technical committee on fundamentals of combustible dusts ...€¦ · agenda for the meeting, which...

National Fire Protection Association

1 Batterymarch Park, Quincy, MA 02169-7471

Phone: 617-770-3000 • Fax: 617-770-0700 • www.nfpa.org

Technical Committee on Fundamentals of

Combustible Dusts

(CMD-FUN)

NFPA Headquarters

1 Batterymarch Park

Quincy, MA 02169-7471

August 8th - 11th

(Meeting will convene at 12 pm on August 8th and adjourn at 12 pm on August 11th.)

1. Chair’s welcome, call to order, and opening remarks at 12 pm (local time, EST)

2. Self-introduction of Committee Members and Guest

3. Approval of Minutes from the May 2015 Second Draft meeting (see Attachment A)

4. Staff liaison report: review of NFPA policies and procedures, committee membership,

A2018 document schedule

5. Review of Public Input

6. Review of Correlating Committee Items, Reserved sections, New material on equipment

(Chapter 8)

7. New business

8. Next meeting

9. Adjourn

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Address List No PhoneFundamentals of Combustible Dusts CMD-FUN

Combustible Dusts

Susan Bershad07/11/2016

CMD-FUN

Paul F. Hart

ChairAmerican International Group, Inc. (AIG)18257 Martin AvenueHomewood, IL 60430-2107

I 8/9/2011CMD-FUN

Elizabeth C. Buc

PrincipalFire & Materials Research Laboratory, LLC33025 Industrial RoadLivonia, MI 48150-1619

RT 8/9/2011

CMD-FUN

Brad D. Burridge

PrincipalNovelis, Inc.639 Players Crossing WayBowling Green, KY 42104

U 03/05/2012CMD-FUN

Brice Chastain

PrincipalGeorgia-Pacific LLC133 Peachtree Street NE, 9th FloorAtlanta, GA 30303Alternate: Richard F. Masta

U 8/9/2011

CMD-FUN

John M. Cholin

PrincipalJ. M. Cholin Consultants Inc.101 Roosevelt DriveOakland, NJ 07436Alternate: Marc T. Hodapp

SE 8/9/2011CMD-FUN

Tom Christman

Principal818 Brochardt BoulevardKnoxville, TN 37934

SE 8/9/2011

CMD-FUN

Randal R. Davis

PrincipalIEP Technologies417-1 South StreetMarlborough, MA 01752-3149Alternate: David Grandaw

M 03/05/2012CMD-FUN

Mark W. Drake

PrincipalLiberty Mutual14125 West 139th StreetOlathe, KS 66062-5885Alternate: Robert C. Berry

I 8/9/2011

CMD-FUN

Robert J. Feldkamp

PrincipalNordson Corporation300 Nordson DriveAmherst, OH 44001Alternate: Edward L. Jones

M 03/05/2012CMD-FUN

Walter L. Frank

PrincipalFrank Risk Solutions, Inc.1110 Shallcross AvenueWilmington, DE 19806

SE 8/9/2011

CMD-FUN

Robert C. Gombar

PrincipalBaker Engineering & Risk Consultants, Inc.707 Hardwood LaneAnnapolis, MD 21401-4570US Beet Sugar AssociationAlternate: Philip J. Parsons

U 8/9/2011CMD-FUN

Dale C. Hansen

PrincipalHarrington Group, Inc.2400 Meadowbrook Parkway, Suite 250Duluth, GA 30096

SE 03/05/2012

CMD-FUN

David M. House

PrincipalI.C. Thomasson Associates, Inc.2950 Kraft Drive, Suite 500Nashville, TN 37204-3683

SE 03/05/2012CMD-FUN

James F. Koch

PrincipalThe Dow Chemical Company1400 BuildingMidland, MI 48667American Chemistry CouncilAlternate: Glenn W. Baldwin

U 03/05/2012

1 of 87


Combustible Dusts


CMD-FUN

Bruce McLelland

PrincipalFike Corporation704 SW 10th StreetBlue Springs, MO 64015-4263Alternate: Jérôme R. Taveau

M 10/18/2011CMD-FUN

Timothy J. Myers

PrincipalExponent, Inc.9 Strathmore RoadNatick, MA 01760-2418

SE 8/9/2011

CMD-FUN

Jim E. Norris

PrincipalBunge North America11720 Borman DrivePO Box 28500St. Louis, MO 63146-1000International Oil Mill Superintendents Assn.

U 03/05/2012CMD-FUN

Jack E. Osborn

PrincipalAirdusco, Inc.4739 Mendenhall Road SouthMemphis, TN 38141-8202

M 8/9/2011

CMD-FUN

Niels H. Pedersen

PrincipalNederman LLCPO Box 429Thomasville, NC 27361-0429

M 03/07/2013CMD-FUN

Jason P. Reason

PrincipalLewellyn Technology2518 Thorium Drive, Apt 3Greenwood, IN 46143

SE 8/9/2011

CMD-FUN

Samuel A. Rodgers

PrincipalHoneywell, Inc.15801 Woods Edge RoadColonial Heights, VA 23834-6059

U 8/9/2011CMD-FUN

Steve Sallman

PrincipalUnited SteelworkersHealth, Safety & Environment60 Boulevard of the AlliesPittsburgh, PA 15222

L 8/9/2011

CMD-FUN

Thomas C. Scherpa

PrincipalDuPont71 Valley RoadSullivan, NH 03445

U 8/9/2011CMD-FUN

Denise N. Statham

PrincipalVF Imagewear/Bulwark Protective Apparel545 Marriott DriveNashville, TN 37214

M 10/18/2011

CMD-FUN

Bill Stevenson

PrincipalCV Technology, Inc.15852 Mercantile CourtJupiter, FL 33478Alternate: Jason Krbec

M 8/9/2011CMD-FUN

Robert D. Taylor

PrincipalPRB Coal Users Group4377 Sandra Kay LaneNewburgh, IN 47630-8596

U 8/9/2011

CMD-FUN

Erdem A. Ural

PrincipalLoss Prevention Science & Technologies, Inc.2 Canton Street, Suite A2Stoughton, MA 02072

SE 03/05/2012CMD-FUN

Robert G. Zalosh

PrincipalFirexplo20 Rockland StreetWellesley, MA 02481

SE 8/9/2011

2 of 87


Combustible Dusts


CMD-FUN

Glenn W. Baldwin

AlternateThe Dow Chemical CompanyPO Box 8361South Charleston, WV 25303American Chemistry CouncilPrincipal: James F. Koch

U 03/07/2013CMD-FUN

Robert C. Berry

AlternateLiberty Mutual Insurance Company1508 Beech CircleWilkesboro, NC 28697-2602Principal: Mark W. Drake

I 10/29/2012

CMD-FUN

David Grandaw

AlternateIEP Technologies2015 Bluemist DriveAurora, IL 60504Principal: Randal R. Davis

M 10/29/2012CMD-FUN

Marc T. Hodapp

AlternateJENSEN HUGHES703 South Milton AvenueBaltimore, MD 21224-3755JENSEN HUGHESPrincipal: John M. Cholin

SE 08/17/2015

CMD-FUN

Edward L. Jones

AlternateNordson Corporation300 Nordson Drive, M/S 42Amherst, OH 44001Principal: Robert J. Feldkamp

M 03/05/2012CMD-FUN

Jason Krbec

AlternateCV Technology, Inc.15852 Mercantile CourtJupiter, FL 33478Principal: Bill Stevenson

M 10/29/2012

CMD-FUN

Richard F. Masta

AlternateGeorgia-Pacific LLC133 Peachtree Street, 7th FloorAtlanta, GA 30303Principal: Brice Chastain

U 8/9/2011CMD-FUN

Philip J. Parsons

AlternateBaker Engineering & Risk Consultants, Inc.319 Stieren StreetSan Antonio, TX 78210-1154US Beet Sugar AssociationPrincipal: Robert C. Gombar

U 08/17/2015

CMD-FUN

Jérôme R. Taveau

AlternateFike Corporation704 SW 10th StreetBlue Springs, MO 64015-4263Principal: Bruce McLelland

M 03/07/2013CMD-FUN

William R. Hamilton

Nonvoting MemberUS Department of LaborOccupational Safety & Health Administration200 Constitution Ave. NW, Room N3609Washington, DC 20210

E 10/18/2011

CMD-FUN

Susan Bershad

Staff LiaisonNational Fire Protection Association1 Batterymarch ParkQuincy, MA 02169-7471

04/16/2014

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COMMITTEE ON FUNDAMENTALS OF COMBUSTIBLE DUSTS TO: COMMITTEE ON FUNDAMENTALS OF COMBUSTIBLE DUSTS FROM: G. R. Colonna, Staff Liaison DATE: October 7, 2014 SUBJ: Minutes of NFPA 652 Second Draft Meeting (Continuation), May 12 – 16, 2014 ________________________________________________________________________________ I. Attendance: (remote attendance noted) Members and Alternates: Paul Hart, Chair, AIG, IL Glenn Baldwin, The Dow Chemical Company, WV (representing ACC) Robert Bitter, Honeywell, Inc., MO (remote attendance) Elizabeth Buc, Fire & Materials Research Laboratory, LLC, MI (remote attendance) Brad Burridge, Novelis, Inc., KY John M. Cholin, J.M. Cholin Consultants Inc., NJ Randall Davis, Fenwal-IEP Technologies, MA Lee DeVito, FIREPRO Incorporated, MA Mark Drake, Liberty Mutual, KS Robert Gombar, Baker Engineering & Risk Consultants, Inc., MD (representing US Beet Sugar Association) (remote attendance) Dale Hansen, Harrington Group, Inc., GA (representing Mars Inc.) David House, I.C. Thomasson Associates, Inc., TN Edward Jones, Nordson Corporation, OH James Koch, The Dow Chemical Company, MI (representing ACC) Richard Masta, Georgia-Pacific LLC, GA (remote attendance) Arthur Mattos, XL Global Asset Protection Services, NC Timothy Myers, Exponent, Inc., Natick, MA (remote attendance) Jim Norris, Bunge North America, MO (International Oil Mill Superintendents Assn.) Jack E. Osborn, Airdusco, Inc., TN Niels Pedersen, Nederman LLC, NC Jason Reason, Lewellyn Technology, IN (remote attendance) Samuel Rodgers, Honeywell, Inc., VA (remote attendance) Steve Sallman, United Steelworkers, PA Thomas Scherpa, DuPont, NH (remote attendance) Denise Statham, VF Imagewear/Bulwark Protective Apparel, TN (remote attendance) Bill Stevenson, CV Technology, Inc., FL Robert Taylor, PRB Coal Users' Group, IN

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CMD-FUN Meeting Minutes

May 12 - 16, 2014; Rosemont, IL

2

Erdem Ural, Loss Prevention Science & Technologies, Inc., MA (remote attendance) Robert Zalosh, Firexplo, MA Susan Bershad, NFPA, Staff Liaison Guests: Chris Aiken, Cargill, Inc., MN Merrill Childs, Cargill, Inc. Guy Colonna, NFPA, MA Ryan Essex, HDR Inc., IL/WI Henry Febo, FM Global, MA (remote attendance) Vincent Giordano, General Electric (remote attendance) Sheila Glesmann, ADA Carbon Solutions, (representing ICAC) (remote attendance) Steve Kroon, Kroon LLC, IN II. Minutes of Meeting 1. The Chair called the meeting to order at 12:22 p.m., Monday, May 12, 2014. He welcomed the members and guests and asked staff to conduct a roll-call of attendees. He then outlined the agenda for the meeting, which is to serve as a continuation of the April conference call meetings, with the work on the agenda to begin with Public Comment 596 related to Chapter 8 content, as Chapter 7, Chapter 9 and some Annex A items were addressed during the conference call meetings. Prior to starting on the Public Comments and Second Revisions, the Committee was asked to consider the minutes from the prior meetings (face-to-face March 12 – 14 and conference call/web meetings April 15 and 28. A motion was made and approved to accept the minutes for those meetings as written. 2. The Committee worked through all items pertaining to Chapter 8, Annex A and other annex items, before returning to items that were tabled for review by Task Groups. Task Groups on the following shared their recommendations with the Committee: use of the terms “enclosure” and “compartment”; use of term “dust deflagration hazard”; Figure 1.3.1; and A.4.2.1.1. At the close of the April 28 remote meeting, members of the task group responsible for developing annex language for A.4.2.1.1 recommended discussing their proposed text. As a reminder, their work stems from action at the initial First Draft meeting related to several Public Comments and remains an open item in terms of creating a Second Revision. However, in discussion at the April 28th meeting, it was requested that the text be included with the meeting minutes so that in preparation for the May 12 – 16 meeting in Chicago, the full Committee could be prepared to take any appropriate action on this task group language. The proposed text included in the minutes is as follows:

Related to Annex A.4.2.1.1; PC 165, 103, 203, 205, 393, 394 [Possible SR]

A.4.2.1.1 Given the fast acting nature of flash fire, deflagration, and explosions

the stated Life Safety Objective recognizes the difficulty if not the impossibility of

protecting occupants in the immediate proximity of the ignition and thus the

stated objective is to protect occupants not in the immediate proximity of ignition.

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CMD-FUN Meeting Minutes

May 12 - 16, 2014; Rosemont, IL

3

However, all available practices should be employed to ensure the safety of all

persons both near and far from the ignition. An example of this might be the

standard’s prescriptive exception relative to the less than 8 cu. ft. air-material

separator not requiring protection; however the intent of the Objective is to

consider the effect of deflagration to occupants in the immediate area of the small

air-material separator and mitigate this hazard if possible. Likewise the

standard has not defined “immediate proximity” in that this could mean within

just feet of the hazard or within the same building or structure and leaves that

judgment to the AHJ. The intent of the Objective is to employ all available and

reasonable protection, techniques, and practices to protect all occupants

understanding that it might not always be achievable.

As a reminder, the Chair formed the four task groups as listed below during the January meeting; the tasks and task group members are listed in the table below:

Chapter 3, enclosure, compartment, and similar, various PC

Chapter 3, Dust Deflagration Hazard, PC 17

Chapter 3, dilute phase conveying, PC 175 and 243

Chapter 4, Annex for 4.2.1.1

Sam Rodgers Dale Hansen Jim Koch Bob Bitter

Tim Myers Walt Frank Todd Baker Tom Scherpa

Paul Hart Tom Scherpa Bill Stevenson Dale Hansen

Dave House Chuck Duthler Jack Osborn Bob Taylor

The task group working on a definition for dilute phase conveying proposed revised text for Chapter 8 instead; the Committee acted on the proposed text as part of a Second Revision action. Completion by the task groups on the remaining Chapter 3 items – enclosure/compartment and dust deflagration hazard – enabled the Committee to address the related open agenda items. 3. Staff agreed to update the Word draft of the standard to show the Second Revisions based on the completion of action on all Public Comments. 4. Next Meeting. As this meeting completed the Second Draft stage of the development process for NFPA 652, there are no more scheduled meetings of the Fundamentals Committee at this stage. The next step in the process will be preparation of the letter ballot and its distribution to the Committee. 5. There being no further business, the meeting was adjourned at 4:45 p.m., Friday, May 16, 2014. Respectfully submitted, G. R. Colonna, Staff Liaison

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Process

StageProcess Step Dates for TC

Dates for TC

with CC

Public Input Closing Date 6/29/2016 6/29/2016

Final date for TC First Draft Meeting 12/7/2016 9/7/2016Posting of First Draft and TC Ballot 1/25/2017 10/19/2016Final date for Receipt of TC First Draft ballot 2/15/2017 11/9/2016Final date for Receipt of TC First Draft ballot ‐ recirc 2/22/2017 11/16/2016Posting of First Draft for CC Meeting 11/23/2016Final date for CC First Draft Meeting 1/4/2017Posting of First Draft and CC Ballot 1/25/2017Final date for Receipt of CC First Draft ballot 2/15/2017Final date for Receipt of CC First Draft ballot ‐ recirc 2/22/2017Post First Draft Report for Public Comment 3/1/2017 3/1/2017

Public Comment closing date 5/10/2017 5/10/2017

Notice published on Consent Standards (Standards that receive No Comments). Note: Date varies and determined via TC ballot.

_ _

Appeal Closing Date for Consent Standards (15 Days) (Standards That Received

No Comments)_ _

Final date for TC Second Draft Meeting 11/8/2017 8/2/2017Posting of Second Draft and TC Ballot 12/20/2017 9/13/2017Final date for Receipt of TC Second Draft Ballot 1/10/2018 10/4/2017Final date for receipt of TC Second Draft ballot ‐ recirc 1/17/2018 10/11/2017Posting of Second Draft for CC Mtg 10/18/2017Final date for CC Second Draft Meeting 11/29/2017Posting of Second Draft for CC Ballot 12/20/2017Final date for Receipt of CC Second Draft ballot 1/10/2018Final date for Receipt of CC Second Draft ballot ‐ recirc 1/17/2018Post Second Draft Report for NITMAM Review 1/24/2018 1/24/2018

Notice of Intent to Make a Motion (NITMAM) Closing Date 2/21/2018 2/21/2018Posting of Certified Amending Motions (CAMs) and Consent Standards 4/4/2018 4/4/2018Appeal Closing Date for Consent Standards (15 Days after posting) 4/19/2018 4/19/2018SC Issuance Date for Consent Standards (10 Days) 4/29/2018 4/29/2018

Tech Session Association Meeting for Standards with CAMs 6/4‐7/2018 6/4‐7/2018

Appeal Closing Date for Standards with CAMs (20 Days after ATM) 6/27/2018 6/27/2018Council Issuance Date for Standards with CAMs* 8/14/2018 8/14/2018

Comment

Stage (Second

Draft)

Tech Session

Preparation

(& Issuance)

Appeals and

Issuance

2018 ANNUAL REVISION CYCLE

Public Input

Stage

(First Draft)

* Public Input Closing Dates may vary according to standards and schedules for Revision Cycles may change. Please check the

NFPA Website for the most up‐to‐date information on Public Input Closing Dates and schedules at www.nfpa.org/document # (i.e.

www.nfpa.org/101) and click on Next Edition tab.

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Public Input No. 25-NFPA 652-2016 [ Global Input ]

This standard was approved on September 7, 2015, less than one year ago. We believe this standard as writtengenerally provides useful procedures for evaluating the combustibility and explosibility of a dust, and woulddiscourage any substantive changes to the existing language at this time.

Statement of Problem and Substantiation for Public Input

Our Statement is not a problem - we are encouraging continuation of the standard as it is written without substantive changes.

Submitter Information Verification

Submitter Full Name: Kelley Green

Organization: Texas Cotton Ginners' Association

Street Address:

City:

State:

Zip:

Submittal Date: Wed Jun 22 10:22:40 EDT 2016

National Fire Protection Association Report http://submittals.nfpa.org/TerraViewWeb/ContentFetcher?commentPara...

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Public Input No. 9-NFPA 652-2016 [ Global Input ]

When referring to the housekeeping of dust-layers that have accumulated on surfaces, replace all references to"cleaning surfaces" with "removal of dust from surfaces".


The use of "cleaning" does not clearly identify that the dust-layer on a surface should not just be dispersed into the air to settle and accumulate elsewhere within the local area.


Submitter Full Name: Joe Aiken

Organization: Safety Solutions Ltd.

Street Address:

City:

State:

Zip:

Submittal Date: Wed May 04 19:46:39 EDT 2016


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Public Input No. 29-NFPA 652-2016 [ New Section after 1.3.3 ]

A.1.3.3(4)

Warehousing includes the storage of bags, super-sacks, or other containers of combustible dusts where no processing or handling ofthe dusts is performed, except for moving closed containers or loaded pallets. If the business activity of the facility or specificareas of the facility are confined to strictly warehousing, then the standard does not apply. However, if the facility is processing orhandling the dusts outside of the closed containers (e.g. opening containers and dispensing dusts), then the facility is required tomeet all of all of the applicable requirements of this standard.


The term "warehousing" in Section 1.3.3(4) is somewhat confusing and is not clear when storage areas are or are not covered under NFPA 652. Thus, annex material is needed to further explain the committee's intent of which facilities or areas of the facility are not covered under the scope and application of NFPA 652.


Submitter Full Name: Jason Reason

Organization: Lewellyn Technology

Street Address:

City:

State:

Zip:

Submittal Date: Fri Jun 24 18:49:15 EDT 2016


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Public Input No. 62-NFPA 652-2016 [ Section No. 1.4.1 ]

1.4.1*

For the purposes of this standard, the industry- or commodity-specific NFPA standards shall include the following:

(1) NFPA 61, Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities

(2) NFPA 484, Standard for Combustible Metals

(3) NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling ofCombustible Particulate Solids

(4) NFPA 655, Standard for Prevention of Sulfure Sulfur Fires and Explosions

(5) NFPA 664, Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities


Fixing typographical error.


Submitter Full Name: Timothy Myers

Organization: Exponent Inc

Street Address:

City:

State:

Zip:



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2.3.2 ASTM Publications.

ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959.

ASTM E1226, Standard Test Method for Explosibility of Dust Clouds, 2012a.

ASTM E1515, Standard Test Method for Minimum Explosible Concentration of Combustible Dusts, 2007 2014 .


Date updates.


Submitter Full Name: Timothy Earl

Organization: GBH International

Street Address:

City:

State:

Zip:

Submittal Date: Tue Jan 05 10:02:43 EST 2016


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Public Input No. 63-NFPA 652-2016 [ New Section after 3.1 ]

Explosible Definition

3.3.X Explosible. A finely-divided combustible particulate solid that can propagate a deflagration when dispersed in air or the process-specific oxidizing media as determined in the screening tests described in Section 5.4.3


The term explosible is used in this and other NFPA combustible dust standards and a uniform definition should be developed.

NFPA 68 includes an alternative definition and another definition is being proposed by the NFPA 484 technical committee.




Street Address:

City:

State:

Zip:



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Extracted from section 3.3.29 of NFPA 61

3.3.X Point-of-Use Dust Collector. A bin vent–type of dust

collector with an integral AMD used to create negative pressure

on enclosed conveying equipment.


Point of use dust collectors are seeing increased use in a variety of industries. This definition is complimentary to the proposed section on these collectors.

Related Public Inputs for This Document

Related Input Relationship

Public Input No. 66-NFPA 652-2016 [New Section after 8.3.5.3] The defined term is used in this requirement.




Street Address:

City:

State:

Zip:



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3.3.x Material modification.

A modification that changes the original design of the equipment or process, or that changes the explosibility properties of thecontents of the equipment.


Section 7.1.2.1 of the standard is unclear as to what constitutes a material modification. This definition will add clarity.


Submitter Full Name: Marie Gargas

Organization: SPI: The Plastics Industry Trade Association

Affilliation: SPI: The Plastics Industry Trade Association

Street Address:

City:

State:

Zip:

Submittal Date: Mon Jun 27 11:04:01 EDT 2016


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Public Input No. 28-NFPA 652-2016 [ Section No. 4.2 ]

4.

2 Objectives2 Objectives .

4.2.1

Life Safety. The design of the facility, processes and equipment shall be based upon the goal of providing a reasonable level of safetyand property protection by meeting the following objectives:

(1) Life safety

(2) Mission continuity

(3) Mitigation of fire spread and explosions

4.2.1.1

*

The facility, processes, and equipment shall be designed, constructed, equipped, and maintained and management systems shall beimplemented to reasonably protect occupants not in the immediate proximity of the ignition from the effects of fire for the time neededto evacuate, relocate, or take refuge.

The objectives stated in Section 4.2 shall be interpreted as intended outcomes of this standard and not as prescriptiverequirements.

4.2.1.2 The objectives stated in Section 4.2 shall be deemed to be met when, consistent with the goal in Section 4.2.1

.2 Theand the provisions in Sections 1.4 and 1.5, the following has been achieved:

(1) T he facility, processes

,and equipment

shall beare designed, constructed

, equipped, and maintained and management systems shall be implemented to reasonably prevent serious injury from flash firesand maintained in accordance with the prescriptive criteria set forth in this standard.

(2) The management systems set forth in this standard are implemented .

4.2.1.3

The facility, processes, and equipment shall be designed, constructed, equipped, and maintained and management systems shall beimplemented to reasonably prevent injury from explosions

Where a performance-based alternative design is used, it shall be documented to meet the same objectives as theprescriptive design it replaces, in accordance with Chapter 6 of this standard .

4.2.

1.4 The structure shall be located, designed, constructed, and maintained to reasonably protect adjacent properties and the publicfrom the effects of fire, flash fire, or explosion

2 Life Safety. The life safety objective shall be deemed to have been met when, consistent with the goal in Section 4.2.1and the provisions in Sections 1.4 and 1.5, the occupants not in the immediate proximity of the ignition are protected from theeffects of fires, flash-fires, and explosions for the time needed to evacuate, relocate, or take refuge in order to prevent seriousinjury .

4.2.

23 *

Mission Mission Continuity.

The facility, processes, and equipment shall be designed, constructed, equipped, and maintained and management systems shall beimplemented to

The mission continuity objective shall be deemed to have been met when, consistent with the goal in Section 4.2.1 and theprovisions in Sections 1.4 and 1.5, the protection features for the facility, processes and equipment limit damage to levels thatensure the ongoing mission, production, or operating capability of the facility to a degree acceptable to the owner/operator.

A. 4.2.

3 * Mitigation3 Other stakeholders could also have mission continuity goals that will necessitate more stringent objectives as well asmore specific and demanding performance criteria. The protection of property beyond maintaining structural integrity longenough to escape is actually a mission continuity objective.


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The mission continuity objective encompasses the survival of both real property, such as the building, and theproduction equipment and inventory beyond the extinguishment of the fire. Traditionally, property protection objectives haveaddressed the impact of the fire on structural elements of a building as well as the equipment and contents inside a building.Mission continuity is concerned with the ability of a structure to perform its intended functions and with how that affects thestructure's tenants. It often addresses post-fire smoke contamination, cleanup, and replacement of damaged equipment orraw materials.

4.2.4* Mitigation of Fire Spread and Explosions.

The facility and processes The mitigation of fire spread and explosions shall be

designed todeemed to have been met when, consistent with the goal in Section 4.2.1 and the provisions in Sections 1.4 and 1.5, theprescribed or performance based alternative design features are incorporated into the facility and processes to prevent ormitigate fires and explosions that can cause failure of adjacent buildings or building compartments , or other enclosures,emergency life safety systems, adjacent properties, adjacent storage, or the

facility’sfacility's structural elements.

A. 4.2.4

* Compliance Options. The objectives in Section Adjacent compartments share a common enclosure surface (wall, ceiling, floor) with the compartment of fire or explosionorigin. The intent is to prevent the collapse of the structure during the fire or explosion.

4.2.5* Compliance Options. The objectives in Section 4.2 shall be achieved by either of the following means:

(1) A prescriptive approach in accordance with Chapters 5, 7, 8, and 9 in conjunction with any prescriptiveprovisions of applicable commodity-specific NFPA standards .

(2) A performance-based approach in accordance with

Chapter 6Chapter 6.

A. 4.2.

5 5 Usually a facility or process system is designed using the prescriptive criteria until a prescribed solution is found to beinfeasible or impracticable. Then the designer can use the performance-based option to develop a design, addressing the fullrange of fire and explosion scenarios and the impact on other prescribed design features. Consequently, facilities are usuallydesigned not by using performance-based design methods for all facets of the facility but rather by using a mixture of bothdesign approaches as needed.

4.2.6 Where a dust fire, deflagration, or explosion hazard exists within a process system, the hazards shall be managed inaccordance with this standard.

4.2.

6 7 Where a dust fire, deflagration, or explosion hazard exists within a

building or buildingfacility compartment, the effects of the fire, deflagration, or explosion shall be managed in accordance with this standard.

Additional Proposed Changes

File Name Description Approved

USBSA_4.2_changes.docx Attached word file of the complete public input to assist.


This revision would implement a decision by the Correlating Committee on Combustible Dusts. In November 2014, the Correlating Committee set up an Objectives Task Group to examine aligning the Objectives provisions for all of the combustible dust standards. The Objectives Task Group had members representing the following NFPA combustible dust standards: 61, 484, 652, 654, and 664. In January 2015, the Correlating Committee reviewed the work product of the Objectives Task Group and created a Correlating Committee Note containing a document with the Objectives language developed by the Objectives Task Group. The Objectives language being recommended in this public comment is the language developed by the Objectives Task Group, and is being submitted solely to implement the intent of the Correlating Committee and the work of its Task Group.


Submitter Full Name: Arthur Sapper

Organization: McDermott Will Emery Llp

Street Address:

City:

State:

Zip:


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1

Public Comment No. ___-NFPA 652-2016 [Section 4.2]

4.2 Objectives.

4.2.1 Life Safety.

4.2.1.1* The facility, processes and equipment, shall be designed, constructed, equipped,

and maintained and management systems shall be implemented to reasonably protect

occupants not in the immediate proximity of the ignition from the effects of fire for the

time needed to evacuate, relocate, or take refuge.

4.2.1.2 The facility, processes and equipment shall be designed, constructed, equipped,

and maintained and management systems shall be implemented to reasonably prevent

serious injury from flash fires.

4.2.1.3 The facility, processes and equipment shall be designed, constructed, equipped,

and maintained and management systems shall be implemented to reasonably prevent

serious injury from explosions.

4.2.1.4 The structure shall be located, designed, constructed, and maintained to

reasonably protect adjacent properties and the public from the effects of fire, flash fire, or

explosion.

4.2.2* Mission Continuity. The facility, processes and equipment shall be designed,

constructed, equipped, and maintained and management systems shall be implemented to

limit damage to levels that ensure the ongoing mission, production, or operating

capability of the facility to a degree acceptable to the owner/operator.

4.2.3* Mitigation of Fire Spread and Explosions. The facility and processes shall be

designed to prevent or mitigate fires and explosions that can cause failure of adjacent

buildings or building compartments or other enclosures, emergency life safety systems,

adjacent properties, adjacent storage, or the facility's structural elements.

4.2.4* Compliance Options. The objectives in Section 4.2 shall be achieved by either

of the following means:

(1) A prescriptive approach in accordance with Chapters 5, 7, 8, and 9 in conjunction

with any prescriptive provisions of applicable commodity-specific NFPA standards.

(2) A performance-based approach in accordance with Chapter 6.

4.2.5 Where a dust fire, deflagration, or explosion hazard exists within a process system,

the hazards shall be managed in accordance with this standard.

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4.2.6 Where a dust fire, deflagration, or explosion hazard exists within a building or

building compartment, the effects of the fire, deflagration, or explosion shall be managed

in accordance with this standard.

4.2 Objectives.

4.2.1 The design of the facility, processes and equipment shall be based upon the goal

of providing a reasonable level of safety and property protection by meeting the

following objectives:

(1) Life safety

(2) Mission continuity

(3) Mitigation of fire spread and explosions

4.2.1.1 The objectives stated in Section 4.2 shall be interpreted as intended outcomes of

this standard and not as prescriptive requirements.

4.2.1.2 The objectives stated in Section 4.2 shall be deemed to be met when, consistent

with the goal in Section 4.2.1 and the provisions in Sections 1.4 and 1.5, the following

has been achieved:

(1) The facility, processes and equipment are designed, constructed and maintained in

accordance with the prescriptive criteria set forth in this standard.

(2) The management systems set forth in this standard are implemented.

4.2.1.3 Where a performance-based alternative design is used, it shall be documented to

meet the same objectives as the prescriptive design it replaces, in accordance with

Chapter 6 of this standard.

4.2.2 Life Safety. The life safety objective shall be deemed to have been met when,

consistent with the goal in Section 4.2.1 and the provisions in Sections 1.4 and 1.5, the

occupants not in the immediate proximity of the ignition are protected from the effects of

fires, flash-fires, and explosions for the time needed to evacuate, relocate, or take refuge

in order to prevent serious injury.

4.2.3* Mission Continuity. The mission continuity objective shall be deemed to have

been met when, consistent with the goal in Section 4.2.1 and the provisions in Sections

1.4 and 1.5, the protection features for the facility, processes and equipment limit damage

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to levels that ensure the ongoing mission, production, or operating capability of the

facility to a degree acceptable to the owner/operator.

A.4.2.3 Other stakeholders could also have mission continuity goals that will necessitate

more stringent objectives as well as more specific and demanding performance criteria.

The protection of property beyond maintaining structural integrity long enough to escape

is actually a mission continuity objective.

The mission continuity objective encompasses the survival of both real property,

such as the building, and the production equipment and inventory beyond the

extinguishment of the fire. Traditionally, property protection objectives have addressed

the impact of the fire on structural elements of a building as well as the equipment and

contents inside a building. Mission continuity is concerned with the ability of a structure

to perform its intended functions and with how that affects the structure's tenants. It often

addresses post-fire smoke contamination, cleanup, and replacement of damaged

equipment or raw materials.

4.2.4* Mitigation of Fire Spread and Explosions. The mitigation of fire spread and

explosions shall be deemed to have been met when, consistent with the goal in Section

4.2.1 and the provisions in Sections 1.4 and 1.5, the prescribed or performance based

alternative design features are incorporated into the facility and processes to prevent or

mitigate fires and explosions that can cause failure of adjacent buildings or building

compartments, or other enclosures, emergency life safety systems, adjacent properties,

adjacent storage, or the facility's structural elements.

A.4.2.4 Adjacent compartments share a common enclosure surface (wall, ceiling, floor)

with the compartment of fire or explosion origin. The intent is to prevent the collapse of

the structure during the fire or explosion.

4.2.5* Compliance Options. The objectives in Section 4.2 shall be achieved by either of

the following means:

(1) A prescriptive approach in accordance with Chapters 5, 7, 8, and 9 in

conjunction with any prescriptive provisions of applicable commodity-specific NFPA

standards.

(2) A performance-based approach in accordance with Chapter 6.

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A.4.2.5 Usually a facility or process system is designed using the prescriptive criteria

until a prescribed solution is found to be infeasible or impracticable. Then the designer

can use the performance-based option to develop a design, addressing the full range of

fire and explosion scenarios and the impact on other prescribed design features.

Consequently, facilities are usually designed not by using performance-based design

methods for all facets of the facility but rather by using a mixture of both design

approaches as needed.

4.2.6 Where a dust fire, deflagration, or explosion hazard exists within a process system,

the hazards shall be managed in accordance with this standard.

4.2.7 Where a dust fire, deflagration, or explosion hazard exists within a facility

compartment, the effects of the fire, deflagration, or explosion shall be managed in

accordance with this standard.

Statement of Problem and Substantiation for Public Comment

This revision would implement a decision by the Correlating Committee on Combustible

Dusts. In November 2014, the Correlating Committee set up an Objectives Task Group

to examine aligning the Objectives provisions for all of the combustible dust standards.

The Objectives Task Group had members representing the following NFPA combustible

dust standards: 61, 484, 652, 654, and 664. In January 2015, the Correlating Committee

reviewed the work product of the Objectives Task Group and created a Correlating

Committee Note containing a document with the Objectives language developed by the

Objectives Task Group. The Objectives language being recommended in this public

comment is the language developed by the Objectives Task Group, and is being

submitted solely to implement the intent of the Correlating Committee and the work of its

Task Group.


Submitter Full Name: ARTHUR SAPPER

Organization: for the United States Beet Sugar Association

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5.2.1

The determination of combustibility or explosibility shall be permitted to be based upon either of the following:

(1) Historical facility data or published data that are deemed to be representative of current materials and process conditions

(2) Analysis of representative samples in accordance with the requirements of 5.4.1 and 5.4.3

This section is very important for industries with dusts that are essentially identical, and should be maintained as written.


There is no problem with this section - we are supporting the section as written.




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Public Input No. 22-NFPA 652-2016 [ Section No. 5.4.1.1 ]

5.4.1.1

Where the combustibility is not known, determination of combustibility shall be determined by one of the following tests:

(1) A screening test based on the UN Recommendations on the Transport of Dangerous Goods: Model Regulations — Manual ofTests and Criteria, Part III, Subsection 33.2.1, Test N.1, “Test Method for Readily Combustible Solids”

(2) Other equivalent fire exposure test methods


There is no problem with this section - we are supporting the section as written.




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5.4.3.1

Where the explosibility is not known, determination of explosibility of dusts shall be determined according to one of the followingtests:

(1) The “Go/No-Go” screening test methodology described in ASTM E1226, Standard Test Method for Explosibility of Dust Clouds

(2) ASTM E1515, Standard Test Method for Minimum Explosible Concentration of Combustible Dusts

(3) An equivalent test methodology


This section should be maintained as written. It provides important information for determination of explosbility. The issue of over-driven results when the 20 L sphere is used is further discussed in published peer reviewed papers by B. Ganesan et al and AnnMarie Fauske. (Ganesan, B., Parnell Jr., C. B., McGee, R. O., & Faulkner, W.B (2015); A critical evaluation of explosible dust testing methods: Part II. Applied Engineering in Agriculture, Vol 31(2) 203-209. http://elibrary.asabe.org/abstract.asp?aid=45458&t=1&redir=aid=45458&confalias=&redir=[volume=31&issue=2&conf=aeaj&orgconf=aeaj2015]&redirType=toc_journals.asp&redirType=toc_journals.asp), and (Fauske, A (2014) Combustible Dust Basics, Part 3: What is Overdriving? http://blog.fauske.com/blog/bid/381834/Combustible-Dust-Basics-Part-3-What-is-Overdriving).




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Sample preservation

5.X.X Samples that may oxidize or degrade in the presence of air shall be maintained in suitable inert gas or vacuum packaging untiltested.


Some materials can oxidize or degrade in air changing their combustibility or explosibility characteristics and should be appropriately preserved between sampling and testing.




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7.1.2 (new 7.1. 2 * and move existing 7.1.2, etc., accordingly)

A DHA shall be completed for all new processes and facility compartments.

7.1.3*

The requirements of Chapter 7 shall apply retroactively in accordance with 7.1.2.1 through 7.1.2.3.

7.1.2 3 .1

For existing processes and facility compartments that are undergoing material modification, the owner/operator shall complete DHAsas part of the project.

7.1.2 3 .2*

For existing processes and facility compartments that are not undergoing material modification, the owner/operator shall schedule andcomplete DHAs of existing processes and facility compartments within a 3-year period from the effective date of the standard. Theowner/operator shall demonstrate reasonable progress in each of the 3 years.

7.1.2 3 .3

For the purposes of applying the provisions of 7.1.2, material modification shall include modifications or maintenance and repairactivities that exceed 25 percent of the original cost.


Although the requirement for a DHA for new processes and facility compartments are "implied" by 5.1 and 5.1.1, it is not specifically required in chapter 7. Such a requirement should not be implied but specifically stated to assure there is no doubt as to the necessity of the DHA for new processes, etc.


Submitter Full Name: Jack Osborn

Organization: Airdusco, Inc.

Street Address:

City:

State:

Zip:

Submittal Date: Tue Jun 28 07:45:44 EDT 2016


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Public Input No. 58-NFPA 652-2016 [ New Section after 7.1.2.3 ]

7.1.2.4. The absence of previous incidents shall not be used as the basis for not performing a DHA.


This requirement is needed because all too often facilities will incorrectly use the fact that no incidents have occurred as basis for not assessing and mitigating potential combustible dust hazards. These facilities have no idea what hazards are present at their facilities and incorrectly use the lack of an incident as justification for not performing a DHA. This requirement clarifies the need to perform a DHA, regardless of whether incidents have occurred or not, at each facility covered under NFPA 652.




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7.1.2.3

For the purposes of applying the provisions of 7.1.2, material modification shall include modifications or maintenance and repairactivities that exceed 25 percent of the original replacement cost.


The original cost of a system and/or equipment 20 or more years old can be a very small fraction of the actual present costs (in comparison). Thus, small changes in a system can result in a requirement for a DHA. Such small changes (e.g. duct changes in a dust collection system, or changes in the discharge of the collected material in the dust collector) are adequately covered by Management of Change requirements. A full DHA should be required for significant changes only and the use of the 25% of replacement cost is more representative of that type of change.




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7.2.4 Review.

The DHA shall be reviewed and updated at least every 5 years.


The DHA should always be reviewed at a predetermined interval to ensure that the hazard assessment and mitigation techniques used during the DHA are still correct and valid. Both NFPA 654 and NFPA 484 both have this 5 year review requirement for DHAs (hazard analyses).




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X.X.Y Where practical, facilities shall consider alternative processes or raw materials that reduce the need to handle combustibledusts.


Inherent safety is currently designated as a reserved section. The technical committee should begin to describe the concepts of inherent safety either through prescriptive requirements or annex material.




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Insert new 8.3.3.3.5 and renumber following sections

8.3.3.3.5* It shall be permitted to use an engineered system managed by a control system together with a variable frequency drive-operated fan. The control system ensures maintaining minimum design air volume flow in main ducts and open branch ducts at alloperating conditions.

A.8.3.3.3.5 In a single main system with multiple drops the main duct is optimized based on the maximum and average workstationutilization to allow system to be operated from minimum air volume flow up to the maximum air volume flow. The control systemmaintains the minimum design air volume flow in the main duct and open branch ducts.

In a system with sub-main ducts the control system must measure air volume flow at hood (or drops), at branches and sub-branchesand automatically adjust minimum design air volume flow in each branch. The controller must ensure that minimum air volume flow ismaintained at each open branch and sub-branch and that minimum design air volume flow is maintained at all open hoods or pickup


Energy requirement for dust systems are significant and often the single largest power consumer in a facility. Multiple tests has shown that the actual demand for vacuum is often in the 20 to 30% of full open design flows. With new technology it is now possible via a control system to manage where vacuum is needed and at the same time assure that minimum design velocities are maintained to prevent accumulation of dust in the ducting and also maintain minimum design flows at each drop.


Submitter Full Name: Niels Pedersen

Organization: Nederman LLC

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Public Input No. 1-NFPA 652-2016 [ New Section after 8.3.4.1.1.2 ]

8.3.4.1.1.3 Rotary drum filters shall be permitted to be located indoors without protection from combustible dust hazards when all ofthe following criteria are met:

(1) The drum filter is designed to prevent the formation of a combustible dust cloud with the air-material separator enclosure housingthe drum filter;

(2) The drum filter has sprinkler protection; and

(3) AMS downstream from the rotary drum filter shall be protected in accordance with Section 8.8.



PublicCommentNo91.pdf NFPA 652 Public Comment No. 91


NOTE: The following Public Input appeared as "Reject but Hold" in Public Comment No. 91 of the A2015 Second Draft Report for NFPA 652 and per the Regs. at 4.4.8.3.1.

Substantiation :Rotary drum filters have long been used in the textile and cellulosic industries, and have proven to be inherently safe from deflagration. The rotating media drum's filter media contains only a minimal amount of dust at any time during use which is never suspended in air-in contrast to baghouse operation. It is only vacuumed off a felt on the rotating drum with vacuum nozzles similar to home vacuum cleaner nozzles and conveyed to a secondary (conventional) AMS (e.g., cyclone) which should be protected in accordance with this standard. As it is written, it appears that this document would disallow interior rotary drum filters by taking away the qualifying requirement of "where an explosion hazard exists" arbitrarily requiring protection on equipment that (i) does not require protection and (ii) is impossible to protect with chemical suppression or relief venting.


Submitter Full Name: TC ON CMD-FUN

Organization: NFPA TC ON FUNDAMENTALS OF COMBUSTIBLE DUSTS

Street Address:

City:

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Zip:

Submittal Date: Mon Jan 04 14:22:59 EST 2016


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8.3.4.1.1.3 Rotary drum filters shall be permitted to be located indoors without protection from combustible dust hazards when all ofthe following criteria are met.

(1) The drum filter is designed to prevent the formation of a combustible dust cloud within the air-material separator enclosure housingthe drum filter;


(3) AMS downstream from the torary drum filter shall be protected in accordance with Section 8.8.



PublicCommentNo400.pdf NFPA 652 Public Comment No. 400



Rotary drum filters have long been used in the textile and cellulosic industries, and have proven to be inherently safe from deflagration. The rotating media drum’s filter media contains only a minimal amount of dust at any time during use which is never suspended in air – in contrast to baghouse operation. It is only vacuumed off a felt on the rotating drum with vacuum nozzles similar to home vacuum cleaner nozzles and conveyed to a secondary (conventional) AMS (e.g., cyclone) which should be protected in accordance with this standard. As it is written, it appears that this document would disallow interior rotary drum filters by taking away the qualifying requirement of “where an explosion hazard exists” arbitrarily requiring protection on equipment that (i) does not require protection and (ii) is impossible to protect with chemical suppression or relief venting.




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Public Comment No. 400-NFPA 652-2013 [ New Section after

8.3.4.1.1.2 ]

8.3.4.1.1.3, New textRotary drum filters shall be permitted to be located indoors without protection from combustible dust hazards when all of the following criteria are met:

(1) The drum filter is designed to prevent the formation of a combustible dust cloud within the air-material separator enclosure housing the drum filter;






Submitter Full Name: MARIE MARTINKO

Organization: SPI

Street Address:

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Submittal Date: Fri Nov 15 09:40:05 EST 2013

Committee Statement

Page500 of 898National Fire Protection Association Report

9/8/2014http://submittals.nfpa.org/TerraViewWeb/ContentFetcher?commentParams=%28Comment...

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8.3.4.1.1.2.1 Rotary drum filters shall be permitted to be located indoors without protection from combustible dust hazards when all ofthe following criteria are met:

(1) The drum filter is designed to prevent the formation of a combustible dust cloud within the air-material separator enclosurehousing the drum filter;





PublicCommentNo219.pdf NFPA 652 Public Comment 219



Rotary drum filters have long been used in the textile and cellulosic industries, and have proven to be inherently safe from deflagration. The rotating media drum’s filter media contains only a minimal amount of dust at any time during use which is never suspended in air – in contrast to baghouse operation. It is only vacuumed off a felt on the rotating drum with vacuum nozzles similar to home vacuum cleaner nozzles and conveyed to asecondary (conventional) AMS (e.g., cyclone) which should be protected in accordance with this standard. As it is written, it appears that this document would disallow interior rotary drum filters by taking away the qualifying requirement of “where an explosion hazard exists” arbitrarily requiring protection on equipment that (i) does not require protection and (ii) is impossible to protect with chemical suppression or relief venting.




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Public Comment No. 219-NFPA 652-2013 [ New Section after

8.3.4.1.1.2 ]

8.3.4.1.1.3, New textComment: Insert the following new section:

8.3.4.1.1.3 Rotary drum filters shall be permitted to be located indoors without protection from combustible dust hazards when all of the following criteria are met:

(1) The drum filter is designed to prevent the formation of a combustible dust cloud within the air-material separator enclosure housing the drum filter;




Substantiation : Rotary drum filters have long been used in the textile and cellulosic industries, and have proven to be inherently safe from deflagration. The rotating media drum’s filter media contains only a minimal amount of dust at any time during use which is never suspended in air – in contrast to baghouse operation. It is only vacuumed off a felt on the rotating drum with vacuum nozzles similar to home vacuum cleaner nozzles and conveyed to a secondary (conventional) AMS (e.g., cyclone) which should be protected in accordance with this standard. As it is written, it appears that this document would disallow interior rotary drum filters by taking away the qualifying requirement of “where an explosion hazard exists” arbitrarily requiring protection on equipment that (i) does not require protection and (ii) is impossible to protect with chemical suppression or relief venting.


Submitter Full Name:

Richard Krock

Organization: The Vinyl Institute

Affilliation:

These materials were developed through a cooperative effort involving the Vinyl Institute's outside counsel, Lawrence P. Halprin of Keller and Heckman LLP, the Vinyl Institute staff and the Vinyl Institute member company representatives. These comments also reflect input we received from other trade associations.

Street Address:

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Submittal Date: Tue Nov 12 14:47:57 EST 2013

Committee Statement



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CommitteeAction:

Rejected but held

Resolution: These comments propose addition of new text regarding rotary drum filters and where they are permitted to be located and with what protection features. The Committee is not familiar enough with these devices and needs more information to verify the type of equipment (does it have a housing or is it more like enclosureless AMS) and how does the design prevent the formation of a dust cloud? Since this type of information has not been provided in the substantiation for these comments, the Committee believes it is appropriate to act at this time to reject, but hold these comments for the next revision cycle.



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Public Input No. 33-NFPA 652-2016 [ New Section after 8.3.4.1.2 ]

8.3.4.1.1.3

Rotary drum filters shall be permitted to be located indoors without protection from combustible dust hazards when all of the followingcriteria are met:

(1) The drum filter is designed to prevent the formation of a combustible dust cloud within the air-material separator enclosurehousing the drum filter;









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Public Input No. 56-NFPA 652-2016 [ Section No. 8.3.4.1.2.1 ]

8.3.4.1.2.1

Wet air–material separators shall be permitted to be located inside when all of the following criteria are met:

(1) Interlocks are provided to shutdown the system if the flow rate of the scrubbing medium is less than the designed minimum flowrate.

(2) The scrubbing medium is not a flammable or combustible liquid.

(3) The separator is designed to prevent the formation of a combustible dust cloud within the air-material separator.

(4) The design of the separator addresses any reaction between the separated material and the scrubbing medium.

NOTE: Because many supplier offer immersion seperators, might consider including, excluding or distiguishing an immesionseperator from a wet knockdown air scrubber, when discussing wet AMS


Better definitions & distinctions of product types & offerings, clarify equipment definitions


Submitter Full Name: Norman Nowosinski

Organization: Nilfisk Industrial Vacuums

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Point of Use Dust Collectors From Section 8.7.2.4 of NFPA 61 (Note the annex material appears to be missing from NFPA 61)

X.X* A point-of-use dust collector shall be permitted to be

mounted directly to conveying equipment in both indoor and

outdoor locations, provided all of the following conditions are

met:

(1) When the point-of-use dust collector is mounted to an

enclosure, such as a bucket elevator leg, the enclosure

shall have explosion protection per the provisions of this

standard. The volume of the dirty air side and of the transition

shall be included in the determination of explosion

protection design.

(2) The point-of-use dust collector shall be mounted directly

to the conveying equipment housing via a transition duct

without an airlock

(3) The transition between the point-of-use dust collector

and the vented equipment shall be designed such that

dust will release from the filter media and return to the

equipment product stream and the transition is not a

collection point for dust accumulation under normal

operations.

(4) The cross-sectional area of the transition connection shall

be equal to or greater than the cross-sectional area of the

point-of-use dust collector.

(5) The point-of-use dust collector shall include an integral

air-moving device on the clean side of the dust collector

to maintain negative pressure.

(6) The point-of-use dust collector shall not be connected to

any other pieces of equipment.

(7) Point-of-use dust collectors that return air to the inside of

buildings shall be capable of a minimum filtering efficiency

of 0.02 g per dry standard cubic meter of airflow

(0.008 grains per dry standard cubic feet of airflow).

A.X.X

The purpose of this dust control method is to remove displaced air from the equipment so that it operates under a slight negativepressure in order to reduce fugitive dust emissions from the equipment; to keep the dust generated (from the material beingconveyed) with the material; and eliminate the propagation hazard of interconnecting the conveying equipment through a central dustcollection system. The dust is not removed from the equipment nor does this approach lower the risk of a dust deflagration within the


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equipment itself. The bin vent should be located near the material inlet point on the conveyor. Little dust should be drawn into the binvent

When used on a bucket elevator leg, it is recommended that the bin vent be installed in the down leg of the bucket elevator leg tofacilitate dust release from the filters. The cross sectional area of the transition between the duct and the leg casing should be 2.5times the cross sectional area of the dust collector inlet. The angle of the transition duct to the leg casing should be no less than 60degrees.

This dust control method should be used in conjunction with a good housekeeping program, equipment maintenance strategy, anddust deflagration mitigation actions as required.


Point of use dust collectors are seeing increased use in multiple industries and the TC should consider providing guidance, such as the new guidance in the 2017 edition of NFPA 61

Related Public Inputs for This Document

Related Input Relationship

Public Input No. 67-NFPA 652-2016 [New Section after 3.3]




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8.4.2.1 Procedure.

8.4.2.1.1*

Housekeeping procedures shall be documented.

8.4.2.1.2*

The methods used for cleaning removal of dust from surfaces shall be selected on the basis of reducing the potential for creating acombustible dust cloud.

The accumulation of a dust-layer on a surface that is subject to heating (e.g. the surface of a bearing, an electrical motor or a heater)could insulate the surface, increasing the surface temperature above the equipment 'T' rating, to the point where the dust couldself-ignite and smolder.

Housekeeping of a dust-layer that has self-ignited and started smoldering could result in full-ignition as the dust disperses during thehousekeeping process. The burning dust could damage the housekeeping equipment, ignite a larger dust-cloud or a flammable gasrelease in the area or initiate smoldering in other dust-layers.

B efore performing houskeeping of a dust-layer on a potentially hot surface, the dust should be tested to confirm whetherself-ignition and smoldering has initiated .

Note that housekeeping of dust-layers settling after a dust flash-fire should also consider the dust to be smoldering.

8.4.2.1.3

Cleaning methods to be used shall be based on the characteristics of the material and , the quantity of material present and therisks that the dust-layer could have self-ignited .


The potential for housekeeping of a self-ignited and smoldering dust layer to initiate a larger conflagration and/or explosion was not addressed.




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Public Input No. 14-NFPA 652-2016 [ Section No. 8.4.2.2.1 ]

8.4.2.2.1*

Portable vacuum cleaners that meet the following minimum requirements shall be permitted to be used to collect combustibleparticulate solids in unclassified (nonhazardous) areas:

(1) Materials of construction shall comply with 8.5.7.1.

(2) Hoses shall be conductive or static dissipative.

(3) All conductive components, including wands and attachments, shall be bonded and grounded.

(4) Dust-laden air shall not pass through the fan or blower.

(5) Electrical motors shall not be in the dust-laden air stream unless listed for Class II, Division 1, locations.

(6)

(7) Vacuum cleaners used for metal dusts shall meet the requirements of NFPA 484.

(8) For the collection of self-heating combustible particulate solids wet type dust collectors shall be used

(9) To prevent the identified occurrence of brush and bulking brush discharges conductive collection bags shall be used

(10) When a possible ignition by a single impact has been identified equipment specifically designed to avoid this hazard shall beconsidered

(11) The owner/operator shall proceed with a Dust Hazards Analysis (DHA) in conformance with Chapter 7


Paragraph 8.4.2.2.1

Based on my experience (I work for a manufacturer of NRTL certified explosion-proof vacuum cleaners) the actual defined minimum requirements in paragraph 8.4.2.2.1do not allow the safe recovery of combustible particulate solids in unclassified (nonhazardous) areas.

It should be mentioned that wet type dust collectors must be used in the case of self-heating combustible particulate solids as they can potentially lead to spontaneous ignition.

Conductive collection bags must be used to prevent the identified occurrence of brush and bulking brush discharges which could be an ignition threat.

Also equipment designed to avoid ignition by a single impact shall be considered when this hazard has been identified during combustible particulate solids collection (Collection of solid element like a metal bolt).

I also suggest reminding the owner/operator to proceed with a Dust Hazards Analysis (DHA) in conformance with Chapter 7


Submitter Full Name: Stephane Briquet

Organization: Tiger Vac International Inc

Affilliation: HAZ-LOC PORTABLE VACUUM CLEANERS ORGANIZATION INC.

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Submittal Date: Tue May 10 13:45:15 EDT 2016

* Where liquids or wet materials are picked up by the vacuum cleaner, paper filter elements shall not be used.


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8.4.2.2.1*

Portable vacuum cleaners that meet the following minimum requirements shall be permitted to be used to collect combustibleparticulate solids in unclassified (nonhazardous) areas:

(1) Materials of construction shall comply with 8.5.7.1.

(2) Hoses shall be conductive or static dissipative.

(3) All conductive components, including wands and attachments, shall be bonded and grounded.

(4) Dust-laden air shall not pass through the fan or blower. (Dust laden air should be defined as any amount of combustible dust inambient or working air - lacking quantitative measures)

(5) Electrical motors shall not be in the dust-laden air stream unless NRTL certified (as a unit) & listed for Class II, Division 1,locations.

(6)

(7) Vacuum cleaners used for metal dusts shall meet the requirements of NFPA 484.


Better definitinions of terms used and requirement for system and components




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* Where liquids or wet materials are picked up by the vacuum cleaner, paper filter elements shall not be used.


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8.4.2.2.2*

In Class II electrically classified (hazardous) locations, portable electrically powered vacuum cleaners shall be NRTL certified(components) & listed for the purpose and location or shall be a fixed-pipe suction system with a remotely located exhauster forpermanant blower assemblies, or for portable models, downstream (of motor or exhaust) filtered with hepa or ulpa filters perclassified rating and an AMS installed in conformance with Section 8.3, and they shall be suitable for the dust being collected.


Differentiate portable units from permanent blower/central vac units...if needed. Also introduce HEPA & ULPA language into downstream filtering requirements for inside exhaust....




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8.4.2.2.3

Where flammable vapors or gases are present, vacuum cleaners shall be listed for Class I ( Strike: " and Class II "- Class II ARE FORDUSTS ONLY, NOT GASES OR VAPORS) hazardous locations.


Correction to erroneous language on class




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8.4.2.4

To minimise the risks associated with using a brush and pan (or broom and shovel) to remove flammable dust, the followingprecautions shall be applied:

(1) The brush/broom must be specifically designed to eliminate the risks of static generation during the brushing process on thespecific surface.

(2) The dust must not be highly flammable as the friction of the brush with the surface could create an ignition source (static sparkor heat)

(3) The typical particle size of the dust must be large enough rapidly settle without generating a significant dust-cloud.

(4) The dust must be locally brushed directly into the pan and removed.

(5) The dust should not be brushed into piles as such brushing would create a larger, more sustained dust-cloud - this wouldincrease the risk of potential ignition and the consequences of combustion.


The use of dust-pan and brush with highly flammable dusts was not addressed




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8.4.2.3* Sweeping, Shoveling, Scoop, and Brush Cleaning Method.

The use of scoops, brooms, and brushes for sweeping and shoveling shall ONLY be a permitted cleaning method they comply withSection 8 .4.2.4.


The use of brooms is permitted without specific safeguards




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8.4.2.6.2*

Where blowdown using compressed air is used, the following precautions shall be followed:

(1) Prior to using compressed air, vacuum Vacuum cleaning, sweeping, or water washdown methods are shall be used prior tousing compressed air to clean surfaces that can be safely accessed.

(2) Dust accumulations in the area after vacuum cleaning, sweeping, or water washdown do not exceed the threshold housekeepingdust accumulation.

(3) Compressed air hoses are equipped with pressure relief nozzles limiting the discharge pressure to 30 psi (207 kPa) inaccordance with OSHA requirements in 29 CFR 1910.242(b).

(4) All electrical equipment, including lighting, potentially exposed to airborne dust in the area during cleaning is suitable for use in aClass II, Division 2, hazardous (classified) location in accordance with NFPA 70.

(5) All ignition sources and hot surfaces capable of igniting a dust cloud or dust layer are shut down or removed from the area.

(6) After blowdown is complete, residual dust on lower surfaces is cleaned prior to re-introduction of potential ignition sources.

(7) Where metal or metal-containing dust or powder under the scope of NFPA 484is present, the requirements of NFPA 484 apply.


This revision places the emphasis on vacuum cleaning, sweeping or water washdown and actually requires those methods first with the term “shall be.”


Submitter Full Name: Jim Muir

Organization: Building Safety Division, Clark County, Washington

Affilliation: NFPA's Building Code Development Committee (BCDC)

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Submittal Date: Thu Jun 16 17:58:50 EDT 2016


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8.4.2.7 Steam Blow Down Method. (Reserved)

This should have precautions based on determining the potential for temperature effects (sublimation/vaporisation), reactions(caramelisation, polymerisation), condensation and concreting, static,


The use of steam looks very specific to a particular industry




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8.4.6.1*

Housekeeping frequency and accumulation goals shall be established to ensure that the accumulated fugitive dust levels on surfacesdo not exceed the threshold approved for housekeeping dust accumulation limits.


This clarifies that the threshold must be approved by the AHJ, as the term is defined.





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8.4.6.1*

Housekeeping frequency and accumulation goals shall be established to ensure that the accumulated fugitive dust levels onsurfaces, excluding non-routine accumulations from process upsets and similar events covered by Section 8.4.6.3, do not exceed thethreshold housekeeping dust accumulation limits.


The recommended changes are required to clarify Section 8.4.6.1 so that it does not conflict with Section 8.4.6.3.





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8.5.3.3

Equipment Open (non-enclosed) equipment that contains combustible dust and is located within the hot work area shall be shutdown, shielded, or both.


There is no apparent reason to shut down or shield closed/enclosed equipment that would protect the enclosed dust from the hot work.





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8.5.5.2*

Bearings Inboard bearings that are directly exposed to a combustible dust atmosphere or that are subject to dust accumulation,either of which poses a deflagration dust ignition hazard, shall be monitored for overheating.


Overheated bearings only pose a deflagration hazard if they are inside a dust cloud, which typically is not the case. Outboard bearings typically are not a problem, and they should be excluded from this requirement.





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Public Input No. 32-NFPA 652-2016 [ New Section after 8.5.6.1.1 ]

8.5.6.1.1

An accumulation of combustible dust will not cause a location to be a Class II location if: (1) the average thickness of the layer doesnot exceed the layer depth criterion (LD) as determined in Section 6.1.3.1 of NFPA 654-2013; and (2) the temperature of the surfaceon which the accumulation of combustible dust is located is at least 25 degrees C below the Minimum Dust Layer Ignition Temperature(MIT-layer) based on "Methods for Determining the Minimum Ignition Temperature of Dusts. Part 1: Dust Layer on a Heated Surface ata Constant Temperature" (International Electrotechnical Commission Document 31H (Central Office) 3 published March 1993) and onASTM E2021, “Standard Test Method for Hot-Surface Ignition Temperature of Dust Layers,” or equivalent testing methods.


There is a critical conflict between the layer thickness that would trigger housekeeping or protective measures under (1) proposed NFPA 652 (and the other NFPA combustible dust standards) and (2) the guidance provided by NFPA 499, Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas. It is completely impractical to provide for a permissible dust accumulation level under the NFPA combustible dust standards and then have it effectively overridden by an overly conservative NFPA guidance document that would require an enormous expenditure of capital to provide classified electrical equipment that would eliminate the ignition sources that were the reason for controlling the dust accumulation in the first place. We believe it is essential to eliminate that conflict and that this is the appropriate mechanism for addressing that conflict and/or initiating the process within NFPA to eliminate that conflict.





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8.5.6.4*

Preventive maintenance programs for electrical equipment and wiring in Class II and Class III locations shall include provisions toverify that dusttight electrical enclosures are not experiencing significant dust ingress.


If it is a dust tight electrical enclosure, there shouldn’t be significant dust ingress. Additionally, the term significant within code text is vague unless defined.





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8.8.3 Fans to Limit Accumulation. (Reserved) - Please note that fans used to limit accumulation do just that - there is stillaccumulation, even a fine coating - and does not preclude the use of good housekeeping practices of vacuuming such areas, andaddressing of dust plumes created by such fans


Cautionary statement on blowdown fans




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8.9.3.1* General.

Where an To the extent feasible, practical and necessary to reduce the risk posed by combustible dust fires and deflagrations to an

acceptable level, where a dust explosion hazard exists within any operating equipment greater than 8 ft3 (0.23 m) of containingvolume, the operating equipment shall be protected from the effects of a deflagration.


Section A.8.9.3.1 conflicts with and acknowledges that Section 8.9.3.1 is infeasible in providing as follows:

A.8.9.3.1 Small containers can pose an explosion hazard; however, explosion protection measures for these units are not always practical. Consideration should be given to explosion hazards when electing to omit protection; 8 ft3 (0.23 m) is roughly the size of a 55 gal (208.2 L) drum.

The standard fails to differentiate between an enclosure and an operating enclosure. The term “dust explosion hazard” is defined as follows:

3.3.15 Dust Explosion Hazard. A dust deflagration hazard in an enclosure that is capable of bursting or rupturing the enclosure due to the development of internal pressure from the deflagration.

It is clearly not only impractical, but infeasible to provide explosion protection to every enclosure of at least 8 ft3 where enclosure is define to include every pipe, tube, etc. It is necessary to perform a risk assessment to identify the enclosures where there is a significant risk of initiating a dust explosion and focus on protecting and isolating those enclosures rather than attempting to protect all enclosures.





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TITLE OF NEW CONTENT

Add the following new section after 8.9.3.3:

8.9.3.4 The requirement in 8.9.3.3 shall not apply to silos and bins where explosion venting is not practical due to silo or bingeometry, building constraints, or both.


The proposed revision would avoid an impractical result, one very likely not intended by the NFPA 652 Technical Committee. Section 8.9.3.3 appears to require that “enclosures” (of more than eight cubic feet in volume) of operating equipment be “designed to withstand” the pressures resulting from a deflagration. NFPA 652 (in Section 3.3.17) uses NFPA 68 (2013)’s definition of “Enclosure” as a “confined or partially confined volume.” NFPA 652’s Annex material for the definition of “Enclosure” (which is also from NFPA 68 (2013)), then includes “silo” and “bin” as examples of enclosures. Section 8.9 ("Explosion Prevention/Protection of NFPA 652") can thus be read to require explosion venting on all silos and bins. This was very likely not intended by the Technical Committee and is impractical in certain applications.

To resolve the issue, we recommend the addition of a provision modeled on one in NFPA 61 (2017), which has the same definition of “Enclosure” as well as the same Annex material as NFPA 652, but which has a provision (Section 8.8.2.1.2.2) that recognizes that explosion venting on silos and bins is at times infeasible by making the explosion venting design requirement in Section 8.8.2.1.2 inapplicable to certain silos and bins. The relevant language in NFPA 61 (2017) is as follows:

8.8 Explosion Prevention/Protection

8.8.1 General

Explosion prevention, relief, and venting, as used in this standard, shall encompass the design and installation of devices and systems to vent the gases and overpressure resulting from a deflagration occurring in equipment, rooms, buildings, or other enclosures so that damage is minimized.

* * *

8.8.2.1.2

The design shall offer the least possible resistance to explosion pressures.

* * *

8.8.2.1.2.2

The requirement in 8.8.2.1.2 shall not apply to bins and silos where explosion venting is not practical due to bin or silo geometry, building constraints, or both.

The new section after 8.9.3.3 of NFPA 652 being recommended recognizes and addresses the impracticality of providing explosion venting on certain silos and bins.




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9.4.6

A thorough inspection of the operating area shall take place, on an as-needed basis a schedule as established by theowner/operator and the manufacturers recommendations, to help ensure that the equipment is in safe operating condition and thatproper work practices are being followed.


What defines the need? Inspections should be on a schedule.





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Public Input No. 24-NFPA 652-2016 [ Section No. A.3.3.5 ]


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A.3.3.5 Combustible Dust.


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The term combustible dust when used in this standard includes powders, fines, fibers, etc.

Dusts traditionally were defined as material 420 μm or smaller (capable of passing through a U.S. No. 40 standard sieve). Forconsistency with other standards, 500 μm (capable of passing through a U.S. No. 35 standard sieve) is now considered anappropriate size criterion. Particle surface area-to-volume ratio is a key factor in determining the rate of combustion. Combustibleparticulate solids with a minimum dimension more than 500 μm generally have a surface-to-volume ratio that is too small to pose adeflagration hazard. Flat platelet-shaped particles, flakes, or fibers with lengths that are large compared to their diameter usually donot pass through a 500 μm sieve, yet could still pose a deflagration hazard. Many particulates accumulate electrostatic charge inhandling, causing them to attract each other, forming agglomerates. Often agglomerates behave as if they were larger particles, yetwhen they are dispersed they present a significant hazard. Consequently, it can be inferred that any particulate that has a minimumdimension less than or equal to 500 μm could behave as a combustible dust if suspended in air or the process specific oxidizer. If theminimum dimension of the particulate is greater than 500 μm, it is unlikely that the material would be a combustible dust, asdetermined by test. The determination of whether a sample of combustible material presents a flash-fire or explosion hazard could bebased on a screening test methodology such as provided in the ASTM E1226, Standard Test Method for Explosibility of Dust Clouds.Alternatively, a standardized test method such as ASTM E1515, Standard Test Method for Minimum Explosible Concentration ofCombustible Dusts, could be used to determine dust explosibility. [654, 2013]

There is some possibility that a sample will result in a false positive in the 20 L sphere when tested by the ASTM E1226 screeningtest or the ASTM E1515 test. This is due to the high energy ignition source overdriving the test. When the lowest ignition energyallowed by either method still results in a positive result, the owner/operator can elect to determine whether the sample is a

combustible dust with screening tests performed in a larger scale (≥1 m3) enclosure, which is less susceptible to overdriving and thuswill provide more realistic results. [654, 2013]

This possibility for false positives has been known for quite some time and is attributed to “overdriven” conditions that exist in the 20 Lchamber due to the use of strong pyrotechnic igniters. For that reason, the reference method for explosibility testing is based on a

1 m3 chamber, and the 20 L chamber test method is calibrated to produce results comparable to those from the 1 m3 chamber formost dusts. In fact, the U.S. standard for 20 L testing (ASTM E1226) states, “The objective of this test method is to develop data that

can be correlated to those from the 1 m3 chamber (described in ISO 6184-1, and VDI 3673)…” ASTM E1226 further states, “Becausea number of factors (concentration, uniformity of dispersion, turbulence of ignition, sample age, etc.) can affect the test results, thetest vessel to be used for routine work must be standardized using dust samples whose KSt and Pmax parameters are known in the

1 m3 chamber.” [654, 2013]

NFPA 68 also recognizes this problem and addresses it stating that “the 20 L test apparatus is designed to simulate results of the

1 m3 chamber; however, the igniter discharge makes it problematic to determine KSt values less than 50 bar-m/sec. Where the

material is expected to yield KSt values less than 50 bar-m/sec, testing in a 1 m3 chamber might yield lower values.” [654, 2013]

Any time a combustible dust is processed or handled, a potential for deflagration exists. The degree of deflagration hazard varies,depending on the type of combustible dust and the processing methods used. [654, 2013]

A dust deflagration has the following four requirements:

(1) Combustible dust

(2) Dust dispersion in air or other oxidant

(3) Sufficient concentration at or exceeding the minimum explosible concentration (MEC)

(4) Sufficiently powerful ignition source such as an electrostatic discharge, an electric current arc, a glowing ember, a hot surface, awelding slag, frictional heat, or a flame

[654, 2013]

If the deflagration is confined and produces a pressure sufficient to rupture the confining enclosure, the event is, by definition, an“explosion.” [654, 2013]

Evaluation of the hazard of a combustible dust should be determined by the means of actual test data. Each situation should beevaluated and applicable tests selected. The following list represents the factors that are sometimes used in determining thedeflagration hazard of a dust:

(1) MEC

(2) MIE

(3) Particle size distribution

(4) Moisture content as received and as tested

(5) Maximum explosion pressure at optimum concentration

(6) Maximum rate of pressure rise at optimum concentration

(7) KSt (normalized rate of pressure rise) as defined in ASTM E1226,Standard Test Method for Explosibility of Dust Clouds

(8) Layer ignition temperature

(9) Dust cloud ignition temperature

(10) Limiting oxidant concentration (LOC) to prevent ignition

(11) Electrical volume resistivity

(12) Charge relaxation time

(13) Chargeability

[654, 2013]


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It is important to keep in mind that as a particulate is processed, handled, or transported, the particle size generally decreases due toparticle attrition. Consequently, it is often necessary to evaluate the explosibility of the particulate at multiple points along the process.Where process conditions dictate the use of oxidizing media other than air (nominally taken as 21 percent oxygen and 79 percentnitrogen), the applicable tests should be conducted in the appropriate process-specific medium. [654, 2013]

This section should be maintained as written. It has been relied upon during the past year for determination of explosbility of dusts. The issue of over-driven results when the 20 L sphere is used is further discussed in published peer reviewed papers by B. Ganesanet al and AnnMarie Fauske. (Ganesan, B., Parnell Jr., C. B., McGee, R. O., & Faulkner, W.B (2015); A critical evaluation ofexplosible dust testing methods: Part II. Applied Engineering in Agriculture , Vol 31(2) 203-209. http://elibrary.asabe.org/abstract.asp?aid=45458&t=1&redir=aid=45458&confalias=&redir=[volume=31&issue=2&conf=aeaj&orgconf=aeaj2015]&redirType=toc_journals.asp&redirType=toc_journals.asp ), (Fauske, A (2014) Combustible Dust Basics, Part 3: What isOverdriving? http://blog.fauske.com/blog/bid/381834/Combustible-Dust-Basics-Part-3-What-is-Overdriving ).


There is no problem with this section. We are supporting this section as written, and offering two papers in support of this section.




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Public Input No. 27-NFPA 652-2016 [ Section No. A.3.3.17 ]

A.3.3.17 Enclosure.

Examples of enclosures include a room, building, vessel, silo, bin, pipe, or duct. [ 68, 2013]


The Annex material for the definition of “Enclosure” can be read to require explosion venting on all silos and bins under the requirements of Section 8.9 of NFPA 652, Explosion Prevention/Protection. Providing explosion venting on all silos and bins is not practical due to silo or bin geometry, building constraints, or both. If the new section after 8.9.3.3 recommended in a separate public comment is not accepted, then the words “silo” and “bin” need to be deleted as well as removing the reference to “[68, 2013]” in the Annex material for the definition of “Enclosure.”




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Public Input No. 68-NFPA 652-2016 [ Section No. A.5.2 ]


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A.5.2


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Test data derived from testing material within a facility Testing actual material from a specific process or area ofthe faciity will result inthe most accurate results for the DHA, performance-based design, and hazard management options. Testing is not required todetermine whether the material has combustibility characteristics where reliable, in-house commodity-specific testing data orpublished data of well-characterized samples (i.e., particle size, moisture content, and test conditions) are available. Published datashould be used for preliminary assessment of combustibility only. However, for protection or prevention design methods, the data canbe acceptable after a thorough review to ensure that they are representative of owner/operator conditions.

The protection or prevention designs are based on explosivity properties, which can vary based on the specific characteristics of thematerial. (See 5.2.2 for characteristics that can affect explosibility properties.) Historical Historical knowledge and experience ofoccurrence or nonoccurrence of process incidents such as flash fires, small fires, sparkling fires, pops, or booms, or evidence ofvessel, tank, or container overpressure should not be used as a substitute for hazard analysis. Process incidents are indications of amaterial or process resulting in combustibility or explosion propensity. Process incidents can be used to guide or select samples forand supplement testing.

The following material properties should be addressed by a DHA for the combustible particulate solids present:

(1) Particle Size. Sieve analysis is a crude and unreliable system of hazard determination. Its greatest contribution in managing thehazard is the ease, economy, and speed at which it can be used to discover changes in the process particulate. In any sample ofparticulate, very rarely are all the particles the same size. Sieve analysis can be used to determine the fraction that would begenerally suspected of being capable of supporting a deflagration.

For a sub-500 micron fraction:

(a) Data presented in terms of the percent passing progressively smaller sieves.

(b) Particles that have high aspect ratios can produce distorted, nonconservative results conservatively large particle sizes .

(2) Particle Size Distribution. The particle size distribution of a combustible particulate solid must be known if the explosion hazardis to be assessed solid is an important parameter in assessing an explosion hazard . Particle size implies a specific surface area(SSA) and affects the numerical measure of other parameters such as MEC, MIE, dP/dtmax , Pmax and KSt . Particles greater

than 500 microns in effective mean particle diameter are generally not considered deflagratory. Most combustible particulatesolids include a range of particle sizes in any given sample. The DHA should anticipate and account for particle attrition andseparation as particulate is handled.

(3) Particle Shape. Due to particle shape and agglomeration, some particulates cannot be sieved effectively. Particulates withnonspheric or noncubic shapes do not pass through a sieve as easily as spheric or cubic particles. For this purpose, long fiberscan behave just as explosively as spherical particulate of a similar diameter . This leads to underestimation of small particlepopulations and to underassessment of the hazard. Particulates with an aspect ratio greater than 3:1 should be suspect. Whenparticulates are poured into vessels, it is common for the fine particles to separate from the large, creating a deflagration hazardin the ullage space.

(4) Particle Aging. Some combustible particulate solid materials could undergo changes in their safety characteristics due to aging.Changes in morphology and chemical composition, for example, can occur from the time a sample is collected to the time ittakes to get that sample into the lab for a test is tested . For materials that are known to age, care must be taken in packagingand shipment. The use of vacuum seals, or an inert gas such as nitrogen, could be required to ensure that the tested sample hasnot changed appreciably due to aging. The lab should be notified in advance of shipment that the material is sensitive to changedue to age so that they will know how to handle it and store it until it is tested.

(5) Particle Attrition. The material submitted for testing should be selected to address the effects of material attrition as it is movedthrough the process. As particulates move through a process they usually break down into smaller particles. Reduction in particlesize leads to an increase in total surface area to mass ratio of the particulate and increases the hazard associated with theunoxidized particulate.

(6) Particle Suspension. Particle suspension maximizes the fuel–air interface. It occurs wherever particulate moves relative to the airor air moves relative to the particulate, such as in pneumatic conveying, pouring, fluidizing, mixing and blending, or particle sizereduction.

(7) Particle Agglomeration. Some particulates tend to agglomerate into clumps. Agglomerating particulates can be more hazardousthan the test data imply if the particulate was not thoroughly deagglomerated when testing was conducted. Agglomeration isusually affected by ambient humidity.

(8) Triboelectric Attraction. Particles with a chemistry that allows electrostatic charge accumulation will become charged duringhandling. Charged particles attract oppositely charged particles. Agglomeration causes particulate to exhibit lower explosionmetrics during testing. Humidification decreases the triboelectric effect.

(9) Hydrogen Bonding. Hydrophilic particulates attract water molecules that are adsorbed onto the particle surface. Adsorbed waterprovides hydrogen bonding to adjacent particles, causing them to agglomerate. Agglomeration causes particulate to exhibit lowerexplosion metrics during testing. Desiccation reduces this agglomerated effect.

(10) Entrainment Fraction. The calculation for a dust dispersion from an accumulated layer should be corrected for the ease ofentrainment of the dust. Fuel chemistry and agglomeration/adhesion forces should be considered. The dispersion is generally afunction of humidity, temperature, and time. Particle shape and morphology and effective particle size should be considered.

(11) Combustible Concentration. When particles are suspended, a concentration gradient will develop where concentration variescontinuously from high to low. There is a minimum concentration that must exist before a flame front will propagate. Thisconcentration depends on particle size and chemical composition and is measured in grams/cubic meter (ounces/cubic foot).This concentration is called the minimum explosible concentration (MEC). A dust dispersion can come from a layer of

accumulated fugitive dust. The concentration attained depends on bulk density of dust layer (measured in grams/m 3), layerthickness, and the extent of the dust cloud. Combustible concentration is calculated as: Concentration = (bulk density)*[(layerthickness)/(dust cloud thickness)]

(12) Competent Igniter. Ignition occurs where sufficient energy per unit of time and volume is applied to a deflagratory particulate


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suspension. Energy per unit of mass is measured as temperature. When the temperature of the suspension is increased to theauto-ignition temperature, combustion begins. Ignitability is usually characterized by measuring the minimum ignition energy(MIE). The ignition source must provide sufficient energy per unit of time (power) to raise the temperature of the particulate to itsautoignition temperature (AIT).

(13) Dustiness/dispersibility. Ignition and sustained combustion occurs where a fuel and competent ignition course source cometogether in an atmosphere (oxidant) that supports combustion. The fire triangle represents the three elements required for a fire.Not all dusts are combustible, and combustible dusts exhibit a range in degree of hazard. All combustible dusts can exhibitexplosion hazards accompanied by propagation away from the source. In the absence of confinement, a flash-fire hazard results.If confined, the deflagration can result in damaging overpressures. Deflagration is the process resulting in a flash fire or anexplosion. The four elements for a flash fire are the following:

(14) A combustible dust sufficiently small enough to burn rapidly and propagate flame

(15) A suspended cloud at a concentration greater than the minimum explosion concentration

(16) The atmosphere to support combustion

(17) An ignition source of adequate energy or temperature to ignite the dust cloud

The heat flux from combustible metal flash fires is greater than organic materials (see Figure A.5.2 ) .

A dust explosion requires the following five conditions:

(1) A combustible dust sufficiently small enough to burn rapidly and propagate flame

(2) A suspended cloud at a concentration greater than the minimum explosion concentration

(3) Confinement of the dust cloud by an enclosure or partial enclosure

(4) The atmosphere to support combustion

(5) An ignition source of adequate energy or temperature to ignite the dust cloud

Figure A.5.2 Elements Required for Fires, Flash Fires, and Explosions.


Made revisions to correct typographical errors and clarify some statements.




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Public Input No. 55-NFPA 652-2016 [ Section No. B.3.4.3 ]

B.3.4.3

The DHA should classify locations into three general categories:

(1) Not a hazard

(2) Maybe a hazard

(3) Deflagration hazard

This will help the owner/operator prioritize management of the hazards. Additionally, it will identify the locations where moreinformation is necessary before a definitive determination can be made. NOTE: It is believed tha the DHA should more specificallydesignate which equipment certified to what class or location, can be used in which category: If the DHA classifies a location to be#2 - Maybe a hazard, does the DHA/AHJ then suggest or require NFPA compliant designed equipment or Class II certifiedequipment?


Asking for clarification on example of use of equipment per simple classification std




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Public Input No. 40-NFPA 652-2016 [ Section No. B.4.5.2.4 ]

B.4.5.2.4

Are there competent igniters available? Yes. In addition to the igniters identified in B.4.5.1.4, a number of ignition mechanisms areintroduced by the fan. further examples are: Overheated drive bearings (especially the inboard bearing) due to bearing failure fromlack of proper lubrication, fatigue, wear, etc., fan impeller/wheel imbalance caused by wear, material accumulation on the blades,bearing failure, etc., which can result in sparking by housing contact.


The examples provided are proven problems that can occur with a material handling (or other industrial) fans. This further assists the reader in understanding the scope of the DHA.




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B.4.5.2.5

What hazard management is in place? SeeB.4.5.1.5. It is difficult to apply hazard management to a material conveyance fan. Usuallyhazard management is applied downstream from the fan Other hazard managment methods would include vibration monitoring(either by personnel on a regular basis or by a monitoring device), temperature monitoring of the drive bearings (by personnel ormonitoring device) and amperage monitoring of the drive motor (amperage is directly related to the air mass flow - the higher theamperage the more air mass flow) .


Such methods of hazard management have been proven successful in monitoring fan performance and indicating problems before they become a significant hazard.




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Public Input No. 42-NFPA 652-2016 [ Section No. B.4.5.7 [Excluding any Sub-Sections] ]

While the drawing shows these as separate components, most mills have an integral discharge fan. Most mills of this type require airflow through the mill as part of the millling process and this is typically provided by a fan package (positive or negative pressuredepending uppon type of system). This fan package can be integral to the mill or as a separate device.


The previous annex indicated that integral fans are typical for such mills, while it is the submitter's experience, with literally hundreds of such devices and systems, that the fan package is separate nearly all the time and that integral fans are the exception and not the norm.




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B.4.5.7.1

Is the particulate deflagrable (explosible)? It depends. What is the target product particle size? If the mill has 1⁄4 in. screens, then theunit is receiving large particles and making them less large, but they're still too large to be considered a deflagrable (explosible)particulate. But there are also included fines. If the mill is reducing the particulate down to 250 μ, then all the particulate would beconsidered deflagrable (explosible). Therefore, the determination of whether the particulate in the mill is deflagrable is based on therange of particle size exiting the mill. It is usually necessary to submit this material for a go/no-go screening test to determine if themixture exiting the mill is capable of propagating a deflagration flame front. However, because no mill is 100% efficient there is alikelihood of combustible dust inside the mill either as accumulations, "remilling" caused by turbulence, wear, etc. Most mills areconsidered frequent sources for sparks and any accumulations in the mill could result in ember production. Also, if there is anintegral fan package such device would normally provide further attrition of the particle sizes. Therefore, using an analysis of theparticle sizes of the normal discharge of the mill could be misleading.


Combustible dust is almost always present in a mill, especially with an integral fan package.




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B.4.5.7.2

Is the particulate suspended in air? Yes. Inside the mill the particulate is in continuous air suspension. In addition if there is anintegral fan package there is suspension by the fan impeller.


Fan influence needs to be considered.




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B.4.5.7.3

Is there sufficient concentration to support deflagration? This again depends on the test data and a sieve analysis Because most millswill produce fines during the milling process (due to remilling, turbulence, accumulations on internal surfaces, wear, etc.) and it isdifficult to be assured the fines concentrations do not exceed the MEC, it is best to assume sufficient combustible dusts are present. However, some low-speed mills (e.g. shredders) designed to produce only large particles may allow a determination from a seiveanalysis and/or testing . Remember that while a sieve analysis is not a definitive criterion for identifying whether a particulate isdeflagrable (explosible), it is a very valuable tool for identifying changes that have occurred in the process that signify a change in thehazard associated with the particulate. It is a management of change and safety assessment audit tool.


Mills are not 100% efficient and the milling process is not truly steady-state as it will vary over time (due to material variations, maintenance levels, wear, etc.). Thus, a sieve analysis is only representative of the time it was taken and does not take into account the changes that occur rapidly and/or over time.




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B.4.5.7.4

Are there competent igniters available? Most mills are capable of igniting the material being milled. If tramp metal gets into theprocess stream it is likely that the particulate will exit burning, at the very least. Also, integral, or external, fan packages representadditional hazards similar to the fan of B.4.5.2.4.


The fan package, whether integral to the mill or separate, represents a significant hazard that should also be considered.




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B.4.5.7.5

What hazard management is in place? Are there magnetic separators or traps on the infeed to the mill? Is there deflagrationsuppression and isolation on the mill? Even if the mill is designed to be strong enough to withstand a deflagration within (many are),the deflagration flame front will exit the mill via the infeed and outfeed. What provisions are in place to isolate the mill from the rest ofthe process? In addition any integral or external (in-line) fan package would require management such as that discussed inB.4.5.2.5.


The fan package needs to be included in the discussion. Assumes the recommended changes of a previous submission for B.4.5.2.5.




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B.4.5.8.4

Are there competent igniters available? Yes. This duct is immediately downstream from the mill and/or fan package , which can be asource of ignition.


The fan which creates the air flow the the mill must also be considered.




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B.4.5.9.2

Is the particulate suspended in air? This depends on the type, make, and model of the screens used. Some agitate the material moreaggressively than others. An analysis of the operating screens for the presence of a dust suspension should be undertaken todetermine if this criterion is satisfied.

Most screens leak dust into the building interior, and that issue has to be addressed Without proper dust collection these devices canemit combustible dusts into the surrounding area .


Without dust collection (usually only on the inlet and outlet portions of the screen to assure the screening process is not inhibited), even with good enclosure of the screen and screening process, dust emissions can and most likely will occur. This is especially true over time when flex connections, seals, etc., tend to wear, etc.




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B.4.5.12.5

What hazard management is in place? The occupants must be protected from dust collector — fires as well as dust collectorexplosions. (In many industries dust collector fires outnumber dust collector explosions.) For dust collector fire, return air diversion toprevent combustion products from entering the building is sufficient. (Generally, dust collectors collecting metallic particulates are notpermitted to return air to the building.) To protect occupants from the dust collector explosion, a common approach is to installdeflagration isolation as well as either deflagration venting or deflagration suppression. If a fire occurs in the dust collector thenaborting (for the smoke, etc.) or other managements methdos should be considered. The protection feature in place should bedocumented.


smoke, etc., should also be considered when returning the air back into a compartment/building.




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technical committee on fundamentals of combustible dusts ...€¦ · agenda for the meeting, which...

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