applying asme boiler code to steam generation systems

5/24/2018 Applying ASME Boiler Code to Steam Generation Systems

Engineering Practice

CHEMICAL ENGINEERING WWW.CHE.COM JANUARY 2013 49

The ASME Boiler and Pressure

Vessel Code (ASME BPVC),which is administered by ASME(New York, N.Y.; www.asme.org;

founded as the American Society ofMechanical Engineers), is a well-es-tablished standard for the design and

fabrication of boilers and pressure ves-sels. ASME code-symbol stamps showcompliance with the requirements ofthe standard, but code stamping ofsteam systems in ethylene and otherlarge heaters can be controversial.

Much of the challenge for those inthe chemical process industries (CPI)stems from the fact that the main focusof the code is on power boilers, ratherthan on petroleum refinery or petro-chemical heaters, so definitions aresometimes not clear. Furthermore, itcan be difficult to define which author-ity has jurisdiction over steam genera-tion systems in the CPI. Even in theU.S., state boiler codes vary among thestates. In other countries, adherence to

ASME standards may or may not berequired, thus leaving it up to the own-ers of the asset to decide. This articleprovides guidance on the requirementsfor stamping within the ASME codeand explains how state boiler codes canaffect the requirements.

Steam-generation systemsWhen it comes to steam-generationsystems, safety is the primary con-

cern for both the owners of the systemand for the authorities that have ju-risdiction over them. All parties wantsafe and reliable equipment designedfor the intended purpose. Section 1 ofthe ASME BPVC contains the rulesfor construction of power boilers [1].

Power boilers are defined as boilersthat generate steam at pressures inexcess of 15 psig, for external use.Most designers and owners of steam-

generation systems from fired heat-ers agree that ASME Code Section 1is the appropriate design code for thesteam system.

Steam systems in fired heaters typi-cally consist of the following: steamdrum; relief valves; boiler-feedwater

preheat tubes; steam-generation tubes;steam superheating tubes; an end-stageor interstage de-superheater; startup

vent and silencer; interconnecting pip-


Martha Choroszy, David Ballow andAli BourjiWorleyParsons

Determining when and how the

ASME boiler code applies to

steam systems in petrochemical

operations can be difficult.

Guidance on the requirements

for boiler code stamping can help

Radiant

section

Steam drum

Transferline

exchanger

Interstage

desuperheater

Economizer

Boiler feed water

Produced steam

Saturated steam

Watercirculation

Steamcirculation

Superheated steam

Convection

sec

tion

Preheated

boiler feed

water

Radiant

section

Steam drum

Economizer

Boiler feed water

Saturated steam

Watercirculation

Saturatedsteam

Superheated steam

Convection

section

Steamgeneration

coils

Superheatercoils

FIGURE 1.Most operatorsagree that Sec-tion 1 of theASME Boilerand PressureVessel code isthe most appro-

priate standardfor steam-generationsystems, suchas the morecommon natu-ral-circulationtype (above)and the forced-circulation type(below)

Applying ASME Boiler Code to

Steam Generation Systems



50 CHEMICAL ENGINEERING WWW.CHE.COM JANUARY 2013

ing; inline instruments;and, for ethylene heaters,a primary transfer line ex-changer (TLE) as shown in

Figure 1. The steam gener-ation system can be one oftwo types: either naturalcirculation or forced circu-lation. The natural circula-tion type is more common.Figure 1 (bottom) shows atypical set-up for a forced-circulation system.

ASME jurisdictionThe jurisdictional limits of

ASME from Section 1 of the

BPVC are shown in Figure2. The figure, Code Juris-dictional Limits for Pip-ing Drum Type Boilers,was adapted from ASME2010 BPVC Section 1, withpermission of ASME [2].

The ASME BPVC de-scribes three areas oftechnical responsibil-ity: the boiler proper, theboiler external piping and

joint, and non-boiler ex-

ternal piping and joint.The boiler proper fallsunder the administrative

jurisdiction and technicalresponsibility of Section 1of the ASME BPVC. Theboiler proper and boilerexternal piping and jointfall under the administrative juris-diction of ASME BPVC and requiremandatory certification, along withcode stamping, ASME data forms andauthorized inspection.

Technical responsibility for boilerexternal piping is assigned to the

ASME section committee of B31.1.Non-boiler external piping and jointis not considered to be within the ju-risdiction of ASME BPVC section 1,and those components are usuallydesigned according to B31.1 in utilityapplications or B31.3 in chemical orrefinery plant applications.

Even the application of the CodeJurisdictional Limits for Piping

Drum Type Boilers to steam systemsin ethylene heaters can be problem-atic, because the language of the sec-tion is clearly intended for a conven-

tional boiler. Most engineers agree,and several U.S. state boiler codesrequire that the steam drum be de-signed to ASME Section 1. In non-codestates, the drum may be designed toSection VIII.

Steam superheat tubes, economizertubes and steam generation tubes arealso designed to meet the require-ments of ASME Section 1.

Stamp requirementsThe ASME BPVC clearly requires allequipment considered to be boilerproper and boiler external pipingand joint to be stamped. Steam sys-tems for ethylene heaters are typi-

cally manufactured by multiple ven-dors and assembled in the field by adifferent contractor. The particular

ASME stamp and partial data re-

port produced depends on the type ofmanufacturer. Table 1 shows a com-mon setup, where multiple vendorsprovide the various components of thesteam system.

Master stampIf compliance with ASME BPVC Sec-tion 1 is required by law, a masterstamp is required. For a forced-flowsteam-generation unit, the code isclear manufacturers of forced-flowsystems must provide a master stamp.For field-assembled boilers, a masterstamp is clearly required.

The master stamp must be providedby whoever has responsibility for the

entire boiler unit. In cases where themanufacturer is not the assembler, themanufacturer or engineering contrac-tor may provide partial data reports to

Single installation

Multiple installation

Drain

Drain

Drain

Drain

CommonheaderDrain

Main steam

Vent

Vents andinstrumentation

Vent

Vent

Control device

PG-58.3.1

PG-58.3.7

Single boiler

Part PFH

Boiler no. 1

Boiler no. 1

Boiler no. 2

Boiler no. 2

Single boiler

Regulating valves

Two or moreboilers fed froma common source

Two or moreboilers fedfrom a com-mon source

PG-68.1

PG-68.2

Soot blowers PG-68.5

Soot blowers PG-68.5

Single installation

Multiple installationPG-58.3.1

PG-58.3.2

PG-58.3.7

Feedwatersystems

PG-58.3.3

PG-58.3.6

Blow-offsingle and multipleinstallations

Administrative jurisdiction and technical responsibility

Non-boiler external piping and joint Not section jurisdiction (see applicable ASME B31 code).

Boiler proper the ASME boiler and pressure vessel code (ASME BPVC) has total

administrative jurisdiction and technical responsibility (refer to section I preamble)Boiler external piping and joint the ASME BPVC has total administrative jurisdiction (mandatorycertification by code symbol stamping, ASME data forms, and authorized inspection) of boiler exter-nal piping and joint. The ASME section committee B31.1 has been assigned technical responsibility

PG-71

Level indicators PG-60

Surface blow

Continuous blow

Chemical feed

Drum sample

Water drum

Inlet header(if used)

Integral

superheater

(if used)

Integral

economizer(if used)

PG-58.3.2

PG-60

Common

headerSteam drum

FIGURE 2. The ASME BPVC describes three areas of technical responsibility: boiler proper;boiler external piping and joint; and non-boiler external piping and joint


CHEMICAL ENGINEERING WWW.CHE.COM JANUARY 2013 51

the assembler, and the assembler mayaffix the stamp jointly with the manu-facturer, according to the rules of sec-tion PG-106 in ASME BPVC Section1. In this case, both the engineeringcontractor and the authorized inspec-tor must sign the P-3A forms providedby the assembler.

The question that arises for steam-generation units on ethylene heatersis this: When adherence to ASMEBPVC Section 1 is voluntary, is a mas-ter stamp required? The answer is no.If compliance is voluntary, the ownerof the system may opt to comply withsome parts of the code, but not others.

Owner requirementsAlmost all owner specifications requirethat the steam drum, primary trans-fer line heat exchanger (TLE; steamside), and boiler proper piping are de-signed according to ASME BPVC Sec-tion 1, and stamped by the supplier.

Few owners require a master stampunless a stamp is required by the localauthority having jurisdiction.

Owner specifications for steam

systems can sometimes be confusing,and at other times do not address thesubject at all. Statements such as thesteam system shall be in accordancewith ASME section 1 can be difficultto interpret.

State boiler code requirementsIn the U.S., the individual statesregulate boilers. There is no federalboiler code that applies to all statesand territories. Not all 50 states haveboiler codes. Most states that do haveboiler codes require compliance with

ASME BPVC Section 1. Some statesgo further and require National BoardRegistration and inspection. A sam-pling of three state boiler-code lawsfollows. While the language containedin the codes for both Mississippi andTexas are clear, the language of otherstates is not.

Mississippi State Boiler Code commonly known as Title 15, Sec-

tion III, part 76 clearly definesany vessel that generates steam atover 15 psig as a power boiler [3]. Itgoes on to say that Boilers and un-

fired pressure vessels to be installedfor operation in Mississippi shallbe designed, constructed, inspected,stamped and installed in accordancewith the applicable ASME Boilerand Pressure Vessel Code, and theserules and regulations.

Texas State Boiler Code, commonlyknown as 16 TAC 65, requires thatany heating boiler, nuclear boiler,power boiler, unfired steam boiler orprocess steam generator that is in-stalled in Texas must be inspected,installed and stamped in conformitywith the applicable section of the

ASME BPVC. Such boilers must beregistered with the National Boardof Boiler and Pressure Vessel Inspec-tors. Exceptions include reinstalledboilers, as well as those exemptedby the Health and Safety Code,755.022 [4].

New Jersey Boiler Code is com-monly called NJAC 12 subchapter

4. In New Jersey, the term boilermeans a closed vessel in which wateris heated, steam is generated, steamis superheated, or any combination

TABLE 1. MULTIPLE VENDORS SUPPLY VARIOUS STEAM-SYSTEM COMPONENTS

Component name Category ASME CodeCode stamp(by vendor)

Code stamp re-quirement(by field assem-bler)

AssemblerStamp(by field as-sembler)

Stamptype

ASMEpartialdatareport

Stamptype


Stamptype


1 Boiler feed water (BFW) feed

piping to pre-heater

Piping ASME B31.1 PP P-4A

A P-3A

2 BFW feed piping tode-superheater


3 BFW pre-heater Equipment ASME SEC. I S P-4A

4 BFW piping to steam drum Piping ASME B31.1 PP P-4A

5 Steam drum Equipment ASME SEC. I S P-4A

6 Pressure-reducing de-superheat-ing stations (PRDs) on steamdrums

Pressure reliefvalve

ASME SEC 1 V P-7

7 Riser and downcomer Vendor piping ASME SEC. I S P-4A S P-4A

8 Primary transfer-line heat ex-changer (TLE), steam-side

Equipment ASME SEC. I S P-4A

9 Primary TLE blowdown Piping ASME B31.1 PP P-4A

10 Super high-pressure (SHP) pip-ing from steam drum


11 Upper steam superheater(USSH)

Equipment ASME SEC. I S P-4A

12 De-superheater Equipment ASME SEC. I S P-4A

13 De-superheater piping Vendor piping ASME SEC. I S P-4A S P-4A

14 Lower steam superheater (LSSH) Equipment ASME SEC. I S P-4A

15 SHP export piping Piping ASME B31.1 PP P-4A



52 CHEMICAL ENGINEERING WWW.CHE.COM JANUARY 2013

thereof, under pressure or vacuum,for external use by the direct applica-tion of heat [5]. The term boilershallinclude fired or waste-heat units for

heating or vaporizing liquids otherthan water where these units areseparate from processing systemsand are complete within themselves.New Jersey requires compliance with

ASME BPVC Section 1 and NationalBoard rules.

Concluding remarksWhile safety remains of the utmostconcern, economics, more than engi-neering, play a great role in defining

the boundaries where the ASME codemay apply. Unless a more specific codeis developed for ethylene units, thedebate about boundaries will continueamong owners, engineering contrac-tors, technology providers and otherstakeholders. In general, more strin-

gent requirements of ASME are ap-plied for ethylene plants in the U.S.,compared to other places in the world.

Edited by Scott Jenkins

AuthorsMartha Choroszyis a chiefprocess engineer at Worley-Parsons (6330 West LoopSouth, Bellaire, Tex. 77401;Phone: 713-407-5000; Email:martha.choroszy@worley-

parsons.com). She receiveda B.S.Ch.E. degree from theMassachusetts Institute ofTechnology and an MBA fromTulane University. She is a li-censed professional engineer

in Texas and a member of AIChE and NFPA.She is the author of numerous publications, a re-cipient of Tulanes Allen Vorholt award and hasserved as a Blue Ribbon Panel Member to definethe National Agenda for the U.S. Core Combus-tion Research Program.

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References

1. ASME Section 1, Boiler and Pressure VesselCode, ASME, July 1, 2010.

2. Reprinted from ASME 2010 BPVC, Section 1,by permission of The ASME (American Society

of Mechanical Engineers.) All rights reserved.3. Mississippi Department of Health, Title 15, Part

III Office of Health Protection, 76 Boiler andPressure Vessel Safety, July 1, 1975.

4. Texas Boiler Administrative Rules 16 TexasAdministrative Code, January 1, 2008.

5. New Jersey Administrative Code(N.J.A.C.) Boilers, Pressure Vessels &Refrigeration,October 6, 2008.

David Ballow is a principalprocess engineer at Worley-Parsons in Houston (Email:[email protected]) and is a professional en-gineer. He received a B.S.Ch.E.degree from Louisiana TechUniversity and is a memberof AIChE.

Ali Bourji is a senior tech-nical director at WorleyPar-sons in Houston (Email: ali.

[email protected]).Bourji received his B.S. andM.S. degrees in chemical en-gineering from the Universityof Houston, and a doctoratedegree from Lamar Univer-sity. He is a professional engi-neer and a member of AIChEand AFPM. Dr. Bourji is the

author of numerous publications and serves onthe Chemical Engineering PhD Advisory Councilat Lamar University.

applying asme boiler code to steam generation systems

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