SERVICE

H-3550 CORROSION

Corrosion may be evaluated as follows:

a. Line and Crevice Corrosion For line and crevice corrosion, the depth

of the corrosion shall not exceed 1/4 of the original wall thickness.

b. Isolated Pitting Isolated pits may be disregarded provided

that:

1. Their depth is not more than one-half the required thickness of the pressure vessel wall (exclusive of corrosion allowance);

2. The total area of the pits does not exceed 7 sq. in. (4500 sq. mm) within any 8 in. (200 mm) diameter circle; and

3. The sum of their dimensions along any straight line within this circle does not exceed 2 in. (50 mm).

c. General Corrosion For a corroded area of considerable size

the thickness along the most critical plane of such area may be averaged over a length not exceeding 20 in. (500 mm). The thickness at the thinnest point shall not be less than 50% of the required wall thickness and the average shall not be less than 75% of the required wall thickness. When general corrosion is identified which exceeds the limits set forth in this paragraph, the pressure vessel shall be removed from service until it is repaired by a qualified organization or permanently retired from service.

H-3560 LEAKS

Leakage is unacceptable. When leaks are identified, the vessel shall be removed from

service until repaired by a qualified repair organization or permanently retired from service.

H-3570 FIRE DAMAGE

Fire damage may be evaluated as follows:

a. Vessels in which bulging exceeds the limits of H-3530(a) or distortion which exceeds the limits of the original code of construction (e.g., Section VIII, Div. 1 of the ASME Code) shall be removed from service until repaired by a qualified organization or permanently retired from service.

b. Common evidence of exposure to fire is:

1. charring or burning of the paint or other protective coat,

2. burning or scarring of the metal,

3. distortion, or

4. burning or melting of the valves.

c. A pressure vessel which has been subjected to the action of fire shall be removed from service until it has been properly evaluated. The general intent of this requirement is to remove from service pressure vessels which have been subject to the action of fire which has changed the metallurgical structure or the strength properties of the steel. This is normally determined by visual examination as described above with particular emphasis given to the condition of the protective coating. If there is evidence that the protective coating has been burned off any portion of the pressure vessel surface, or if the pressure vessel is burned, warped, or distorted, it is assumed that the pressure vessel has been overheated. If, however, the protective coating is only smudged, discolored, or

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blistered and is found by examination to be intact underneath, the pressure vessel shall not be considered affected within the scope of this requirement. Vessels that have been involved in a fire and show no distortion shall be requalified for continued service by retesting using the hydrostatic test procedure applicable at the time of original fabrication.

H-4000 RECORDS

A permanent record shall be maintained for each vessel repaired by a qualified organization. The record shall include the following:

a. An ASME Manufacturer’s Data Report or, if the vessel is not ASME Code stamped, other equivalent specifications.

b. Form R-1 Report of Welded Repair or other equivalent document describing the extent of all repairs to the vessel.

H-5000 CONCLUSIONS

Any defect or deficiency in the condition, operating, and maintenance practices of the pressure vessel should be evaluated at the time of inspection and decision made for the correction of such defect or deficiency.

Installation Requirements

Appendix I

377


378

APPENDIX I — INSTALLATION REQUIREMENTS

I-1300 APPLICATION OF THESE RULES

a. As referenced in lower case letters, the terms “owner”, “user” or “owner/user” means any person, firm or corporation legally responsible for the safe opera-tion of the boiler, pressure vessel, pip-ing or other pressure-retaining item. Further, where the term owner is used, it shall mean the owner, or user, or the owner’s or user’s designee, except for I-1300(b).

b. Where the owner is required to perform an activity, it is intended that the owner or the owner’s designee may perform the activity; however, the owner retains responsibility for compliance with these rules.

c. These rules refer to documentation obtained from the jurisdiction (installa-tion permit, operating permit). It is not intended to require the jurisdiction to is-sue such permits but rather a caution to owners and installers that such permits may be required.

I-2000 POWER BOILERS

I-2100 INTRODUCTION

I-2110 SCOPE

This section provides requirements for the installation of power boilers as defined in I-2120. For installation of items that do not fall within the scope of this section, refer to the following as applicable:

I-3000 Heating Boilers and Potable Water HeatersI-4000 Pressure VesselsI-5000 Piping

I-1000 INSTALLATION REQUIREMENTS

I-1100 INTRODUCTION

The proper installation of boilers, pressure vessels, piping and other pressure-retaining items is essential for safe and satisfactory operation. The owner-user is responsible for ensuring that installations meet all the requirements of the jurisdiction at the point of installation including licensing, registra-tion or certification of those performing installations. The following are minimum requirements and users of this document are cautioned that it is not a substitute for sound engineering evaluations of a particu-lar installation. Where mandated by a juris-diction, these requirements are mandatory. Where a jurisdiction establishes different requirements or where a conflict exists, the rules of the jurisdiction prevail.

I-1200 PURPOSE

a. The purpose of these rules is to establish minimum requirements, which, if fol-lowed, will ensure that pressure-retain-ing items, when installed, may be safely operated, inspected and maintained.

b. It should be recognized that many of the requirements included in these rules must be considered in the design of the pressure-retaining item by the manufacturer. However, the owner-user is responsible for ensuring that the installation complies with all the appli-cable requirements contained herein. Further, the installer is responsible for complying with the applicable sections when performing work on behalf of the owner-user.


379

I-2120 POWER BOILERS

A power boiler is a closed vessel in which water or other liquid is heated, steam or vapor generated, steam or vapor is super-heated, or any combination thereof, under pressure for use external to itself, by the direct application of energy from the com-bustion of fuels or from electricity or solar energy. The term boiler includes fired units for heating or vaporizing liquids other than water but does not include fired process heaters and systems. The term boiler also shall include the apparatus used to generate heat and all controls and safety devices as-sociated with such apparatus or the closed vessel.

a. Power Boiler – a boiler in which steam or other vapor is generated at a pressure in excess of 15 psig (100 kPa) for use external to itself.

b. High Temperature Boiler – a boiler in which water or other fluid is heated and operates at a pressure in excess of 160 psig (1.1 MPa) and/or temperature in excess of 250°F (120°C).

c. Electric Boiler – a power boiler as de-scribed above in which the source of heat is electricity.

I-2200 CERTIFICATION, INSPECTION AND JURISDICTIONAL REQUIREMENTS

I-2210 RESPONSIBILITY

The owner is responsible for satisfying ju-risdictional requirements for certification and documentation. When required by jurisdictional rules applicable to the loca-tion of installation, the boiler shall not be operated until the required documentation has been provided to the owner and the jurisdiction.

I-2220 EQUIPMENT CERTIFICATION

All boilers shall have documented certifica-tion from the manufacturer indicating that the boiler complies with the requirements of the code of construction. The certifica-tion shall identify the revision level of the code of construction to which the boiler was fabricated.

I-2230 JURISDICTIONAL REVIEW

a. The owner shall determine jurisdictional requirements (i.e., certificates, permits, licenses, etc.) before installing the equip-ment. The organization responsible for installation shall obtain all permits required by the jurisdiction prior to commencing installation.

b. The owner shall determine jurisdictional requirements (i.e., certificates, permits, licenses, etc.) before operating the equip-ment. The owner shall obtain operating certificates, permits, etc. required by the jurisdiction prior to commencing opera-tion.

I-2240 INSPECTION

All boilers shall be inspected after installa-tion and prior to commencing operation.

I-2300 GENERAL REQUIREMENTS

I-2310 SUPPORTS, FOUNDATIONS AND SETTINGS

Each boiler and its associated piping must be safely supported. Design of supports, foundations and settings shall consider vibration, movement (including thermal movement) and loadings (including flooded conditions) in accordance with jurisdictional


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requirements, manufacturer’s recom-men-dations and/or other industry standards, as applicable.

I-2320 STRUCTURAL STEEL

a. If the boiler is supported by structural steel work, the steel supporting mem-bers shall be so located or insulated that the heat from the furnace will not affect their strength.

b. Structural steel shall be installed in accordance with jurisdictional require-ments, manufacturer’s recommenda-tions and/or other industry standards, as applicable.

I-2330 CLEARANCES

a. Boiler installations shall allow for nor-mal operation, maintenance, and inspec-tions. There shall be at least 36 in. (900 mm) of clearance on each side of the boiler to enable access for maintenance and/or inspection activities. Boilers operated in battery shall not be installed closer than 48 in. (1200 mm) from each other. The front or rear of any boiler shall not be located nearer than 36 in. (900 mm) from any wall or structure. Alternative clearance in accordance with the manufacturer’s recommendations are subject to acceptance by the jurisdic-tion.

b. Boilers shall be installed to allow for removal and installation of tubes.

c. Boilers with a top-opening manhole, shall have at least 84 in. (2100 mm) of clearance from the manhole to the ceil-ing of the boiler room.

d. Boilers without top-opening manholes shall have at least 36 in. (90 mm) of clearance from the top of the boiler or as recommended by the manufacturer.

e. Boilers with a bottom opening shall have at least 12 in. (300 mm) of unobstructed clearance.

I-2340 BOILER ROOM REQUIREMENTS

I-2341 EXIT AND EGRESS

Two means of exit shall be provided for boiler rooms exceeding 500 sq. ft. (46.5 sq. m) floor area and containing one or more boilers having a fuel capacity of 1,000,000 Btu/hr. (293 W/hr.) or more (or equivalent electrical heat input). Each elevation shall be provided with at least two means of egress, each to be remotely located from the other. A platform at the top of a single boiler is not considered an elevation.

I-2342 LADDERS AND RUNWAYS

a. All walkways, runways, and platforms shall:

1. be of metal construction;

2. be provided between or over the top of boilers which are more than 8 ft. (2.8 m) above the operating floor to afford accessibility for normal operation, maintenance and inspec-tion;

3. be constructed of safety treads, standard grating, or similar material and have a minimum width of 30 in. (750 mm);

4. be of bolted, welded, or riveted con-struction;

5. be equipped with handrails 42 in. (1050 mm) high with an interme-diate rail and 4 in. (100 mm) toe-board.


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b. Stairways which serve as a means of ac-cess to walkways, runways, or platforms shall not exceed an angle of 45 degrees from the horizontal and be equipped with handrails 42 in. (1050 mm) high with an intermediate grid.

c. Ladders which serve as a means of ac-cess to walkways, runways, or platforms shall:

1. be of metal construction and not less than 18 in. (450 mm) wide;

2. have rungs that extend through the side members and are permanently secured;

3. have a clearance of not less than 30 in. (750 mm) from the front of rungs to the nearest permanent object on the climbing side of the ladder;

4. have a clearance of not less than 6-1/2 in. (165 mm) from the back of rungs to the nearest permanent object;

5. have a clearance width of at least 15 in. (390 mm) from the center of the ladder on either side across the front of the ladder.

d. There shall be at least two permanently installed means of egress from walk-ways, runways, or platforms that exceed 6 ft. (2 cm) in length.

I-2343 DRAINS

At least one floor drain shall be installed in the boiler room.

I-2344 WATER

A convenient water supply shall be pro-vided for flushing out the boiler and its

appurtenances, adding water to the boiler while it is not under pressure and cleaning the boiler room floor.

I-2400 SOURCE REQUIREMENTS

I-2410 FEEDWATER

I-2411 VOLUME

The source of feedwater shall be capable of supplying a sufficient volume of water as determined by the boiler manufacturer in order to prevent damage to the boiler when all the safety relief valves are discharging at full capacity.

I-2412 CONNECTION

a. To prevent thermal shock, feedwater shall be introduced into a boiler in such a manner that the water will not be discharged directly against surfaces exposed to gases of high temperature or to direct radiation from the flame.

b. For boiler operating pressures of 400 psi (2700 kPa) or higher, the feedwater inlet through the drum shall be fitted with shields, sleeves, or other suitable means to reduce the effects of temperature dif-ferentials in the shell or head.

c. Feedwater other than condensate return shall not be introduced through the blowoff.

d. Boilers having more than 500 sq. ft. (46.5 sq. m.) of water heating surface shall have at least two means of sup-plying feedwater. For boilers that are fired with solid fuel not in suspension, and boilers whose setting or heat source can continue to supply sufficient heat to cause damage to the boiler if the feed-water supply is interrupted, one such


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Boiler Pressure, Boiler Feedwater Pumppsi (MPa) Discharge Pressure,* psi (MPa)

200 (1.5) 250 (1.7) 400 (3) 475 (3.3) 800 (5.5) 925 (6.4) 1,200 (8) 1,350 (9.3)

*based on 34.5 lbs. (15.5 kg) of evaporation per hour @ 212°F (100°C)

For forced-flow steam generators with no fixed steam or water line, each source of feedwater shall be capable of supplying feed-water to the boiler at a minimum pressure equal to the expected maximum sustained pressure at the boiler inlet corresponding to operation at maximum designed steaming capacity with maximum allowable pressure at the superheater outlet.

Control devices may be installed on feed-water piping to protect the pump against overpressure.

I-2414 VALVES

a. The feedwater piping shall be provided with a check valve and a stop valve. The stop valve shall be located between the check valve and the boiler.

b. When two or more boilers are fed from a common source, there shall also be a globe or regulating valve on the branch to each boiler located between the check valve and the feedwater source.

c. When the feedwater piping is divided into branch connections and all such connections are equipped with stop and check valves, the stop and check valve in the common source may be omitted.

d. On single boiler-turbine unit installa-tions, the boiler feedwater stop valve may be located upstream from the boiler feedwater check valve.

means of supplying feedwater shall not be subject to the same interruption as the first method. Boilers fired by gaseous, liquid, or solid fuel in suspension may be equipped with a single means of sup-plying feedwater provided means are furnished for the immediate removal of heat input if the supply of feedwater is interrupted.

e. For boilers having a water heating sur-face of not more than 100 sq. ft. (9 sq. m.), the feedwater piping and connection to the boiler shall not be smaller than NPS 1/2 (DN 15). For boilers having a water heating surface more than 100 sq. ft. (9 sq. m.), the feedwater piping and connection to the boiler shall not be less than NPS 3/4 (DN 20).

Electric boiler feedwater connections shall not be smaller than NPS 1/2 (DN 15).

f. High temperature water boilers shall be provided with means of adding water to the boiler or system while under pres-sure.

I-2413 PUMPS

Boiler feedwater pumps shall have dis-charge pressure in excess of the boiler rated pressure (MAWP) in order to compensate for frictional losses, entrance losses, regulat-ing valve losses, and normal static head, etc. Each source of feedwater shall be capable of supplying feedwater to the boiler at a minimum pressure of three percent higher than the highest setting of any safety valve on the boiler plus the expected pressure drop across the boiler. The following table is a guideline for estimating feed pump differential:


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e. If a boiler is equipped with duplicate feedwater supply arrangements, each such arrangement shall be equipped as required by these rules.

f. A check valve shall not be a substitute for a stop valve.

g. A combination feedwater stop-and-check valve in which there is only one seat and disk and a valve stem is pro-vided to close the valve when the stem is screwed down shall be considered only as a stop valve, a separate check valve shall be installed.

h. Whenever globe valves are used on feedwater piping, the inlet shall be un-der the disk of the valve.

i. Stop valves and check valves shall be placed on the inlet of economizers or feedwater-heating devices.

j. The recirculating return line for a high temperature water boiler shall be pro-vided with the stop valve, or valves, required for the main discharge outlet on the boiler.

I-2420 FUEL

Fuel systems, whether coal, oil, gas or other substance shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommen-dations and/or industry standards, as applicable.

I-2430 ELECTRICAL

a. All wiring for controls, heat generating apparatus, and other appurtenances necessary for the operation of the boiler or boilers should be installed in accor-dance with the provisions of national

or international standards and comply with the applicable local electrical codes.

b. A manually operated remote shutdown switch or circuit breaker should be lo-cated just outside the boiler room door and marked for easy identification. Consideration should also be given to the type and location of the switch to safeguard against tampering. If the boiler room door is on the building ex-terior the switch should be located just inside the door. If there is more than one door to the boiler room, there should be a switch located at each door.

1. For atmospheric-gas burners, and oil burners where a fan is on a common shaft with the oil pump, the com-plete burner and controls should be shut off.

2. For power burners with detached auxiliaries, only the fuel input sup-ply to the firebox need be shut off.

c. Controls and Heat Generating Appara-tus

1. Oil and gas-fired and electrically heated boilers and water heaters shall be equipped with suitable primary (flame safeguard) safety controls, safety limit switches, and burners or electric elements as required by a nationally or interna-tionally recognized standard.

2. The symbol of the certifying organi-zation15 which has investigated such equipment as having complied with a nationally recognized standard shall be affixed to the equipment and shall be considered as evidence

15 Organizations – A certifying organization is one that provides uniform testing, examination, and listing procedures under established, nationally recognized standards, and that is acceptable to the authorities having jurisdiction.


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that the unit was manufactured in accordance with that standard.

3. These devices shall be installed in accordance with jurisdictional and environmental requirements, manu-facturer’s recommendations and/or industry standards as applicable.

I-2440 VENTILATION AND COMBUSTION AIR

a. The boiler room shall have an adequate air supply to permit clean, safe combus-tion, minimize soot formation and main-tain a minimum of 19.5% oxygen in the air of the boiler room. The combustion and ventilation air may be supplied by either an unobstructed air opening or by power ventilation or fans.16

b. Unobstructed air openings shall be sized on the basis of 1 sq. in. (650 sq. mm) free area per 2000 Btu/hr. (586 W/hr.) maximum fuel input of the combined burners located in the boiler room, or as specified in the National Fire Protec-tion Association (NFPA) standards for oil and gas burning installations for the particular job conditions. The boiler room air supply openings shall be kept clear at all times.

c. Power ventilators or fans shall be sized on the basis of 0.2 cfm (0.0057 cu meters per minute) for each 1000 Btu/hr. (293 W/hr.) of maximum fuel input for the combined burners of all boilers and wa-ter heaters located in the boiler room.

d. When power ventilators or fans are used to supply combustion air they shall be installed with interlock devices so that the burners will not operate without an adequate number of ventilators/fans in operation.

e. The size of openings specified in I-2440(b) may be reduced when special engineered air supply systems ap-proved by the jurisdiction are used.

I-2450 LIGHTING

The boiler room should be well lighted and it should have an emergency light source for use in case of power failure.

I-2460 EMERGENCY VALVES AND CONTROLS

All emergency shut-off valves and controls shall be accessible from a floor, platform, walkway or runway. Accessibility shall mean within a 6 ft. (2 m) elevation of the standing space and not more than 12 in. (300 mm) horizontally from the standing space edge.

I-2500 DISCHARGE REQUIREMENTS

I-2510 CHIMNEY OR STACK

Chimneys or stacks shall be installed in accordance with jurisdictional and envi-ronmental requirements, manufacturer’s recommendations and/or industry stan-dards, as applicable.

16 Fans – When combustion air is supplied to the boiler by an independent duct, with or without the employment of power ventilators or fans, the duct shall be sized and installed in accordance with the manufacturer ’s recommendations. However, ventilation for the boiler room must still be considered.


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I-2520 ASH REMOVAL

Ash removal systems shall be installed in accordance with jurisdictional and envi-ronmental requirements, manufacturer’s recommendations and/or industry stan-dards, as applicable.

I-2530 DRAINS

I-2531 CONNECTION

a. Each boiler shall have at least one drain pipe fitted with a stop valve at the low-est point of the boiler. If the connection is not intended for blowoff purposes, a single valve is acceptable if it can be locked in the closed position or a blank flange can be installed downstream of the valve. If the connection is intended for blowoff purposes, requirements of I-2650 shall be followed.

b. For high temperature water boilers, the minimum size of the drain pipe shall be NPS 1 (DN 25).

c. Drain pipes, valves and fittings within the same drain line shall be the same size.

d. The discharge from the drain shall be piped to a safe location.

I-2532 PRESSURE RATING

a. When the maximum allowable work-ing pressure of the boiler is equal to or less than 100 psi (700 kPa), the drain pipe, valve and fittings shall be rated for at least 100 psi (700 kPa) and 220°F (105°C).

b. When the maximum allowable work-ing pressure of the boiler exceeds 100 psi (700 kPa), the drain pipe, valve and

fittings shall be rated for at least the maximum allowable working pressure and temperature of the boiler.

I-2533 PARTS

a. When parts (economizers, etc.) are in-stalled with a stop valve between the part and the boiler or the part cannot be completely drained through the drain on the boiler, a separate drain shall be installed on each such part. These drains shall meet the requirements of this para-graph.

b. Each water column shall have a drain pipe fitted with a stop valve at the low-est point of the water column. The stop valve shall have the capability of being locked in the closed position while the boiler is under pressure. The mini-mum size of the drain shall be NPS 3/4 (DN 20) and all other requirements of this paragraph shall be met.

I-2600 OPERATING SYSTEMS

I-2610 BREECHING AND DAMPERS

Breeching and dampers shall be installed in accordance with jurisdictional and en-vironmental requirements, manufacturer’s recommendations and/or industry stan-dards, as applicable.

I-2620 BURNERS AND STOKERS

Burners and stokers shall be installed in accordance with jurisdictional and envi-ronmental requirements, manufacturer’s recommendations and/or industry stan-dards, as applicable.


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I-2630 STEAM SUPPLY

a. Provisions shall be made for the expan-sion and contraction of steam mains connected to boiler(s) so that there shall be no undue strain transmitted to the boiler(s). Steam reservoirs shall be installed on steam mains when heavy pulsations of the steam currents cause vibration of the boiler shell plates.

b. Each discharge outlet of the boiler drum or superheater outlet, shall be fitted with a stop valve located at an accessible point in the steam-delivery line and as near the boiler nozzle as is convenient and practicable. The valve shall be equipped to indicate from a dis-tance whether it is closed or open, and shall be equipped with a slow-opening mechanism. When such outlets are over NPS 2 (DN 50), the valve or valves used on the connection shall be of the outside-screw-and-yoke-rising-spindle type, so as to indicate from a distance by the position of its spindle whether it is closed or open, and the wheel may be carried either on the yoke or attached to the spindle. In the case of a single boiler and prime mover installation, the stop valve may be omitted provided the prime mover throttle valve is equipped with an indicator to show whether the valve is open or closed and is designed to withstand the required hydrostatic test pressure of the boiler.

c. Stop valves and fittings shall comply with the appropriate national standard except that austenitic stainless steel is not permitted for water wetted ser-vice.

d. Stop valves and fittings shall be rated for the maximum allowable working pressure of the boiler and shall be at least rated for 100 psi (700 kPa) at the expected steam temperature at the valve or fitting, in accordance with the appro-priate national standard.

e. The nearest stop valve or valves to the superheater outlet shall have a pressure rating at least equal to the minimum set pressure of any safety valve on the superheater and at the expected super-heated steam temperature; or at least equal to 85% of the lowest set pressure of any safety valve on the boiler drum at the expected steam temperature of the superheater outlet, whichever is greater.

f. Ample provision for gravity drain shall be provided when a stop valve is so located that water or condensation may accumulate. The gravity drain(s) shall be located such that the entire steam supply system can be drained.

g. When boilers are connected to a com-mon header, the connection from each boiler having a manhole opening shall be fitted with two stop valves having an ample freeblow drain between them. The discharge of this drain shall be visible to the operator while operating the valve. The stop valves shall consist of one stop check valve (set next to the boiler) and a second valve of the out-side-screw-and-yoke type; or two valves of the outside-screw-and-yoke type.

h. The second steam stop valve shall have a pressure rating at least equal to that required for the expected steam tem-perature and pressure at the valve, or the pressure rating shall be not less than 85% of the lowest set pressure of any safety valve on the boiler drum and for the expected temperature of the steam at the valve, whichever is greater.

i. Pressure-reducing valves may be installed in the steam supply piping downstream from the required stop valve or valves.


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I-2640 CONDENSATE AND RETURN

Each condensate return pump where prac-ticable, shall be provided with an automatic water level control set to maintain an ad-equate water level. Condensate tanks shall be vented to the atmosphere.

I-2650 BLOWOFF

a. Except for forced-flow steam generators with no fixed steam or water line, each boiler shall have a blowoff pipe, fitted with a stop valve, in direct connection with the lowest water space practicable. When the maximum allowable work-ing pressure of the boiler exceeds 100 psi (700 kPa) there shall be two valves installed.

The blowoff piping for each electric boiler pressure vessel having a nominal water content not exceeding 100 gal. (380 l) is required to extend through only one valve.

b. One of the blowoff valves shall be a slow-opening valve. When a second valve is required, the second valve may be a quick-opening or slow-opening valve.

c. Two independent slow-opening valves or a slow-opening valve and quick-opening valve may be combined in one body and may be used provided the combined fitting is the equivalent of two independent slow-opening valves or a slow-opening valve and a quick-open-ing valve, and provided further that the failure of one to operate cannot affect the operation of the other.

d. Straight-run globe valves or valves where dams or pockets can exist for the collection of sediment shall not be used.

e. The blowoff valve or valves and the pipe and fittings between them and the boiler shall be of the same size. The minimum size of pipe and fittings shall be NPS 1 (DN 25), except boilers with 100 sq. ft. (9 sq. m.) of heating surface or less may be NPS 3/4 (DN 20). The maximum size of pipe and fittings shall not exceed NPS 2-1/2 (DN 65).

For electric boilers, the minimum size of blowoff pipes and fittings shall be NPS 1 (DN 25), except for boilers of 100 kW input or less the minimum size may be NPS 3/4 (DN 20).

f. Fittings and valves shall comply with the appropriate national standard ex-cept that austenitic stainless steel and malleable iron are not permitted.

g. When the maximum allowable work-ing pressure exceeds 100 psi (700 kPa), blowoff piping shall be at least Schedule 80 and the required valves and fittings shall be rated for at least 1.25 times the maximum allowable working pressure of the boiler. When the maximum allow-able working pressure exceeds 900 psi (6 MPa), blowoff piping shall be at least Schedule 80 and the required valves and fittings shall be rated for at least the maximum allowable working pressure of the boiler plus 225 psi (1.6 MPa).

h. All blowoff piping, when exposed to furnace heat, shall be protected by fire brick or other heat resisting material so constructed that the piping may be readily inspected.

i. On a boiler having multiple blowoff pipes, a single master stop valve may be placed on the common blowoff pipe from the boiler and one stop valve on each individual blowoff. Either the mas-ter valve or the valves on the individual blowoff lines shall be of the slow-open-ing type.


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j. The discharge of blowoff pipes shall be located so as to prevent injury to person-nel.

k. All waterwalls or water screens that do not drain back into the boiler and integral economizers forming part of a boiler shall be equipped with blowoff piping and valves conforming to the requirements of this paragraph.

l. Blowoff piping from a boiler may not discharge directly into a sewer. A blow-off tank, constructed to the provisions of a code of construction acceptable to the jurisdiction, shall be used where condi-tions do not provide an adequate and safe open discharge.

m. Galvanized pipe shall not be used.

n. Boiler blowoff systems shall be con-structed in accordance with the Guide for Blowoff Vessels.

o. Where necessary to install a blowoff tank underground, it shall be enclosed in a concrete or brick pit with a remov-able cover so that inspection of the en-tire shell and heads of the tank can be made.

Piping connections used primarily for continuous operation, such as decon-centrators on continuous blowdown systems, are not classed as blowoffs but the pipe connections and all fittings up to and including the first shutoff valve shall be equal at least to the pressure re-quirements for the lowest set pressure of any safety valve on the boiler drum and with the corresponding saturated-steam temperature. Further, such connections shall not exceed NPS 2-1/2 (DN 65).

I-2700 CONTROLS AND GAGES

I-2710 WATER

a. Each automatically steam-fired boiler shall be equipped with at least two low-water fuel cutoffs. The water inlet shall not feed water into the boiler through a float chamber.

Each electric steam boiler of the resis-tance element type shall be equipped with an automatic low-water cut-off on each boiler pressure vessel, so located as to automatically cut off the power supply to the heating elements before the surface of the water falls below the visible part of the glass. No low-water cut-off is required for electrode type boilers.

b. Designs embodying a float and float bowl shall have a vertical straightaway drainpipe at the lowest point in the water equalizing pipe connections by which the bowl and the equalizing pipe can be flushed and the device tested.

c. The water column shall be directly con-nected to the boiler. Outlet connections (except for damper regulator, feedwater regulator, low-water fuel cutoff, drains, steam gages, or such apparatus that does not permit the escape of an appreciable amount of steam or water) may not be placed on the piping that connects the water column to the boiler.

d. Straight-run globe valves of the ordi-nary type shall not be used on piping that connects the water column to the boiler. Where water columns are seven feet or more above the floor level, ad-equate means for operating gage cocks or blowing out the water glass shall be provided.


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e. When automatic shutoff valves are used on piping that connects the water column to the boiler, they shall conform to the requirements of the code of con-struction for the boiler.

f. When shutoff valves are used on the connections to a water column, they shall be either outside-screw-and-yoke or lever-lifting-type gate valves or stop cocks with levers permanently fastened thereto and marked in line with their passage, or of such other through-flow constructions to prevent stoppage by deposits of sediment and to indicate by the position of the operating mechanism whether they are in open or closed posi-tion; and such valves or cocks shall be locked or sealed open.

g. Each steam boiler having a fixed water-line shall have at least one water-gage glass except that boilers operated at pressures over 400 psi (3 MPa) shall be provided with two water gage glasses which may be connected to a single wa-ter column or connected directly to the drum. The gage glass connections and pipe connection shall be not less than NPS 1/2 (DN 15). Each water-gage glass shall be equipped with a valved drain.

Electric steam boilers shall have at least one water gage glass. On electrode type electric boilers the gage glass shall be located as to indicate the water levels both at startup and maximum steam load conditions, as established by the boiler manufacturer. On resistance el-ement type electric steam boilers the lowest visible part of the gage glass shall be located at least 1 in. (25 mm) above the lowest permissible water level established by the manufacturer.

h. The lowest visible part of the water-gage glass shall be at least 2 in. (50 mm) above the lowest permissible water level which

shall be that level at which there will be no danger of overheating any part of the boiler when in operation.

i. For all installations where the water-gage glass or glasses are more than thirty feet (9 m.) from the boiler operat-ing floor, it is recommended that water level indicating or recording gages be installed at eye height from the operat-ing floor.

j. Boilers of the horizontal firetube type shall be so set that when the water is at the lowest reading in the water-gage glass there shall be at least 3 in. (75 mm) of water over the highest point of the tubes, flues or crown sheet.

k. Each water-gage glass shall be equipped with a top and a bottom shutoff valve of such through-flow construction as to prevent blockage by deposits of sedi-ment and to indicate by the position of the operating mechanism whether they are in the open or closed position. The pressure-temperature rating shall be at least equal to that of the lowest set pres-sure of any safety valve on the boiler drum and the corresponding saturated steam temperature.

I-2720 PRESSURE

I-2721 GAGE REQUIREMENTS

a. Each steam boiler shall have a pressure gage connected to the steam space or to the steam connection to the water col-umn. When a pressure reducing valve is installed in the steam supply piping, a pressure gage shall be installed on the low pressure side of the pressure-reduc-ing valve.


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b. The dial range shall not be less than 1.5 times the pressure at which the lowest safety relief valve is set.

c. The dial range should be no greater than two times the pressure at which the low-est safety relief valve is set.

I-2722 CONNECTION

a. For a steam boiler the gage or connec-tion shall contain a syphon or equivalent device which will develop and maintain a water seal that will prevent steam from entering the gage tube. A valve or cock shall be placed in the gage connection adjacent to the gage. An additional valve or cock may be located near the boiler providing it is locked or sealed in the open position. No other shut-off valves shall be located between the gage and the boiler.

b. Pressure gage connections shall be suit-able for the maximum allowable work-ing pressure and temperature, but if the temperature exceeds 406°F (208°C) brass or copper pipe or tubing shall not be used. The connections to the boiler, except for the syphon, if used, shall not be less than NPS 1/4 (DN 8). Where steel or wrought iron pipe or tubing is used, it shall not be less than 1/2 in. (13 mm inside diameter. The minimum size of a syphon, if used, shall be 1/4 in. (6 mm) inside diameter.

I-2730 TEMPERATURE

Each high temperature water boiler shall have a temperature gage or other report-ing device located to provide an accurate representation of the temperature at or near the boiler outlet.

I-2800 PRESSURE RELIEF VALVES

I-2810 VALVE REQUIREMENTS

a. Safety valves are designed to relieve steam.

b. Safety relief valves are valves designed to relieve either steam or water, depend-ing on the application.

c. Safety and safety relief valves are to be manufactured in accordance with a national or international standard.

d. Deadweight or weighted-lever pressure relieving valves shall not be used.

e. For high temperature water boilers, safety relief valves shall have a closed bonnet, and safety relief valve bodies shall not be constructed of cast iron.

f. Safety and safety relief valves with an inlet connection greater than NPS 3 (DN 80) used for pressure greater than 15 psig (100 kPa), shall have a flange inlet connection or a welding-end inlet connection. The dimensions of flanges subjected to boiler pressure shall con-form to the applicable standards.

g. When a safety or safety relief valve is exposed to outdoor elements which may affect operation of the valve, it is permis-sible to shield the valve with a cover. The cover shall be properly vented and ar-ranged to permit servicing and normal operation of the valve.

I-2820 NUMBER

At least one National Board capacity certi-fied safety or safety relief valve shall be installed on the boiler. If the boiler has more


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than 500 sq. ft. (46 sq. m.) of heating surface, or if an electric boiler has a power input of more than 1,100 kw, two or more National Board capacity certified safety or safety relief valves shall be installed.

I-2830 LOCATION

a. Safety or safety relief valves shall be placed on, or as close as physically pos-sible, to the boiler proper.

b. Safety or safety relief valves shall not be placed on the feedline.

c. Safety or safety relief valves shall be con-nected to the boiler independent of any other connection without any unneces-sary intervening pipe or fittings. Such intervening pipe or fittings shall not be longer than the face-to-face dimension of the corresponding tee fitting of the same diameter and pressure rating as listed in the applicable standards.

TABLE I-2840-1 — Minimum Pounds of Steam per Hour per Square Foot of Heating Surface (kg/hr/sq cm)

Firetube Boiler Watertube BoilersBoiler heating surface Hand-fired 5 (2112) 6 (2543) Stoker-fired 7 (2956) 8 (3378) Oil-, gas- or pulverized-fuel-fired 8 (3378) 10 (4223)

Waterwall heating surface Hand-fired 8 (3378) 8 (3378) Stoker-Fired 10 (4223) 12 (5068) Oil-, gas- or pulverized-fuel-fired 14 (5912) 16 (6756)

Copper finned water tubes Hand-fired 4 (1689) 4 (1689) Stoker-Fired 5 (2112) 5 (2112) Oil-, gas- or pulverized-fuel-fired 5 (2112) 6 (2534)

NOTES:When a boiler is fired only by a gas having a heat value not in excess of 200 Btu/cu. ft. (7.5 J/cu. cm.), the minimum relieving capacity may be based on the values given for hand-fired boilers above.

For firetube boiler units exceeding 8000 Btu/sq. ft. (9120 J/sq. cm.) (total Fuel Btu (J) Input divided by total heating surface), the factor from the table will be increased by 1 (422.3) for every 1000 Btu/sq. ft. (1140 J/ sq. cm.) above 8000 (9120 J/sq. cm.). For units less than 7000 Btu/sq. ft. (7980 J/sq. cm.), the factor from the table will be decreased by 1 (422.3) for every 1000 Btu/sq. ft. (1140 J/sq. cm.) below 7000 (7980 J/sq. cm.).

For watertube boiler units exceeding 16000 Btu/sq. ft. (18240 J/sq. cm.) (total fuel Btu input divided by the total heating surface), the factor fromthe table will be incresed by 1 (422.3) for every 1000 Btu/sq. ft. (1140 J/sq. cm.) above 16000 (18240 J/sq. cm.). For units with less than 15000 Btu/sq. ft. (17100 J/sq. cm.), the factor in the table will be decreased by 1 (422.3) for every 1000 Btu/sq. ft. (1140 J/sq. cm.) below 15000 (17100 J/sq. cm.).

The heating surface shall be compued for that side of the boiler surface exposed to the products of com-bustion, exclusive of the superheating surface. In computing the heating surface for this purpose, only the tubes, fireboxes, shells, tube sheets, and the projected area of headers need to be considered, except that for vertical firetube steam boilers, only that portion of the tube surface up to the middle gage cock is to be computed.


392

I-2840 CAPACITY

a. The pressure-relieving valve capacity for each boiler shall be such that the valve or valves will discharge all the steam that can be generated by the boiler without allowing the pressure to rise more than 6% above the highest pressure at which any valve is set and in no case to more than 6% above the maximum allowable working pressure of the boiler.

b. The minimum relieving capacity for oth-er than electric boilers and forced-fl ow steam generators with no fi xed steam line and waterline, shall be estimated for the boiler and waterwall heating surfaces as given in Table I-2840-1, but in no case may the minimum relieving capacity be less than the maximum de-signed steaming capacity as determined by the manufacturer.

c. The required relieving capacity in pounds per hour of the safety or safety relief valves on a high temperature wa-ter boiler shall be determined by divid-ing the maximum output in Btu at the boiler nozzle obtained by the fi ring of any fuel for which the unit is designed by one thousand.

d. The minimum safety or safety relief valve relieving capacity for electric boil-ers is 3.5 lbs./hr./kW. (1.6 kg./hr./kW.) input.

e. If the safety or safety relief valve capac-ity cannot be computed, or if it is desir-able to prove the computations, it may be checked by any one of the following methods; and if found insufficient, additional relieving capacity shall be provided:

1. By performing an accumulation test, that is, by shutting off all other steam discharge outlets from the boiler and forcing the fi res to the maximum.

This method should not be used on a boiler with a superheater or reheater or on a high temperature water boiler.

2. By measuring the maximum amount of fuel that can be burned and com-puting the corresponding evapora-tive capacity upon the basis of the heating value of the fuel.

3. By determining the maximum evaporative capacity by measur-ing the feedwater. The sum of the safety valve capacities marked on the valves shall be equal to or greater than the maximum evaporative capacity of the boiler. This method may not be used on high tempera-ture water boilers.

I-2850 SET PRESSURE

One or more safety or safety relief valves on the boiler proper shall be set at or below the maximum allowable working pressure. If additional valves are used, the highest pres-sure setting shall not exceed the maximum allowable working pressure by more than 3%. The complete range of pressure settings of all the safety relief valves on a boiler shall not exceed 10% of the highest pressure to which any valve is set. Pressure setting of safety relief valves on high temperature water boilers may exceed this 10% range.

I-2860 FORCED-FLOW STEAM GENERATOR

For a forced-fl ow steam generator with no fi xed steamline and waterline, equipped with automatic controls and protective in-terlocks responsive to steam pressure, safety valves may be installed in accordance with the following, as an alternative:

a. One or more power-actuated pressure-relieving valves shall be provided in


393

direct communication with the boiler when the boiler is under pressure and shall receive a control impulse to open when the maximum allowable work-ing pressure at the superheater outlet is exceeded. The total combined reliev-ing capacity of the power-actuated pressure-relieving valves may be not less than 10% of the maximum design steaming capacity of the boiler under any operating condition as determined by the manufacturer. The valves shall be located in the pressure part system where they will relieve the overpressure. An isolating stop valve of the outside-screw-and-yoke type may be installed between the power-actuating pressure-relieving valve and the boiler to permit repairs provided an alternate power-actuated pressure-relieving valve of the same capacity is so installed as to be in direct communication with the boiler.

b. Spring-loaded safety valves shall be provided having a total combined relieving capacity, including that of the power-actuated pressure-relieving valve, of not less than one hundred percent of the maximum designed steaming capacity of the boiler, as de-termined by the manufacturer. In this total, credit in excess of 30% of the total relieving capacity may not be allowed for the power-actuated pressure-reliev-ing valves actually installed. Any or all of the spring-loaded safety valves may be set above the maximum allowable working pressure of the parts to which they are connected, but the set pressures shall be such that when all these valves (together with the power-actuated pres-sure-relieving valves) are in operation the pressure will not rise more than 20% above the maximum allowable working pressure of any part of the boiler, except for the steam piping between the boiler and the prime mover.

c. When stop valves are installed in the water-steam flow path between any two sections of a forced-flow steam generator with no fixed steamline and waterline:

1. The power-actuated pressure-reliev-ing valve shall also receive a control impulse to open when the maximum allowable working pressure of the component, having the lowest pres-sure level upstream to the stop valve, is exceeded.

2. The spring-loaded safety valve shall be located to provide overpressure protection for the component having the lowest working pressure.

3. A reliable pressure-recording de-vice shall always be in service and records kept to provide evidence of conformity to the above require-ments.

I-2870 SUPERHEATERS

a. Every attached superheater shall have one or more safety valves. The location shall be suitable for the service intended and shall provide the overpressure protection required. The pressure drop upstream of each safety valve shall be considered in determining the set pres-sure and relieving capacity of that valve. If the superheater outlet header has a full, free, steam passage from end to end and is so constructed that steam is supplied to it at practically equal inter-vals throughout its length so that there is a uniform flow of steam through the superheater tubes and the header, the safety valve or valves may be located anywhere in the length of header.

b. The pressure relieving capacity of the safety valve or valves on an attached superheater may be included in deter-mining the number and size of the safety valves for the boiler provided there are


394

no intervening valves between the su-perheater safety valve and the boiler and the discharge capacity of the safety relief valve or valves, on the boiler, as distinct from the superheater, is at least 75% of the aggregate capacity required.

c. Every independently fired superheater that may be shut off from the boiler and permit the superheater to become a fired pressure vessel shall have one or more safety valves having a discharge capacity equal to six pounds of steam per/hr./sq. ft. (29 kg. per sq. m.) of su-perheater surface measured on the side exposed to the hot gases.

d. Every safety valve used on a superheater discharging superheated steam at a temperature over 450°F (230°C) shall have a casing, including the base, body, bonnet, and spindle constructed of steel, steel alloy, or equivalent heat-resistant material. The valve shall have a flanged inlet connection or a welding-end inlet connection. The seat and disk shall be constructed of suitable heat-erosive and corrosive-resistant material, and the spring fully exposed outside of the valve casing so that it is protected from contact with the escaping steam.

I-2871 ECONOMIZERS

An economizer that may not be isolated from a boiler does not require a safety relief valve. Economizers which may be isolated from a boiler or other heat transfer device, allowing the economizer to become a fired pressure vessel, shall have a minimum of one safety relief valve. Discharge capacity, rated in lbs./hr (kg/hr), of the safety relief valve or valves shall be calculated from the maximum expected heat absorbtion rate in BTU/hr (Joules/hr) of the economizer, and will be determined from manufacturer

date, divided by 1000. The safety relief valve shall be located as close as possible to the economizer outlet.

I-2880 PRESSURE-REDUCING VALVES

a. Where pressure-reducing valves are used, one or more safety or safety relief valves shall be installed on the low pressure side of the reducing valve in those installations where the piping or equipment on the low pressure side does not meet the requirements for the steam supply piping.

b. The safety or safety relief valves shall be located as close as possible to the pres-sure reducing valve.

c. Capacity of the safety or safety relief valves shall not be less than the total amount of steam that can pass from the high pressure side to the low pressure side and be such that the pressure rating of the lower pressure piping or equip-ment shall not be exceeded.

d. The use of hand-controlled bypasses around reducing valves is permissible. The bypass around a reducing valve may not be greater in capacity than the reducing valve unless the piping or equipment is adequately protected by safety or safety relief valves or meets the requirements of the high pressure system.

I-2890 MOUNTING AND DISCHARGE REQUIREMENTS

a. Every boiler shall have outlet connec-tions for the safety or safety relief valve, or valves, independent of any other outside steam connection, the area of


395

opening shall be at least equal to the aggregate areas of inlet connections of all of the attached safety or safety relief valves. An internal collecting pipe, splash plate, or pan may be used, provided the total area for inlet of steam thereto is not less than twice the aggre-gate areas of the inlet connections of the attached safety or safety relief valves. The holes in such collecting pipes shall be at least 1/4 in. (6 mm) in diameter and the least dimension in any other form of opening for inlet of steam shall be 1/4 in. (6 mm). If safety or safety relief valves are attached to a separate steam drum or dome, the opening be-tween the boiler proper and the steam drum or dome shall be not less than ten times the total area of the safety valve inlet.

b. Every safety or safety relief valve shall be connected so as to stand in an upright position with spindle vertical.

c. The opening or connection between the boiler and the safety or safety relief valve shall have at least the area of the valve inlet. No valve of any descrip-tion may be placed between the safety or safety relief valves and the boiler, nor on the discharge pipe between the safety or safety relief valves and the atmosphere. When a discharge pipe is used, the cross-sectional area shall not be less than the full area of the valve outlet or of the total of the areas of the valve outlets, discharging thereinto and shall be as short and straight as possible and arranged to avoid undue stresses on the valve or valves.

d. When two or more safety valves are used on a boiler, they may be mounted either separately or as twin valves made by placing individual valves on Y-bases, or duplex valves having two valves in the same body casing. Twin valves made

by placing individual valves on Y-bases or duplex valves having two valves in the same body shall be of equal size.

e. When two valves of different sizes are mounted singly, the relieving capacity of the smaller valve shall not be less than 50% of that of the larger valve.

f. When a boiler is fitted with two or more safety relief valves on one connection, this connection to the boiler shall have a cross-sectional area not less than the combined areas of inlet connections of all the safety relief valves with which it connects.

g. All safety or safety relief valves shall be piped to a safe point of discharge so located or piped as to be carried clear from running boards or platforms. Ample provision for gravity drain shall be made in the discharge pipe at or near each safety or safety relief valve, and where water or condensation may collect. Each valve shall have an open gravity drain through the casing below the level of the valve seat. For iron- and steel- bodied valves exceeding NPS 2 (DN 50), the drain hole shall be tapped not less than NPS 3/8 (DN 10).

h. Discharge piping from safety relief valves on high temperature water boil-ers shall have adequate provisions for water drainage as well as steam vent-ing.

i. If a muffler is used on a safety or safety relief valve, it shall have sufficient out-let area to prevent back pressure from interfering with the proper operation and discharge capacity of the valve. The muffler plates or other devices shall be so constructed as to avoid a possibility of restriction of the steam passages due to deposits. Mufflers shall not be used on high temperature water boiler safety relief valves.


396

I-2900 TESTING AND ACCEPTANCE

I-2910 GENERAL

a. Care shall be exercised during instal-lation to prevent loose weld material, welding rods, small tools and miscella-neous scrap metal from getting into the boiler. Where possible, an inspection of the interior of the boiler and its appurte-nances shall be made for the presence of foreign debris prior to making the final closure.

b. The Inspector shall inspect for safe operation all boilers and connected appurtenances and all pressure piping connecting them to the appurtenances and all piping up to and including the first stop valve, or the second stop valve when two are required.

c. The wall thickness of all pipe connec-tions shall comply with the require-ments of the code of construction for the boiler.

d. All threaded pipe connections shall engage at least five full threads of the pipe or fitting.

e. In bolted connections, the bolts, studs and nuts shall be marked as required by the original code of construction and be fully engaged (i.e., the end of the bolt or stud shall protrude through the nut).

f. Washers shall only be used when speci-fied by the manufacturer of the part being installed.

I-2920 PRESSURE TEST

Prior to initial operation, the completed boiler, including pressure piping, water columns, super heaters, economizers, stop valves, etc., shall be pressure tested in ac-cordance with the original code of construc-tion. Any pressure piping and fittings such as water column, blowoff valve, feedwater regulator, super heater, economizer, stop valves, etc., which are shipped connected to the boiler as a unit, shall be hydrostatically tested with the boiler and witnessed by an Inspector.

I-2930 NONDESTRUCTIVE EXAMINATION

Boiler components and subcomponents shall be nondestructively examined as required by the governing code of construction.

I-2940 SYSTEMS TESTING

Prior to final acceptance, an operational test shall be performed on the complete instal-lation. The test data shall be recorded and the data made available to the jurisdictional authorities as evidence that the installation complies with the provisions of the govern-ing code(s) of construction. This operational test may be used as the final acceptance of the unit.

I-2950 FINAL ACCEPTANCE

A boiler may not be placed into service until its installation has been inspected and accepted by the appropriate jurisdictional authorities.


397

I-2960 BOILER INSTALLATION REPORT

a. Upon completion, inspection and ac-ceptance of the installation, the installer shall complete and certify the Boiler Installation Report (Report I-1).

b. The I-1 Boiler Installation report shall be submitted as follows:

1. One copy to the owner

2. One copy to the jurisdiction, if required.

I-3000 HEATING BOILERS AND POTABLE WATER HEATERS

I-3100 INTRODUCTION

I-3110 SCOPE

The scope of this section shall apply to those steam boilers, hot water boilers, and potable water heaters as defined in I-3120. For in-stallation of items that do not fall within the scope of this section, refer to the following as applicable:

I-2000 Power BoilersI-4000 Pressure VesselsI-5000 Piping (ASME B31 Series)

I-3120 DEFINITIONS

I-3121 STEAM HEATING BOILERS

Steam heating boilers are steam boilers in-stalled to operate at pressures not exceeding 15 psi (100 kPa).

I-3122 HOT WATER HEATING

AND HOT WATER SUPPLY BOILERS

Hot water heating and hot water supply boilers are hot water boilers installed to operate at pressures not exceeding 160 psi (1100 kPa) and/or temperatures not ex-ceeding 250°F (120°C), at or near the boiler outlet.

I-3123 POTABLE WATER HEATERS

a. Potable water heaters are corrosion re-sistant water heaters supplying potable hot water at pressures not exceeding 160 psi (1100 kPa) and temperatures not in excess of 210°F (100°C).

b. Water heaters are exempted from I-3000 when none of the following limitations is exceeded:

1. Heat input of 200,000 Btu/hr (60 kW/hr)

2. Water temperature of 210°F (100°C)

3. Nominal water containing capacity of 120 gallons (454 l), except that they shall be equipped with safety devices in accordance with the re-quirements of I-3837.



The owner is responsible for satisfying ju-risdictional requirements for certification and documentation. When required by


398

jurisdictional rules applicable to the loca-tion of installation, the boiler shall not be operated until the required documentation has been provided to the owner and the jurisdiction.


All boilers shall have documented certifica-tion from the manufacturer indicating that the boiler complies with the requirements of the code of construction. The certifica-tion shall identify the revision level of the code of construction to which the boiler was fabricated.


a. The owner shall determine jurisdictional requirements (i.e., certificates, permits, licenses, etc.) before installing the equip-ment. The organization responsible for installation shall obtain all permits required by the jurisdiction prior to commencing installation.

b. The owner shall determine jurisdic-tional requirements (i.e., certificates, permits, licenses, etc.) before operating the equipment. The owner shall obtain operating certificates, permits, etc. re-quired by the jurisdiction prior to com-mencing operation.

I-3240 INSPECTION

All boilers shall be inspected after installa-tion and prior to commencing operation.


I-3310 SUPPORTS

Each heating boiler shall be supported by

masonry and/or structural supports of sufficient strength and rigidity to safely support the heating boiler and its contents without vibration in the heating boiler or its connecting piping and to allow for expan-sion and contraction.

I-3311 METHODS OF SUPPORT FOR STEAM HEATING, HOT WATER HEATING AND HOT WATER SUPPLY BOILERS

a. Loadings

1. The design and attachment of lugs, hangers, saddles, and other supports shall take into account the stresses due to hydrostatic head of fully flooded equipment in determining the minimum thicknesses required. Additional stresses imposed by ef-fects other than working pressure or static head which increase the aver-age stress by more than 10% of the allowable working stress shall also be taken into account. These effects include the weight of the component and its contents, and the method of support.

2. In applying the requirements of (1) above, provision shall be made for localized stresses due to concen-trated support loads, temperature changes, and restraint against move-ment of the boiler due to pressure. Lugs, hangers, brackets, saddles, and pads shall conform satisfac-torily to the shape of the shell or surface to which they are attached or are in contact.

b. Horizontal Return Firetube Boilers

1. Boilers over 72 in. (1800 mm) in diameter A horizontal-return tubular boiler

over 72 in. (1800 mm) in diameter


399

shall be supported from steel hang-ers by the outside-suspension type of setting, independent of the fur-nace wall. The hangers shall be so designed that the load is properly distributed.

2. Boilers over 54 in. (1350 mm) up to 72 in. (1800 mm) in diameter

A horizontal-return tubular boiler over 54 in. (1330 mm) and up to and including 72 in. (1800 mm) in diameter shall be supported by the outside-suspension type of setting, or at four points by not less than

eight steel brackets set in pairs, the brackets of each pair to be spaced not over 2 in. (5 cm) apart and the load to be equalized between them. See Fig. I-3311A.

3. Boilers up to 54 in. (1350 mm) in diameter A horizontal-return boiler up to and

including 54 in. (137 cm) in diameter shall be supported by the outside-suspension type of setting, or by not less than two steel brackets on each side.

FIGURE I-3311A — Spacing and weld details for supporting lugs in pairs on hori-zontal-return tubular boiler

FIGURE I-3311B — Welded bracket connection for horizontal-return tubular boiler

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400

c. Supporting Members If the boiler is supported by structural

steel work, the steel supporting mem-bers shall be so located or insulated that the heat from the furnace will not impair their strength.

d. Lugs or Hangers Lugs, hangers, or brackets made of ma-

terials in accordance with the require-ments of the code of construction may be attached by fusion welding provided they are attached by fi llet welds along the entire periphery or contact edges. Figure I-3311B illustrates an accept-able design of hanger bracket with the additional requirement that the center pin be located at the vertical center line over the center of the welded contact surface. The bracket plates shall be spaced at least 2-1/2 in. (64 mm) apart, but this dimension shall be increased if necessary to permit access for the weld-ing operation. The stresses computed by dividing the total load on each lug, hanger, or bracket, by the minimum cross-sectional area of the weld shall not exceed 2800 psi (19 MPa). Where it is impractical to attach lugs, hang-ers, or brackets by welding, studs with not less than 10 threads/in. (approx. 4 threads/cm) may be used. In computing the shearing stresses, the root area at the bottom of the thread shall be used. The shearing and crushing stresses on studs shall not exceed that permitted by the code of construction.

I-3320 SETTINGS

Steam heating, hot water heating and hot water supply boilers of wrought materials of the wet-bottom type having an external width of over 36 in. (900 mm) shall be sup-ported so as to have a minimum clearance of 12 in. (300 mm) between the bottom of the boiler and the fl oor to facilitate inspec-tion. When the width is 36 in. (900 mm) or

less, the clearance between the bottom of the boiler and the fl oor line shall be not less than 6 in. (150 mm), except when any part of the wet bottom is not farther from the outer edge than 12 in. (300 mm), this clearance shall be not less than 4 in. (100 mm). Boiler insulation, saddles, or other supports shall be arranged so that inspection openings are readily accessible.

I-3330 STRUCTURAL STEEL

a. If the boiler is supported by structural steel work, the steel supporting mem-bers shall be so located or insulated that the heat from the furnace will not affect their strength.

b. Structural steel shall be installed in accordance with jurisdictional require-ments, manufacturer’s recommenda-tions, and/or industry standards as appropriate.

I-3340 CLEARANCES

a. Heating boilers shall have a minimum distance of at least 36 in. (900 mm) between the top of the heating boiler and any overhead structure and at least 36 in. (900 mm) between all sides of the heating boiler and adjacent walls, structures, or other equipment. Heat-ing boilers having manholes shall have at least 60 in. (150 mm) of clearance between the manhole opening and any wall, ceiling, piping, or other equipment that may prevent a person from entering the heating boiler. Alternative clearance in accordance with the manufacturer’s recommendations are subject to accep-tance by the jurisdiction.

b. Modular heating boilers that require individual units to be set side by side, front to back or by stacking shall pro-vide clearances in accordance with the


401

manufacturer’s recommendations, sub-ject to acceptance by the jurisdiction.

c. Heating boilers shall be located so that adequate space is provided for proper operation, maintenance17, and inspec-tion of equipment and appurtenances.

I-3350 BOILER ROOM REQUIREMENTS

I-3351 EXIT AND EGRESS

Two means of exit shall be provided for boiler rooms exceeding 500 sq. ft. (46 sq. m) of floor area and containing one or more boilers having a fuel capacity of 1,000,000 Btu/hr. (293 kW/hr.) or more (or equivalent electrical heat input). Each elevation shall be provided with at least two means of egress, each to be remotely located from the other. A platform at the top of a single boiler is not considered an elevation.

I-3352 LADDERS AND RUNWAYS

a. All walkways, runways, and platforms shall:

1. Be of metal construction

2. Be provided between or over the top of boilers which are more than 8 ft. (2.8 m.) high from the operat-ing floor to afford accessibility for the operation and servicing of the boilers

3. Be constructed of safety treads, stan-dard grating, or similar material and have a minimum width of 30 in. (775 mm)

4. Be of bolted, welded, or riveted construction

5. Be equipped with handrails 42 in. (107 cm) high with an intermediate rail and 4 in. (10 cm) toeboard.

b. Stairways which serve as a means of ac-cess to walkways, runways, or platforms shall not exceed an angle of 45 degrees from the horizontal and be equipped with handrails 42 in. (1000 mm) high with an intermediate grid.

c. Ladders which serve as a means of ac-cess to walkways, runways, or platforms shall:

1. Be of metal construction and not less than 18 in. (450 mm) wide

2. Have rungs that extend through the side members and are permanently secured

3. Have a clearance of not less than 30 in. (775 mm) from the front of rungs to the nearest permanent object on the climbing side of the ladder

4. Have a clearance of not less than 6-1/2 in. (170 mm) from the back of rungs to the nearest permanent object

5. Have a clearance width of at least 15 in. (400 mm) from the center of the ladder on either side across the front of the ladder.

d. There shall be at least two permanently installed means of egress from walk-ways, runways, or platforms that exceed 6 ft (1800 mm) in length

I-3353 VENTILATION AND COMBUSTION AIR

The boiler room shall have an adequate air supply to permit clean, safe combustion,

17 Maintenance – This includes the removal of tubes.


402

minimize soot formation and maintain a minimum of 19.5% oxygen in the air of the boiler room. The combustion and ventilation air may be supplied by either an unobstructed air opening or by power ventilators or fans.

a. Unobstructed air openings shall be sized on the basis of 1 sq. in. (6.5 sq. cm) free area per 2000 Btu/hr. (586 W/hr.) maximum fuel input of the combined burners located in the boiler room, or as specified in the National Fire Protec-tion Association (NFPA) standards for oil and gas burning installations for the particular job conditions. The boiler room air supply openings shall be kept clear at all times.

b. Power ventilators or fans shall be sized on the basis of 0.2 cfm (.0057 cm/m.) for each 1,000 Btu/hr. (293 W/hr.) of maximum fuel input for the combined burners of all boilers and/or water heat-ers located in the boiler room.

c. When power ventilators or fans are used to supply combustion air, they shall be installed with interlock devices so that the burners will not operate without an adequate number of ventilators/fans in operation.

d. When combustion air is supplied to the heating boiler by an independent duct, with or without the employment of power ventilators or fans, the duct shall be sized and installed in accordance with the manufacturer’s recommenda-tions. However, ventilation for the boiler room must still be considered.

I-3354 LIGHTING

The boiler room should be well lighted and it should have an emergency light source for use in case of power failure.

I-3355 EMERGENCY VALVES AND CONTROLS

All emergency shut-off valves and controls shall be accessible from a floor, platform, walkway or runway. Accessibility shall mean within a six foot elevation of the standing space and not more than 12 in. (300 mm) horizontally from the standing space edge.

I-3400 SOURCE REQUIREMENTS

I-3410 WATER

a. A means to add water to or fill the boiler, while not under pressure, shall be pro-vided. A valve or threaded plug may be used to shut off the fill connection when the boiler is in service.

b. Water fill connections shall be installed and provisions should be made to pre-vent boiler water from back-feeding into the service water supply.

c. Provision should also be made in ev-ery boiler room for a convenient water supply which can be used to flush out the boiler and to clean the boiler room floor.

I-3420 FUEL

Fuel systems, whether coal, oil, gas or other substance shall be installed in accordance with jurisdictional and environmental requirements, manufacturer’s recommen-dations and/or industry standards, as ap-plicable.

I-3430 ELECTRICAL

a. All wiring for controls, heat generating apparatus, and other appurtenances necessary for the operation of the boiler


403

or boilers shall be installed in accordance with the provisions of national or inter-national standards and comply with the applicable local electrical codes.

b. A manually operated remote shutdown switch or circuit breaker should be lo-cated just outside the boiler room door and marked for easy identification. Consideration should also be given to the type and location of the switch to safeguard against tampering. If the boiler room door is on the building ex-terior the switch should be located just inside the door. If there is more than one door to the boiler room, there should be a switch located at each door.

1. For atmospheric-gas burners, and oil burners where a fan is on a common shaft with the oil pump, the com-plete burner and controls should be shut off.

2. For power burners with detached auxiliaries, only the fuel input sup-ply to the firebox need be shut off.

c. Controls and Heat Generating Appara-tus

1. Oil and gas-fired and electrically heated boilers and water heaters shall be equipped with suitable primary (flame safeguard) safety controls, safety limit switches, and burners or electric elements as required by a nationally or interna-tionally recognized standard.

2. The symbol of the certifying organi-zation18 which has investigated such equipment as having complied with a nationally recognized standard shall be affixed to the equipment

and shall be considered as evidence that the unit was manufactured in accordance with that standard.

3. These devices shall be installed in accordance with jurisdictional and environmental requirements, manu-facturer’s recommendations and/or industry standards as applicable.

I-3500 DISCHARGE REQUIREMENTS

I-3510 CHIMNEY OR STACK

Chimneys or stacks shall be installed in accordance with jurisdictional and envi-ronmental requirements, manufacturer’s recommendations and/or industry stan-dards, as applicable.

I-3520 ASH REMOVAL

Ash removal systems shall be installed in accordance with jurisdictional and envi-ronmental requirements, manufacturer’s recommendations and/or industry stan-dards, as applicable.

I-3530 DRAINS

Unobstructed floor drains, properly located in the boiler room, will facilitate proper cleaning of the boiler room. Floor drains which are used infrequently should have water poured into them periodically to pre-vent the entrance of sewer gasses and odors. If there is a possibility of freezing, an envi-ronmentally safe antifreeze mixture should be used in the drain traps. Drains receiving blowdown water should be connected to

18 Organization – A certifying organization is one that provides uniform testing, examination, and listing procedures under established, nationally recognized standards, and that is acceptable to the authorities having jurisdiction.


404

the sanitary sewer by way of an acceptable blowdown tank or separator or an air gap which will allow the blowdown water to cool to at least 140°F (60°C) and reduce the pressure to 5 psig (35 kPa) or less.

I-3600 OPERATING SYSTEMS

I-3610 OIL HEATERS

a. A heater for oil or other liquid harmful to boiler operation shall not be installed directly in the steam or water space within a boiler.

b. Where an external-type heater for such service is used, means shall be provided to prevent the introduction into the boiler of oil or other liquid harmful to boiler operation.

I-3620 BREECHING AND DAMPERS

Breeching and dampers shall be installed in accordance with jurisdictional and en-vironmental requirements, manufacturer’s recommendations and/or industry stan-dards, as applicable.

I-3630 BURNERS AND STOKERS

Burners and stokers shall be installed in accordance with jurisdictional and envi-ronmental requirements, manufacturer’s recommendations and/or industry stan-dards, as applicable.

I-3640 FEEDWATER, MAKEUP WATER, AND WATER SUPPLY

a. Steam Boilers Feedwater or water treatment shall be

introduced into a boiler through the

return piping system. Alternatively, feedwater or water treatment may be introduced through an independent connection. The water flow from the independent connection shall not dis-charge directly against parts of the boiler exposed to direct radiant heat from the fire. Feedwater or water treatment shall not be introduced through openings or connections provided for inspection or cleaning, safety valve, water column, water gage glass, or pressure gage. The feedwater pipe shall be provided with a check valve near the boiler and a stop valve or cock between the check valve and the boiler or between the check valve and the return pipe system.

b. Hot Water Boilers Makeup water may be introduced into

a boiler through the piping system or through an independent connection. The water flow from the independent connection shall not discharge directly against parts of the boiler exposed to di-rect radiant heat from the fire. Makeup water shall not be introduced through openings or connections provided exclusively for inspection or cleaning, safety relief valve, pressure gage, or temperature gage. The makeup water pipe shall be provided with a check valve near the boiler and a stop valve or cock between the check valve and the boiler or between the check valve and the piping system.

c. Potable Water Heaters

1. Water supply shall be introduced into a water heater through an in-dependent water supply connection. Feedwater shall not be introduced through openings or connections provided for cleaning, safety relief valves, drain, pressure gage, or temperature gage.


405

2. If the water supply pressure to a water heater exceeds 75% of the set pressure of the safety relief valve, a pressure reducing valve is re-quired.

I-3650 STOP VALVES

I-3651 STEAM HEATING, HOT WATER HEATING AND HOT WATER SUPPLY BOILERS

a. For Single Installations Stop valves shall be located at an ac-

cessible point in the supply and return pipe connections, as near the boiler as is convenient and practicable.

b. For Multiple Boiler Installations A stop valve shall be used in each sup-

ply and return pipe connection of two or more boilers connected to a common system. See Figures I-3651A, I-3651B, and I-3651C.

c. Type of Stop Valve(s)

1. All valves or cocks shall conform with the applicable portions of an acceptable code of construction and may be ferrous or nonferrous.

2. The minimum pressure rating of all valves or cocks shall be at least equal to the pressure stamped upon the boiler, and the temperature rating of such valves or cocks, including all internal components, shall be not less than 250°F (120°C).

3. Valves or cocks shall be flanged, threaded or have ends suitable for welding or brazing.

4. All valves or cocks with stems or spindles shall have adjustable pres-sure-type packing glands and, in

addition, all plug-type cocks shall be equipped with a guard or gland. The plug or other operating mechanism shall be distinctly marked in line with the passage to indicate whether it is opened or closed.

5. All valves or cocks shall have tight closure when under boiler hydro-static test pressure.


Stop valves shall be installed in the supply and discharge pipe connections of a water heater installation to permit draining the water heater without emptying the sys-tem.

I-3660 RETURN PIPE CONNECTIONS

a. The return pipe connections of each boiler supplying a gravity return steam heating system shall be so arranged as to form a loop substantially as shown in Figure I-3651B so that the water in each boiler cannot be forced out below the safe water level.

b. For hand-fi red boilers with a normal grate line, the recommended pipe sizes detailed as “A” in Fig. I-3651A and Fig. I-3651A and Fig. I-3651AI-3651B are NPS 1-1/2 (DN 40) for 4 sq. ft. (0.37 sq. m.) or less fi rebox area at the normal grate line, NPS 2-1/2 (DN 65) for areas more than 4 sq. ft. (0.37 sq m) up to 14.9 sq. ft. (1.38 sq. m.), and NPS 4 (DN 100) for 15 sq. ft. (1.39 sq. m.) or more.

c. For automatically fi red boilers which do not have a normal grate line, the recom-mended pipe sizes detailed as “A” in Figures I-3651A and Figures I-3651A and Figures I-3651A I-3651B are NPS 1-1/2 (DN 40) for boilers with minimum required safety valve relieving capacity 250 lb./hr. (113 kg./hr.) or less, NPS 2-


406

General Note:Return connections shown for a multiple boiler installation may not alwaysinsure that the system will operate properly. In order to maintain proper water levels in multipleinsure that the system will operate properly. In order to maintain proper water levels in multipleinsure that the system will operate properlyboiler installations, it may be necessary to install supplementary controls or suitable devices.

Note:(1) Recommended for 1 in. and larger safety valve discharge.

From receiver tank

Solenoidvalve

Check valve

Stop valve

Stop valve

Check valveBlowoffvalve/drain

Blowoffvalve/drain

From receiver tank

Solenoidvalve

Single ReturnShown

To receivertank

Safety valvedischarge piping(with union)


To receivertank

F & T traphigh level“spill”

F & T traphigh level“spill”

Multiple ReturnsShown

Safetyvalve

Safetyvalve

Low-waterfuel cutoff

Pump controland gage glass

Pressurecontrols

Steam gageHeatingsupply

Stop valve

Pressurecontrols

Steam gage

Low-water fuelcutoff pump controland gage glass

Steam main

Stop valve

Drippanelbow

Alternativesafety valvedischargepiping[Note (1)]

“A”

FIGURE I-3651-a — Steam boilers in battery – pumped return – acceptable piping installation

1/2 (DN 65) for boilers with minimum required safety valve relieving capacity from 251 lb./hr. (114 kg./hr.) to 2000 lb./hr. (987 kg./hr.), inclusive, and NPS 4 (DN 100) for boilers with more than 2000 lb./hr. (987 kg./hr.) minimum required safety valve relieving capacity.

d. Provision shall be made for cleaning the interior of the return piping at or close to the boiler. Washout openings may be used for return pipe connections and the washout plug placed in a tee or a cross so that the plug is directly opposite and as close as possible to the opening in the boiler.

I-3670 BOTTOM BLOWOFF AND DRAIN VALVES

I-3671 STEAM HEATING, HOT WATER HEATING AND HOT WATER SUPPLY BOILERS

a. Bottom Blowoffs Each steam boiler shall have a bottom

blowoff connection fi tted with a valve or cock connected to the lowest water space practicable with a minimum size as shown in Table I-3671A. The dis-


407

FIGURE I-3651-b — Steam boilers in battery – gravity return – acceptable piping installation

charge piping shall be full size to the point of discharge.

b. Boilers having a capacity of 25 gallons (95 l) or less are exempt from the above requirements, except that they shall have a NPS 3/4 (DN 20) minimum drain valve.

c. Drains Each steam or hot-water boiler shall

have one or more drain connections, fitted with valves or cocks connecting

to the lowest water containing spaces. All parts of the boiler must be capable of being drained (the boiler design will dictate the number and size of drains). The minimum size of the drain piping, valves, and cocks shall be NPS 3/4 (DN 20). The discharge piping shall be full size to the point of discharge.

When the blowoff connection is located at the lowest water containing space, a separate drain connection is not re-quired.

General Note:Return connections shown for a multiple boiler installation may not alwaysinsure that the system will operate properly. In order to maintain proper water levels in multipleboiler installations, it may be necessary to install supplementary controls or suitable devices.

Note:(1) Recommended for 1 in. and larger safety valve discharge.

Check valve

Stop valve

Stop valve

Blowoffvalve/drain

Blowoffvalve/drain

Single ReturnShown



F & T trap

Multiple ReturnsShown

Safetyvalve

Safetyvalve

Low-waterfuel cutoff

Water columnand gage glass

Pressurecontrols

Steam gage

HeatingsupplyStop valve

Pressurecontrols

Steam gage

Low-water fuelcutoff andgage glass

Steam main

Stop valve

Drippanelbow

Alternativesatety valvedischargepiping[Note (1)]

“A”

Heating return

Check valve

Return loopconnection

LowestPermissiblewaterline

Toreturnheader


408

FIGURE I-3651-c — Hot-water boilers in battery – acceptable piping installation

d. Minimum Pressure Rating The minimum pressure rating of valves

and cocks used for blowoff or drain purposes shall be at least equal to the pressure stamped on the boiler but in no case less than 30 psi (200 kPa). The tem-perature rating of such valves and cocks shall not be less than 250°F (120°C).


a. Drain Valve

1. Each water heater shall have a bot-tom drain pipe connection fitted with a valve or cock connected with the lowest water space practicable. The minimum size bottom valve shall be NPS 3/4 (DN 20).

Alternate expansiontank with diaphragm(required on eachboiler)

General Notes:(1) Recommended control. See HG-614. Acceptable shutoff valves or cocks in the connecting piping may be installedfor convenience of control testing and/or service.(2) The common return header stop valves may be located on either side of the check valves.

Alternate make-upwater arrangement

Pressurereducingvalve

Drain valve

Stopvalve (2)

Air vent

Checkvalve

Heatingreturn

Drainvalve

Checkvalve

Stopvalve (2)

Stopvalve

Stopvalve

Safetyreliefvalve

Safety relief valvedischarge piping(with union)

Internallow-waterfuel cut-off(alternatearrangement)

Maximumtemperaturelimit control

Temperaturepressure gage

High limitcontrol

Safety relief valvedischagre piping(with union)

Safetyreliefvalve

PressurereducingvalveMake-up

water

Expansiontank

High limitcontrol

Maximumtemperaturelimit control

Temperaturepressure gage

External low-waterfuel cut-off (1)

Preferred location ofcirculating pump

Heatingsupply


409

FIGURE I-3651-d — A typical acceptable piping installation for storage water heat-ers in battery

Note:(1) Recirculation system may be gravity or pump actuated.

Water Heater with TopRelief Opening

Water Heater with SideRelief Opening

PressureReducing Valveif Required

Expansion Tankif Required Drain Valve with

Suitable Drain

Water Heaterwith VerticalTop SafetyRelief Opening

To Open Drain

Point of Use

To Open Drain

Water Heaterwith SideSafety ReliefOpening & within4 in. of the topof the shell

Drain Valve

Cold Water Supply

Drain Valve

OpticalRecirculation Line[Note (1)]

FIGURE I-3651-e — A typical acceptable piping installation for flow through water heater with provisions for piping expansion

Opticalrecirculationline

Drain valve

Flow switch onflow throughwater heater


410

TABLE I-3671A — Size of Bottom Blow-off Piping, Valves and Cocks

Minimum Required Blowoff Piping, ValvesSafety Valve and Cocks Size,Capacity, lb of in. (mm) (min.)steam/hr (Note 1)

up to 500 3/4 (19)501 to 1,250 1 (25)1,251 to 2,500 1-1/4 (32)2,501 to 6,000 1-1/2 (38)6,001 and larger 2 (50)

Note 1: To determine the discharge capacity of safety relief valves in terms of Btu, the relieving capacity in lb of steam/hr is multiplied by 1,000.

TABLE I-3651.2 — Expansion Tank Capacities for a Water Heater (Note 1)

Tank Capacities, gal System Prepressurized NonpressurizedVolume, Diaphragm Type Typegal (l)

50 (190) 1 3100 (380) 2 6200 (760) 3 12300 (1150) 4 18400 (1520) 5 24500 (1900) 6 301,000 (3800) 12 602,000 (7600) 24 120

Note 1: Capacities in this table are given as a guide to reduce or eliminate relief valve weeping under conditions of partial water system demands or oc-casional water draw during recovery.

System volume includes water heater capacity plus all piping capacity for a recirculation system or water heater capacity only for a nonrecirculation system.

The capacities are based upon a water temperature rise from 40°F to 180°F (4°C to 80°C), 60 psi fill pres-sure, maximum operating pressure of 125 psi, 20% water recovery, and an acceptance factor of 0.465 for prepressurized types and 0.09156 for nonpre-pres-surized types. A procedure for estimating tank sizes for other design conditions may be found in Chapter 12 of the 1996 HVAC Systems and Equip-ment volume of the ASHRAE Handbook.

2. Any discharge piping connected to the bottom drain connection shall be full size to the point of discharge.

I-3680 MODULAR STEAM HEATING AND HOT WATER HEATING BOILERS

I-3681 INDIVIDUAL MODULES

a. The individual modules shall comply with all the requirements of the code of construction and this paragraph. The individual modules shall be limited to a

maximum input of 400,000 Btu/hr. (gas) (117 kW/hr.), 3 gal./hr. (oil) (11.4 l/hr.), or 117 kW (electricity).

b. Each module of a modular steam heat-ing boiler shall be equipped with:

1. Safety valve, see I-3810

2. Blowoff valve, see I-3671(a)

3. Drain valve, see I-3671(c).

c. Each module of a modular hot water heating boiler shall be equipped with:

1. Safety relief valve, see I-3820

2. Drain valve, see I-3671(c).

I-3682 ASSEMBLED MODULAR BOILERS

a. The individual modules shall be mani-folded together at the job-site without any intervening valves.

b. The assembled modular steam heating boiler shall also be equipped with:

1. Feedwater connection, see I-3640

2. Return pipe connection, see I-3660.


411

c. The assembled modular hot water boiler shall also be equipped with:

1. Makeup water connection, see I-3640

2. Provision for thermal expansion, see I-3690

3. Stop valves, see I-3651(a) (treating the assembled modular boiler as a single unit).

I-3690 PROVISIONS FOR THERMAL EXPANSION IN HEATING BOILERS

I-3691 EXPANSION TANKS AND PIPING FOR STEAM HEATING, HOT-WATER HEATING AND HOT- WATER SUPPLY BOILERS

a. Expansion Tanks for Hot-Water Heating and Hot-Water Supply Boilers

All hot-water heating systems incor-porating hot-water tanks or fl uid relief columns shall be so installed as to pre-vent freezing under normal operating conditions.

1. Heating Systems With Open Expansion Tank

An indoor overfl ow from the upper portion of the expansion tank shall be provided in addition to an open vent, the indoor overfl ow shall be carried within the building to a suit-able plumbing fi xture or drain.

2. Closed Heating Systems An expansion tank shall be installed

that will be consistent with the vol-ume and capacity of the system. If the system is designed for a working pressure of 30 psi (200 kPa) or less, the tank shall be suitably designed for a minimum hydrostatic test

pressure of 75 psi (525 kPa). Expan-sion tanks for systems designed to operate above 30 psi (200 kPa) shall be constructed in accordance with an acceptable code of construction. Provisions shall be made for drain-ing the tank without emptying the system, except for prepressurized tanks. The minimum capacity of the closed type expansion tank may be determined from Tables I-3691A and I-3691B or from the following formula where the necessary infor-mation is available:

Vt = [(0.00041T-0.0466)Vs]/ [(Pa/Pf) - (Pa/Po)] where,

Vt = minimum volume of tanks, gallons (l)

Vs = volume of system, not including tanks, gallons (l) T = average operating temperature, °F (°C) Pa = atmospheric pressure, psia (kPa) Pf = fi ll pressure, psia (kPa)f = fi ll pressure, psia (kPa)f Po = maximum operating pressure, psia (kPa)

3. Hot-Water Supply Systems If a system is equipped with a check

valve or pressure reducing valve in the cold water inlet line, consider-ation should be given to the instal-lation of an airtight expansion tank or other suitable air cushion. Other-wise due to the thermal expansion of the water, the safety relief valve may lift periodically. If an expansion tank is provided, it shall be constructed in accordance with an acceptable code of construction. Except for pre-pressurized tanks, which should be installed on the cold water side, provisions shall be made for drain-ing the tank without emptying the system. See Fig. I-3651D for a typical acceptable installation.


412

TABLE I-3691A — Expansion Tank Ca-pacities for Gravity Hot Water Systems(Based on two-pipe system with average operat-ing water temperature 170°F (77°C), using case iron column radiation with heat emission rate 150 Btu/hr sq. ft. (44 W/hr sq. 0.3 m) equivalent direction radiation.)

Installed Equivalent Tank Capacity,Direct Radiation, sq. ft. gallon(Note 1)

up to 350 18up to 450 21up to 650 24up to 900 30up to 1,100 35up to 1,400 40up to 1,600 2- 30up to 1,800 2- 30up to 2,000 2- 35up to 2,400 2- 40

Note 1: For systems with more than 2,400 sq. ft. of installed equivalent direct water radiation, the required capacity of the cushion tank shall be in-creased on the basis of 1 gal tank capacity/33 sq. ft. of additional equivalent direct radiation.

b. Piping for Steam Heating, Hot-Water Heating and Hot-Water Supply Boilers

Provisions shall be made for the expan-sion and contraction of steam and hot water mains connected to boiler(s) so there will be no undue strain transmit-ted to the boiler(s). See Figs. I-3651A, I-3651B, and I-3651C for typical schematic arrangements of piping incorporating strain absorbing joints for steam and hot water heating boilers.

I-3692 EXPANSION TANKS AND PIPING FOR POTABLE WATER HEATERS

a. Expansion Tanks If a system is equipped with a check

valve or pressure-reducing valve in the cold water inlet line, consideration should be given to the installation of an airtight expansion tank or other suitable air cushion. Otherwise, due to the ther-mal expansion of the water, the safety relief valve may lift periodically. If an expansion tank is provided, it shall be constructed in accordance with an ac-ceptable code of construction. The mini-mum capacity of the expansion tank may be determined from Table I-3651.2. See Fig. I-3651D for a typical acceptable installation. Except for prepressurized diaphragm type tanks, which should be installed on the cold water side, provi-sions shall be made for draining the tank without emptying the system.

b. Piping Provisions shall be made for the expan-

sion and contraction of hot water mains connected to water heater(s) so that there will be no undue strain transmit-ted to the water heater(s). See Figures

I-3651D and I-3651E for typical schemat-ic arrangements of piping incorporating strain absorbing joints.

I-3700 INSTRUMENTS, FITTINGS, AND CONTROLS

I-3710 STEAM HEATING BOILERS

I-3711 STEAM GAGES

a. Each steam boiler shall have a steam gage or a compound steam gage con-nected to its steam space or to its water column or to its steam connection. The gage or connection shall contain a si-phon or equivalent device which will develop and maintain a water seal that will prevent steam from entering the gage tube. The connection shall be so arranged that the gage cannot be shut off from the boiler except by a cock placed in the pipe at the gage and provided


413

with a tee- or lever- handle arranged to be parallel to the pipe in which it is located when the cock is open. The connections to the boiler shall be not less than NPS 1/4 (DN 8). Where steel or wrought iron pipe or tubing is used, the connection and external siphon shall be not less than NPS 1/2(DN 15). The minimum size of a siphon if used, shall be NPS 1/4 (DN 8). Ferrous and non-ferrous tubing having inside diameters at least equal to that of standard pipe sizes listed above may be substituted for pipe.

b. The scale on the dial of a steam boiler gage shall be graduated to not less than 30 psi (200 kPa) nor more than 60 psi (400 kPa). The travel of the pointer from 0 psi (0 kPa) to 30 psi (200 kPa) pressure shall be at least 3 in. (75 mm).

I-3712 WATER GAGE GLASSES

a. Each steam boiler shall have one or more water gage glasses attached to the water column or boiler by means of valved fittings not less than NPS 1/2 (DN 15), with the lower fitting provided with a drain valve of a type having an unrestricted drain opening not less than NPS 1/4 (DN 8) to facilitate cleaning. Gage glass replacement shall be possible under pressure. Water glass fittings may be attached directly to a boiler. Boilers having an internal vertical height of less than 10 in. (250 mm) may be equipped with a water level indicator of the glass bulls-eye type provided the indicator is of sufficient size to show the water at both normal operating and low-water cutoff levels.

b. The lowest visible part of the water gage glass shall be at least 1 in. (25 mm) above the lowest permissible water level rec-ommended by the boiler manufacturer. With the boiler operating at this lowest permissible water level, there shall be no danger of overheating any part of the boiler.

c. In electric boilers of the submerged elec-trode type, the water gage glass shall be so located to indicate the water levels both at startup and under maximum steam load conditions as established by the manufacturer.

d. In electric boilers of the resistance ele-ment type, the lowest visible part of the water gage shall be located at least 1 in. (25 mm) above the lowest permissible water level specified by the manufactur-er. Each electric boiler of this type shall also be equipped with an automatic low-water cut-off on each boiler pres-sure vessel so located as to automatically cut off the power supply to the heating elements before the surface of the water falls below the visible part of the glass.

TABLE I-3691B — Expansion Tank Ca-pacities for Forced Hot Water Systems (Note 1)(Based on average operating water temperature 195°F [91°C], fill pressure 12 psig [80 kPa], and maximum operating pressure 30 psig [200 kPa])

Tank Capacities, gal (l) System Prepressurized NonpressurizedVolume, Diaphragm Type Typegal (l)

100 (380) 9 (34) 15 (57) 200 (760) 17 (65) 30 (114) 300 (1150) 25 (95) 45 (170) 400 (1500) 33 (125) 60 (230) 500 (1900) 42 (160) 75 (285) 1000 (3800) 83 (315) 150 (570) 2000 (7600) 165 (625) 300 (1150)

Note 1: System volume includes volume of water in boiler, radiation, and piping, not including the expansion tank. Expansion tank capacities are based on an acceptance factor of 0.4027 for pre-pressurized types and 0.222 for nonpressurized types. A procedure for estimating systemvolume and determining expansion tank sized for other design conditions may be found in Chapter 12 of the 1996 HVAC Systems and Equipment Volume of the ASHRAE Handbook.


414

e. Tubular water glasses on electric boil-ers having a normal water content not exceeding 100 gallons (380 l) shall be equipped with a protective shield.

NOTE: Transparent material other than glass may be used for the water gage provided that the material will remain transparent and has proved suitable for the pressure, temperature, and corrosive conditions expected in service.

I-3713 WATER COLUMN AND WATER LEVEL CONTROL PIPES

a. The minimum size of ferrous or nonfer-rous pipes connecting a water column to a steam boiler shall be NPS 1 (DN 25). No outlet connections, except for damper regulator, feedwater regulator, steam gages, or apparatus which does not permit the escape of any steam or water except for manually operated blowdown, shall be attached to a water column or the piping connecting a water column to a boiler (see I-3640[a]) for in-troduction of feedwater into a boiler). If the water column, gage glass, low-water fuel cut-off, or other water level control device is connected to the boiler by pipe and fittings, no shutoff valves of any type shall be placed in such pipe and a cross or equivalent fitting to which a drain valve and piping may be attached shall be placed in the water piping connection at every right angle turn to facilitate cleaning. The water column drain pipe and valve shall be not less than NPS 3/4 (DN 20).

b. The steam connections to the water column of a horizontal firetube wrought boiler shall be taken from the top of the shell or the upper part of the head, and the water connection shall be taken from a point not above the center line of the

shell. For a cast-iron boiler, the steam connection to the water column shall be taken from the top of an end section or the top of the steam header, and the water connection shall be made on an end section not less than 6 in. (150 mm) below the bottom connection to the water gage glass.

I-3714 PRESSURE CONTROL

Each automatically fired steam boiler shall be protected from overpressure by two pres-sure-operated controls.

a. Each individual automatically fired steam boiler shall have a safety limit control that will cut off the fuel supply to prevent steam pressure from exceeding the 15 psi (100 kPa) maximum allowable working pressure of the boiler. Each control shall be constructed to prevent a pressure setting above 15 psi (100 kPa).

b. Each individual steam boiler or each system of commonly connected steam boilers shall have a control that will cut off the fuel supply when the pressure reaches an operating limit, which shall be less than the maximum allowable pressure.

c. Shutoff valves of any type shall not be placed in the steam pressure connec-tion between the boiler and the controls described in (a) and (b) above. These controls shall be protected with a siphon or equivalent means of maintaining a water seal that will prevent steam from entering the control. The connections to the boiler shall not be less than NPS 1/4 (DN 8), but where steel or wrought iron pipe or tubing is used, they shall not be less than NPS 1/2 (DN 15). The mini-mum size of an external siphon shall be NPS 1/4 (DN 8) or 3/8 in. (10 mm)


415

O.D. nonferrous tubing. For manifold connections, the minimum size shall be as specified in the original code of construction.

I-3715 AUTOMATIC LOW-WATER FUEL CUT-OFF AND/OR WATER FEEDING DEVICE

a. Each automatically fired steam- or vapor-system boiler shall have an au-tomatic low-water fuel cutoff so located as to automatically cut off the fuel sup-ply when the surface of the water falls to the lowest visible part of the water gage glass. If a water feeding device is installed, it shall be so constructed that the water inlet valve cannot feed water into the boiler through the float chamber and so located as to supply requisite feedwater.

b. Such a fuel cutoff or water feeding device may be attached directly to a boiler. A fuel cut-off or water feeding device may also be installed in the tapped openings available for attaching a water glass direct to a boiler, provided the connections are made to the boiler with nonferrous tees or Y’s not less than NPS 1/2 (DN 15) between the boiler and water glass so that the water glass is at-tached directly and as close as possible to the boiler; the run of the tee or Y shall take the water glass fittings, and the side outlet or branch of the tee or Y shall take the fuel cut-off or water feeding device. The ends of all nipples shall be reamed to full-size diameter.

c. Fuel cutoffs and water feeding devices embodying a separate chamber shall have a vertical drain pipe and a blowoff valve not less than NPS 3/4 (DN 20), located at the lowest point in the water equalizing pipe connections so that the chamber and the equalizing pipe can be flushed and the device tested.

I-3716 MODULAR STEAM HEATING BOILERS

a. Each module of a modular steam boiler shall be equipped with:

1. Steam gage, see I-3711

2. Water gage glass, see I-3712

3. Pressure control, see I-3714(a)

4. Low water cutoff, see I-3715.

b. The assembled modular steam heating boiler shall also be equipped with a pressure control. See I-3714(b).

I-3717 INSTRUMENTS, FITTINGS, AND CONTROLS MOUNTED INSIDE BOILER JACKETS

Any or all instruments, fittings, and controls required by these rules may be installed inside of boiler jackets provided the water gage and pressure gage on a steam boiler are visible through an opening or openings at all times.

I-3720 HOT WATER HEATING OR HOT WATER SUPPLY BOILERS

I-3721 PRESSURE OR ALTITUDE GAGES

a. Each hot water heating or hot water supply boiler shall have a pressure or altitude gage connected to it or to its flow connection in such a manner that it cannot be shut off from the boiler ex-cept by a cock with tee or lever handle, placed on the pipe near the gage. The handle of the cock shall be parallel to the pipe in which it is located when the cock is open.


416

b. The scale on the dial of the pressure or altitude gage shall be graduated ap-proximately to not less than 1-1/2 nor more than 3-1/2 times the pressure at which the safety relief valve is set.

c. Piping or tubing for pressure or altitude gage connections shall be of nonferrous metal when smaller than NPS 1 (DN 25).

I-3722 THERMOMETERS

Each hot water heating or hot water sup-ply boiler shall have a thermometer so located and connected that it shall be eas-ily readable. The thermometer shall be so located that it shall at all times indicate the temperature of the water in the boiler at or near the outlet.

I-3723 TEMPERATURE CONTROL

Each automatically fired hot water heating or hot water supply boiler shall be protected from over-temperature by two temperature-operated controls.

a. Each individual automatically fired hot water heating or hot water supply boiler shall have a safety limit control that will cut off the fuel supply to prevent water temperature from exceeding the maximum allowable temperature at the boiler outlet. This water temperature safety control shall be constructed to prevent a temperature setting above the maximum allowable temperature.

b. Each individual hot water heating or hot water supply boiler or each system of commonly connected boilers without intervening valves shall have a control that will cut off the fuel supply when the water temperature reaches an oper-ating limit, which shall be less than the maximum allowable temperature.

I-3724 LOW WATER FUEL CUTOFF

a. Each automatically fired hot water boiler with heat input greater than 400,000 Btu/hr (117 kW/hr.) shall have an au-tomatic low-water fuel cutoff which has been designed for hot water service, and it shall be so located as to automatically cut off the fuel supply when the surface of the water falls to the level established in (b) below.

b. As there is no normal waterline to be maintained in a hot-water boiler, any location of the low-water fuel cut-off above the lowest safe permissible water level established by the boiler manufac-turer is satisfactory.

c. A coil-type boiler or a watertube boiler with heat input greater than 400,000 Btu/hr. (117 kW/hr.) requiring forced circulation to prevent overheating of the coils or tubes shall have a flow-sensing device installed in lieu of the low-water fuel cut-off required in (a) above to au-tomatically cut off the fuel supply when the circulating flow is interrupted.

d. A means shall be provided for testing the operation of the external low-water fuel cutoff without resorting to draining the entire system. Such means shall not render the device inoperable except as follows. If the means temporarily iso-lates the device from the boiler during this testing, it shall automatically return to its normal position. The connection may be so arranged that the device can-not be shut off from the boiler except by a cock placed at the device and provided with a tee or lever-handle arranged to be parallel to the pipe in which it is located when the cock is open.


417

I-3725 MODULAR HOT WATER HEATING BOILERS

a. Each module of a modular hot water heating boiler shall be equipped with:

1. Pressure/altitude gage, see I-3721

2. Thermometer, see I-3722

3. Temperature control, see I-3723(a).

b. The assembled modular hot water heat-ing boiler shall be equipped with:

1. Temperature control, see I-3723(b)

2. Low water fuel cutoff, see I-3724.

I-3726 INSTRUMENTS, FITTINGS, AND CONTROLS MOUNTED INSIDE BOILER JACKETS

Any or all instruments, fittings, and controls required by these rules may be installed in-side of boiler jackets provided the thermom-eter and pressure gage are visible through an opening or openings at all times.


I-3731 TEMPERATURE CONTROLS

Each individual automatically fired water heater, in addition to the operating control used for normal water heater operation shall have a separate high limit temperature actu-ated combustion control that will automati-cally cut off the fuel supply. The temperature range of the high limit temperature actuated control shall not allow a setting over 210°F (100°C).

a. On gas-fired water heaters, the high limit temperature control when actu-

ated shall shut off the fuel supply with a shutoff means other than the operating control valve. Separate valves may have a common body.

b. On electrically heated water heaters, the high limit temperature control when actuated shall cut off all power to the operating controls.

c. On oil-fired water heaters, the high limit temperature control when actuated shall cut off all current flow to the burner mechanism.

d. On indirect water heating systems, the high limit temperature control when ac-tivated shall cut off the source of heat.

I-3732 THERMOMETER

Each installed water heater shall have a thermometer so located and connected that it shall be easily readable. The thermometer shall be so located that it shall at all times indicate the temperature of the water in the water heater at or near the outlet.

I-3800 PRESSURE RELIEVING VALVES

I-3810 SAFETY VALVE REQUIREMENTS FOR STEAM BOILERS

a. Safety valves are to be manufactured in accordance with a national or interna-tional standard.

b. Each steam boiler shall have one or more National Board capacity certified safety valves of the spring pop type adjusted and sealed to discharge at a pressure not to exceed 15 psi (100 kPa).


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c. No safety valve for a steam boiler shall be smaller than NPS 1/2 (DN 15). No safety valve shall be larger than NPS 4-1/2 (DN 115). The inlet opening shall have an inside diameter equal to, or greater than, the seat diameter.

d. The minimum valve capacity in pounds (kilograms) per hour shall be the greater of that determined by dividing the maximum Btu (Watts) output at the boiler nozzle obtained by the firing of any fuel for which the unit is installed by 1000, or shall be determined on the basis of the pounds (kilograms) of steam generated per hour per square foot (square meter) of boiler heating surface as given in Table I-3820. For cast-iron boilers, the minimum valve capacity shall be determined by the maximum output method. In many cases a greater relieving capacity of valves will have to be provided than the minimum speci-fied by these rules. In every case, the requirement of I-3810(e) shall be met.

e. The safety valve capacity for each steam boiler shall be such that with the fuel burning equipment installed, and oper-ated at maximum capacity, the pressure cannot rise more than 5 psi (35 kPa) above the maximum allowable working pressure.

f. When operating conditions are changed, or additional boiler heating surface is installed, the valve capacity shall be increased, if necessary, to meet the new conditions and be in accordance with I-3810(e). The additional valves required, on account of changed conditions, may be installed on the outlet piping pro-vided there is no intervening valve.

I-3820 SAFETY RELIEF VALVE REQUIREMENTS FOR HEATING OR HOT-WATER SUPPLY BOILERS

a. Safety relief valves are to be manufac-tured in accordance with a national or international standard

b. Each hot-water heating or hot-water supply boiler shall have at least one National Board capacity certified safety relief valve, of the automatic reseating type set to relieve at or below the maxi-mum allowable working pressure of the boiler.

c. Hot-water heating or hot-water supply boilers limited to a water temperature not in excess of 210°F (100°C) may have, in lieu of the valve(s) specified in (b) above, one or more National Board capacity certified temperature and pres-sure safety relief valves of the automatic reseating type set to relieve at or below the maximum allowable working pres-sure of the boiler.

d. When more than one safety relief valve is used on either hot-water heating or hot-water supply boilers, the additional valves shall be National Board capacity certified and may have a set pressure within a range not to exceed 6 psi (40 kPa) above the maximum allowable working pressure of the boiler up to and including 60 psi (400 kPa), and 5% for those having a maximum allowable working pressure exceeding 60 psi (400 kPa).

e. No safety relief valve shall be smaller than NPS 3/4 (DN 20) nor larger than NPS 4-1/2 (DN 115) except that boil-ers having a heat input not greater than15,000 Btu/hr. (15.8 4.4 W/hr.) may be equipped with a rated safety relief valve of NPS 1/2 (DN 15).


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minimum specifi ed by these rules. In every case, the requirements of I-3820(h) shall be met.

g. When operating conditions are changed, or additional boiler heating surface is installed, the valve capacity shall be increased, if necessary, to meet the new conditions and shall be in accordance with I-3820(h). The additional valves required, on account of changed con-ditions, may be installed on the outlet piping provided there is no intervening valve.

h. Safety relief valve capacity for each boiler with a single safety relief valve

f. The required steam relieving capacity, in pounds per hour, of the pressure relieving device or devices on a boiler shall be the greater of that determined by dividing the maximum output in Btu (Watts) at the boiler nozzle obtained by the fi ring of any fuel for which the unit is installed by 1,000, or shall be determined on the basis of pounds (ki-lograms) of steam generated per hour per square foot (square meter) of boiler heating surface as given in Table I-3820. For cast-iron boilers, the minimum valve capacity shall be determined by the maximum output method. In many cases a greater relieving capacity of valves will have to be provided than the

TABLE I-3820 — Minimum Pounds of Steam per Hour per Square Foot of Heating Surface

Firetube Boilers Watertube BoilersBoiler heating surfaceHand-fi red 5 (2112) 6 (2534)Stoker-fi red 7 (2956) 8 (3378)Oil-, gas-, or pulverized-fuel-fi red 8 (3378) 10 (4223)

Waterwall heating surfaceHand-fi red 8 (3378) 8 (3378)Stoker-fi red 10 (4223) 12 (5068)Oil-, gas-, or pulverized- fuel-fi red 14 (5912) 16 (6756)

Copper fi nned watertubeshand-fi red 4 (1689) 4 (1689)Stoker-fi red 5 (2112) 5 (2112)Oil-, gas-, or pulverized-fuel-fi red 5 (2112) 6 (2534)

NOTES:When a boiler is fi red only by a gas having a heat value not in excess of 200 Btu per cubic foot, the minimum relieving capacity may be based on the values given for hand-fi red boilers above.

For fi retube boiler units exceeding 8000 Btu/sq. ft. (total Fuel Btu Input divided by total heating surface), the factor from the table will be increased by 1 for every 1000 Btu./sq. ft. above 8000. For units with less than 7000 Btu/sq. ft., the factor from the table will be decreased by 1 for every 1000 Btu/sq. ft. below 7000.

For watertube boiler units exceeding 16000 Btu/sq. ft. (total fuel Btu input divided by the total heating surface), the factor from the table will be increased by 1 for every 1000 Btu/sq. ft. above 16000. For units with less than 15000 Btu/sq. ft., the factor in the table will be decreased by 1 for every 1000 Btu/sq. ft. below 15000.

The heating surface shall be computed for that side of the boiler surface exposed to the products of combus-tion, exclusive of the superheating surface. In computing the heating surface for this purpose, only the tubes, fi reboxes, shells, tube sheets, and the projected area of headers need be considered, except that for vertical fi retube steam boilers, only that portion of the tube surface up to the middle gage cock is to be computed.


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shall be such that, with the fuel burning equipment installed and operated at maximum capacity, the pressure cannot rise more than 10% above the maximum allowable working pressure. When more than one safety relief valve is used, the over pressure shall be limited to 10% above the set pressure of the highest set valve allowed by I-3820(b).

I-3830 MOUNTING SAFETY AND SAFETY RELIEF VALVES FOR STEAM HEATING, HOT-WATER HEATING, AND HOT-WATER SUPPLY BOILERS

I-3831 PERMISSIBLE MOUNTING

Safety valves and safety relief valves shall be located at the top side19 of the boiler. They shall be connected directly to a tapped or flanged opening in the boiler, to a fitting connected to the boiler by a short nipple, to a Y-base, or to a valveless header con-necting steam or water outlets on the same boiler. Coil- or header- type boilers shall have the safety valve or safety relief valve located on the steam or hot water outlet end. Safety valves and safety relief valves shall be installed with their spindles verti-cal. The opening or connection between the boiler and any safety valve or safety relief valve shall have at least the area of the valve inlet.

I-3832 REQUIREMENTS FOR COMMON CONNECTIONS FOR TWO OR MORE VALVES

a. When a boiler is fitted with two or more safety valves on one connection, this connection shall have a cross-sectional area not less than the combined areas of inlet connections of all the safety valves with which it connects.

b. When a Y-base is used, the inlet area shall be not less than the combined outlet areas. When the size of the boiler requires a safety valve or safety relief valve larger than NPS 4-1/2 (DN 115), two or more valves having the required combined capacity shall be used. When two or more valves are used on a boiler, they may be single, directly attached or mounted on a Y-base.

I-3833 THREADED CONNECTIONS

A threaded connection may be used for at-taching a valve.

I-3834 PROHIBITED MOUNTINGS

Safety and safety relief valves shall not be connected to an internal pipe in the boiler.

I-3835 USE OF SHUTOFF VALVES PROHIBITED

No shutoff of any description shall be placed between the safety or safety relief valve and the boiler, or on discharge pipes between such valves and the atmosphere.

19 Side – The top side of the boiler shall mean the highest practible part of the boiler proper but in no case shall the safety valve be located below the normal operating level and in no case shall the safety relief valve be located below the lowest permissible water level.


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I-3836 SAFETY AND SAFETY RELIEF VALVE DISCHARGE PIPING

a. A discharge pipe shall be used. Its inter-nal cross-sectional area shall be not less than the full area of the valve outlet or of the total of the valve outlets discharg-ing therein to and shall be as short and straight as possible and so arranged as to avoid undue stress on the valve or valves. A union may be installed in the discharge piping close to the valve out-let. When an elbow is placed on a safety or a safety relief valve discharge pipe, it shall be located close to the valve outlet downstream of the union.

b. The discharge from safety or safety relief valves shall be so arranged that there will be no danger of scalding at-tendants. The safety or safety relief valve discharge shall be piped away from the boiler to the point of discharge, and there shall be provisions made for prop-erly draining the piping. The size and arrangement of discharge piping shall be such that any pressure that may exist or develop will not reduce the relieving capacity of the relieving devices below that required to protect the boiler.

I-3837 TEMPERATURE AND PRESSURE SAFETY RELIEF VALVES

Hot water heating or supply boilers limited to a water temperature of 210°F (100°C) may have one or more National Board capacity certified temperature and pressure safety relief valves installed. The requirements of I-3831 through I-3836 shall be met, except as follows:

a. A Y-type fitting shall not be used.

b. If additional valves are used, they shall be temperature and pressure safety re-lief valves.

c. When the temperature and pressure safety relief valve is mounted directly on the boiler with no more than 4 in. (100 mm) maximum interconnecting piping, the valve may be installed in the horizontal position with the outlet pointed down.

I-3840 SAFETY AND SAFETY RELIEF VALVES FOR TANKS AND HEAT EXCHANGERS

I-3841 STEAM TO HOT WATER SUPPLY

When a hot water supply is heated indi-rectly by steam in a coil or pipe within the service limitations set forth in I-3100, the pressure of the steam used shall not exceed the safe working pressure of the hot water tank, and a safety relief valve at least NPS 1 (DN 25), set to relieve at or below the maximum allowable working pressure of the tank, shall be applied on the tank.

I-3842 HIGH TEMPERATURE WATER TO WATER HEAT EXCHANGER20

When high temperature water is circulated through the coils or tubes of a heat exchanger to warm water for space heating or hot wa-ter supply, within the service limitations set forth in I-3100, the heat exchanger shall be equipped with one or more National Board capacity certified safety relief valves set to relieve at or below the maximum allowable working pressure of the heat exchanger, and of sufficient rated capacity to prevent the heat exchanger pressure from rising more than 10% above the maximum allowable working pressure of the vessel.

20 Exchanger – Suggested installation practices for the secondar side of heat exchangers.


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I-3843 HIGH TEMPERATURE WATER TO STEAM HEAT EXCHANGER19

When high temperature water is circulated through the coils or tubes of a heat exchanger to generate low pressure steam, within the service limitations set forth in I-3100, the heat exchanger shall be equipped with one or more National Board capacity certified safety valves set to relieve at a pressure not to exceed 15 psi (100 kPa), and of sufficient rated capacity to prevent the heat exchanger pressure from rising more than 5 psi (35 kPa) above the maximum allowable working pressure of the vessel. For heat exchangers requiring steam pressures greater than 15 psi (100 kPa), refer to I-2000 or I-4000.

I-3850 SAFETY RELIEF VALVE REQUIREMENTS FOR POTABLE WATER HEATERS

a. Each water heater shall have at least one National Board capacity certified temperature and pressure safety relief valve. No safety relief valve shall be smaller than NPS 3/4 (DN 20).

b. The pressure setting shall be less than or equal to the maximum allowable working pressure of the water heater. However, if any of the other components in the hot water supply system (such as valves, pumps, expansion or storage tanks, or piping) have a lesser working pressure rating than the water heater, the pressure setting for the relief valve(s) shall be based upon the component with the lowest maximum allowable work-ing pressure rating. If more than one safety relief valve is used, the additional valve(s) may be set within a range not to exceed 10% over the set pressure of the first valve.

c. The required relieving capacity in Btu/hr. (Watts/hr.) of the safety relief valve

shall not be less than the maximum al-lowable input unless the water heater is marked with the rated burner input capacity of the water heater on the cas-ing in a readily visible location, in which case the rated burner input capacity may be used as a basis for sizing the safety relief valves. The relieving capacity for electric water heaters shall be 3500 Btu/hr. per kw. (Watts/hr./kW.) of input. In every case, the following requirements shall be met. Safety relief valve capac-ity for each water heater shall be such that with the fuel burning equipment installed and operated at maximum capacity the pressure cannot rise more than 10% above the maximum allowable working pressure.

d. If operating conditions are changed or additional heating surface is installed, the safety relief valve capacity shall be increased, if necessary, to meet the new conditions and shall be in accordance with the above provisions. In no case shall the increased input capacity exceed the maximum allowable input capacity. The additional valves required, on account of changed conditions, may be installed on the outlet piping provid-ing there is no intervening valve.

I-3851 INSTALLATION

Safety relief valves shall be installed by ei-ther the installer or the manufacturer before a water heater is placed in operation.

I-3852 PERMISSIBLE MOUNTINGS

Safety relief valves shall be connected di-rectly to a tapped or flanged opening in the top of the water heater, to a fitting connected to the water heater by a short nipple, to a Y-base, or to a valveless header connecting water outlets on the same heater. Safety


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relief valves shall be installed with their spindles upright and vertical with no hori-zontal connecting pipe, except that, when the safety relief valve is mounted directly on the water heater vessel with no more than 4 in. (100 mm) maximum interconnecting piping, the valve may be installed in the horizontal position with the outlet pointed down. The center line of the safety relief valve connection shall be no lower than 4 in. (100 mm) from the top of the shell. No piping or fitting used to mount the safety valve shall be of nominal pipe size less than that of the valve inlet.

I-3853 REQUIREMENTS FOR COMMON CONNECTION FOR TWO OR MORE VALVES

a. When a water heater is fitted with two or more safety relief valves on one con-nection, this connection shall have a cross-sectional area not less than the combined areas of inlet connections of all the safety release valves with which it connects.

b. When a Y-base is used, the inlet area shall be not less than the combined outlet areas.

c. When the size of the water heater re-quires a safety relief valve larger than NPS 4-1/2 (DN 115), two or more valves having the required combined capacity shall be used. When two or more valves are used on a water heater, they may be single, directly attached, or mounted on a Y-base.

I-3854 THREADED CONNECTIONS

A threaded connection may be used for at-taching a valve.

I-3855 PROHIBITED MOUNTINGS

Safety relief valves shall not be connected to an internal pipe in the water heater or a cold water feed line connected to the water heater.

I-3856 USE OF SHUTOFF VALVES PROHIBITED

No shutoff of any description shall be placed between the safety relief valve and the water heater, or on discharge pipes between such valves and the atmosphere.

I-3857 SAFETY RELIEF VALVE DISCHARGE PIPING

a. When a discharge pipe is used, its inter-nal cross-sectional area shall be not less that the full area of the valve outlet or of the total of the valve outlets discharg-ing therein to, and shall be as short and straight as possible and so arranged as to avoid undue stress on the valve or valves. When an elbow is placed on a safety relief discharge pipe, it shall be located close to the valve outlet.

b. The discharge from safety relief valves shall be so arranged that there will be no danger of scalding attendants. When the safety relief valve discharge is piped away from the water heater to the point of discharge, there shall be provisions for properly draining the piping and valve body. The size and arrangement of discharge piping shall be such that any pressure that may exist or develop will not reduce the relieving capacity of the relieving devices below that required to protect the water heater.


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I-3910 PRESSURE TEST

Prior to initial operation, the completed boiler, individual module, or assembled module, shall be subject to a pressure test in accordance with the requirements of the original code of construction.

I-3920 FINAL ACCEPTANCE

a. In addition to determining that all equipment called for is furnished and installed in accordance with the plans and specifi cations, all controls shall be tested by a person familiar with the control system.

b. Before any new heating plant (or boiler) is accepted for operation, a fi nal (or ac-ceptance) inspection shall be completed and all items of exception corrected.

I-3930 BOILER INSTALLATION REPORT

a. Upon completion, inspection and ac-ceptance of the installation, the installer shall complete and certify the (I-1) Boiler Installation Report.

b. The I-1 Boiler Installation report shall be submitted as follows:

1. One copy to the Owner.

2. One copy to the jurisdiction, if re-quired.

I-3940 TABLES AND FIGURES

a. Table I-3691A Expansion Tank Capaci-Table I-3691A Expansion Tank Capaci-Table I-3691Aties for Gravity Hot-Water Systems

b. Table I-3691B Expansion Tank Capacities for Forced Hot-Water Systems

c. Table I-3651.2 Expansion Tank Capaci-ties for a Hot-Water Heater

d. Table I-3671A Size of Bottom Blowoff Table I-3671A Size of Bottom Blowoff Table I-3671APiping, Valves and Cocks

e. Table I-3820 Minimum Pounds of Steam Per Hour Per Square Foot of Heating Surface

f. Figure I-3311A Spacing and Weld Details Figure I-3311A Spacing and Weld Details Figure I-3311Afor Supporting Lugs in Pairs on Hori-zontal Return Tubular Boilers

g. Figure I-3311B Welded Bracket Con-nection for Horizontal Return Tubular Boilers

h. Figure I-3651A Steam Boilers in Battery Figure I-3651A Steam Boilers in Battery Figure I-3651APumped Return Acceptable Piping In-stallation

i. Figure I-3651B Steam Boilers in Bat-tery Gravity Return Acceptable Piping Installation

j. Figure I-3651C Hot-Water Boilers in Bat-tery Acceptable Piping Installation

k. Figure I-3651D Storage Water Heaters in Battery Acceptable Piping Installation

l. Figure I-3651E Flow Through Water Heater Without Provision for Piping Expansion Acceptable Piping Installa-tion


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I-4000 PRESSURE VESSELS

I-4100 INTRODUCTION

I-4110 SCOPE

This section provides requirements for the installation of pressure vessels as defined in I-4120. For installation of items that do not fall within the scope of this section, refer to the following as applicable:

I-2000 Power BoilersI-3000 Heating Boilers and Potable Water HeatersI-5000 Piping

I-4120 PRESSURE VESSELS

Pressure vessels are containers other than boilers or piping used for the containment of pressure.



The owner is responsible for satisfying ju-risdictional requirements for certification and documentation. When required by ju-risdictional rules applicable to the location of installation, the pressure vessel shall not be operated until the required documenta-tion has been provided to the owner and the jurisdiction.


All pressure vessels shall have documented certification from the manufacturer indicat-ing that the pressure vessel complies with all requirements of the code of construction. The certification shall identify the revision level of the code of construction to which the pressure vessel was fabricated.


a. The owner shall determine jurisdictional requirements, (i.e., certificates, permits, licenses, etc.) before installing the equip-ment. The organization responsible for installation shall obtain all permits required by the jurisdiction prior to commencing installation.

b. The owner shall determine jurisdictional requirements, (i.e., certificates, permits, licenses, etc.) before operating the equip-ment. The owner shall obtain operating certificates, permits, etc. required by the jurisdiction prior to commencing opera-tion.

I-4240 INSPECTION

All pressure vessels shall be inspected af-ter installation and prior to commencing operation.


I-4310 SUPPORTS

Each pressure vessel shall be safely sup-ported. The potential for future hydrostatic pressure tests of the vessel after installation shall be considered when designing vessel supports.


426

I-4320 CLEARANCES

a. All pressure vessel installations must allow sufficient clearance for normal operation, maintenance, and inspection (internal and external).

b. Orientation of nozzles, manways and attachments shall be such that suf-ficient clearance between the nozzles, manways and attachments and the surrounding structure(s) is maintained during installation, the attachment of associated piping, and operation.

I-4330 PIPING

Piping loads on the vessel nozzles shall be considered. Piping loads include weight of the pipe, weight of the contents of the pipe, expansion of the pipe from temperature and pressure changes. The effects of piping vibration on the vessel nozzles shall also be considered.

I-4700 INSTRUMENTS AND CONTROLS

I-4710 LEVEL INDICATING DEVICES

Steam drums of unfired steam boilers shall be provided with two level indicating de-vices. Direct level indicating devices may be connected to a single water column or connected directly to the drum and the connections and pipe shall be not less than NPS 1/2 (DN 15). Indirect level indicating devices acceptable to the jurisdiction may be used.

I-4720 PRESSURE INDICATING DEVICES

The need for pressure indicating devices should be considered in the design of the pressure vessel, and when required, shall be at least 25% above the highest set pressure of the pressure relief device.

I-4800 PRESSURE RELIEF DEVICES

All pressure vessels shall be protected by pressure relief devices in accordance with the following requirements.

I-4810 DEVICE REQUIREMENTS

a. Pressure relief devices are to be manu-factured in accordance with a national or international standard and be certified for capacity (or resistance to flow for rupture disk devices) by the National Board.

b. Dead weight or weighted lever pressure relief valves shall not be used.

c. An unfired steam boiler shall be

equipped with pressure relief valves as required in I-2800.

d. Pressure relief devices shall be selected

(i.e., material, pressure, etc.) and in-stalled such that their proper function-ing will not be hindered by the nature of the vessel’s components.

I-4820 NUMBER OF DEVICES

At least one device shall be provided for protection of a pressure vessel. Pressure vessels with multiple chambers with differ-ent maximum allowable working pressures shall have a pressure relief device to protect each chamber under the most severe coin-cident conditions.


427

I-4830 LOCATION

a. The pressure relief device shall be in-stalled directly on the pressure vessel, unless the source of pressure is external to the vessel and is under such positive control that the pressure cannot exceed the maximum allowable working pres-sure, then the device may be installed elsewhere in the system provided it is in communication with the vessel at all times.

b. Pressure relief devices intended for use in compressible fluid service shall be connected to the vessel in the vapor space above any contained liquid, or in the piping system connected to the vapor space.

c. Pressure relief devices intended for use in liquid service shall be connected be-low the normal liquid line.

I-4840 CAPACITY

a. The pressure relief device(s) shall have sufficient capacity to assure that the pressure vessel is not exposed to pres-sure greater than that specified in the original code of construction.

b. If an additional hazard can be created by exposure of a pressure vessel to fire or other unexpected source of exter-nal heat, supplemental pressure relief devices shall be installed to provide any additional capacity which may be required.

c. Vessels connected together by a system of piping not containing valves which can isolate any pressure vessel may be considered as one unit when determin-ing capacity requirements.

d. Heat exchangers and similar vessels shall be protected with a pressure relief device of sufficient capacity to avoid overpressure in case of internal failure

e. When a non-reclosing device is installed

between a pressure relief valve and the pressure vessel, the reduction in capacity due to installation of the non-reclosing device shall be determined in accordance with the code of construc-tion by use of a National Board certified Combination Capacity Factor (CCF). For rupture disks, if a certified combination capacity factor is not available the capac-ity of the pressure relief valve shall be multiplied by 0.9 and this value used as the capacity of the combination installa-tion.

f. The owner shall document the basis for selection of the pressure relief devices used, including capacity, and have such calculations available for review by the jurisdiction.

I-4850 SET PRESSURE

a. When a single pressure relief device is used, the set pressure marked on the device shall not exceed the maximum allowable working pressure.

b. When more than one pressure relief de-vice is provided to obtain the required capacity, only one pressure relief device set pressure needs to be at the maximum allowable working pressure. The set pressures of the additional pressure relief devices shall be such that the pres-sure cannot exceed the overpressure permitted by the code of construction.


428

I-4860 INSTALLATION AND DISCHARGE PIPING REQUIREMENTS

a. The opening through all pipe and fit-tings between a pressure vessel and its pressure relief device shall have at least the area of the pressure relief device in-let. The characteristics of this upstream system shall be such that the pressure drop will not reduce the relieving capac-ity below that required or adversely af-fect the proper operation of the pressure relief device.

b. A non-reclosing device installed be-tween a pressure vessel and a pressure relief valve shall meet the requirements of I-4860(a).

c. The opening in the pressure vessel wall shall be designed to provide unob-structed flow between the vessel and its pressure relief device.

d. When two or more required pressure relief devices are placed on one con-nection, the inlet cross sectional area of this connection shall be sized either to avoid restricting flow to the pressure relief devices or made at least equal to the combined inlet areas of the pres-sure relief devices connected to it. The flow characteristics of the upstream system shall satisfy the requirements of I-4860(a).

e. There shall be no intervening stop valves

between the vessel and its pressure relief device(s), or between the pressure relief device(s) and the point of discharge except under the following conditions:

1. When these stop valves are so con-structed or positively controlled that the closing of the maximum number of block valves at one time will not reduce the pressure relieving ca-

pacity below the required relieving capacity; or,

2. Upon specific acceptance of the ju-risdiction, when necessary for the continuous operation of processing equipment of such a complex nature that shutdown of any part is not fea-sible, a full area stop valve between a pressure vessel and its pressure relief device may be provided for inspection and repair purposes only. This stop valve shall be arranged so that it can be locked or sealed open, and it shall not be closed except by an authorized person who shall remain stationed there during that period of operation while the valve remains closed. The valve shall be locked or sealed in the open position before the authorized person leaves the station.

3. A full area stop valve may also be placed on the discharge side of a pressure relief device when its dis-charge is connected to a common header for pressure relief devices to prevent discharges from these other devices from flowing back to the first device during inspection and repair. This stop valve shall be arranged so that it can be locked or sealed open, and it shall not be closed except by an authorized person who shall remain stationed there during that period of operation while the valve remains closed. The valve shall be locked and sealed in the open posi-tion before the authorized person leaves the station. This valve shall only be used when a stop valve on the inlet side of the pressure relief device is first closed.

4. A pressure vessel in a system where the pressure originates from an out-side source may have a stop valve


429

between the vessel and the pressure relief device, and this valve need not be sealed open, provided it also closes off that vessel from the source of the pressure.

f. Pressure relief device discharges shall be arranged such that they are not a hazard to personnel or other equipment and, when necessary, lead to a safe location for disposal of fluids being relieved.

g. Discharge lines from pressure relief devices shall be designed to facilitate drainage or be fitted with drains to prevent liquid from collecting in the discharge side of a pressure relief device. The size of discharge lines shall be such that any pressure which may exist or develop will not reduce the relieving capacity of the pressure relief device, or adversely affect the operation of the pressure relief device.

h. Pressure relief devices shall be installed so they are readily accessible for inspec-tion, repair or replacement.


a. The installer shall exercise care dur-ing installation to prevent loose weld material, welding rods, small tools and miscellaneous scrap metal from get-ting into the vessel. The installer shall inspect the interior of the vessel and its appurtenances where possible prior to making the final closures for the pres-ence of foreign debris.

b. The completed pressure vessel shall be pressure tested in the shop or in the field in accordance with the original code of construction. When required by the jurisdiction, owner or user, the Inspector shall witness the pressure test

of the completed installation, including piping to the pressure gage, pressure re-lief device, and, if present, level control devices.

I-5000 PIPING

I-5100 INTRODUCTION

I-5110 SCOPE

This section provides requirements for the installation of pressure piping. For instal-lation of items that do not fall within the scope of this section, refer to the following sections as applicable:

I-2000 Power BoilersI-3000 Heating Boilers and Potable Water

HeatersI-4000 Pressure Vessels

I-5120 ADDITIONS TO EXISTING PIPING

Additions to existing piping systems shall conform to this section. That portion of the existing piping system that is not part of the addition need not comply to this sec-tion provided the addition does not result in a change in piping system operation or function that would exceed the design conditions of the existing piping system or result in unsafe conditions.



The owner is responsible for satisfying ju-risdictional requirements for certification


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and documentation. When required by jurisdictional rules applicable to the loca-tion of installation, the piping shall not be operated until the required documentation has been provided to the owner and the jurisdiction.


Piping shall have documented certification from the fabricator and/or installer when required by the code of construction. The certification, when required, shall identify the revision level of the code of construction to which the piping was designed, fabri-cated and installed.


a. The owner shall determine jurisdictional requirements, (i.e., certificates, permits, licenses, etc.) before installing the equip-ment. The organization responsible for installation shall obtain all permits required by the jurisdiction prior to commencing installation.

b. The owner shall determine jurisdic-tional requirements, (i.e., certificates, permits, licenses, etc.) before operat-ing the equipment. The owner shall obtain operating certificates, permits, etc. required by the jurisdiction prior to commencing operation.

I-5240 INSPECTION

All piping shall be inspected after installa-tion and prior to commencing operation.

I-5250 OPERATING PERMIT

The owner shall obtain any operating permit(s) required by the jurisdiction, prior to placing the piping into service.

I-5300 LAYOUT AND CONFIGURATION

I-5310 PROXIMITY TO OTHER EQUIPMENT AND STRUCTURES

The arrangement of the piping and its ap-purtenances shall take into consideration the location of other structures and equip-ment adjacent to the piping which may result in interference and/or damage as a result of expansion, contraction, vibration or other movements.

I-5320 FLANGES AND OTHER NON-WELDED JOINTS

The layout of the piping shall take into consideration the need to maintain piping joints and required access for maintenance and inspection.

I-5330 VALVES

Consideration should be given to the ap-propriate location and orientation of valves necessary for safe operation and isolation of the piping.

I-5400 MATERIALS

All materials for piping and its appurte-nances shall comply with the requirements of the code of construction.

I-5500 HANGERS AND SUPPORTS

Support of piping shall consider loads imposed on equipment or existing piping to which it is attached. Non-piping at-tachments such as ladders and walkways, equipment supports, temporary supports, structural supports, etc. shall not be con-nected to the piping unless such loads have


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been considered in the design of the piping and its supports. Design of hangers and supports for piping shall consider loads imposed by pressure testing. The installer shall remove pins from non-rigid hangers, seal plugs from hydraulic snubbers and temporary supports used for installation prior to placing the piping in service.

I-5600 PROTECTION AND CLEANING

The installer shall exercise care during in-stallation to prevent loose weld material, welding rods, small tools and miscellaneous scrap metal from getting into the piping. The installer shall inspect, and where nec-essary clean, the interior of the piping and its appurtenances where possible prior to making the final closures for the presence of foreign debris.

I-5700 WELDING AND BRAZING

The installer should consider the impact of performing any preheating, welding, braz-ing or postweld heat treatment on valves, instrumentation or other heat sensitive equipment and, where appropriate, review the equipment manufacturer ’s recom-mended installation procedures prior to performing the work.

I-5800 PRESSURE RELIEF DEVICES

When required by the original code of construction, piping shall be protected by pressure relief devices in accordance with the following requirements.

I-5810 DEVICE REQUIREMENTS

a. Pressure relief devices are to be manu-factured in accordance with a national or international standard and be certified

for capacity (or resistance to flow for rupture disc devices) by the National Board.

1. In certain cases piping standards

permit the use of regulators which may include integral pressure relief valves to limit the pressure in a pip-ing system. In this case, capacity certification of the pressure relief valve is not required.

b. Dead weight or weighted lever pressure relief devices shall not be used.

c. Pressure relief devices shall be selected (i.e., material, pressure, etc.) and in-stalled such that their proper function-ing will not be hindered by the nature of the piping system’s contents.

I-5820 NUMBER OF DEVICES

At least one pressure relief device shall be provided for protection of a piping system. A pressure relief device installed on a pres-sure vessel or other component connected to the piping system may be used to meet this requirement. Portions of piping systems with different maximum allowable working pressures shall have a pressure relief device to protect each portion separately.

I-5830 LOCATION

The pressure relief device may be installed at any location in the system provided the pressure in any portion of the system can-not exceed the maximum allowable work-ing pressure. Pressure drop to the pressure relief device under flowing conditions shall be considered when determining pressure relief device location. The device shall be in communication with the piping system it is protecting at all times.


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I-5840 CAPACITY

a. The pressure relief device(s) shall have sufficient capacity to assure that the pip-ing is not exposed to pressures greater than that specified in the original code of construction.

b. When a non-reclosing device is installed between a pressure relief valve and the pipe, the reduction in capacity due to installation of the non-reclosing device shall be determined in accordance with the code of construction by use of a National Board certified Combination Capacity Factor (CCF). For rupture disks, if a certified combination capacity factor is not available, the capacity of the pressure relief valve shall be multiplied by 0.9 and this valve used as the capacity of the combination installation.

c. The owner shall document the basis for selection of the pressure relief devices used, including capacity, and have such calculations available for review by the jurisdiction.

I-5850 SET PRESSURE

a. When a single pressure relief device is used, the set pressure marked on the device shall not exceed the maximum allowable working pressure, except when allowed by the original code of construction.

b. When more than one pressure relief de-vice is provided to obtain the required capacity, only one pressure relief device set pressure needs to be at the maximum allowable working pressure. The set pressures of the additional pressure relief devices shall be such that the pres-sure cannot exceed the overpressure permitted by the code of construction.

I-5860 INSTALLATION AND DISCHARGE PIPING REQUIREMENTS

a. The opening through all pipe and fitting between a piping system and its pres-sure relief device shall have at least the area of the pressure relief device inlet. The characteristics of this upstream system shall be such that the pressure drop will not reduce the relieving ca-pacity below that required or adversely affect the operation of the pressure relief device.

b A non-reclosing device installed be-tween a piping system and a pressure relief valve shall meet the requirements of I-5860(a).

c. The opening in the pipe shall be de-signed to provide unobstructed flow between the pipe and its pressure relief device.

d. When two or more required pressure relief devices are placed on the con-nection, the inlet cross sectional area of this connection shall be sized either to avoid restricting flow to the pressure relief devices or made at least equal to the combined inlet areas of the pres-sure relief devices connected to it. The flow characteristics of the upstream system shall satisfy the requirements of I-5860(a).

e. There shall be no intervening stop valves between the piping system and its pres-sure relief device(s), or between the pressure relief device(s) and the point of discharge except under the following conditions:

1. When these stop valves are so con-structed or positively controlled that the closing of the maximum number


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of block valves at one time will not reduce the pressure relieving ca-pacity below the required relieving capacity; or,

2. Upon specific acceptance of the ju-risdiction, when necessary for the continuous operation of processing equipment of such a complex nature that shutdown of any part is not fea-sible, a full area stop valve between a piping system and its pressure relief device may be provided for inspec-tion and repair purposes only. This stop valve shall be arranged so that it can be locked or sealed open, and it shall not be closed except by an authorized person who shall remain stationed there during that period of operation while the valve remains closed. The valve shall be locked or sealed in the open position before the authorized person leaves the station.

3. A full area stop valve may be placed on the discharge side of a pressure relief device when its discharge is connected to a common header for pressure relief devices to prevent discharges from these other devices from flowing back to the first device during inspection and repair. This stop valve shall be arranged so that it can be locked or sealed open, and it shall not be closed except by an authorized person who shall remain stationed there during that period of operation while the valve remains closed. The valve shall be locked or sealed in the open position before the authorized person leaves the station. This valve shall only be used when a stop valve on the inlet side of the pressure relief device is first closed.

4. A piping system where the pressure originates from an outside source may have a stop valve between the system and the pressure relief device, and this valve need not be sealed open, provided it also closes off that vessel from the source of pressure.

f. Pressure relief device discharges shall be arranged such that they are not a hazard to personnel or other equipment and when necessary, lead to a safe location for disposal of fluids being relieved.

g. Discharge lines from pressure relief devices shall be designed to facilitate drainage or be fitted with drains to prevent liquid from collecting in the discharge side of a pressure relief device. The size of discharge lines shall be such that any pressure which may exist or develop will not reduce the relieving capacity of the pressure relief device, or adversely affect the operation of the pressure relief device.

h. Pressure relief devices shall be installed so they are accessible for inspection, repair or replacement.

I-5900 EXAMINATION, INSPECTION AND TESTING

THE OWNER SHALL ENSURE THAT ALL EXAMINATIONS, INSPECTIONS AND TESTS REQUIRED BY THE CODE OF CONSTRUCTION HAVE BEEN PER-FORMED PRIOR TO OPERATION.


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Guide to Jurisdictions for Authorization of Owners-Users to Make Adjustments to Pressure Relief Valves

Appendix J

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436


APPENDIX J — GUIDE TO JURISDICTIONS FOR AUTHORIZATION OFOWNERS-USERS TO MAKE ADJUSTMENTS TO PRESSURE RELIEF VALVES

J-1000 GENERAL

It is recommended that before an owner-user or their designees be authorized to make ad-justments as defined in paragraph RE-1023, the following requirements should be met:

J-1010 TRAINING

The user shall establish a documented in-house training program. This program shall establish training objectives and provide a method of evaluating the training effective-ness. As a minimum, training objectives for knowledge level shall include:

a. Applicable ASME Code and NBIC re-quirements;

b. Responsibilities within the organization’s quality system;

c. Knowledge of the technical aspects and mechanical skills for making set pressure and/or blowdown adjustments to pres-sure relief valves;

d. Knowledge of the technical aspects and mechanical skills for marking of pressure relief valve adjustments.

If the user established a designee, the designee shall establish a training program and make their documentation available to the user and the jurisdictional authority.

J-1020 DOCUMENTATION

Each user shall document the evaluation and acceptance of an employee’s or designee’s qualifications.

J-1020 QUALITY SYSTEM

A written quality system shall be established by either the user or the designee with a writ-ten description available to the jurisdictional authority.

The written description shall include at a minimum:

a. Calibration of Test Equipment: This shall describe the method of periodic calibra-tion of instruments and pressure gages. Documentation of these calibrations should include the standard used and the results. All calibration standards shall be calibrated against the equipment having valid relationships to nationally recog-nized standards.

b. Valve Testing, Setting and Sealing: This system shall include provisions that each valve shall be tested, set and all external adjustments sealed according to the re-quirements of the applicable ASME Code Section and NBIC RE-1023.

c. Valve Marking: An effective marking system shall be established to ensure proper marking of the metal tag required by RE-1023. The written quality system shall include a description of drawing of the metal tag.

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APPENDIX J — GUIDE TO JURISDICTIONS FOR AUTHORIZATION OF OWNERS-USERS TOMAKE ADJUSTMENTS TO PRESSURE RELIEF VALVES

J-1040 EXTERNAL ADJUSTMENTS

Only external adjustments to restore the re-quired set pressure and/or performance of a pressure relief valve shall be made under the provisions of RE-1023.

J-1050 REPAIRS

If disassembly, change of set pressure, or ad-ditional repairs are necessary, the valve shall be repaired by an organization which meets the requirements of the NBIC.

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Inspection, Repairs, and Alterationsfor Yankee Dryers

Appendix K

439


440

APPENDIX K — INSPECTION, REPAIR, AND ALTERATION OF YANKEE DRYERS

K-1000 INSPECTION OF YANKEE DRYERS (ROTATING CAST-

IRON PRESSURE VESSELS) WITH FINISHED SHELL OUTER SURFACES

K-1010 SCOPE

This part describes guidelines for the inservice inspection of a Yankee dryer. A Yankee dryer is a rotating steam-pressurized cylindrical vessel commonly used in the paper industry, and is made of cast iron, finished to a high surface quality and characterized by a center shaft connecting the heads.

“Yankee dryers” are primarily used in the pro-duction of tissue-type paper products. When used to produce machine glazed (MG) paper, the dryer is termed an MG cylinder. A wet paper web is pressed onto the finished dryer surface using one or two pressure (pressing) rolls. Paper is dried through a combination of mechanical dewatering by the pressure roll(s); thermal drying by the pressurized Yankee dryer and a steam heated or fuel fired hood. After drying, the paper web is removed from the dryer.

The dryer is typically manufactured in a range of outside diameters from eight (8) to twenty three (23) feet (2.4 m to 7 m), widths from eight (8) to twenty eight (28) feet (2.4 m to 8.5 m), pressurized and heated with steam up to 160 psi (1100 kPa), and rotated at speeds up to 7000 ft/min (2135 m/min). Typical pressure roll loads against the Yankee dryer are up to 600 pounds per lineal inch (105 kN/m). A thermal load results from the drying process due to difference in temperature between in-

ternal and external shell surfaces. The dryer has an internal system to remove steam and condensate. These vessels can weigh up to 220 tons (200 tonnes).

The typical Yankee dryer is an assembly of several large castings. The shell is normally a gray iron casting, in accordance with ASME designation SA-278. Shells internally may be smooth bore or ribbed. Heads, center shafts and journals may be gray cast iron, ductile cast iron, or steel.

K-1020 ASSESSMENT OF INSTALLATION

The Inspector verifies that the owner or user is properly controlling the operating condi-tions of the dryer. The Inspector does this by reviewing the owner’s comprehensive assess-ments of the complete installation, operating environment, maintenance, and operating history.

The dryer is subjected to a variety of loads over its life. Some of the loads exist individu-ally, while others are combined. Consideration of all the loads that can exist on a Yankee dryer is required to determine the maximum allow-able operating parameters. There are four loads that combine during normal operation to create the maximum operating stresses, usually on the outside surface of the shell at the axial center line. These are:

a. Pressure load due to internal steam pres-sure;

b. Inertial load due to dryer rotation;

APPENDIX K — INSPECTION, REPAIRS, AND ALTERATIONS FOR YANKEE DRYERS

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c. Thermal gradient load due to the drying of the web;

d. Pressure roll load (line or nip load)21 due to pressing the wet web onto the dryer.

Steam pressure, inertial, and thermal gradi-ent loads impose steady-state stresses. These stresses typically change when the dryer shell thickness (effective thickness for ribbed dryers) is reduced to restore a paper-mak-ing surface, the grade of tissue is changed or speed of the dryer is changed.

The pressure roll(s) load imposes an alternat-ing stress on the shell face. The resulting maxi-mum stress is dependent on the magnitude of the alternating and steady-state stresses.

Section VIII, Div. 1, of the ASME Code only provides specifi c requirements for the analysis of pressure loads. Although the Code requires analysis of other loads, no specifi c guidance for thermal, inertial, or pressure roll loads is provided. Hence, additional criteria must be applied by the manufacturer to account for all the steady-state and alternating stresses.

To maintain product quality, the dryer surface is periodically refurbished by grinding. This results in shell thickness reduction. Therefore, the manufacturer does not provide a single set of maximum allowable operating parameters relating steam pressure, rotational speed, and pressure roll load for a single design shell thickness. The manufacturer, or another quali-fi ed source acceptable to the Inspector, instead provides a series of curves that graphically defi nes these maximum allowable operating parameters across a range of shell thicknesses. This document is known as the “De-rate Curve.” See Figure K-1020.

In addition to the loads on the dryer due to normal operation, other non-standard load events can occur. These non-standard load events should be recorded in an operation or maintenance log. Examples of non-standard load events include:

a. Excessive thermal load due to local or global heating rate during warm-up;

b. Excessive thermal load due to local or global cooling rate during shut-down;

c. Excessive thermal load due to inappropri-ate use or malfunctioning auxiliary heat-ing devices causing localized heating;

d. Excessive thermal load due to the mis-application or uncontrolled application of water or other fl uids for production, cleaning or fi re fi ghting;

e. Impact load.

If non-standard load events have occurred, then the Inspector should ensure that an ap-propriate assessment of the structural integ-rity on the dryer has been performed.

K-1030 CAUSES OF DETERIORATION AND

DAMAGE

Three types of deterioration or damage typi-cally encountered in Yankee dryers are local thinning, cracking, and corrosion. Many times these mechanisms are interrelated, one being the precursor of another.

21 Pressure roll load, line load, and nip load are terms that are used interchangeably to refer to the interaction between the pressure roll(s) and the Yankee dryer. It is called “nip” load because the pressure roll is rubber-covered and is pressed up against the Yankee with enough force to create a nip (or pinch) that forces the paper into line contact between the rolls and provides some mechanical dewatering. The paper then sticks onto the Yankee surface and follows the Yankee dryer for thermal dewatering by the steam-heated Yankee surface. This “nip load” is called a “line load” because the units are load (force) per length of line contact. The units are pounds per linear inch (PLI) and kiloNewtons per meter (kN/m).


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K-1031 LOCAL THINNING

Internally, a Local Thin Area (LTA) can oc-cur on the pressure-retaining surfaces due to steam and condensate erosion, mechanical wear, and impact, and removal of material flaws. These assume features ranging from broad shallow areas washed-out by erosion, to more groove-like flaws, including gouges and indentations from contacting metal parts.

Externally, the process is typically one of wear-corrosion in circumferential bands. Except on the shell edges, local thinning never achieves significant depth because the papermaking process will tolerate only the smallest depar-ture from surface contour. On the shell edges,

beyond the papermaking surface, wear-cor-rosion may advance to comparatively greater depths. However, the stresses are far less in this area than under the papermaking surface, so the wear is inconsequential in consider-ations of load-carrying ability. Only in the instance of steam leakage between flanges, has the resultant local thinning ever been implicated in Yankee failure.

Steam leakage is detrimental to the long-term structural integrity of the vessel, in that the escaping steam, under high velocity, erodes ever-widening paths in the cast-iron sur-faces over which it passes, thinning the cross section. Steam cutting of connecting bolts is another possible outcome. Either result

FIGURE K-1020 Approve reorganization and update of Part RB to be incorporated into Draft2003 Addendum which will result in the Public Review Comment ph

��


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reduces load-carrying capacity of the part. A safety hazard can also be created for operating personnel, who may be burned by the high velocity steam jets.

a. Interface leakage, including joints and bolted connections

1. Joint Interface Corrosion Jacking forces, which develop from

the expansion of corrosion products between head-to-shell flanges, cause flange separation and create leakage paths between the flanges and/or through the bolt holes.

2. Insufficient Joint Clamping Force Through inadequate design, improper

assembly, loss of washer/gasket, or stress corrosion cracking of connect-ing bolts, the clamping force between mating flanges is insufficient to retain internal pressure.

3. Washer/Gasket Functional Loss Deterioration, caused by corrosion or

expulsion, provides a path for escap-ing steam and condensate.

4. Flange Machining Variation Variations in surface contour of flange

faces may create leakage paths.

5. Through-Wall Leakage Cast iron inherently exhibits shrink-

age porosity. Where porosity linkages occur between internal and external surfaces, a path for steam leakage is made available. Such leakage is largely an operational issue, as holes are formed in the paper product, de-manding expedient attention.

K-1032 CRACKING

Cracks in cast-iron parts are problematic be-cause of the relatively low fracture toughness compared with standard, more ductile pres-sure vessel materials and because strength-ening repair through welding is prohibited. Furthermore, Yankee dryers are subject to both low and high-cycle fatigue loading. Con-sequently, considerable emphasis is placed upon quality inspection for and timely reme-diation of cracks, the central causes of which (in Yankee dryers) are:

a. Through joints and bolted connections

1. Joint Interface Corrosion Jacking forces, which develop from

the expansion of corrosion products between head-to-shell flanges, cause flange separation and create leakage paths between the flanges and/or through the bolt holes.

2. Insufficient Joint Clamping Force Through inadequate design, improper

assembly, loss of washer/gasket, or stress corrosion cracking of connect-ing bolts, the clamping force between mating flanges is insufficient to retain internal pressure.

3. Washer/Gasket Functional Loss Deterioration, caused by corrosion or

expulsion, provides a path for escap-ing steam and condensate.

4. Flange Machining Variation Variations in surface contour of flange

faces may create leakage paths.

b. Through-Wall Leakage Cast iron inherently exhibits shrinkage

porosity. Where porosity linkages occur between internal and external surfaces, a path for steam leakage is made available. Such leakage in the shell is largely an operational issue, as holes are formed in the paper product, demanding expedient attention.


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c. Impact from Objects Passing Through the Yankee/Pressure Roll Nip

Because of cast iron’s low fracture tough-ness, it is especially intolerant of local, high impact loads.

d. Stress Magnification Around Drilled Holes Surface defects, caused by porosity and

indentations, are frequently repaired with driven plugs, having some level of inter-ference fit. Pumping ports, threaded for a tapered pipe fitting, are often installed as a standard Yankee design feature for sealant injection into flange interfaces. When installed, both produce an area of increased stress, local to the hole’s edge. In the case of driven plugs this stress can be exaggerated by excessive interference fits and by closely-grouped or over-lapping plugs. Over-torque of threaded, tapered plugs can cause cracks to develop at the periphery of the hole.

e. Thermal Stress and/or Microstructural Change from Excessive Local Heating and Cooling

Transient thermal stresses are usually the highest encountered by a Yankee dryer. Temperature differential through and between parts can be of such magnitude as to exceed the strength of the material. When abnormal thermal loads occur, non-destructive examination is crucial to ensure the vessel’s fitness-for-service. Microstructural change and transient thermal stresses, sufficiently high to cause cracking in Yankee dryers, have resulted, or could result, from:

• bearing failure • rapid warm-up• excessive steam temperature• heat from fires• application of water sprays to fight

fires and remove paper jams • continuous and excessive local cooling

from water sprays

• operating heating or cooling systems while the Yankee is stationary; e.g., high temperature air impingement hoods, infra-red heating devices, coat-ing showers

• welding and electrical arcs on cast- iron parts

• excessive local temperature due to improper thermal spray application

f. Joint Interface Corrosion The products of corrosion occupy a larger

volume than the base metal. The forces created by this expansion are sufficient to cause cracking in cast-iron flanges. Without remediation, expansion will continue until failure occurs. Corrosion products form in the presence of moisture in the crevice created between flanges, wherever the clamping force is insufficient to maintain contact between the mating surfaces.

g. Stress-Corrosion Cracking of Structural Bolts

Stress-corrosion cracking (SCC) is the result of the combination of a corroding agent, material sensitivity, tensile stress, and temperature. At stress levels suffi-ciently high to induce SCC in the presence of a corrosive medium, attack proceeds along or through grain boundaries per-pendicular to the direction of maximum tensile stress. Cracking can initiate with little or no evidence of general corro-sion.

K-1033 CORROSION

Corrosion culminates with a failure in com-ponent functionality by diminishing load-carrying capacity or by generating forces beyond the material’s strength. In addition to SCC, corrosion-jacking (head to shell joint), wear-corrosion, and deterioration of washers described above, oxygen pitting and general


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corrosion wastage need to be considered as potential failure causes. These latter two cor-rosion conditions are the result of inadequate boiler water treatment. Oxygen pitting has been encountered, but rarely.

K-1040 INSPECTIONS

Yankee dryers should be inspected on a rou-tine-periodic basis. However, as a minimum, the Yankee dryer should be inspected inter-nally and externally at least one time every two years.

As appropriate, the following items should be included:

• head-to-shell joint • shell out-of-roundness• shell centerline thickness • tilt of head flange • integrity and security of internal parts• spigot fit of flanged joints (head-to-shell,

head-to-journal)• integrity of structural bolts and studs • previously identified areas of deteriora-

tion and damage

When a non-standard load event occurs, or a material non-conformity is noted, an inspec-tion should be performed to assess fitness for continued service. This inspection may involve testing methods not typically used in routine inspections and may also involve removal of material samples for destructive testing.

K-1050 NONDESTRUCTIVE EXAMINATION

Nondestructive examination (NDE) methods shall be implemented by individuals qualified and experienced with the material to be tested using written NDE procedures. For Yankee dryers, cast iron knowledge and experience are essential.

Typical nondestructive examination methods may be employed to determine indication length, depth, and orientation (sizing) of dis-continuities in Yankee dryers. Magnetic par-ticle, specifically the wet fluorescent method, and dye penetrant methods are applicable in the evaluation of surface-breaking indications. Ultrasonic testing is the standard method for evaluation of surface-breaking and embedded indications. Radiographic methods are useful in the evaluation of embedded indications. Acoustic Emission Testing can be used to locate and determine if a linear indication is active; i.e., propagating crack. Metallographic analysis is useful in differentiating between original casting discontinuities and cracks.

When nondestructive testing produces an indication, the indication is subject to inter-pretation as false, relevant, or non-relevant. If it has been interpreted as relevant, the nec-essary subsequent evaluation will result in a decision to accept, repair, replace, monitor, or adjust the maximum allowable operating parameters.

K-1060 PRESSURE TESTING

Hydrostatic testing is not recommended due to the weight of water required to fill the large internal volume of a Yankee dryer. The additional weight can lead to support struc-ture (floor) overload, deformation of the high tolerance dryer surface and internal contami-nation. Hydrostatic testing requires special support of the Yankee dryer shell to minimize damage to the journals and bearings.

When pressure testing is desired to evalu-ate forms of deterioration, acoustic emission testing, with steam or air, is recommended. Typically, the test pressure used is the operat-ing pressure.


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K-2000 GENERAL REQUIREMENTS FOR REPAIRS AND ALTERATIONS TO YANKEE DRYERS K-2010 SCOPE

This section provides additional requirements for repairs and alterations to Yankee dryer pressure-retaining components and shall be used in conjunction with K-1000.

K-2020 REPLACEMENT PARTS

Yankee dryer replacement pressure-retaining parts shall be fabricated in accordance with the manufacturer’s design and the original code of construction. Yankee dryer pressure-retaining parts may include:

• shell• heads• center shaft, stay, or trunnion• stay bars• structural bolting• journals

Replacement of non-pressure-retaining parts, when different from the manufacturer’s de-sign, shall be evaluated for any possible effect on the pressure-retaining parts.

K-2030 EXAMINATIONS AND TEST METHODS

In addition to the requirements of RC-2051 and RC-3031, the following are recommended:

a. Acoustic emission testing

b. Metallographic examination when ther-mal damage is suspected due to opera-tional or repair activities, microstructure analysis.

K-2040 DETERMINATION OF ALLOWABLE OPERATING

PARAMETERS

A Yankee dryer is designed and intended to have its shell thickness reduced over the life of the vessel through routine wear and grinding. The Yankee dryer shell is ground on the outside surface to restore the quality or shape of the papermaking surface, essential to the manufacturing of tissue or other paper products.

Design documentation is required which dictates the maximum allowable operating parameters as shell thickness is reduced. Calculations, used to determine those pa-rameters, are in accordance with ASME Code requirements for primary membrane stress and design criteria based upon other relevant stress categories; e.g., fatigue and maximum principal stress. Calculation of these parameters requires that the respective stresses, resulting from the imposed loads, be compared to the appropriate material strength properties. Hence, knowledge of the applied stresses in the shell and the tensile and fatigue properties of the material are essential.

Yankee dryers are subjected to a variety of loads that create several categories of stress. Yankee dryers are designed such that the stress of greatest concern typically occurs on the outside surface at the axial centerline of the shell.

a. Steam Pressure Load – The internal steam pressure is one of the principal design loads applied to the Yankee dryer. The steam pressure expands the shell radially, causing a predominately circumferential membrane tensile stress. Because the shell is constrained radially by the heads at either end of the shell, the steam pressure also causes a primary bending stress in the vicinity of the head-to-shell joint. The ends


447

of the shell are in tension on the inside and compression on the outside due to the steam pressure. The steam pressure also causes a bending stress in the heads.

b. Inertia Load – The rotation of the Yankee dryer causes a circumferential membrane stress in the shell similar to that caused by the steam pressure load. This stress is included in the design of the shell and in-creases with dryer diameter and speed.

c. Thermal Gradient Load – The wet sheet, applied to the shell, causes the outside surface to cool and creates a thermal gra-dient through the shell wall. This thermal gradient results in the outside surface being in tension and the inside surface in compression. With this cooling, the average shell temperature is less than the head temperature, which creates bending stresses on the ends of the shell and in the heads. The ends of the shell are in tension on the outside and compression on the inside.

Other thermal loading also occurs on a Yankee. The use of full width showers for a variety of papermaking purposes affects the shell similar to a wet sheet. The use of edge sprays produce high bending stress in the ends of the shell due to the mechanical restraint of the heads.

Warm-up, cool-down, hot air impinge-ment from the hood, moisture profiling devices, fire fighting, and wash-up can all produce non-uniform thermal stresses in the pressure containing parts of the Yankee dryer. Heating or cooling different portions of the Yankee dryer at different rates causes these non-uniform stresses.

d. Line Load – The line load from the contact-ing pressure roll(s), results in an alternat-ing, high cycle, bending stress in the shell.

This stress is greatest at the centerline of the shell. The load of the pressure roll deflects the shell radially inward causing a circumferential compressive stress on the outside surface and a tensile stress on the inside. Because the shell has been deflected inward at the pressure roll nip, it bulges outward about 30 degrees on each side of the nip. The outward bulge causes a tensile stress on the outside shell surface at that location and a correspond-ing compressive stress on the inside. Since the shell is passing under the pressure roll, its surface is subjected to an alternating load every revolution.

K-2041 ASME CODE PRIMARY MEMBRANE STRESS CRITERION

Yankee dryers are typically designed and fab-ricated in accordance with Section VIII, Div. 1, of the ASME Code. The maximum allowable stress for cast iron is specified in UCI-23 of the ASME Code.

Section VIII, Div. 1, requires design stresses to be calculated such that any combination of loading expected to occur simultaneously during normal operation of the Yankee dryer will not result in a general primary stress exceeding the maximum allowable stress value of the material. In the ASME Code, the combination of loading resulting in the primary membrane stress is interpreted to be composed only of the circumferential stress from steam pressure. Sometimes, the stress from the inertial loading is included in this consideration.

In Section VIII, Div. 1, it is very important to note that no formulas are given for determin-ing the stresses from thermal gradient loads, inertial loads, and pressure roll nip loads. Hence, additional criteria need to be incor-


448

porated to establish the maximum allowable operating parameters of the Yankee dryer. As the thickness of the shell is reduced, one or more of these criteria will control the various operating parameters. Two such additional criteria are based upon the maximum princi-pal and fatigue stress.

a. Maximum Principal Stress Criterion The maximum principal stress in a Yankee

shell is the sum of the stresses that are simultaneously applied to the shell, and is always aligned in the circumferential direction. The purpose of this criterion is to recognize the paper making application of the Yankee dryer and to prevent cata-strophic failure, by including all stresses. The ASME Code does not provide specific formulas for the full array of dryer stresses encountered in a paper making applica-tion.

b. Fatigue Stress Criterion Under normal operation, the stresses

due to the steam pressure, inertial and thermal gradient loads are considered to be steady-state stresses. When acting simultaneously, the sum of these stresses must be calculated and combined with the alternating stress due to the pressure roll line load. A fatigue stress criterion limits the alternating stress at a given mean stress using fatigue failure criteria described by the Goodman or Smith Dia-gram. The purpose of this limitation is to prevent crack initiation in the outside wall due to the combination of stresses.

K-2042 ADJUSTING THE MAXIMUM ALLOWABLE OPERATING PARAMETERS OF THE YANKEE DRYER DUE TO A REDUCTION IN SHELL THICKNESS FROM GRINDING OR MACHINING

The outside surface of the Yankee dryer shell is routinely ground to restore the quality of the

papermaking surface. The papermaking sur-face degrades due to wear, corrosion, and local thinning. As the shell thickness is reduced, the maximum allowable operating parameters are adjusted. Adjustment of the maximum allow-able operating parameters requires accurate shell thickness measurements.

Over the life of the Yankee dryer, the adjust-ment of the maximum allowable operating pa-rameters will require that the original design pressure and/or the pressure roll line load be reduced. After the maximum allowable oper-ating parameters are adjusted per the De-rate Curve, the appropriate load limiting devices are reset (e.g., steam safety relief valve, line load limiting device).

K-2043 DOCUMENTATION OF SHELL THICKNESS AND ADJUSTED MAXIMUM ALLOWABLE OPERATING PARAMETERS

Yankee dryers are designed and intended to have the shell thickness reduced over the life of the vessel as a result of routine wear and grinding. Yankee shell grinding is routinely performed to restore the quality or shape of the papermaking surface.

Design documentation, a De-rate Curve, is required, which dictates the maximum allow-able operating parameters, based on imposed loads over a range of shell thickness. The documentation shall be obtained from the original dryer manufacturer or from another qualified source acceptable to the Inspector.

Yankee dryer shell grinding requires accurate shell thickness measurements in conjunction with the De-rate Curve in order to set load-limiting devices. The resulting shell thickness and maximum allowable operating param-eters after grinding shall be documented, and the Inspector notified that load-limiting device settings have changed.


449

K-2050 STAMPING

Stamping is not required for repairs which do not affect the pressure-retaining capability of the Yankee shell, as indicated on the De-rate Curve, or other pressure-retaining parts as indicated on the original Manufacturer’s Data Report.

Stamping is required for repairs which do affect the pressure-retaining capability of the Yankee shell, as indicated on the De-rate Curve, or other pressure-retaining parts as indicated on the original Manufacturer’s Data Report.

Stamping is required for alterations as listed in K-4020.

Stamping, when required, shall meet the requirements for stamping in RC-3040. The location of stamping shall be described in the remarks section of Form R-2.

K-3000 YANKEE DRYER REPAIR METHODS

K-3010 SCOPE

This section provides additional requirements for repair methods to Yankee dryer pressure-retaining components and shall be used in conjunction with K-1000 and K-2000.

K-3020 REPAIR GUIDE FOR YANKEE DRYERS

Welding or brazing shall not be used on any Yankee dryer pressure-retaining component manufactured from cast iron. The Manufactur-er’s Data Report shall be carefully reviewed to determine the material of construction of each Yankee Dryer component such as shell, heads, and journals.

Structural deterioration or damage caused by corrosion, thinning, or cracking shall not be re-paired until their extent has been determined by suitable nondestructive examination.

The user shall have a plan covering the scope of the repair. The plan shall ensure that the work involved is compatible with the original design specification and good engineering practices.

All repair work shall be documented.

K-3030 PROCEDURES WHICH DO NOT REQUIRE STAMPING

OR NAMEPLATE ATTACHMENT

All repair procedures, shall be acceptable to the Inspector, and when verified by the owner-user to not affect pressure-retaining capability of the Yankee dryer, do not require stamping or nameplate attachment. Exam-ples of repairs are:

Grinding and machining:

• removal of shell overhung flange• removing bolt-stop ring for test speci-

mens• head/Shell joint corrosion removal• journal grinding• shell surface grinding (crowning)• crack removal• head flange OD reduction• back spot facing of flange surfaces (head,

shell, journal)

Metallizing (full face, spot, edge):

• applying a metallized coating• grinding of a metallized coating

Epoxy filling of surface imperfection

Installation of spoiler bars


450

Maintain/repair/ replace internal condensate removal system

Driven plug repair when completed as de-scribed in K-3053.

K-3050 DAMAGE REPAIR

K-3051 REPAIR OF LOCAL THINNING

A Local Thin Area (LTA) may develop in a pressure-retaining part or may result from the original casting process. Inservice thin areas may result from mechanical wear, erosion-corrosion caused by steam and condensate flow, corrosion, impact damage, or grinding for the removal of material flaws.

Evaluation of thinning for repair shall con-sider the unique design and loading character-istics of the Yankee dryer. Local thin areas are often analyzed as specific cases by the finite element method.

a. When a LTA is evaluated by finite ele-ment method, analysis should consider the location of the thin area and account for strength provided by the vessel cen-tershaft and heads in addition to the strength provided by the shell alone. Such structural analysis should consider all relevant loads to ensure safe operation of the shell according to the De-rate Curve, or other pressure-retaining parts as indi-cated on the original Manufacturer’s Data Report.

b. Following evaluation and determina-tion of maximum allowable operating parameters, a LTA can be coated or filled to prevent further wear or deterioration. Grooves and gouges should always be lightly ground to remove sharp notches and edges. Welding or brazing repairs are NOT permitted on cast-iron pressure-retaining components.

c. Where the LTA is of sufficient size to cause a reduction in maximum allowable oper-ating parameters according to the De-rate Curve, an R-2 Form shall be submitted.

d. Depending upon the cause of the LTA, further monitoring may be necessary to ensure deterioration has been arrested.

e. Inspection data, including all thickness readings and corresponding locations used to determine the minimum and av-erage thicknesses, and the accompanying stress analysis, should be included in the documentation and retained for the life of the vessel.

K-3052 TREATMENT OF CRACK-LIKE FLAWS

Crack-like flaws are planar flaws which are predominantly characterized by a length and depth with a sharp root radius. They may either be embedded or surface breaking. In some cases it may be advisable to treat volu-metric flaws, such as aligned porosity, inclu-sions, and laps, as planar flaws, particularly when such volumetric flaws may contain microcracks at the root.

a. Knowledge of local stress level and clas-sification, and of flaw origin, type, size, location, and angle relative to the princi-pal stress direction is essential in making determinations regarding remediation. It is also important to know whether the crack is active. Acoustic Emissions Testing can be used to determine if the crack is active. Various other methods of nondestructive examination may be employed to determine crack length and depth. Ultrasonics is the recommended sizing technique for depth and inclina-tion of crack-like flaws. Magnetic particle, specifically the wet fluorescent technique, and dye penetrant methods are applicable in determining the length of a surface

A04


451

flaw. Radiographic methods may also be useful. Metallographic analysis is crucial in differentiating between original casting flaws and cracks.

b. Remediation of crack-like flaws, that have been determined to be cracks, is most often accomplished through removal via grinding or machining. Because cast iron is categorized as a brittle material, this is the conservative approach regarding crack-like flaws. Welding/brazing repairs are NOT permitted for cast-iron parts.

c. Crack-like flaws that have been identi-fied as cracks, but which developed from normal service exposure or excessive operating conditions, shall be remediated by appropriate means regardless of loca-tion.

d. Crack-like flaws that have been identified as cracks that developed through non-standard load events, such as by water hoses from operation or firefighting or me-chanical damage, shall be remediated if in the shell. Cracks in other pressure-retain-ing parts, shall be analyzed, documented, and monitored to ensure their presence will not be, or have not been, affected by current operating conditions.

e. Crack-like flaws that are not identified as cracks, but existed in the original mate-rial; i.e., material flaws, shall be analyzed, documented, and monitored to ensure their presence will not be, or have not been, affected by current operating condi-tions.

All documents pertaining to the crack-like flaw assessment shall be retained for the life of the vessel. Documentation should address the engineering principles em-ployed, including stress analysis methods and flaw sizing, the source of all material data used, identification of any potential material property degradation mecha-

nisms and the associated influence on the propagation of flaw, and the criteria applied to the assessment procedures.

K-3053 DRIVEN PLUG REPAIR

Shell surface imperfections may be repaired with smooth, driven plugs as described in ASME Section VIII, Div. 1, UCI-78, with the following additional requirements:

a. Maximum plug length (depth) shall be limited to 20% of shell effective thickness, and plug diameter shall not exceed the plug length (depth).

b. Total surface area of plugs shall not exceed 4 sq. in. in an 8 in. diameter circle (2580 sq. mm in a 200 mm diameter circle).

c. Average number of shell plugs shall not exceed one plug per 1 sq. ft. (1 plug per 0.1 sq. m) of the surface.

d. The land distance between edges of plugs shall be at least equal to the diameter of the larger plug.

e. The plug material shall conform in all respects to the material specification of the base material.

f. The installed plug shall have an interfer-ence fit. The average hold diameter is determined after the plug hole is drilled or reamed. The maximum plug diameter shall not exceed 1.012 times the average hole diameter. This provides an interfer-ence fit while minimizing the residual stresses.

g. All plug repair work shall be documented in the form of a plug repair map or other suitable method of recording and retained in the dryer’s permanent file.

A04


452

K-4000 ALTERATIONS TO YANKEE DRYERS

K-4010 SCOPE

This section provides additional requirements for alterations to Yankee dryer pressure-retaining components and shall be used in conjunction with K-1000 and K-2000.

K-4020 ALTERATION TYPES

Any change in the Yankee dryer (shell, heads, center shaft, fasteners), as described on the original Manufacturer’s Data Report, which affects the pressure-retaining capability shall be considered an alteration. Examples of alterations are:

a. Drilling/enlarging of bolt holes in castings for larger diameter bolts;

b. Replacement of structural bolts differing in size, material, or design, from those described on the Manufacturer’s Data Report;

c. Removal of shell overhung flange;

d. Journal machining;

e. Head flange outside diameter reduction;

f. Machining of head flange or shell flange surface to remove corrosion;

g. Operating above the nameplate tempera-ture.

Alteration procedures shall be written, re-viewed, approved, and accepted by the In-spector prior to the start of work.

453

Interpretations

These interpretations are not part of the NBIC and are provided for information only.

Indices are provided for Interpretations of the 1995 and later edi-tions/addenda of the NBIC.

Previously issued interpretations are included for convenience. Users of the Code are cautioned to check the validity of these interpretations prior to use.

454


PARAGRAPH INDEX

Foreword ......................................................................................................................... 95-20

Code Cases 1923 .................................................................................................................. 98-24 .......................................................................................................................... 98-56 1945 .................................................................................................................. 98-24 .......................................................................................................................... 98-56 2203 .................................................................................................................. 98-12

RA-2130 Procedure for Obtaining or Renewing a National Board Certifi cate of Authorization ......................................................................... 98-21RA-2151 Outline of Requirements for a Quality System for Qualifi cation for the National Board “R” Symbol Stamp .................. 98-13RA-2231 Condition of Use .............................................................................................. 98-2RA-2262 Nameplate Contents ...................................................................................... 98-25 .......................................................................................................................... 98-26 .......................................................................................................................... 95-26RA-2274 Use of Owner/User Personnel During Repairs ........................................ 01-12RA-2281 Test Medium and Testing Equipment ......................................................... 98-17RA-2330 Procedure for Obtaining or Renewing a National Board “NR” Certifi cate of Authorization ................................................................ 98-7 .......................................................................................................................... 98-41RA-3020 Prerequisites for Accreditation .................................................................... 98-16RA-3050 General Conditions ....................................................................................... 98-11

RB-3234 Pressure Testing ............................................................................................. 95-38RB-3237 Inspection Interval ......................................................................................... 98-19RB-3238 Conditions that Affect Remaining Life Evaluation .................................. 01-26 ............................................................................................................................ 98-3 .......................................................................................................................... 95-57RB-3550 Operational Inspection ................................................................................. 95-55RB-3640 Inspection of Parts and Appurtenances ....................................................... 98-9RB-4000 Restamping or Replacement of Nameplates ............................................. 98-35 .......................................................................................................................... 95-47RB-4010 Replacement of Stamped Data ..................................................................... 01-13

RC-1000 General Requirements .................................................................................. 95-19RC-1010 Scope ................................................................................................................ 98-22RC-1020 Construction Standard .................................................................................. 95-36 .......................................................................................................................... 95-48RC-1040 Materials ......................................................................................................... 01-28RC-1050 Replacement Parts ......................................................................................... 98-14 .......................................................................................................................... 98-27 .......................................................................................................................... 98-28 .......................................................................................................................... 98-37 .......................................................................................................................... 95-48RC-1090 Welding ........................................................................................................... 01-27 ............................................................................................................................ 98-6 .......................................................................................................................... 95-51RC-1110 Nondestructive Examination ....................................................................... 01-24 .......................................................................................................................... 98-10 .......................................................................................................................... 95-41

455

INTERPRETATIONS

RC-2031 Routine Repairs .............................................................................................. 01-19 .......................................................................................................................... 01-20 .......................................................................................................................... 01-22 .......................................................................................................................... 01-23 ............................................................................................................................ 98-1 ............................................................................................................................ 98-4 .......................................................................................................................... 98-18 .......................................................................................................................... 98-31 .......................................................................................................................... 98-42 .......................................................................................................................... 95-27 .......................................................................................................................... 95-28 .......................................................................................................................... 95-31 .......................................................................................................................... 95-33 .......................................................................................................................... 95-53RC-2050 Examination and Test .................................................................................... 98-27 .......................................................................................................................... 98-33 .......................................................................................................................... 98-36 .......................................................................................................................... 95-27 .......................................................................................................................... 95-32 .......................................................................................................................... 95-39 .......................................................................................................................... 95-54RC-2051 Pressure Testing Repairs ............................................................................... 01-15RC-2070 Documentation ............................................................................................... 01-29 .......................................................................................................................... 95-50RC-2082 Repair Plan ..................................................................................................... 01-14RC-3000 Alterations to ASME Section VIII, Div. 2 .................................................... 01-16RC-3020 Design .............................................................................................................. 98-14 .......................................................................................................................... 95-22RC-3021 Calculations .................................................................................................... 01-17RC-3022 Re-rating .......................................................................................................... 01-11 .......................................................................................................................... 98-14 .......................................................................................................................... 98-15 .......................................................................................................................... 98-20 .......................................................................................................................... 98-32RC-3030 Examination and Test .................................................................................... 98-15 .......................................................................................................................... 98-34 .......................................................................................................................... 98-38RC-3050 Documentation ............................................................................................... 01-25 .......................................................................................................................... 95-50

RD-1010 Scope .................................................................................................................. 98-6RD-2020 Scope .................................................................................................................. 98-8RD-2030 Wasted Areas .................................................................................................. 98-42RD-2050 Re-Ending or Piecing Pipes or Tubes .......................................................... 98-36RD-2060 Patches ............................................................................................................. 95-52RD-2070 Stays ................................................................................................................. 98-40

Appendix 2 Stamping and Nameplate Information ...................................................... 95-24

Appendix 4 Glossary of Terms .......................................................................................... 95-21 .......................................................................................................................... 95-29 .......................................................................................................................... 95-34 .......................................................................................................................... 95-43 .......................................................................................................................... 95-45

456


Appendix 5 National Board Forms ................................................................................... 98-39 .......................................................................................................................... 95-25 .......................................................................................................................... 95-30 .......................................................................................................................... 95-40 .......................................................................................................................... 95-42

Appendix 6 Examples of Repairs and Alterations .......................................................... 01-21 .......................................................................................................................... 98-23 .......................................................................................................................... 98-29 .......................................................................................................................... 98-30 .......................................................................................................................... 95-44 .......................................................................................................................... 95-46 .......................................................................................................................... 95-48 .......................................................................................................................... 95-49Appendix 8 Repairs ............................................................................................................. 01-18

SUBJECT INDEX

Alterations to ASME Section VIII, Div. 2 ................................................................................. 01-16alternatives to PWHT ................................................................................................................... 98-6attachments ............................................................................................................................ 98-1blisters, repair of ........................................................................................................................... 98-9calculations .......................................................................................................................... 01-17deaerators, inspection of ............................................................................................................. 98-9defi nition of repair ...................................................................................................................... 98-23 .......................................................................................................................... 98-29 .......................................................................................................................... 98-30 .......................................................................................................................... 95-43 .......................................................................................................................... 95-45 .......................................................................................................................... 95-46 .......................................................................................................................... 95-49defi nition of alteration ................................................................................................................ 95-21 .......................................................................................................................... 95-36 .......................................................................................................................... 95-44 .......................................................................................................................... 95-45defi nition of inspector ................................................................................................................ 95-29defi nition of non-load bearing .................................................................................................. 95-33demonstration requirements ..................................................................................................... 98-41derating .......................................................................................................................... 98-20deterioration .......................................................................................................................... 01-26documentation .......................................................................................................................... 01-25 .......................................................................................................................... 95-50examples of repairs and alterations .......................................................................................... 01-21inspection interval ....................................................................................................................... 98-19inspection interval ....................................................................................................................... 95-57joint review demonstration requirements ............................................................................... 98-21material thickness ....................................................................................................................... 98-36materials .......................................................................................................................... 01-28MTR .......................................................................................................................... 98-37nameplates .......................................................................................................................... 95-24non “U” stamped vessels ........................................................................................................... 95-23

457

INTERPRETATIONS

nondestructive examination ...................................................................................................... 01-24 .......................................................................................................................... 98-10nuclear components ...................................................................................................................... 98-7original code of construction ..................................................................................................... 95-19out-of-service ............................................................................................................................ 98-3owner-user inspection ................................................................................................................ 98-11 .......................................................................................................................... 98-16piping .......................................................................................................................... 98-22pressure relief valves .................................................................................................................... 98-2 .......................................................................................................................... 98-13 .......................................................................................................................... 98-17 .......................................................................................................................... 98-24 .......................................................................................................................... 98-25 .......................................................................................................................... 98-26 .......................................................................................................................... 95-26 .......................................................................................................................... 95-55 .......................................................................................................................... 95-56pressure testing .......................................................................................................................... 98-15 .......................................................................................................................... 98-27 .......................................................................................................................... 98-33 .......................................................................................................................... 98-34 .......................................................................................................................... 98-38 .......................................................................................................................... 95-27 .......................................................................................................................... 95-32 .......................................................................................................................... 95-39 .......................................................................................................................... 95-38pressure testing repairs .............................................................................................................. 01-15qualifi cation of welders/welding procedures ........................................................................ 95-51quality system manual ............................................................................................................... 98-13“R” forms .......................................................................................................................... 98-39 .......................................................................................................................... 95-27 .......................................................................................................................... 95-28 .......................................................................................................................... 95-30 .......................................................................................................................... 95-40 .......................................................................................................................... 95-42 .......................................................................................................................... 95-48 .......................................................................................................................... 95-50repairs .......................................................................................................................... 01-18repair plan .......................................................................................................................... 01-14reclassifi cation .......................................................................................................................... 95-22replacement nameplates ............................................................................................................ 98-35 .......................................................................................................................... 95-47replacement parts ........................................................................................................................ 98-14 .......................................................................................................................... 98-27 .......................................................................................................................... 98-28 .......................................................................................................................... 01-29replacement of stamped data .................................................................................................... 01-13re-rating .......................................................................................................................... 01-11 .......................................................................................................................... 98-14 .......................................................................................................................... 98-15 .......................................................................................................................... 98-32routine repairs .......................................................................................................................... 01-19 .......................................................................................................................... 01-20routine repairs (continued) ........................................................................................................ 01-22

458


.......................................................................................................................... 01-23 ............................................................................................................................ 98-1 ............................................................................................................................ 98-4 .......................................................................................................................... 98-18 .......................................................................................................................... 98-31 .......................................................................................................................... 98-42 .......................................................................................................................... 95-25 .......................................................................................................................... 95-27 .......................................................................................................................... 95-28 .......................................................................................................................... 95-31 .......................................................................................................................... 95-53 .......................................................................................................................... 95-54stays .......................................................................................................................... 95-40timing of repairs ............................................................................................................................ 98-5 .......................................................................................................................... 95-41use of editions/addenda ............................................................................................................ 95-20use of owner/user personnel during repairs .......................................................................... 01-12welding .......................................................................................................................... 01-27window patch .......................................................................................................................... 95-52

459

INTERPRETATIONS

INTERPRETATION NBI 92-4Question: Is it the intent of Chapter III, Supplement 1 that boiler or pressure vessel tube replace-

ment using tubes of an equal or greater allowable stress value be considered a repair when the replacement material satisfies the original ASME Code requirements and such replacement has been accepted by an ASME Code stamp holder or a registered professional engineer?

Reply: No. However, a revision to the 1989 Edition of the NBIC, published in the January 1990 BULLETIN, revised these requirements.

INTERPRETATION NBI 92-5Question: In some instances, the NBIC provides alternative requirements that may be applied

when accepted by the jurisdiction. How may alternative requirements be applied at an installation located in an area where there is no jurisdiction?

Reply: It is the intent of the NBIC that where there is no jurisdiction, alternative requirements may be accepted by the Authorized Inspection Agency responsible for signing the R-1 form.

INTERPRETATION NBI 92-6Question: When a jurisdiction adopts the NBIC, does the jurisdiction adopt any other jurisdiction’s

authorization for an out of state organization to perform repairs?

Reply: No.

INTERPRETATION NBI 92-7Question: When an alteration/re-rating is performed where one organization performs the required

design calculation and a second organization performs the necessary physical work, how may alteration/re-rating be performed by the two organizations?

Reply: It is the intent of the NBIC that the certification of the alteration/re-rating performed by the two organizations may be accomplished in accordance with the following pro-cedure:

1. The “R” Certificate Holder performing the design function shall complete an R-1 Form certifying the design change. The following statement shall be included under remarks on the R-1 form: Design Only.

2. The “R” Certificate Holder performing the field activities, including the pressure test-ing and stamping, shall complete a second R-1 Form certifying the field activities. The “R” Certificate Holder performing the field activities shall be responsible for collecting and distributing all data report forms.

460


INTERPRETATION NBI 93-1Question: Is it a requirement of the Code that the Inspector who performs the acceptance inspec-

tion and certifies the R-1 Form be the same Inspector who authorized the initiation of the repair or alteration?

Reply: No. However, the Inspector who performs the acceptance inspection and certifies the R-1 Form must be employed by the same Authorized Inspection Agency as the Inspec-tor who authorized the repair or alteration.

INTERPRETATION NBI 93-2Question 1: May a fillet welded patch plate be installed as an alteration?

Reply 1: No.

Question 2: May a reinforced opening through the shell be added to a pressure vessel as an altera-tion?

Reply 2: Yes, provided the reinforcing pad meets all the applicable requirements of Section VIII, Division 1 of the ASME Boiler and Pressure Vessel Code, including the provision of weep holes in the reinforcing pad.

INTERPRETATION NBI 93-4Subject: Chapter III, R-301.2 Acceptance of Repairs and Alterations, 1992 editionQuestion: May an Owner-User Commissioned Inspector perform acceptance inspections and sign

an R-1 Form for alterations performed by the Owner-User Inspector’s employer when the employer holds a valid “R” Certificate of Authorization?

Reply: No.

INTERPRETATION NBI 93-5Subject: Chapter III, R-503(d), 1992 editionQuestion: If a pressure test required for a re-rated vessel is less than or equal to the hydrostatic

test performed during construction, is a new pressure test required after the re-rating is completed?

Reply: No, provided no physical work is performed.

INTERPRETATION NBI 93-6Subject: Chapter III, Re-rating, 1992 editionQuestion: Do the rules of the NBIC permit the re-rating of a completed boiler or pressure vessel

to a higher MAWP by performing radiography and recalculating the pressure using a higher joint efficiency?

Reply: No.

461

INTERPRETATIONS

INTERPRETATION NBI 94-1Subject: Chapter III, 1989 editionQuestion: For repair of valves, other than safety, safety relief and relief valves, covered and required

by B31.1 as part of the boiler external piping, is it a requirement of the NBIC that an organization repairing such valves have a valid “R” Certificate of Authorization?

Reply: No.

INTERPRETATION NBI 94-2Subject: Chapter III, Paragraph R-301.1, 1992 editionQuestion: Is it a requirement of the Code the inspector give prior approval for a repair of a routine

nature?

Reply: Yes (Chapter III, R-301.1, page 33).

INTERPRETATION NBI 95-1Subject: Application of the NBIC All EditionsQuestion: In applying the rules of the NBIC, what edition of the NBIC governs the inspection of

a pressure vessel that was built prior to the latest edition of the Code?

Reply: The laws/regulations of the jurisdiction in which the object is located specify which edition of the Code applies to the object. If there is no jurisdiction, the latest edition is applicable.

INTERPRETATION NBI 95-2Subject: R-307 Replacement Parts 1992 Edition with the 1993 AddendaQuestion: When a material change has been specified by the owner for a replacement tube bundle,

altered to upgrade the performance, which will be installed into an existing heat ex-changer shell by mechanical means (no welding), is Form R1, Report of Welded Repair or Alteration, required by R-307.1(c) necessary in addition to the manufacturer’s partial data report supplied by the parts manufacturer?

Reply: Yes. The organization, in possession of a valid Certificate of Authorization for the use of the “R” symbol stamp, that installs the part and affixes the nameplate is responsible for completing the R-1 form.

462


INTERPRETATION NBI 95-3Subject: R-200 Definition of Terms R-404 Authorization of Organizations Making Repairs R-505 Authorization of Organizations Making Alterations 1992 Edition with the 1993 AddendaQuestion 1: An inservice ASME stamped pressure vessel manufactured to the ASME Boiler and

Pressure Vessel Code, Section VIII, Division 1, has its shell diameter turned down below original tolerances. The diameter is then built back up by fusion welding using weld metal having a chemical composition and tensile strength similar to that of the base metal, only to be remachined back to its original tolerances. This is done to provide more wear resistance and also to extend the useful life of the vessel. Is this procedure considered a repair?

Reply 1: Yes.

Question 2: Is the procedure specified in Question (1) considered an alteration if the weld metal has a chemical composition and tensile strength that are not similar to that of the base metal?

Reply 2: Yes.

Question 3: In order to perform the procedures specified in Questions 1 and 2 above to ASME Code vessels and maintain their integrity, in accordance with the NBIC is it required that the organization performing the work hold an “R” Certificate?

Reply 3: Yes.

INTERPRETATION NBI 95-4Subject: U-107 Inspection for Corrosion and Other Deterioration 1992 Edition with the 1993 AddendaQuestion: Is U-107(b) applicable to areas that have wall loss resulting from grinding?

Reply: Yes.

INTERPRETATION NBI 95-5Subject: Purpose and Scope of the NBIC 1992 Edition with the 1993 AddendaQuestion: At what point following the completion of a new power boiler, heating boiler or pres-

sure vessel may the NBIC be used?

Reply: When all requirements of the construction code have been met.

INTERPRETATION NBI 95-6Subject: R-401.2.2 Access Openings 1992 Edition with the 1993 AddendaQuestion: May a fillet welded patch plate be installed as a repair?

Reply: No.

463

INTERPRETATIONS

INTERPRETATION NBI 95-7Subject: Appendix C-R, 3.0 Administrative Procedures 1992 Edition with the 1994 AddendaQuestion: May a renewed “R” Certificate of Authorization be issued based upon a manual review

of an “N” type Certificate of Authorization?

Reply: Yes.

INTERPRETATION NBI 95-8Subject: Appendix C-R, Guide for Completing Form R-1, Report of Welded Repair or Alteration 1992 Edition with the 1994 AddendaQuestion: For instruction 13 of the guide for completing Form R-1, is a manufacturer’s serial

number acceptable for “stamped identification?”

Reply: Noting the manufacturer’s serial number is one acceptable method to address “stamped identification.”

INTERPRETATION NBI 95-9Subject: Chapter III, Supplement 3 Welding Methods as an Alternative to Postweld Heat Treatment 1992 Edition with the 1994 AddendaQuestion: Is it the intent of the 1994 Addendum to the NBIC to prohibit the use of “controlled

preheat” as an alternative method of postweld heat treatment in the repair of pressure vessels?

Reply: Method 1 as shown in the 1992 Edition was inadvertently omitted from the 1994 ad-dendum. The omission should be considered an errata.

INTERPRETATION NBI 95-10Subject: R-301.2.2 Owner-User Acceptance Inspection of Repairs 1992 Edition with the 1994 AddendaQuestion 1: May an Owner-User obtain an “R” Certificate of Authorization?

Reply 1: Yes.

Question 2: May repairs performed by the Owner-User holding an”R” Certificate of Authorization be inspected by Owner-User Commissioned Inspectors?

Reply 2: Yes.

Question 3: May acceptance inspections of alterations be performed by Owner-User Commissioned Inspectors?

Reply 3: No. Acceptance inspections for alterations must be performed by an Inspector employed by an Authorized Inspection Agency (insurance company or jurisdiction).

464


INTERPRETATION NBI 95-11Subject: R-503 Re-rating a Boiler or Pressure Vessel 1992 Edition with the 1994 AddendaQuestion: Do the rules of the NBIC permit the re-rating of a complete boiler or pressure vessel to

a higher MAWP by removing existing weld seams, re-weld seams, performing radiog-raphy and recalculating using a higher joint efficiency?

Reply: No.

INTERPRETATION NBI 95-12Subject: U-107 Inspection for Corrosion and Other Deterioration 1992 Edition with the 1994 AddendaQuestion 1: May the provisions of U-107 Inspection for Corrosion and Other Deterioration of the

1992 Edition, 1994 Addenda of the NBIC be applied to a vessel of any size?

Reply 1: Yes, provided the owner-user’s inspection program has been approved by the jurisdic-tion.

Question 2: When applying U-107(b) in question 1, may any of the readings taken along the length of the properly oriented line (circumferential or longitudinal) be less than the required thickness for pressure?

Reply 2: Yes, as long as the average of the readings taken along the line is equal to or greater than the required thickness for pressure.

INTERPRETATION NBI 95-13Subject: U-106 Maximum Period Between Inspections 1992 Edition with the 1994 AddendaQuestion 1: Does Chapter V mandate the type of inspection to be performed?

Reply 1: No. The type of inspection (internal, external, NDE, etc.) is established by the owner-user and the Inspector provided the inspection method provides sufficient information to determine if the vessel can be safely operated.

Question 2: In accordance with paragraph U-106, may a “complete on-stream evaluation of pressure vessels” be performed in lieu of an internal inspection?

Reply 2: Yes.

Question 3: U-106(c) states that under specific circumstances and when the corrosion rate is known to be zero a vessel need not be internally inspected. Does this mean that an internal inspection is required when the corrosion rate is not zero?

Reply 3: U-106(c) provides guidance for a specific situation. The requirements of U-106(c) are not related to the requirements of U-106(b).

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INTERPRETATIONS

INTERPRETATION NBI 95-14Subject: R-202 Alteration 1992 Edition with the 1994 AddendaQuestion: May a welded repair to a pressure vessel be performed without postweld heat treat-

ment or acceptable alternative to postweld heat treatment, when the pressure vessel as reported on the data report was postweld heat treated during construction?

Reply: No.

INTERPRETATION NBI 95-15Subject: R-307 Replacement of Pressure Parts 1992 Edition with the 1994 AddendaQuestion: Is it permissible to use an assembly from an inservice pressure vessel as a replacement

part for the repair/alteration of a second vessel?

Reply: Yes, provided the intended repair/alteration has the concurrence of the jurisdiction and the Authorized Inspection Agency.

INTERPRETATION NBI 95-16Subject: R-302.1 Welding Procedure Specifications 1992 Edition with the 1994 AddendaQuestion: Is it permissible for a repair organization to carry out repairs using qualified weld pro-

cedure specifications supplied by an owner-user of the boiler, pressure vessel or piping to be repaired?

Reply: No.

INTERPRETATION NBI 95-17Subject: R-404 Authorization of Organizations Making Repairs 1992 Edition with the 1994 AddendaQuestion 1: Is it the intent of the NBIC to permit documented repairs (Form R-1) regardless of

whether documented or undocumented repairs have been performed in the past?

Reply 1: Yes, provided the original construction was to the ASME Code.

Question 2: When an “R” Certificate Holder performs a repair on a vessel, does the Certificate Holder assume responsibility for the work performed by others on the vessel?

Reply 2: No.

466


INTERPRETATION NBI 95-18Subject: Appendix C-NR, NR-1000 Scope and Applicability 1992 Edition with the 1994 AddendaQuestion 1: Is it a requirement of the NBIC that the rules of Appendix C-NR be applied to any re-

pair or modification performed on an ASME Section III N-Stamped item, even though the installed item is not located in a Class 1, 2, or 3 system within the ASME Section XI Program boundaries established by the Owner in accordance with regulatory safety system classification so as to maintain its ASME Section III Code integrity?

Reply 1: No. The rules of Appendix C-NR are not required for repairs or modifications to ASME Section III items installed outside of ASME Section XI system boundaries.

Question 2: Is it a requirement of the NBIC that any work performed on an item prior to its instal-lation in a Class 1, 2, or 3 system within the ASME Section XI Program be performed under the rules of Appendix C-NR?

Reply 2: Yes. Upon completion of the construction Code, any repairs or modifications of an item intended for service in an ASME Section XI system must be performed under the rules of Appendix C-NR to maintain the Code integrity of the item.

Question 3: Is it permissible for the owner to reuse an ASME Section III N-Stamped item that was installed in a location not within the ASME Section XI Class 1, 2, or 3 system, provided all work performed on the item was in accordance with the rules of Appendix C-NR?

Reply 3: Yes. Under the described conditions, the Code integrity would be maintained for pos-sible reuse of the item in an ASME Section XI Class 1, 2, or 3 system application.

Question 4: Under the requirements of Appendix C-NR, is it permissible for the owner to reuse an ASME Section III N-Stamped item that was installed in a location not within the ASME Section XI Class 1, 2, or 3 system even though work had been performed on the item outside the rules of Appendix C-NR?

Reply 4: No. An item on which repair or modification activities have been performed outside of the rules of Appendix C-NR may not be subsequently used in an application which requires compliance with the rules of Appendix C-NR.

INTERPRETATION NBI 95-19Subject: RC-1000 General Requirements 1995 EditionQuestion: When the NBIC references “the original code of construction,” is it required to use the

edition and addenda of that code as used for construction?

Reply: No. The term “original code of construction” refers to the document itself, not the edition/addenda of the document. Repairs and alterations may be performed to the edition/addenda used for the original construction or a later edition/addenda most applicable to the work.

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INTERPRETATIONS

INTERPRETATION NBI 95-20Subject: Foreword, 1995 EditionQuestion: May the requirements of an earlier Edition and Addenda of the NBIC be used when

performing a repair or alteration?

Reply: Yes.

INTERPRETATION NBI 95-21Subject: Appendix 4, Definition of Alteration, 1995 EditionQuestion: May an ASME Section VIII, Division 1 pressure vessel that has postweld heat treatment

reported on an ASME Manufacturer’s Data Report, be repaired by welding without subsequent postweld heat treatment or postweld heat treatment alternatives?

Reply: No. This is an alteration.

INTERPRETATION NBI 95-22Subject: RC-3020 Design, RC-3021 Calculations, 1995 EditionQuestion: May the rules of RC-3020 and RC-3021 be followed to reclassify a vessel originally

constructed to ASME, Section III, to ASME, Section VIII?

Reply: No. The NBIC does not provide rules for reclassification of pressure-retaining items.

INTERPRETATION NBI 95-23Subject: RC-1010 Scope, 1995 EditionQuestion: May repairs to cargo containers that are designed to ASME Section VIII, Division 1,

but are not stamped with the “U” Symbol be documented on the form R-1, if the repair facility maintains the National Board “R” Symbol?

Reply: Yes.

INTERPRETATION NBI 95-24Subject: Appendix 2, 1995 EditionQuestion 1: Are nameplates required to have the same layout as the figures shown in Appendix

2?

Reply 1: No. However, all information shown in the figures must be included on the stamping or nameplate and the National Board Certificate number must appear directly below the symbol stamp.

Question 2: Are the instructions (MAWP, ° F, etc.) shown in the figures in Appendix 2 required to be included on the stamping or nameplate?

Reply 2: Yes. However, the words “Certificate Holder” and “National Board “R” Certificate Number” may be omitted.

468


INTERPRETATION NBI 95-25Subject: Appendix 5, Form R-1, 1995 EditionQuestion: Is it required that the Inspector perform a physical inspection of routine repairs to en-

able completion of the Certificate of Inspection block on Form R-1?

Reply: No. When the Remarks section of Form R-1 includes the Statement “Routine Repairs” in accordance with RC-2031(d), it is understood that the inspection signed for by the Inspector is a document review and that a physical inspection may not have been per-formed.

INTERPRETATION NBI 95-26Subject: RA-2262 Nameplate Contents, 1995 Edition, 1995 AddendumQuestion: Is it the intent of RA-2262 (NB-65, paragraph 9.2(a)) that the capacity and type model

number be included on the valve repair nameplate only when this information has been changed?

Reply: Yes.

INTERPRETATION NBI 95-27Subject: RC-2031 Routing Repairs RC-2050 Pressure Testing RC-2060 Stamping RC-2072 Distribution 1995 EditionQuestion 1: May the repair of cracks or pinholes be considered a routine repair?

Reply 1: The scope of routine repairs are defined in RC-2031. The nature of the defect is not a criteria for determining whether the repair is routine.

Question 2: Is the registration of R-1 forms an option?

Reply 2: Yes, see RC-2072. However, the jurisdiction may require registration (RC-1150).

Question 3: May the “R” Symbol Stamp be applied to a repaired item whether or not the R1 form is registered with the National Board?

Reply 3: Yes, provided all of the requirements of the NBIC are met. See RC-2060.

Question 4: Who is responsible for determining whether or not it is practical to perform a pressure test of a repaired item?

Reply 4: The “R” Certificate Holder. See RC-2050(a).

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INTERPRETATIONS

INTERPRETATION NBI 95-28Subject: RC-2031 Routine Repairs 1995 EditionQuestion: Do the provisions in RC-2031(a) for waiving the inprocess involvement of the Inspector

on routine repairs include waiving the requirement for the Inspector to sign the Form R-1 as addressed in RC-2071(b)?

Reply: No. The requirements of RC-2071(b) are applicable for all repairs, including routine repairs. See RC-2031(d).

INTERPRETATION NBI 95-29Subject: RC-1070 Inspector 1995 EditionQuestion: Is it the intent of the NBIC that a jurisdiction as defined in Appendix 4 which is not a

member of the National Board, employ Inspectors for inspection of repairs and altera-tions as referenced in RC-1070(a)?

Reply: Yes, RC-1070(a) does not restrict the jurisdiction to only National Board Members.

INTERPRETATION NBI 95-30Subject: Data Report Forms 1995 EditionQuestion 1: May repairs or alterations performed in accordance with the requirements of API-510

be documented on NBIC forms R-1 or R-2?

Reply 1: No.

Question 2: May repairs or alterations performed in accordance with the requirements of API-510 be accepted by the Inspector?

Reply 2: This is outside the scope of the NBIC.

INTERPRETATION NBI 95-31Subject: RC-2031 Routine Repairs 1995 Edition, 1995 AddendumQuestion: Do the provisions in RC-2031(b) for waiving the inprocess involvement of the Inspector on routine repairs include waiving the requirement for the Inspector to wit-

ness a pressure test as addressed in RC-1130?

Reply: Yes.

INTERPRETATION NBI 95-32Subject: RC-2050 Pressure Testing 1995 Edition, 1995 AddendumQuestion: In RC-2050(a), does the expression “shall be pressure tested at 80% of the maximum al-

lowable working pressure stamped on the pressure-retaining item or operating pressure, whichever is greater” mean not less than the greater of 80% of the maximum allowable working pressure or the operating pressure?

Reply: Yes.

470


INTERPRETATION NBI 95-33Subject: RC-2031(a)(2) Definition of “non-load bearing” 1995 EditionQuestion: Does the NBIC specify a quantitative value below which an attachment is considered

non-load bearing?

Reply: No, “non-load bearing attachment” is a generally accepted design term referring to items that transmit an inconsequential load onto the pressure retaining boundary.

INTERPRETATION NBI 95-33(a)Subject: Appendix C-R, 4.0 (f) 1992 Edition with the 1994 AddendumQuestion: May an “R” Certificate of Authorization holder with field repair in the scope of its “R”

Certificate perform repairs and alterations in other shops owned by the Certificate Holder?

Reply: No. Each shop must have its own certificate.

INTERPRETATION NBI 95-34Subject: Appendix 4, Definition of an Authorized Inspection Agency 1995 EditionQuestion 1: In Appendix 4, the definition of an Authorized Inspection Agency refers to the National

Board Rules and Regulations. If an Inspector is assigned to a shop that only holds an “R” Certificate of Authorization and performs inspections of repairs and alterations to pressure-retaining items, is the Authorized Inspector Supervisor required to audit the performance of the Inspector as specified in 3.4.3.(d) of the National Board Rules and Regulations?

Reply 1: No.

Question 2: In Appendix 4, the definition of an Authorized Inspection Agency refers to the National Board Rules and Regulations. If an Inspector is assigned to a shop that only holds an “R” Certificate of Authorization and performs inspections of repairs and alterations to pressure-retaining items, is the Inspector required to monitor the quality program?

Reply 2: No; however, the Inspector shall assure compliance with the requirements of the NBIC. See RC-1130.

INTERPRETATION NBI 95-35Subject: R-200 Definition of Terms 1992 Edition with the 1994 AddendumQuestion 1: Is the welding in of a plug to seal tubes in a boiler or pressure vessel considered a re-

pair?

Reply 1: Yes.

Question 2: Does the NBIC apply to plugging tubes by welding plugs to tubes and/or their joints to tube sheets of tubes that have leaked, tubes that have corroded to an unacceptable thin wall thickness, and tubes required to be removed from service for operating reasons in boilers and pressure vessels?

Reply 2: Yes.

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INTERPRETATIONS

INTERPRETATION NBI 95-36Subject: RC-1020 Construction Standards 1995 Edition with the 1995 AddendumQuestion: When work is performed under the NBIC to a code other than the original code of

construction, is it required that the work be classified as an alteration?

Reply: No, see RC-1020. The use of a different design basis code does not necessarily require work to be classified as an alteration; however, the concurrence of the Inspector and the jurisdiction is required for this determination.

INTERPRETATION NBI 95-37Withdrawn

INTERPRETATION NBI 95-38Subject: RB-3234 Pressure Testing 1995 Edition with the 1995 AddendumQuestion: Does RB-3234 allow for an in-service pressure test in excess of 1-1/2 times the MAWP

adjusted for temperature?

Reply: No, where any provision of the NBIC presents a direct or implied conflict with any regulation, the jurisdictional regulation shall govern. However, in these circumstances, the activity cannot be documented as meeting the requirements of the NBIC.

INTERPRETATION NBI 95-39Subject: RC-2050 Pressure Testing 1995 Edition with the 1995 AddendumQuestion: Is the performance of a pressure test in accordance with RC-2050(a) required after a

routine repair?

Reply: Yes, except as permitted by RC-2050(g).

INTERPRETATION NBI 95-40Subject: Appendix 5, Form R-2 Report of Alteration 1995 Edition with the 1995 AddendumQuestion 1: Does the NBIC require that the Data Report Forms used to report repairs and alterations

be identical to the forms shown in Appendix 5?

Reply 1: Yes.

Question 2: May the Data Report Forms used for repairs and alterations be computer generated?

Reply 2: Yes, provided they are identical to the forms shown in Appendix 5.

472


INTERPRETATION NBI 95-41Subject: RC-1110 Nondestructive Examination 1995 Edition with the 1995 AddendumQuestion 1: When performing in-service inspection, radiographic examination uncovers indications

in welds made by the original manufacturer that are in excess of that allowed by the original code of construction. Is it a requirement that these welds be repaired?

Reply 1: The decision as to whether or not to perform a repair of deficiencies discovered during in-service inspection is outside the scope of the Code. See RB-3280.

Question 2: When nondestructive examination of a repair weld reveals indications in excess of that allowed by the original code of construction, must the indication be removed or reduced to an acceptable size?

Reply 2: Yes.

INTERPRETATION NBI 95-42Subject: RC-2070 Documentation RC-3050 Documentation 1995 Edition with the 1995 AddendumQuestion: When work classified as an alteration is performed in conjunction with work on the

same pressure-retaining item classified as a repair, do both Form R-1 and Form R-2 need to be prepared?

Reply: No, as long as the repair work is identified on Form R-2 along with the alteration work.

INTERPRETATION NBI 95-43Subject: Appendix 5, Definition of Repair 1995 Edition with the 1995 AddendumQuestion: May the welding of a new circumferential seam in a completed, code stamped and

certified ASME Code pressure vessel be classified as a repair?

Reply: Yes.

INTERPRETATION NBI 95-44Subject: Appendix 6, Item C-5 Examples of Alterations 1995 Edition with the 1995 AddendumQuestion: For a boiler stamped in accordance with the ASME Code, Section I, is it the intent of

Appendix 6, paragraph C.5 that an increase in heating surface be considered an altera-tion only when the resulting change requires an increase in the relieving capacity of the safety valves?

Reply: Yes.

473

INTERPRETATIONS

INTERPRETATION NBI 95-45Subject: Appendix 4 Definition of Repair 1995 Edition with the 1995 AddendumQuestion 1: Providing there is no work performed on pressure-retaining items, is the removal of

a coal grate, installation of new burners, brick wall modifications, and concrete and refractory work outside the scope of the NBIC?

Reply 1: Yes, provided the required safety or safety relief valve relieving capacity is not in-creased.

Question 2: In a high temperature water boiler, is an increase in the maximum design output in Btu/hr, which requires an increase in the safety relief valve relieving capacity considered an alteration in accordance with the NBIC?

Reply 2: Yes.

INTERPRETATION NBI 95-46Subject: Appendix 6, B-7 1995 Edition with the 1995 AddendumQuestion 1: May the example of a repair given in Appendix 6, paragraph B-7 apply to a nozzle or

an opening for which the axis is not perpendicular to the wall or head of a pressure-retaining item?

Reply 1: Yes, provided calculations to determine availability of reinforcement (compensation) for such construction is not a consideration of the original code of construction.

Question 2: May the example of a repair given in Appendix 6, paragraph B-7 apply to nozzles and openings larger than NPS 3?

Reply 2: Yes, provided calculations to determine availability of reinforcement (compensation) for such construction is not a consideration of the original code of construction.

INTERPRETATION NBI 95-47Subject: RB-4020 1995 Edition with the 1995 AddendumQuestion: When replacing a nameplate, may the National Board number be stamped on the re-

placement nameplate by the original manufacturer when the manufacturer no longer holds an ASME Certificate of Authorization?

Reply: Yes, provided the requirements of RB-4000 are met.

474


INTERPRETATION NBI 95-48Subject: RC-1020, RB-1050(a) & Appendix 6, B-6 1995 Edition with the 1995 AddendumQuestion 1: May retubing and testing a boiler whose original code of construction is ASME Section

IV be documented on an R-1 if the replacement tubes are expanded as permitted in ASME Section IV, HG-360.2?

Reply 1: Yes, provided all applicable requirements of the NBIC are met.

Question 2: May repairs to saddles, frames or supports of pressure vessels be documented on an R-1?

Reply 2: Yes, provided all applicable requirements of the NBIC are met.

INTERPRETATION NBI 95-49Subject: Appendix 6, B-17 1995 Edition with the 1995 AddendumQuestion: Does the example of a repair given in Appendix 6, paragraph B-17 apply only to mate-

rial changes within a single P number?

Reply: No.

INTERPRETATION NBI 95-50Subject: RC-2072 and RC-3052 1995 Edition with the 1996 AddendumQuestion: Does the term “attachment” as used in RC-2072 and RC-3052 refer to Material Test

Reports?

Reply: No, the term applies to R-3, R-4 and Manufacturer’s Partial Data Reports.

INTERPRETATION NBI 95-51Subject: RC-1090 1995 Edition with the 1996 AddendumQuestion: May an “R” Certificate Holder use weld procedures and welders qualified by a techni-

cally competent group or agency?

Reply: Yes, as permitted by RC-1092 or when allowed by the original code of construction.

INTERPRETATION NBI 95-52Subject: RD-2060 Patches, Figure 8 1995 Edition with the 1996 AddendumQuestion 1: Is there a maximum length to width ratio for the tube window patch configuration?

Reply 1: No, the NBIC does not specify dimensions for the patch.

Question 2: Is there a maximum dimension allowed for the tube window patch?

Reply 2: No, the NBIC does not specify dimensions for the patch.

475

INTERPRETATIONS

INTERPRETATION NBI 95-53Subject: RD-2031 Routine Repairs 1995 Edition with the 1995 AddendumQuestion 1: Is the addition of a nozzle penetrating through a head or shell considered a routine

repair?

Reply 1: No.

Question 2: Is a pipe nozzle that penetrates a head or shell considered a section of pipe used in RC-2031?

Reply 2: No.

INTERPRETATION NBI 95-54Subject: RC-2050 Pressure Testing 1995 Edition with the 1996 AddendumQuestion: In accordance with RC-1130 is it required that the Inspector witness any pressure test

of a repair or alteration?

Reply: Yes, except as provided by RC-2031 (b).

INTERPRETATION NBI 95-55Subject: RB-3550 Operational Inspection 1995 Edition with the 1996 AddendumQuestion: Under the provisions of paragraph RB-3550, may a repair organization that meets the

requirements of RA-2220 act as the designee of a pressure vessel user to make adjust-ments to a steam service pressure relief valve with air as the test media, provided that:

a) the jurisdiction has authorized such adjustments; b) no “VR” Symbol is applied to the pressure relief valve?

Reply: Yes.

INTERPRETATION NBI 95-56Subject: RA-2231 (b)(1) Acceptance of Code Cases 1923 and 1945 when used in Original Construction 1995 Edition with the 1996 AddendumQuestion: Under the provisions of paragraph RA-2231 (b)(1) is it permissible for a “VR” stamp-

holder to repair a restricted lift valve when ASME Code Case 1923-2 or 1945-3 was used in the original construction?

Reply: Yes, provided no change is made in valve lift.

476


INTERPRETATION NBI 95-57Subject: RB-3238(e) Above Ground Vessels 1995 Edition with the 1996 AddendumQuestion 1: Does the interval of the lesser of five (5) years or 1/4 life refer only to an initial external

inspection?

Reply 1: No.

Question 2: Does the NBIC establish an inspection interval for periodic external examinations?

Reply 2: Yes. The external inspection interval is defined in RB-3238 (e) & (f) with remaining life calculated as per RB-3236.

INTERPRETATION VR86-10Question: May a pressure relief valve repair organization be qualified for a “VR” certificate of

authorization utilizing mobile test facilities for shop and field use provided the require-ments of NB-65 (NBIC)are met and the repair organization applies and successfully surveys for a “VR” certificate of authorization?

Reply: Yes

INTERPRETATION VR-1-1986Question: It is permissible to apply the “VR” stamp to a valve repaired under an ASME Code sec-

tion other than that for which it was originally stamped and National Board capacity certified?

Reply: No

INTERPRETATION VR-87-2Question: Under the provisions of NB-65, paragraph 11.1.3, (NBIC RA-2283) is it permissible to

use an auxiliary lifting device in shop to establish the valves set pressure?

Reply: Yes, provided this procedure is addressed in the quality control manual and also covered in the scope.

INTERPRETATION VR-88-1Question: May a “VR” applicant, who also submits liquid valves for and successfully acquires

capacity certification as an assembler in accordance with Section VIII of the ASME Boiler and Pressure Vessel Code, qualify for a scope of work which includes liquid as test me-dium without submitting a repaired valve as required by NB-65, revision 7, paragraph 2.2.1(b) (NBIC RA-2224(b))?

Reply: No

477

INTERPRETATIONS

INTERPRETATION VR-88-2Question 1: Is it permissible to apply the “VR” stamp to a repaired “UV” stamped valve to be tested

and set on air or steam while the manufacturer’s nameplate indicates capacity certifica-tion in steam or air respectively?

Reply 1: Yes, provided: 1. The valve holds National Board capacity certification for both media;

2. The original manufacturer’s specifications are checked and required modifications are made for the medium to be changed to;

3. The spring is verified for the application;

4. The Owner-User specifically requests the change;

5. The original capacity is lined through, yet left legible on the original nameplate, and the new capacity indicated on the repair nameplate.

Question 2: May a repair organization change the Code status (e.g. change a “V” symbol stamped valve to a “UV”,”HV” or “NV” symbol stamped valve or vice-versa) of a repaired pres-sure relief valve?

Reply 2: No

INTERPRETATION VR-88-04Question: Is it a requirement before issuance or renewal of Certificates of Authorization that an-

nual audits be performed under paragraph 10.2(d) of NB-65 (NBIC RA-2273) if no field work was performed?

Reply: No

INTERPRETATION VR-89-01Question: In accordance with Appendix B, Part II, item 2 of NB-65 (NBIC Appendix 7, Part II, item

2), is it permissible to apply the “NR” - “VR” stamp to “NV” stamped National Board certified pressure relief valves that were manufactured prior to 1971 ASME Code, Sec-tion III, which did not specify Class 1, 2 or 3?

Reply: Yes

INTERPRETATION VR89-05Question: In accordance with NB-65 paragraph 11.1(a) (NBIC RA-2281), is it permissible to apply

the “VR” stamp without conducting the performance testing of a Pilot Operated Pres-sure Relief Valve in their final combined configuration?

Reply: No

478


INTERPRETATION VR-90-01Question: May one of the valves which is submitted for replacement testing in accordance with

paragraph 2.3.1(c) of NB-65 (NBIC-2228(c))be considered to meet one of the two valve minimum as required in paragraph 2.2.1(b) of NB-65 (NBIC RA-2224(b))?

Reply: No

INTERPRETATION VR91-03Question: Is it permissible for a manufacturer to apply the “VR” symbol to valves repaired at one

location in accordance with NB-65, paragraph 8.3.1(a) (NBIC RA-2258(a)), to valves of identical design manufactured by the same organization at a different location whose capacity certifications were in accordance with ASME Code Interpretations I-86-23, IV-86-11 and VIII-1-86-52?

Reply: Yes, provided that the following conditions are met: 1. Each “VR” certificate holder has met the requiremetns of NB-65, paragraph 8.3.1(a)

(NBIC RA-2258(a))and holds a valid ASME Certificate of Authorization, as appropriate for Code Symbol stamps “V”, “HV”, or “UV”.

2. The “VR” certificate holder may only apply the “VR” symbol to repaired valves of the same design as covered by his ASME Certificate of Authorization.

3. The “VR” certificate holder maintains an approved quality control system to ensure that all NB-65 (NBIC)requirements are met.

INTERPRETATION VR-92-01Question: For the repair of pressure relief valves at an owner-user’s facility, for the owner-user’s

own use, may temporary contract personnel be considered the owner-user’s personnel for the purpose of assisting a “VR” certificate holder in the performance of pressure relief valve repairs, provided the requirements of paragraph 10.3 of NB-65 (NBIC RA-2274) are met?

Reply: Yes

INTERPRETATION VR92-02Question: May Code Case 2071 be applied to a “VR” production valve being tested in accordance

with paragraph 11.1.1(a) of NB-65 (NBIC RA-2281)when it is marked with the Code Case number?

Reply: Yes

INTERPRETATION VR92-03Question: May Code Case 2071 be applied to a “VR” production valve being tested in accordance

with 11.1.1(a) of NB-65 (NBIC RA-2281) when it is not marked with the Code Case number?

Reply: No

479

INTERPRETATIONS

INTERPRETATION VR92-04Question: May Code Case 2071 be applied to a “VR” verification valve submitted in accordance

with paragraph 2.3 of NB-65 (NBIC RA-2224(b))when it is not marked with the Code Case number?

Reply: No

INTERPRETATION VR92-05Question: May Code Case 2071 be applied to a “VR” verification valve submitted in accordance

with paragraph 2.3 of NB-65 (NBIC RA-2224(b))when it is marked with the Code Case number?

Reply: No

INTERPRETATION VR93-02Question: Is it permissible for a manufacturer who has obtained a “VR” Certificate of Authoriza-

tion under the provisions of Paragraph 8.3.1(a) of NB-65 (NBIC RA-2258(a)) to apply a “VR” Stamp to valves they had previously ASME Code stamped as an assembler or to valves manufactured by the organization they were an assembler for?

Reply: No

INTERPRETATION VR93-08Question: May a pressure relief valve used at a location other than that of the certificate holder be

tested in accordance with NB-65 paragraph 11.2 (NBIC RA-2282)?

Reply: Yes, provided the repair activities are within the scope stated on the certificate, both locations are within the same metropolitan area and owned and operated by the same user, and the quality control manual addresses provisions for using only qualified per-sonnel for final adjustments.

INTERPRETATION VR94-01Question: Does paragraph 3.4 of NB-65 (NBIC RA-2242) permit steam test facilities which are not

located at the address of record?

Reply: Yes, provided the steam test facility, location and control of all aspects of the testing are described in the quality control manual and verification testing of required valve(s) is performed in accordance with NB-65, paragraph 2.2.1(b) and 2.3 (NBIC pars. RA-2224(b) and RA-2228) . These controls shall include the measures used to ensure only employees of the certificate holder perform any adjustments to the valves being tested as required by paragraphs 11.0 and 12.0 (NBIC RA-2281 and RA-2290). The address of testing shall be recorded on the document required by NB-65 paragraph 8.2.1(i)(2) (NBIC RA-2258(i)(1)) for each steam valve.

480


INTERPRETATION VR94-02Question: May an applicant who has shop equipment (including test equipment for air and/ or

water) extend their “VR” Certificate of Authorization to include field-only repairs of ASME Section I pressure relief valves in accordance with NB-65 paragraph 2.2.4 (NBIC RA-2242)?

Reply: No. Paragraph 10.2 (NBIC RA-2272) permits only a “VR” Certificate of Authorization for field repair both as an extension of their in-shop/plant scope or as a field-repair-only scope.

INTERPRETATION 98-1Subject: RC-2031(a)(1) 1995 Edition with the 1997 AddendumQuestion: In RC-2031(a)(1), does the phrase “and their attachments” refer to such items as: (a) joining of pipe to pipe and tube to tube; (b) attachments such as clips, lugs, rings, devices, skirts, etc.; (c) nozzles and other connections welded to shells, drums and headers?

Reply: (a) No. (b) Yes, provided postweld heat treatment is not required by the original code of con-

struction for the attachment weld. (c) No.

INTERPRETATION 98-2Subject: RA-2231 Conditions of Use 1995 Edition with the 1996 AddendumQuestion: Does RA-2231(b) require that the “VR” stamp be applied only to pressure relief valves

which meet the following conditions: (a) the valves are stamped with an ASME “V”, “UV”, or “NV” Code Symbol or marked

with an ASME “HV” Symbol and have been capacity certified on the applicable fluid by the National Board; and

b) have been dissembled, inspected and repaired such that the valve’s condition and performance are equivalent to the standards for new valves in the year they were manufactured?

Reply: Yes.

INTERPRETATION 98-3Subject: RB-3238 Interrupted Service 1995 Edition with the 1995 AddendumQuestion 1: Does paragraph RB-3238(f) of the NBIC define when a pressure vessel is inservice or

out-of-service?

Reply 1: No, the NBIC does not define out-of-service or in-service. This is subject to jurisdictional requirements.

Question 2: When returning a pressure vessel to service, do the requirements of paragraph RB-3238(f) apply even if the pressure vessel was inspected to other requirements while not inservice?

Reply 2: Yes.

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INTERPRETATION 98-4Subject: RC-2031 Routine Repair 1995 Edition with the 1996 AddendumQuestion 1: Does RC-2031(a)(1) limit routine repairs to a single tube or pipe?

Reply 1: No.

Question 2: May the repair of more than one tube or pipe be classified as a routine repair?

Reply 2: Yes, subject to the acceptance of the jurisdiction and the Inspector.

INTERPRETATION 98-5Subject: Foreward 1995 Edition with the 1996 AddendumQuestion: Do the rules of the NBIC require the repair of a pressure-retaining item when the pres-

sure-retaining item no longer complies with the original code of construction?

Reply: No, the NBIC does not provide rules for determining when a repair must be performed. (See RB-3180 and RB-3280).

INTERPRETATION 98-6Subject: RC-1090 Welding RD-1010 Scope 1995 Edition with the 1996 AddendumQuestion 1: May the rules of the original code of construction be used for welding non-pressure

parts to a pressure-retaining item?

Reply 1: Yes.

Question 2: Is it required that the alternative methods shown in RD-1000 be applied to repairs and alterations?

Reply 2: No. RD-1000 includes alternatives that may be used in lieu of the original code of con-struction. When an alternative method is used, all requirements of the alternative must be met.

482


INTERPRETATION 98-7Subject: RA-2330(d) 1995 Edition with the 1996 AddendumQuestion 1: If an ASME Section III component is installed in a location outside the ASME Section

XI program boundary, is it a requirement of RA-2330(d) that ASME Section XI activities (e.g., VT-2 examination) be performed as part of an “NR” repair or replacement activ-ity?

Reply 1: Yes.

Question 2: Is it permissible for an Owner to use an ASME Section III component previously installed in a location outside of the Section XI program boundary in a location within the ASME Section XI boundary as long as all previous work performed on the item was performed in accordance with NBIC requirements?

Reply 2: Yes, provided the component is examined in accordance with the appropriate ASME Section XI requirements for its intended use.

INTERPRETATION 98-8Subject: RD-2010 Scope 1995 Edition with the 1996 AddendumQuestion: May a “blister” in a pressure-retaining item be repaired by the drilling of a hole in the

center of the blister, hammering the blister flat, and rewelding the hole?

Reply: When the NBIC does not specify or otherwise limit the repair technique to be used, it is the responsibility of the “R” Certificate Holder with the concurrence of the Inspector to choose the appropriate technique. However, the chosen technique must remove the defect.

INTERPRETATION 98-9Subject: RB-3640 1995 EditionQuestion: Does the NBIC (NBIC) require an atmospheric deaerator vessel to be inspected in ac-

cordance with part RB-3640?

Reply: No. Part RB provides recommendations for the conduct of inspections; however, the jurisdiction may mandate the use of RB-3600.

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INTERPRETATION 98-10Subject: RC-1110 1995 EditionQuestion 1: Do the buttwelded joints used to replace a portion of a tube sheet in an ASME Section I

firetube boiler require the same nondestructive examination as longitudinal buttwelded joints in an ASME Section I boiler?

Reply 1: Yes.

Question 2: If the Reply to question #1 above is “Yes” and the NDE requirements of the original code of construction are not possible or practicable, may alternative NDE methods be used?

Reply 2: Yes, RC-1110 permits the use of alternative NDE methods that are acceptable to the Inspector and, where required, the jurisdiction.

INTERPRETATION 98-11Subject: RA-3050 1995 Edition with the 1996 AddendumQuestion 1: Are inservice inspections performed under the Owner-User accreditation program valid

when the inspected items are intended for lease or rent, or installed for use at other locations?

Reply 1: No.

Question 2: Are repair inspections performed by an Owner-User inspection organization valid when the item(s) repaired are intended for lease or rent, or installed for use at another organization’s location?

Reply 2: No.

Question 3: May an inspector who is employed by an accredited Owner-User inspection organiza-tion perform repair authorization and acceptance inspections for pressure-retaining items not owned or used by the Owner-User accredited inspection organization?

Reply 3: No.

INTERPRETATION 98-12Subject: Use of Code Case 2203 in Repairs 1995 Edition with the 1996 AddendumQuestion: Under the provisions of paragraph RA-2231(b)(1), is it permissible to apply ASME

Code Case 2203 and convert a pressure relief valve by removing the lifting device that is required by Section VIII, Division 1, paragraph UG-136(a)(3) and Section VIII, Divi-sion 2, paragraph I-101?

Reply: Yes, provided that the “VR” Certificate Holder verifies that: 1. All of the requirements of ASME Code Case 2203 are met, and 2. That all of the requirements of the NBIC concerning conversions, and specifically,

paragraphs R-2231(b)(2) and RA-2262(b)(3) are met.

484


INTERPRETATION 98-13Subject: RA-2151r 1995 Edition with the 1996 AddendumQuestion: Does RA-2151r require an “R” Certificate Holder to list or reference, in the Quality

System Manual, the specific construction codes that may be used while performing repairs or alterations?

Reply: No; however, the Quality System Manual must include provisions for addressing requirements imposed by specific construction codes used for repairs and alterations.

INTERPRETATION 98-14Subject: Appendix 6, Examples of Repairs and Alterations RC-1050 Replacement Parts RC-3022 Re-rating RC-3020 Design 1998 EditionQuestion 1: Does the example of an alteration given in Appendix 6, paragraph C.7, for replacement

of a pressure retaining part with a material of different allowable stress from that used in the original design, apply to use of the same material when later editions/addenda of the original code of construction permit higher allowable stresses for that material?

Reply 1: Yes, when use of the higher allowable stress value results in a reduction in material thickness.

Question 2: Does the example of a repair given in Appendix 6, paragraph B.17, for replacement of a pressure retaining part with a material of different nominal composition and equal or greater allowable stress from that used in the original design, apply to use of the same material when later editions/addenda of the original code of construction permit higher allowable stresses for that material?

Reply 2: Yes, provided there is no reduction in material thickness.

Question 3: When a replacement part is constructed using higher allowable stress values permitted by a later edition/addenda of the original code of construction and the replacement part is thinner than the part being replaced, is it required that an “R” Certificate Holder perform calculations and inspections to verify that the connecting welds and the af-fected portions of the pressure-retaining items are in compliance with the original code of construction?

Reply 3: Yes.

Question 4: May a pressure-retaining item be re-rated using a later edition/addenda of the original code of construction which permits higher allowable stress values for the material than was used in the original construction?

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Reply 4: Yes, in compliance with the following minimum criteria: (a) The “R” Certificate Holder verifies (by calculations and other means) that the re-

rated item can be satisfactorily operated at the new service conditions (e.g., stiffness, buckling, external mechanical loadings, etc.),

(b) The pressure-retaining item is not used for lethal service, (c) The pressure-retaining item is not in high-cycle operation or fatigue service (i.e.,

loadings other than primary membrane stress are controlling design considerations.), (d) The pressure-retaining item was constructed to the 1968 Edition or later edition/ad-

denda of the original code of construction, (e) The pressure-retaining item is shown to comply with all relevant requirements of

the edition/addenda of the code of construction which permits the higher allowable stress values (e.g., reinforcement, toughness, examination, pressure testing, etc.),

(f) The pressure-retaining item has a satisfactory operating history and current inspec-tion of the pressure-retaining item verifies that the item exhibits no unrepaired damage (e.g., cracks, corrosion, erosion, etc.),

(g) The re-rating is acceptable to the Inspector and, where required, the jurisdiction, (h) All other requirements of Part RC are met, and (i) Use of this Interpretation is documented in the Remarks Section of Form R2.

Question 5: May a new minimum required wall thickness be calculated for a pressure-retaining item by using a later edition/addenda of the original code of construction which permits higher allowable stress values for the material than was used in the original construc-tion?

Reply 5: Yes, in compliance with the following minimum criteria: (a) The “R” Certificate Holder verifies (by calculations and other means) that the affected

portions of the pressure-retaining item can be satisfactorily operated (e.g., stiffness, buckling, external mechanical loadings, etc.),

(b) The pressure-retaining item is not used for lethal service, (c) The pressure-retaining item is not in high-cycle operation or fatigue service (i.e.,

loadings other than primary membrane stress are controlling design considerations.), (d) The pressure-retaining item was constructed to the 1968 Edition or later edition/ad-

denda of the original code of construction, (e) The pressure-retaining item is shown to comply with all relevant requirements of

the edition/addenda of the code of construction which permits the higher allowable stress values (e.g., reinforcement, toughness, examination, pressure testing, etc.),

(f) The pressure-retaining item has a satisfactory operating history and current inspection of the pressure-retaining item verifies that the item exhibits no unrepaired damage (e.g., cracks, etc.). Areas of corrosion or erosion may be left in place provided the remaining wall thickness is greater than the new minimum thickness,

(g) The design change is acceptable to the Inspector and, where required, the jurisdic-tion,

(h) All other requirements of Part RC are met, and (i) Use of this Interpretation is documented in the Remarks Section of Form R2.

486


INTERPRETATION 98-15Subject: RC-3022 & RC-3030(h) Pressure Testing Requirements Related to Re-rating Activities 1995 Edition with the 1996 AddendumQuestion 1: If calculations and current thickness measurements indicate that a pressure-retaining

item may be altered by re-rating only (no physical work being done), may the original pressure test as recorded on the Manufacturer’s Data Report be used to satisfy RC-3022(d), if the pressure test is at least equal to the calculated test pressure required to verify the integrity of said alteration, subject to the approval of the Inspector and the requirements of the jurisdiction?

Reply 1: Yes.

Question 2: If the maximum allowable working pressure (MAWP) of a pressure-retaining item must be reduced, due to wall thinning below the minimum wall thickness required to contain the MAWP stated on the manufacturer’s data report and on the ASME stamped nameplate, but the maximum allowable temperature is increased, is it the intent of the NBIC that this be considered a re-rate?

Reply 2: Yes. Any increase in pressure or temperature is considered a re-rate in accordance with RC-3022.

Question 3: If the maximum allowable working pressure (MAWP) of a pressure-retaining item must be reduced, due to wall thinning below the minimum wall thickness required to contain the MAWP stated on the manufacturer’s data report and on the ASME stamped nameplate, but the maximum allowable temperature is increased, is it the intent of the NBIC that this is, in effect, a derate and outside the scope of the NBIC?

Reply 3: No. Any increase in pressure or temperature is considered a re-rate in accordance with RC-3022.

INTERPRETATION 98-16Subject: RA-3020 Prerequisites for Accreditation 1998 EditionQuestion: May an Inspector, holding a National Board Owner-User Commission and employed

by an Owner-User Inspection Organization, perform inspections at more than one of his/her employer’s facilities which are National Board accredited Owner-User Orga-nizations?

Reply: Yes, provided this is described in each Quality System Manual and is acceptable to the jurisdiction(s) where the inspections will be performed.

INTERPRETATION 98-17Subject: RA-2281 Testing Medium and Testing Equipment 1998 EditionQuestion: For testing in accordance with paragraph RA-2281(a), is it permissible to use the 1998

ASME Code Section I blowdown requirements for valves built to earlier Code edi-tions?

Reply: Yes.

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INTERPRETATION 98-18Subject: RC-2031 (a)(1) Routine Repairs 1998 Edition with the 1998 AddendumQuestion: In RC-2031 (a)(1), does the phrase “and their attachments” refer to items such as: flanges,

welded couplings, welded fittings for thermometers or pressure gages, or other types of pressure-retaining items?

Reply: No.

INTERPRETATION 98-19Subject: RB-3237 Inspection Interval 1998 Edition with the 1998 AddendumQuestion: Where there are services in which pressure-retaining items are used which restrict

human access due to radiological or toxicological concerns, is it permissible to utilize degradation analysis to extend the interval, or exempt the vessel from internal or on-stream evaluation?

Reply: Yes, provided it is acceptable to the jurisdiction (see RB-1000). The NBIC provides guid-ance only in establishing inspection intervals or exemptions (see RB-3237 and RB-3238). The jurisdiction is the final authority on inspection intervals or exemptions.

INTERPRETATION 98-20 Subject: RC-3022 Re-rating 1998 Edition with the 1998 AddendaQuestion 1: Is derating a vessel to a lower MAWP considered an alteration or a re-rating?

Reply 1: Neither. The NBIC does not address derating. See RC-3022, footnote 1.

Question 2: In lieu of derating a corroded vessel and affixing nameplates with the new MAWP, may the pressure relief device set pressure be reduced to less than the calculated MAWP based upon actual remaining wall thickness, if the calculations are conducted in accordance with RC-3020 and RC-3021?

Reply 2: This is outside the scope of the NBIC. The jurisdiction in which the pressure vessel is located should be contacted to determine the specific procedures to be followed.

INTERPRETATION 98-21Subject: RA-2130 (f) 1998 Edition with the 1998 AddendaQuestion: Is it required that an applicant for an “R” Certificate of Authorization, whose program

includes repair of ASME Section VIII, Division 2 pressure vessels, demonstrate the ca-pability to comply with the applicable requirements of RC- 2080 to ensure the program satisfies RA-2130 (f)?

Reply: Yes.

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INTERPRETATION 98-22Subject: RC-1010 Scope 1998 EditionQuestion 1: Does the NBIC address ASME B31 piping codes? Reply 1: Yes. See the definition of “pressure-retaining item” in Appendix 4.

Question 2: Is a nameplate required for piping system repairs/alterations performed in accordance with the NBIC?

Reply 2: Yes. Question 3: When multiple repairs or alterations are described on a single “R” data report form,

may a single nameplate be used?

Reply 3: Yes.

INTERPRETATION 98-23Subject: Appendix 6, B-7 1995 Edition with the 1995 AddendumQuestion: Is the head or shell thickness limited to 3/8 in. in thickness when installing a new NPS

3 nozzle as stated in Appendix 6, paragraph B-7?

Reply: No. The example is correct for a vessel constructed in accordance with ASME Code, Section VIII, Division 1.

INTERPRETATION 98-24Subject: Restricted Lift per Code Case 1923 & 1945 1998 Edition with the 1998 AddendaQuestion: May a “VR” Certificate holder perform a conversion, as defined in RA-2242(c), of a

pressure relief valve from one certified design type to another certified type which was certified by the manufacturer in accordance with ASME Code Cases 1923 or 1945?

Reply: Yes, provided all NBIC requirements pertaining to conversions are met and the certifi-cate holder receives from the valve manufacturer specifications and instructions which include the additional marking requirements of the applicable code case.

INTERPRETATION 98-25Subject: RA-2262(b)(3) 1998 Edition with the 1998 AddendaQuestion: Does RA-2262(b)(3) require the repair organization to mark out the type/model number if

the type/model number was changed prior to the implementation of RA-2262(b)(3)?

Reply: Yes, and the new type or model number shall be stamped on the repair nameplate in accordance with paragraph RA-2262-(a)(7).

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INTERPRETATION 98-26Subject: RA-2262(b)(1) 1998 Edition with the 1998 AddendaQuestion: May the spring on a pressure relief valve be reset within the guidelines of ASME Section

1, PG-72.3 or Section VIII, Div. 1, UG-126(c), as applicable, provided the repair activities are within the scope stated on the “VR” holder’s certificate and the requirements of paragraph RA-2262(b)(1) are met?

Reply: Yes, provided the set pressure is within the manufacturer’s spring range.

INTERPRETATION 98-27Subject: RC-2050(b) Pressure Testing RC-1050 Replacement Parts 1995 Edition with the 1996 AddendumQuestion 1: Does the term replacement parts, as used in RC-2050(b), include replacement parts as

defined in RC-1050(a)?

Reply 1: No. RC-1050(a) describes parts supplied as material on which no fabrication welding is performed.

Question 2: Is it the intent of the 1995 Edition with the 1996 Addendum that the term replacement parts, as used in RC-2050(b), include replacement parts as defined in RC-1050(b)?

Reply 2: No. The 1997 Addendum clarifies these requirements.

Question 3: Does the term replacement parts, as used in RC-2050(b), include replacement parts as defined in RC-1050(c) and RC-1050(d)?

Reply 3: Yes.

490


INTERPRETATION 98-28Subject: RC-1050(c) Replacement Parts Fabricated by an “R” Certificate Holder Appendix 6 Pressure Retaining Replacement Items RC-1050 Definition of New Replacement Parts 1998 EditionQuestion 1: Does RC-1050(c) of the NBIC permit the holder of an “R” Certificate to fabricate by

welding new and exact pressure retaining replacement parts for an ASME stamped item that the “R” stamp holder is repairing?

Reply 1: No. ASME replacement parts fabricated by welding that require shop inspection by an Authorized Inspector shall be fabricated by an organization having an appropriate ASME Certificate of Authorization.

Question 2: An ASME stamped item is determined to be corroded beyond repair and the only sal-vageable part is the ASME Code stamping or nameplate. Is it the intent of the NBIC to permit a holder of an “R” Certificate only to build a complete new and exact pressure retaining replacement item using the original ASME construction Code, Section, Edi-tion and Addenda and same materials, transfer and document the transfer of the ASME stamping or nameplate on an R-1 Form to the new pressure-retaining item and stamp the repair with the “R” stamp?

Reply 2: No.

Question 3: Does the NBIC define the point at which a repair becomes new construction?

Reply 3: No.

INTERPRETATION 98-29Subject: Appendix 6 Tube Placement 1998 Edition with the 1998 AddendumQuestion 1: Is the replacement of heat exchanger tube material with a material that has a different

nominal composition and an allowable stress equal to or greater than the original mate-rial considered a repair?

Reply 1: Yes, provided that the thickness of the replacement material is equal to or greater than the original material thickness, and provided the replacement material satisfies the material and design requirements of the original code of construction under which the vessel was built.

Question 2: Is the replacement of heat exchanger tube material with a material that has a different nominal composition and an allowable stress less than the original material considered an alteration?

Reply 2: Yes. See Appendix 6, C7.

Question 3: May tube replacement(s) be considered a routine repair if authorization is obtained in accordance with RC-2030?

Reply 3: Yes, provided the tube material is NPS 5 or less.

Question 4: Does the NBIC require a tube replacement, which is considered to be a repair, to be documented on an R-1 Form when no welding is performed?

Reply 4: No. The NBIC does not address the documentation of non-welded repairs.

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INTERPRETATION 98-30Subject: Appendix 6C Example of Alteration Due to Grinding or Machining 1998 EditionQuestion 1: A pressure-retaining item has its surface ground or machined to remove imperfections

caused during operation. Is the resulting reduction in outside diameter, length, and thickness caused by such grinding or machining considered an alteration as described in Appendix 6, Item C4?

Reply 1: No, unless the changes affect the pressure-containing capability of the pressure-retain-ing item.

Question 2: A pressure-retaining item has its surface ground or machined to remove imperfections caused during operation. The grinding and machining reduces the item’s thickness, length and outside diameter. Must such grinding or machining be performed by a holder of an “R” Certificate of Authorization?

Reply 2: No.

INTERPRETATION 98-31Subject: RC-2031 Replacement of a Nozzle as Routine Repair 1998 Edition with the 1998 AddendaQuestion: Is the replacement of a nozzle which is NPS 5 or less considered a routine repair regard-

less of weld thickness?

Reply: No, RC-2031 (a)(1) does not address nozzles.

INTERPRETATION 98-32Subject: RC-3022 Re-rating Using Higher Joint Efficiency Allowed by Later Edition of Original Code of Construction 1998 EditionQuestion: Is it permissible to re-rate a pressure vessel using an increased joint efficiency of 1.0 in

accordance with a later edition/addenda of the original code of construction if all of the butt joints were 100% radiographed in the original construction?

Reply: No.

INTERPRETATION 98-33Subject: RC-2051 Liquid Pressure Test of Repairs 1998 EditionQuestion: Is it a requirement of the NBIC that a liquid pressure test be applied after a repair?

Reply: No. The “R” Certificate Holder is required to verify the integrity of the repair. The combination of tests and/or examinations to be performed is subject to the acceptance of the Inspector and, where required, the jurisdiction.

492


INTERPRETATION 98-34Subject: RC-3030 Examination and Testing 1995 Edition with the 1996 AddendumQuestion: When the design rated capacity of a boiler is increased without physical work such that

the design pressure and temperature are unaffected, is it required to perform a pressure test in accordance with the NBIC?

Reply: No.

INTERPRETATION 98-35Subject: RB-4000 Restamping or Replacement of Nameplate 1998 Edition with the 1999 AddendumQuestion 1: Do the requirements of RB-4020 apply to vessels that are removed from a plant site or

manufacturer’s facility and are repaired or altered by an “R” Certificate Holder?

Reply 1: Yes. Question 2: May an “R” Certificate Holder attach a replacement nameplate supplied by the original

manufacturer, after proper identification has been established and in the presence of an Inspector, on an ASME vessel?

Reply 2: Yes, provided all requirements of RB-4000 are met.

Question 3: When a nameplate is to be placed on an ASME vessel, which jurisdiction must approve the attachment of the replacement nameplate?

Reply 3: The jurisdiction where the vessel is located.

Question 4: When the original manufacturer is no longer in business, may an “R” Certificate Holder provide a replacement nameplate describing the design conditions of the ASME ves-sel?

Reply 4: No. The jurisdiction should be contacted when the original manufacturer is no longer in business.

INTERPRETATION 98-36Subject: RD-2050 1998 Edition with the 1999 AddendumQuestion: In RD-2050, does the thickness required by the original code of construction refer to the

material thickness originally supplied?

Reply: Yes.

INTERPRETATION 98-37Subject: RC-1050(a) Material Requirements 1998 Edition with the 1999 AddendumQuestion: If a repair or alteration requires the use of material in accordance with RC-1050(a), are

material test reports that include actual mechanical test properties required to be fur-nished?

Reply: Unless otherwise specifically addressed in the NBIC, all materials, including marking and test reports, shall comply with the original code of construction.

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INTERPRETATION 98-38Subject: RC-3031(c) NDE in lieu of Pressure Testing 1998 Edition with the 1999 AddendumQuestion: Would the desire to save time and/or expense constitute pressure testing as not being

practicable?

Reply: No. The determination of “practicable” is based on technical consideration of the nature and scope of the alteration activity.

INTERPRETATION 98-39Subject: R-1 and R-2 Forms 1998 Edition with the 1999 AddendumQuestion: A pressure-retaining item is repaired or altered in accordance with the NBIC. The

pressure-retaining item and its Manufacturer’s Data Report are not registered with the National Board. Is it required that the Inspector list his/her National Board Commis-sion Number (including endorsements) in the “Certificate of Design Change Review” and “Certificate of Inspection” blocks of the appropriate Form R-1 and R-2?

Reply: Yes. See Appendix 5, instruction 28 in the Guide for Completing National Board R Forms.

INTERPRETATION 98-40Subject: RD-2070 Stays 1998 Edition with the 1998 AddendumQuestion: Is the replacement of a threaded stay with a welded stay always classified as a repair?

Reply: No. In some cases, the design of threaded stays and welded stays will differ, which may change the MAWP. In such cases, the work shall be performed as an alteration.

INTERPRETATION 98-41Subject: RA-2330(g) 1998 Edition with the 1998 AddendumQuestion: May a holder of an ASME Certificate of Accreditation use documentation of the ASME

survey to demonstrate compliance with Part RA-2330(g) of the NBIC?

Reply: No. RA-2330(g) provides the alternative to demonstration for an ASME “N” type Cer-tificate of Authorization.

INTERPRETATION 98-42Subject: RC-2031, RD-2030(d) Weld Buildup of Boiler Tubes’ Wasted Areas 1998 Edition with the 1999 AddendumQuestion: May weld buildup of wasted areas on boiler tubes addressed by RD-2030(d) be consid-

ered a routine repair in accordance with RC-2031(a)(1)?

Reply: Yes, provided all requirements of RC-2031 are met.

494


INTERPRETATION 98-43Subject: Foreward, Appendix 4, Appendix 5 1998 Edition with the 1999 Addendum Question 1: Two pressure vessels are constructed and individually stamped with the ASME Code

“U” stamp. May the connection of the two vessels by a single circumferential weld be performed in accordance with the NBIC?

Reply 1: Yes.

Question 2: Are changes in the dimensions of a pressure vessel beyond that described on the data report considered an alteration?

Reply 2: Yes, if the changes affect the pressure containing capability of the pressure vessel. See Appendix 4, Glossary of Terms and Appendix 6.C, Examples of Alterations.

INTERPRETATION 98-44Subject: RC-1093, Welder Performance Qualification Using SWPS 1995 Edition with 1997 Addenda Question 1: When not prohibited by the original code of construction, may a welder-performance

qualification test be conducted in accordance with the standard welding procedure selected to do the repair?

Reply 1: Yes.

INTERPRETATION 01-01Subject: RA-2330(g) Demonstration for an “NR” Certificate of Authorization 1998 Edition with the 1999 Addenda Question 1: Does Part RA-2300 require an implementation demonstration of an applicant’s quality

program for issue of an “NR” Certificate of Authorization?

Reply 1: Yes.

Question 2: If an applicant for an “NR” Certificate of Authorization holds an ASME N-type Cer-tificate of Authorization, has demonstrated implementation of their quality program within the previous 12 months, and can verify by documentation that they are capable of implementing their quality program in compliance with Part RA-2300, is it required that further implementation verification be performed for issue of the “NR” Certificate?

Reply 2: No.

INTERPRETATION 01-02Subject: RC-2031(a)(3)Weld Metal Build-Up 1998 Edition with the 1999 Addenda Question: If a pressure-retaining item has multiple areas requiring a weld metal build-up, does

the 100 sq. in. limit described in RC-2031(a)(3) apply to the sum of the areas to be re-paired?

Reply: Yes.

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INTERPRETATIONS

INTERPRETATION 01-03Subject: Appendix 4, Pressure-Retaining Item 1998 Edition with the 2000 Addenda Question 1: When heat exchangers consisting of tubes and tube sheets (e.g., feedwater heaters) are

manufactured and certified in accordance with an original code of construction, are repairs to the tubes and tubesheets within the scope of the NBIC?

Reply 1: Yes.

Question 2: Is the determination of primary and secondary pressure parts, for the purposes of re-pairs, within the scope of the NBIC?

Reply 2: No.

INTERPRETATION 01-04Subject: RC-2050, RC-3030, RA-2151(m) Calibration of Pressure Gages 1998 Edition with the 2000 Addenda Question 1: Does the NBIC require a pressure gage to be calibrated in accordance with the “R”

Certificate Holder’s Quality System Manual for pressure tests conducted in accordance with RC-2050 and RC-3030?

Reply 1: Yes.

Question 2: May the operational pressure gage be used for pressure tests performed to the require-ments of RC-2050 or RC-3030?

Reply 2: Yes, provided accuracy of the pressure gage can be assured in accordance with the “R” Certificate Holder’s Quality System as required by RA-2151(m).

INTERPRETATION 01-05Subject: RA-2330(n) “NR” Program Audits 1998 Edition with the 2000 Addenda Question 1: Is it required that the annual audit of the “NR” Certificate Holder, as addressed by RA-

2330(n), be conducted if there has been no repair, modification, or replacement activity performed under the program during the previous year?

Reply 1: Yes.

Question 2: Is the Authorized Nuclear Inspector required to be present during the annual audit of the “NR” Certificate Holder required by RA-2330(n)?

Reply 2: No, the NBIC does not specify the make-up of the audit team.

496


INTERPRETATION 01-06Subject: RA-2010 Accreditation of Repair Organizations 1998 Edition with the 2000 Addenda Question 1: Is it a requirement of the NBIC that an organization performing repairs to pressure relief

valves be accredited in accordance with RA-2200?

Reply 1: Yes, per RA-2010(d).

Question 2: Must the “VR” symbol be applied to the repair tag on the valve to satisfy RA-2010(d)?

Reply 2: Yes, per RA-2262(a)(2).

INTERPRETATION 01-07Subject: RA-2030(a) Owner-User Inspection Organization 1998 Edition with the 2000 Addendum Question: Is it a requirement that a user of pressure-retaining items (having legal responsibility

for the safe operation of those pressure-retaining items also having and maintaining an established inspection program meeting the requirements of the National Board rules with National Board commissioned O/U inspectors who are continuously employed by the user) also be the owner?

Reply: No. Provided the user’s established inspection program is acceptable to the jurisdiction or jurisdictional authority where the user is located.

INTERPRETATION 01-08Subject: RB-3853 Manually Operated Locking Devices 1998 Edition with the 2000 Addenda Question: In accordance with RB-3853, is a locking device operated by a manually controlled elec-

tric hydraulic pump, which exercises a hydraulic ram, which in turn holds the locking device in position, considered a manually operated mechanism?

Reply: Yes. If the action taken to engage and disengage a locking device of a quick acting closure requires manual operation, then it is a manual device. The need for operator action to start the motor is considered manual operation.

INTERPRETATION 01-09Subject: RC-2031(a)(1) Routine Repairs 1998 Edition with the 2000 Addenda Question: Is the seal welding of tubes which are five NPS in diameter and less considered a routine

repair?

Reply: Yes.

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INTERPRETATION 01-10Subject: RD-1000 Alternative Postweld Heat Treatment Methods 1998 Edition with the 2000 Addenda Question: Are the methods described in Part RD-1000 applicable when Postweld Heat Treat-

ment is a mandatory requirement by the original Code of Construction due to service requirements (for example, lethal service as described by ASME Section VIII, Division I UW-2(a))?

Reply: Yes.

INTERPRETATION 01-11Subject: RC-3022 Re-rating Based on Joint Efficiency 2001 EditionQuestion: Is it the intent of the NBIC to prohibit the re-rating of a pressure-retaining item to a

higher MAWP by performing radiography in accordance with all the relevant require-ments of the edition/addenda of the code of construction and recalculating the MAWP to verify that the item can be satisfactorily operated at the new service conditions?

Reply: Yes. These requirements have been clarified in the 2002 Addendum.

INTERPRETATION 01-12 Subject: RA-2274 Use of Owner/User Personnel during repairs of pressure relief valves 2001 EditionQuestion 1: Are Owner/User personnel considered to be assisting and working under the direct

supervision and control of the “VR” Certificate Holder technician(s) in accordance with RA-2274(c) if the Certificate Holder’s personnel leave the repair site during any state of the repair?

Reply 1: No.

Question 2: Is the “VR” Certificate Holder responsible in accordance with para. RA-2256(h) for ensuring that only those Owner/User parts accepted by the “VR” Certificate Holder are installed into the repaired valve?

Reply 2: Yes.

Question 3: Are the Owner/User personnel performing repair activities required to sign-off at each operation of the document required by para. RA-2256(i).

Reply 3: No, sign-offs shall be in accordance with the “VR” Certificate Holder’s quality control system.

Question 4: Under RA-2274, may a “VR” Certificate Holder establish a permanent shop facility at an Owner/User’s premises, using the field repair scope of their “VR” Certificate of Authorization.

Reply 4: No, see para. RA-2234.

498


INTERPRETATION 01-13Subject: RB-4010 Replacement of Stamped Data 2001 EditionQuestion 1: May the “traceability” of a pressure vessel be determined by its comparison to inspec-

tion records, drawings and the original data report matching its physical dimensions without the presence of permanent markings on the vessel when replacing a missing nameplate?

Reply 1: Yes, when such information is sufficient to conclusively establish identification of the item, such as for a one-of-a-kind item or item unique to a plant or system.

Question 2: When a jurisdictional authority does not exist, is permission to replace stamped data required by any other authority other than an Inspector from the original Authorized Inspection Agency that certified the item?

Reply 2: No.

Question 3: When the original manufacturer of a pressure vessel replaces a missing nameplate, must the manufacturer and/or Owner/User prove that the vessel still meets the design criteria on the replacement nameplate?

Reply 3: No.

INTERPRETATION 01-14Subject: RC-2082(b) Repair Plan (Sec. VIII, Div. 2) AIA Acceptance 2001 EditionQuestion: Is it the intent of paragraph RC-2082(b) to prohibit the Owner/User Inspection Orga-

nization from performing the required acceptance inspection and signing of the Form R-1?

Reply: No, when all requirements of RA-3050 are met.

INTERPRETATION 01-15Subject: RC-2051 Pressure testing repairs by isolating the repaired portion of a pressure-retaining

item 2001 EditionQuestion 1: When performing a pressure test of a repair, is it permissible to isolate and pressure

test the repaired area of a pressure-retaining item such that the remaining parts of the pressure-retaining item are not subjected to the pressure test?

Reply 1: Yes.

Question 2: When performing a pressure test of an alteration where there has not been an increase in temperature or maximum allowable working pressure, is it permissible to isolate the pressure test the altered area of a pressure-retaining item such that the remaining parts of the pressure-retaining item are not subjected to the pressure test?

Reply 2: Yes.

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INTERPRETATIONS

INTERPRETATION 01-16Subject: RC-3000 Alterations to ASME Section VIII, Div. 2 Pressure Vessels 2001 EditionQuestion 1: Does the absence of reference to pressure vessels built in accordance with ASME Sec-

tion VIII, Div. 2 in RC-3000 prohibit them from being altered by a company with an appropriate Certificate of Authorization to use the “R” stamp?

Reply 1: No.

Question 2: For alterations to ASME Section VIII, Div. 2 vessels, is the approving Inspector required to be employed by the “R” stamp holder’s inspection agency?

Reply 2: No, the Inspector may be employed by any of the organizations listed in RC-1070.

INTERPRETATION 01-17Subject: RC-3021 Calculations 2001 EditionQuestion 1: Do published standard values for the pressure rating of pipe along with the design

pressure satisfy the calculation requirements of RC-3021?

Reply 1: No.

Question 2: Do published standard values for the pressure temperature ratings of fitting along with the design pressure satisfy the calculation requirements of RC-3021?

Reply 2: Yes, when permitted by the original code of construction.

INTERPRETATION 01-18Subject 8-5000(b) Repairs 2001 Edition with 2001 AddendumQuestion: In Appendix 8-5000(b), does the phrase “specification most applicable to the work”

include standards or specifications other than those originally used to construct the vessel?

Reply: No.

INTERPRETATION 01-19Subject: RC-2031(a)(1) Routine Repairs 2001 Edition with 2001 AddendumQuestion: Does the phrase “replacement of tubes or pipes, or sections thereof (5) NPS in diameter

and under” include the removal and replacement of a section of tube or pipe with like material?

Reply: Yes, provided the replacement material conforms to the requirements of the original Code of Construction.

500


INTERPRETATION 01-20Subject: RC-2031(a)(1) Routine Repairs 2001 Edition with 2001 AddendumQuestion: May the replacement of a partial section of piping (internal or external) that includes

a welded fitting, such as a flange, forged elbow, or sockolet, be considered a routine repair in accordance with RC-2031?

Reply: No. RC-2031(a)(1) does not address fittings.

INTERPRETATION 01-21Subject: Appendix 6, Part B Examples of Repairs 2001 Edition with 2001 AddendumQuestion: A pressure-retaining item was originally fabricated with post weld heat treatment. The

post weld heat treatment was noted on its Manufacturers Data Report. Welding (such as that listed in Appendix 6, Part B) was performed on this pressure-retaining item using one of the alternative welding methods (as described in RD-1000) in lieu of post weld heat treatment. Is this welding considered to be a repair?

Reply: Yes.

INTERPRETATION 01-22Subject: RC-2031 Routine Repairs 2001 Edition with 2001 AddendumQuestion: When a repair conforms to the requirements of RC-2031(a)(1) and post weld heat treat-

ment is required by the original Code of Construction, may the repair be considered routine?

Reply: Yes, subject to acceptance of the jurisdiction.

INTERPRETATION 01-23Subject: RC-2031(a)(1) Routine Repairs 2001 Edition with 2001 AddendumQuestion: Is the repair or replacement of a fitting or valve, five (5) NPS in diameter and under

considered a routine repair?

Reply: No.

501

INTERPRETATIONS

INTERPRETATION 01-24Subject: RC-1110(a) Nondestructive Examination 2001 Edition with 2001 AddendumQuestion 1: When not prohibited by the original Code of Construction rules for NDE personnel

qualification, does the NBIC prohibit the use of welders or welding operators qualified to Section IX to visually examine tack welds made by another qualified welder within the same organization that are to be left in place and incorporated into a final weld?

Reply 1: No.

Question 2: When not prohibited by the original Code of Construction, may qualified welders or welding operators making tack welds that will be incorporated into a final weld visu-ally examine their own tack welds?

Reply 2: Yes, when described in the Quality System.

Question 3: In lieu of identifying welders or welding operators making tack welds that become part of a final pressure retaining weld or structural attachment weld, may the “R” Certificate Holder provide a procedure in the Quality System that permits the Inspector to verify that such tack welds were made by qualified welders or welding operators?

Reply 3: Yes.

INTERPRETATION 01-25Subject: RC-3050 Documenting Alterations Performed by Two R Certificate Organizations 2001 Edition with 2001 AddendumQuestion: An “R” Certificate organization performs the design portion of an alteration. Another

“R” Certificate organization performs the necessary construction work on the alteration. Is it the intent of RC-3050 that the “R” Certificate Holder performing the design initiate the Form R-2 used to record and register the alteration?

Reply: Yes

INTERPRETATION 01-26Subject: RB-3238(f) Criteria for determining actual thickness and maximum deterioration 2001 Edition with 2002 AddendumQuestion 1: Does RB-3238(f)(1) to (f)(3) apply to all vessels and not just vessels in interrupted ser-

vice?

Reply 1: No.

Question 2: The tolerance criteria in RB-3238(f)(1) is used to determine the appropriate NDE. Does this tolerance criteria apply to periodic thickness measurements?

Reply 2: No.

Question 3: Is the tolerance criteria referenced in RB-3238(f)(1) either a plus or minus value?

Reply 3: Yes.

502


INTERPRETATION 01-27Subject: RC-1090 Welding 2001 Edition with 2002 AddendumQuestion: May an “R” Certificate Holder perform welding using the services of individual welders

not in his employ when it is allowed by the original Code of Construction governing the work and when the “R” Certificate Holder satisfies all of the applicable conditions established by the original Code of Construction to control the use of such welders?

Reply: Yes, provided the controls are described in the “R” Certificate Holder’s Quality System manual.

INTERPRETATION 01-28Subject: RC-1040 Materials 2001 Edition with 2002 AddendumQuestion: Is it prohibited to use material that has been previously in service for replacement mate-

rial for a repair if that material otherwise conforms to the requirements of the original Code of Construction?

Reply: No, provided the use of the material has the concurrence of the Jurisdiction and Au-thorized Inspection Agency.

INTERPRETATION 01-29Subject: RC-2070 Installation of Replacement Parts 2001 Edition with 2002 AddendumQuestion: When a replacement part is fabricated by welding and documentation is required by

RC-1050, but does not require welding in order to install, must the repair be documented on a Form R-1?

Reply: No, the NBIC neither requires nor prohibits documenting this installation on a Form R-1.

INTERPRETATION 01-30Subject: RC-1050(c) Fabrication and Installation by R Stamp Holder 2001 Edition with 2002 AddendumQuestion 1: When ASME is the original code of construction, does RC-1050(c) permit an owner

holding an “R” Stamp to fabricate replacement parts and have the parts installed in the owner’s boiler by another “R” Stamp holder?

Reply 1: No. RC-1050(c) requires these replacement parts to be fabricated by an ASME Certificate Holder.

Question 2: When ASME is the original code of construction, does RC-1050(c) permit an owner holding an “R” stamp to fabricate replacements parts and document those parts by stamping with the owner’s “R” symbol, a unique serial number, and complete a Form R-3?

Reply 2: No. RC-1050(c) requires replacements parts to be documented on an ASME Manufac-turer’s Partial Data Report by an ASME Certificate Holder.

503

INTERPRETATIONS

INTERPRETATION 01-31Subject: RB-3238 Applicability of remaining life evaluation 2001 Edition with 2002 AddendumQuestion: Is it the intent of the NBIC that the procedure for determining remaining life contained

in RB-3238 be applicable to both boilers and pressure vessels?

Reply: No.

INTERPRETATION 01-32Subject: Introduction 2001 Edition with 2002 AddendumQuestion: Does reference of a code or standard in the Introduction to the NBIC (NBIC) imply it is

always acceptable for use?

Reply: No. The jurisdiction retains the responsibility to decide which codes or standards to adopt for use.

INTERPRETATION 01-33Subject: Requirement of UG-45 2001 Edition with 2002 AddendumQuestion: In evaluating a corroded nozzle on an inservice pressure vessel, do the requirements

of UG-45 have to be met?

Reply: Yes, unless another industry accepted method adopted by the jurisdiction is ap-proved.

INTERPRETATION 01-34Subject: RD-1040 and RD-1060 Alternative welding methods 2001 Edition with 2002 AddendumQuestion 1: Does RD-1060(h)(2) require that the buttering layers be deposited only using the SMAW

process?

Reply 1: No.

Question 2: Is it the intent of RD-1040(i)(6) that the shielding gas dewpoint temperature be below -60°F?

Reply 2: Yes. This paragraph is worded incorrectly. A revision to correct this requirement has been prepared.

Question 3: Is it the intent of RD-1060 that the temper bead technique be used in welding a test coupon for qualification of the WPS when Alternative Welding Method 4 is to be used for repair welding

Reply 3: Yes. The controlled bead deposition technique in RD-1060 Alternative Welding Method 4, shall be used for the qualification of the procedure in accordance with the changes in the 2004 Edition of the NBIC.

504


INTERPRETATION 01-35Subject: RC-1040 Fabrication and installation by “R” Stamp Holder 2001 Edition with 2002 AddendumQuestion: During the course of a repair or alteration is the pre-assembly of a part for a pressure-re-

taining item considered fabrication of a replacement part as addressed in RC-1050(c)?

Reply: No.

INTERPRETATION 01-36Subject: RC-1020(b) Requirement to know code of construction prior to repair 2001 Edition with 2002 AddendumQuestion: In order to apply the “R” stamp to a vessel that was repaired or altered, must that vessel

first be constructed in accordance with the ASME code or some other recognized code or standard.

Reply: No.

INTERPRETATION 01-37Subject: RC-1140 and RC-3040 Mechanical Stamping 2001 Edition with 2003 AddendumQuestion 1: Is application, by mechanical means only, of the stamping or nameplate for a re-rating

when no physical changes are made to the pressure-retaining item considered to be the construction portion of the alteration?

Reply 1: No.

Question 2: Is application by welding of the nameplate for a re-rating when no physical changes are made to the pressure-retaining item considered to be the construction portion of the alteration?

Reply 2: Yes.

INTERPRETATION 01-38Subject: RD-3022(d) Re-rating 2001 Edition with 2003 Addendum

Question 1: For a re-rating when no physical changes are made to the pressure-retaining item, is the pressure test, if performed, considered to be the construction portion of the alteration requiring construction certification on the Form R-2 by an “R” Certificate Holder?

Reply 1: No.

Question 2: Does the NBIC prohibit an “R” Certificate Holder with “design only” scope from per-forming and assuming responsibility for the pressure test of a re-rating when no physical changes have been made to the pressure-retaining item?

Reply 2: No, provided controls for performing the pressure test are addressed in the QC manual.

505

INTERPRETATIONS

INTERPRETATION 01-39Subject: RC-3051 2001 Edition with 2003 AddendumQuestion: The “R” Certificate Holder with “design only” scope certifies the design of a re-rat-

ing when no physical changes are made to the pressure-retaining item and performs and assumes responsibility for the pressure test of the re-rating. Is the Inspector that witnessed the pressure test required to complete and sign the Certificate of Inspection portion of the Form R-2?

Reply: Yes.

INTERPRETATION 01-40Subject: RC-2051(e), RC-3031(c), RC-2050, RC-3030(c) 2001 Edition with 2003 AddendumQuestion: If pressure testing is not practicable and if concurrence of the owner, Inspector and

jurisdiction is obtained where applicable, may the Visual Testing (VT) NDE method be used to satisfy the NBIC requirement?

Reply: Yes.

INTERPRETATION 01-41Subject: Appendix 2 and Appendix 5 2001 Edition with 2003 AddendumQuestion: In the event of an alteration to a boiler in which the boiler heating surface and steaming

capacity is increased, is the new heating surface or new steaming capacity of this boiler required to be stamped on the new nameplate, boiler or R-2 form?

Reply: No, however, the exact scope of work must be included in Form R-2, which should include the added heating surface and/or steaming capacity.

507

IndexComing with 2005 Addendum.

508
