technical committee on combustible metals and …

TECHNICAL COMMITTEE ON COMBUSTIBLE METALS AND METAL DUSTS NFPA 484 Second Draft Meeting Agenda July 15-17, 2020 11:00 AM – 5:00 PM ET

Teleconference

1. Call to Order. Mark Drake, Chair

2. Attendance.

3. Approval of Meeting Minutes from NFPA 484 First Draft Meeting, August 6-8, 2019. (Attachment A)

4. Staff Updates. Laura Moreno, NFPA Staff

• Committee membership update. (Attachment B)

• Annual 2021 revision cycle schedule. (Attachment C)

• Overview of NFPA Process.

5. Review of Public Comments: NFPA 484. (Attachment D)

6. Review of Committee Inputs: NFPA 484. (Attachment E)

7. Review of First Draft Ballot Comments: NFPA 484. (Attachment F)

8. Task Group Reports. (will be distributed prior to meeting)

a) Legacy Metals. Donna Bruce, Chair

b) Additive Manufacturing. Elizabeth Buc, Chair

c) Realignment with NFPA 652. Jack Osborn, Chair

d) Portable Vacuum Cleaners. Jack Osborn, Chair

9. Old Business.

a) Annex language for 12.11 on portable electronic equipment. Sam Rodgers

b) Review Chapter 14 Nanometal Powders for consistency with Chapter 15 Additive Manufacturing. Additive Manufacturing Task Group

c) Verify consistency of “conductive or static dissipative” in all chapters. Ashok Dastidar

d) Verify consistency of “powder” vs “metal powder” throughout the document. Mark Rosenberger

10. NFPA 660 Dust Consolidation: Review Task Group Reports on NFPA 652 Fundamental Requirements. (will be distributed prior to meeting)

11. New Business.

12. Next Meeting.

13. Adjourn.

TECHNICAL COMMITTEE ON COMBUSTIBLE METALS AND METAL DUSTS

NFPA 484 First Draft Meeting Minutes

August 6-8, 2019 8:00 AM – 5:00 PM CT Hilton St. Louis at the Ballpark

1 South Broadway, St. Louis, MO 63102

Attendees

Committee Members: Mark Drake, Chair Liberty Mutual Donna Bruce KEMET Electronics Corporation Steve Barwin SLM Solutions NA Elizabeth Buc* Fire & Materials Research Laboratory, LLC Brad Burridge Novelis, Inc. Tom Christman Gregory Creswell* Cambridge-Lee Industries Eli Horden* The Boeing Company Kevin Kreitman Albany Fire Department Jack Osborn Airdusco, Inc. Mark Rosenberger Los Alamos National Laboratory Andrew Ryerson FM Global Greg Super The Aluminum Association, Inc. Patrick Thornton Oak Ridge National Laboratory David Young Idaho National Laboratory Robert Zalosh* Firexplo Jason Angell* Liberty Mutual Ashok Ghose Dastidar* Fauske & Associates, LLC Ryan Giberson Clayton Associates Warren Greenfield* WG Associates LLC Laura Jacobsen* The Boeing Company Shay Massey Oak Ridge National Laboratory James Vickery Exponent Laura Moreno, Staff Liaison National Fire Protection Association

Guests: Paul Bates* UL LLC J Kirt Boston Donaldson Balu V. Nair* UL LLC Dan Peterson* Nilfisk Jason Reason SEAM Group

ATTACHMENT A

Mike Walters SEAM Group

*Participated by teleconference

1. Call to Order. Mark Drake, Chair, called the meeting to order at 8:02 AM, August 6th, 2019.

2. Introductions. Committee, teleconference participants and guests made self-introductions.

3. Approval of Meeting Minutes. Minutes from Pre-Draft Meeting February 6 – 7, 2019 were reviewed and approved as submitted.

4. Staff Updates. Laura Moreno, NFPA Staff, provided updates on safety, membership, guests, the Annual 2021 revision cycle schedule, and an overview of the NFPA process.

5. Review of Public Input: NFPA 484. The Technical Committee reviewed Public Inputs to NFPA 484, and developed First Revisions and Committee Inputs as necessary. These will be available in the First Draft Report at www.nfpa.org/484next by February 26, 2020.

• At the Second Draft meeting, the committee will consider adding additional annex language to section 12.11 on portable electrical and electronic equipment to address vaping. Sam Rodgers will draft language.

• The committee will also consider adding annex material to 13.2.4.4.13.2, recirculation of clean air exhaust.

6. Task Group Reports. The following task groups provided their reports and recommendations.

• Legacy Metals. The task group presented their work and revisions were made to the Legacy Metals chapter (now Chapter 17, First Revision 51) as well as Chapter 9 where some common requirements were consolidated and moved from Chapters 14-17 (First Revision 50). The task group will continue to work before the Second Draft meeting to review the changes and check for any omissions. Task group members are Donna Bruce (Chair), David Young, Patrick Thornton, Kevin Kreitman, Ryan Condon, Greg Creswell, Greg Super, Peter Downing, Brad Burridge, Mark Drake, Sam Rodgers and Jason Angell.

• Additive Manufacturing. The task group presented a revision to the Additive Manufacturing chapter, which will be Chapter 15 in the First Draft (First

http://www.nfpa.org/484next

Revision 23). The task group will continue working on the chapter, and will consider adding annex material to 15.2.3.2.1 to explain the need for emergency shutdown devices. The task group will also review and further develop language for Storage of Powders (Committee Input 22). Task group members are Elizabeth Buc (Chair), Jack Osborn, Dehong Kong, Eli Horden, Laura Jacobsen, Jason Reason, Warren Greenfield, Bob Zalosh, Erdem Ural, and Tom Christman.

• Realignment with NFPA 652. The task group presented a revised layout for NFPA 484 to align with NFPA 652, and the committee created First Revision 49. The task group will need to continue work, particularly to review Chapters 8 and 9 to remove extraneous material. Jack Osborn (Chair), Mark Drake, Daniel Hubert, Brad Burridge, Patrick Thornton, Sam Rodgers, Kevin Kreitman, and James Vickery.

• Dust Collection. The recommendations from this task group were submitted as Public Input and addressed accordingly.

• Nanometal, ultrafine particle, nanopowder. Revisions were created to address particle size distribution characterization (First Revision 17, A.5.3.2) and the size of ultrafine particles (First Revision 47, 3.3.26.2).

7. New Business.

• The committee heard an update on the work of the NEC and Dust Correlating Task Group, including proposed revisions to NFPA 484, to clearly include ignitible fibers/flyings to draw the connection to the NFPA 70 application and to remove any prescriptive limitation or prohibition for use of the Zone system for classification. Committee Input 14 was created and the committee will review the language after the NFPA 499 Second Draft meeting has been held.

• A Task Group on Portable Vacuum Cleaners was formed to review requirements in Chapter 13 vs Section 11.6. The Committee discussed that Section 11.6 should focus on operational aspects and Chapter 13 should focus on the design. The task group members are Jack Osborn (chair), Ryan Giberson, James Vickery, Brad Burridge, and Sam Rodgers.

• The committee identified areas to address at the Second Draft stage:

o Review Chapter 14 Nanometal Powders for consistency with Chapter 15 Additive Manufacturing

o Verify consistency of “conductive or static dissipative” in all chapters

o Verify consistency of use of “powder” vs “metal powder” throughout the document

8. Next Meeting. The committee will hold a teleconference meeting on January 14,2020 at 11:00 AM Eastern to discuss task group progress prior to the Second Draftmeeting. The committee would like to hold the Second Draft meeting in conjunctionwith the NFPA 652 Second Draft meeting, the week of June 8 or the week of June 22in Asheville, NC or Charlotte, NC.

9. Adjournment. The meeting was adjourned at 12:45 PM on August 8, 2019.

Address List No PhoneCombustible Metals and Metal Dusts CMD-CMM

Combustible Dusts

Laura E. Moreno07/06/2020

CMD-CMM

Mark W. Drake

ChairLiberty Mutual14125 West 139th StreetOlathe, KS 66062-5885Alternate: Jason L. Angell

I 3/4/2008CMD-CMM

Donna R. Bruce

SecretaryKEMET Electronics CorporationPO Box 5928Greenville, SC 29606

U 1/14/2005

CMD-CMM

Steve James Barwin

PrincipalSLM Solutions NA48561 Alpha Drive, Suite 300Wixom, MI 48393

M 08/17/2017CMD-CMM

Philip Basile

PrincipalClayton Associates1650 Oak StreetLakewood, NJ 08701Alternate: Ryan Giberson

M 11/30/2016

CMD-CMM

Elizabeth C. Buc

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

RT 1/10/2008CMD-CMM

Brad D. Burridge

PrincipalNovelis, Inc.639 Players Crossing WayBowling Green, KY 42104Alternate: Jason Hudson

U 8/9/2011

CMD-CMM

Tom Christman

Principal818 Brochardt BoulevardKnoxville, TN 37934

SE 4/1/1994CMD-CMM

Ryan Condon

PrincipalATI-Wah Chang1600 Old Salem Road NEAlbany, OR 97321-4548Alternate: Scott Ryan

M 04/08/2015

CMD-CMM

Gregory F. Creswell

PrincipalCambridge-Lee Industries86 Tube DriveReading, PA 19605

M 04/05/2016CMD-CMM

Ashok Ghose Dastidar

PrincipalFauske & Associates, LLC16W070 83rd StreetBurr Ridge, IL 60527-5802

U 08/09/2012

CMD-CMM

Scott G. Davis

PrincipalGexCon US4833 Rugby Avenue, Suite 100Bethesda, MD 20814-3035

SE 08/09/2012CMD-CMM

Scott E. Dillon

PrincipalCrane Engineering2355 Polaris Lane NorthSuite 120Plymouth, MN 55447-4777

SE 10/4/2007

CMD-CMM

Peter F. Downing

PrincipalEnvironment & Safety Solutions, Inc.120 Main Street, Suite 201Hightstown, NJ 08520

SE 8/5/2009CMD-CMM

Michael David Heroux

PrincipalAmerican International Group, Inc. (AIG)20691 Pembrooke OvalStrongsville, OH 44149Alternate: Paul F. Hart

I 12/06/2019

1

ATTACHMENT B


Combustible Dusts


CMD-CMM

Eli Horden

PrincipalThe Boeing CompanyPO Box 3707MC 17-WESeattle, WA 98124Alternate: Laura Jacobsen

U 04/08/2015CMD-CMM

Daniel J. Hubert

PrincipalAmerex/Janus Fire Systems1102 Rupcich DriveMillennium ParkCrown Point, IN 46307-7542

M 3/1/2011

CMD-CMM

Dehong Kong

PrincipalPrinceton Safety Solutions, Inc.5 Spruce CourtPlainsboro, NJ 08536

SE 8/9/2011CMD-CMM

Kevin Kreitman

PrincipalAlbany Fire Department4105 Moose Run Drive SWAlbany, OR 97321-5160Alternate: Scott D. Cowan

E 1/16/1998

CMD-CMM

Timothy J. Myers

PrincipalExponent, Inc.9 Strathmore RoadNatick, MA 01760-2418Alternate: James Eamon Vickery

SE 4/14/2005CMD-CMM

Jack E. Osborn

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

M 11/30/2016

CMD-CMM

Nicholas S. Reding

PrincipalFike Corporation704 SW 10th StreetBlue Springs, MO 64015Alternate: Lon L. Scholl

M 08/08/2019CMD-CMM

Samuel A. Rodgers

PrincipalHoneywell, Inc.15801 Woods Edge RoadColonial Heights, VA 23834-6059Alternate: Shanker Pershad

U 3/1/2011

CMD-CMM

Mark S. Rosenberger

PrincipalLos Alamos National LaboratoriesPO Box 1663, M791Los Alamos, NM 87545Alternate: Keenan Thomas Dotson

U 8/9/2011CMD-CMM

Andrew Ryerson

PrincipalFM Global1151 Boston-Providence TrnpkNorwood, MA 02062FM Global

I 08/17/2017

CMD-CMM

Gregory M. Super

PrincipalEckart AmericaPO Box 747Painesville, OH 44077The Aluminum Association, Inc.

M 08/11/2014CMD-CMM

Patrick A. Thornton

PrincipalOak Ridge National LaboratoryUT-BattellePO Box 2008, MS 6470Oak Ridge, TN 37931Alternate: Shay Elliott Massey

U 8/5/2009

CMD-CMM

Erdem A. Ural

PrincipalLoss Prevention Science & Technologies, Inc.659 Pearl Street, Suite A2Stoughton, MA 02072

SE 3/4/2009CMD-CMM

Richard S. Varga

PrincipalNiagara Metallurgical Products400 Jones RoadStoney Creek, ON L8E 5P4 CanadaAlternate: John E. McConaghie

U 1/15/2004

2


Combustible Dusts


CMD-CMM

David K. Young

PrincipalIdaho National Laboratory1955 N. Fremont AvenueMS 3406Idaho Falls, ID 83415Alternate: Brion Russell Pearson

RT 10/4/2007CMD-CMM

Robert G. Zalosh

PrincipalFirexplo20 Rockland StreetWellesley, MA 02481Alternate: Warren Greenfield

SE 8/5/2009

CMD-CMM

Stephen Zimmerman

PrincipalIntrepid Electronic Systems358 West StreetPittsburg, CA 94565-1954

IM 12/08/2015CMD-CMM

Jason L. Angell

AlternateLiberty Mutual675 Trails EndLancaster, KY 40444-7252Principal: Mark W. Drake

I 12/08/2015

CMD-CMM

Scott D. Cowan

AlternateAlbany Fire DepartmentPO Box 490Albany, OR 97321Principal: Kevin Kreitman

E 08/17/2015CMD-CMM

Keenan Thomas Dotson

AlternateLos Alamos National Laboratories (LANL)Ms K493Los Alamos, NM 87545Principal: Mark S. Rosenberger

U 04/03/2019

CMD-CMM

Ryan Giberson

AlternateClayton Associates1650 Oak StreetLakewood, NJ 08701Principal: Philip Basile

M 08/17/2017CMD-CMM

Warren Greenfield

AlternateWG Associates LLC31 Drayton PlaceWayne, NJ 07470Principal: Robert G. Zalosh

SE 04/03/2019

CMD-CMM

Paul F. Hart

AlternateAmerican International Group, Inc. (AIG)18257 Martin AvenueHomewood, IL 60430-2107Principal: Michael David Heroux

I 8/2/2010CMD-CMM

Jason Hudson

AlternateNovelis, Inc.1950 Vaughn Road North WestKennesaw, GA 30144Principal: Brad D. Burridge

U 11/30/2016

CMD-CMM

Laura Jacobsen

AlternateThe Boeing Company310 15th Street Apartment 5Huntington Beach, CA 92648Principal: Eli Horden

U 04/05/2016CMD-CMM

Shay Elliott Massey

AlternateOak Ridge National LaboratoryP.O. Box 2008, MS 6424Oak Ridge, TN 37831-6424Principal: Patrick A. Thornton

U 04/11/2018

CMD-CMM

John E. McConaghie

AlternateLuxfer MEL Technologies/Magnesium Elektron Powders NJ100 Ridgeway BoulevardManchester, NJ 08759Principal: Richard S. Varga

U 1/1/1990CMD-CMM

Brion Russell Pearson

AlternateIdaho National LaboratoryPo Box 16251955 Fremont MS 6134Idaho Falls, ID 83415Principal: David K. Young

RT 12/06/2019

3


Combustible Dusts


CMD-CMM

Shanker Pershad

AlternateHoneywell InternationalPerformance Materials and Technology15801 Woods Edge RoadColonial Heights, VA 23834Principal: Samuel A. Rodgers

U 04/02/2020CMD-CMM

Scott Ryan

AlternateAllegheny Technologies Inc. (ATI)3875 Aeropointe ParkwayMonroe, NC 28110Principal: Ryan Condon

M 08/17/2017

CMD-CMM

Lon L. Scholl

AlternateFike/Suppression Systems Inc.155 Nestle Way, Suite 104Breinigsville, PA 18031-1526Principal: Nicholas S. Reding

M 03/05/2012CMD-CMM

James Eamon Vickery

AlternateExponent9 Strathmore RoadNatick, MA 01760Principal: Timothy J. Myers

SE 04/11/2018

CMD-CMM

William R. Hamilton

Nonvoting MemberUS Department of LaborOccupational Safety & Health Administration200 Constitution AvenueNW, Room N3609Washington, DC 20210

E 3/4/2009CMD-CMM

Albert Muller

Member Emeritus39 Still Hollow RoadLebanon, NJ 08833-4417

SE 1/1/1985

CMD-CMM

Robert W. Nelson

Member Emeritus28 Wing RoadPO Box 418Pocasset, MA 02559

SE 1/1/1969CMD-CMM

Laura E. Moreno

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

1/31/2018

4

Process Stage Process Step Dates for TCDates for TC

with CC

Public InputStage (First Draft)

Public Input Closing Date* 6/26/2019 6/26/2019

Final Date for TC First Draft Meeting 12/04/2019 9/04/2019

Posting of First Draft and TC Ballot 1/22/2020 10/16/2019

Final date for Receipt of TC First Draft ballot 2/12/2020 11/06/2019

Final date for Receipt of TC First Draft ballot ‐ recirc 2/19/2020 11/13/2019

Posting of First Draft for CC Meeting 11/20/2019

Final date for CC First Draft Meeting 1/02/2020

Posting of First Draft and CC Ballot 1/22/2020

Final date for Receipt of CC First Draft ballot 2/12/2020

Final date for Receipt of CC First Draft ballot ‐ recirc 2/19/2020

Post First Draft Report for Public Comment 2/26/2020 2/26/2020

Comment Stage(Second Draft)

Public Comment Closing Date* 5/06/2020 5/06/2020

Notice Published on Consent Standards (Standards that received no Comments)Note: Date varies and determined via TC ballot.

Appeal Closing Date for Consent Standards (Standards that received no Comments)

Final date for TC Second Draft Meeting 11/04/2020 7/29/2020

Posting of Second Draft and TC Ballot 12/16/2020 9/09/2020

Final date for Receipt of TC Second Draft ballot 1/06/2021 9/30/2020

Final date for receipt of TC Second Draft ballot ‐ recirc 1/13/2021 10/07/2020

Posting of Second Draft for CC Meeting 10/14/2020

Final date for CC Second Draft Meeting 11/25/2020

Posting of Second Draft for CC Ballot 12/16/2020

Final date for Receipt of CC Second Draft ballot 1/06/2021

Final date for Receipt of CC Second Draft ballot ‐ recirc 1/13/2021

Post Second Draft Report for NITMAM Review 1/20/2021 1/20/2021

Tech SessionPreparation (&

Issuance)

Notice of Intent to Make a Motion (NITMAM) Closing Date 2/17/2021 2/17/2021

Posting of Certified Amending Motions (CAMs) and Consent Standards 3/31/2021 3/31/2021

Appeal Closing Date for Consent Standards 4/15/2021 4/15/2021

SC Issuance Date for Consent Standards 4/26/2021 4/26/2021

Tech Session Association Meeting for Standards with CAMs

Appeals andIssuance

Appeal Closing Date for Standards with CAMs

SC Issuance Date for Standards with CAMs

TC = Technical Committee or PanelCC = Correlating Committee

As of 12/13/2017

ATTACHMENT C

Public Comment No. 6-NFPA 484-2020 [ New Section after 1.4.2 ]

TITLE OF NEW CONTENT

After the sections at first recommended by Correlating Committee Note No. 8 (1.4.1, 1.4.2 and 1.4.3), addthe following to implement the Correlating Committee's most recent recommendation:

1.4.4 Where a conflict between a requirement of NFPA 652 and a requirement of this standard exists, the requirement

of this standard shall apply.

Additional Proposed Changes

File Name Description Approved

CDCC_Note_No._8_Dec._6_2019_.pdf

CDCC Note No. 8 (Dec. 6, 2019) (before CDCC later recommendation)

CDCC_Note_No._8_Dec._6_2019_.pdf

CDCC, Excerpt from March 10, 2020, Report, Sample Conflict Section for Combined [Combustible Dust] Document (adding additional conflict provision)

Excerpt_Item_20-4-21a_from_Minutes_of_Standards_Council_Meeting_April_1_2020_.pdf

Excerpt (Item 20-4-21a) from Minutes of Standards Council Meeting (April 1, 2020) (accepting CDCC new conflict language)

Statement of Problem and Substantiation for Public Comment

The NFPA 484 Technical Committee recently received Combustible Dust Correlating Committee Note No. 8 (attached), which recommended amendments to NFPA 484’s conflicts provisions. The amendments originally set out in Note 8 were as follows:

1.4 Conflicts. 1.4.1 Where a requirement specified in this industry-specific standard differs from a requirement specified

in NFPA 652, the requirement in this standard shall be permitted to be used. 1.4.2 Where a requirement specified in this standard specifically prohibits a requirement specified in

NFPA 652, the prohibition in this standard shall apply. 1.4.3 Where this standard neither prohibits nor provides a requirement, the requirement in NFPA 652

shall apply.

However, Note No. 8 does not reflect the Correlating Committee’s most up-to-date views. The Correlating Committee’s current views are instead reflected in paragraph 1.4.5 of the “Sample Conflict Section for Combined [Combustible Dust] Document” that the Correlating Committee adopted on March 10, 2020 (also attached), as part of its report to the NFPA Standards Council, and that the Standards Council approved on April 1, 2020 in Action Item No. 20-4-21-a (see the third attachment to this submission). That paragraph, as adapted to NFPA 484, would read as follows:

National Fire Protection Association Report https://submittals.nfpa.org/TerraViewWeb/ContentFetcher?commentPar...

1 of 13 7/6/2020, 2:56 PM

ATTACHMENT D

1.4.4 Where a conflict between a requirement of NFPA 652 and a requirement of this standard exists, the requirement of this standard shall apply.

The Correlating Committee based its provision on paragraph 1.4.5 of NFPA 652 (2019) (“Where a conflict between a general requirement of this standard and a specific requirement of this standard exists, the specific requirement shall apply.”). (The paragraph could be further clarified and improved by substituting “provision” for “requirement” but that is not strictly necessary.)

By making clear that NFPA 484 may differ from NFPA 652, this paragraph helps preserve the independence of the various technical committees.

Arthur G. Sapper• Representing the United States Beet Sugar Association;• Participating (alternate) member of the NFPA Combustible Dust Correlating Committee

Related Item

• https://www.nfpa.org/assets/files/AboutTheCodes/484/484_A2021_CMD_AAC_FD_CorrelatingNotes.pdf

• http://submittals.nfpa.org/TerraViewWeb/ViewerPage.jsp?id=484-2019.ditamap&pubStatus=FDR

Submitter Information Verification

Submitter Full Name: Arthur Sapper

Organization: Ogletree Deakins

Affiliation: United States Beet Sugar Association

Street Address:

City:

State:

Zip:

Submittal Date: Thu Apr 30 12:13:22 EDT 2020

Committee: CMD-CMM


2 of 13 7/6/2020, 2:56 PM

Public Comment No. 7-NFPA 484-2020 [ Section No. 1.4.2 ]

1.4.2

Where a requirement specified in this standard specifically prohibits a requirement specified in NFPA 652,the prohibition in this standard shall apply.


NFPA 484 Technical Committee recently received Combustible Dust Correlating Committee Note No. 8, which recommended amendments to NFPA 484’s conflicts provisions. The amendments originally set out in Note 8 were as follows:

1.4 Conflicts.1.4.1 Where a requirement specified in this industry-specific standard differs from a requirement specified in NFPA 652, the requirement in this standard shall be permitted to be used.1.4.2 Where a requirement specified in this standard specifically prohibits a requirement specified in NFPA 652, the prohibition in this standard shall apply.1.4.3 Where this standard neither prohibits nor provides a requirement, the requirement in NFPA 652 shall apply.

However, Note No. 8 does not reflect the Correlating Committee’s most up-to-date views. The Correlating Committee’s current views are instead reflected in paragraph 1.4.5 of the “Sample Conflict Section for Combined [Combustible Dust] Document” that the Correlating Committee adopted on March 10, 2020, as part of its report to the NFPA Standards Council, and that the Standards Council approved on April 1, 2020 in Action Item No. 20-4-21-a. That paragraph, as adapted to NFPA 484, would read as follows:



Related Item

• CR


Submitter Full Name: Jess McCluer

Organization: National Grain and Feed Associ

Street Address:

City:

State:

Zip:

Submittal Date: Fri May 01 13:56:15 EDT 2020

Committee: CMD-CMM


3 of 13 7/6/2020, 2:56 PM


1.4.2

Where a requirement specified in this standard specifically prohibits a requirement specified in NFPA 652,the prohibition in this standard shall apply.


NFPA 484 Technical Committee recently received Combustible Dust Correlating Committee Note No. 8, which recommended amendments to NFPA 484’s conflicts provisions. The amendments originally set out in Note 8 were as follows:

1.4 Conflicts.1.4.1 Where a requirement specified in this industry-specific standard differs from a requirement specified in NFPA 652, the requirement in this standard shall be permitted to be used.1.4.2 Where a requirement specified in this standard specifically prohibits a requirement specified in NFPA 652, the prohibition in this standard shall apply.1.4.3 Where this standard neither prohibits nor provides a requirement, the requirement in NFPA 652 shall apply.

However, Note No. 8 does not reflect the Correlating Committee’s most up-to-date views. The Correlating Committee’s current views are instead reflected in paragraph 1.4.5 of the “Sample Conflict Section for Combined [Combustible Dust] Document” that the Correlating Committee adopted on March 10, 2020, as part of its report to the NFPA Standards Council, and that the Standards Council approved on April 1, 2020 in Action Item No. 20-4-21-a. That paragraph, as adapted to NFPA 484, would read as follows:



By making clear that NFPA 484 may differ from NFPA 652, this paragraph helps preserve the independence of the various technical committees.

Related Item

• NFPA 484


Submitter Full Name: Eamon Monahan

Organization: Corn Refiners Association

Street Address:

City:

State:

Zip:

Submittal Date: Tue May 05 14:02:41 EDT 2020

Committee: CMD-CMM


4 of 13 7/6/2020, 2:56 PM


2.3.2 ASTM Publications.

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

ASTM E11, Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves, 2017.

ASTM E136, Standard Test Method for Behavior of Materials in a Assessing Combustibility of MaterialsUsing a Vertical Tube Furnace at 750°C, 2019 2019a .

ASTM E1226, Standard Test Method for Explosibility of Dust Clouds, 2012a 2019 .

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

ASTM E2019, Standard Test Method for Minimum Ignition Energy of a Dust Cloud in Air, 2003, reapproved2019.

ASTM E2931, Standard Test Method for Limiting Oxygen (Oxidant) Concentration of Combustible DustClouds, 2013, reapproved 2019.

ASTM F1002, Standard Performance Specification for Protective Clothing and Materials for Use byWorkers Exposed to Specific Molten Substances and Related Thermal Hazards, 2015.

ISO/ASTM 52900, Standard Terminology for Additive Manufacturing — General Principles — Terminology,2015.


updates

Related Item

• fr19


Submitter Full Name: Marcelo Hirschler

Organization: GBH International

Street Address:

City:

State:

Zip:


Committee: CMD-CMM


5 of 13 7/6/2020, 2:56 PM



2.3.5 UL Publications. Underwriters Laboratories Inc, 333 Pfingsten Rd, Northbrook, IL 60062-2096.

UL 2011, Outline of Investigation for Machinery, 2019.


This public comment is linked to another public comment that adds UL 2011 as a listing requirement for additive manufacturing.

Related Item

• PI 64 • PI 66


Submitter Full Name: Kelly Nicolello

Organization: UL LLC

Street Address:

City:

State:

Zip:


Committee: CMD-CMM


6 of 13 7/6/2020, 2:56 PM

Public Comment No. 13-NFPA 484-2020 [ Section No. 5.5.1 [Excluding any Sub-

Sections] ]

The explosibility of metals, metal powders, metal dusts, and alloys of these materials shall be determined byusing the flow chart in Figure 5.5.1.

For aluminum, hafnium, magnesium, tantalum, tanium, zirconium, and similar alloys or mixtures with adiaba cflame temperature higher than 3300°C, unless KSt and Pmax are determined in nominal 1 m3 or larger calibrated testvessels, the KSt value shall be mul plied by a factor of 2 for applica on of the design methods [NFPA 68, § 6.1.2.3,A.6.1.2.3; ASTM E1226, § 5.4].

Figure 5.5.1 Determination of Explosibility.


Rationale: There is a growing amount of evidence that the 20-l sphere underestimates metal dusts explosibility characteristics KSt and Pmax compared to the 1-m3 chamber [Refs 1-10]. The severity of metal dusts deflagrations does not scale well when using the KSt concept and cubic law. The KSt value of aluminum, in particular, can double in the 1-m3 chamber compared to the 20-l sphere. This increase in the larger vessel has been attributed to the effect ofthermal radiation which can be an order of magnitude greater for metal dusts compared to common organic dusts.This situation is concerning since it can lead to the undersizing of explosion protection systems. As a precaution,ASTM E1226 and NFPA 68 now recommend to measure the explosion severity of the most reactive metal dusts ina 1-m3 chamber.This proposed text reproduces what can be found in NFPA 68, 2018 edition, §6.1.2.3 (also in line with new ASTME1226, 2019 edition, §5.4).

References:1. Taveau, J.R., Vingerhoets, J., Snoeys, J., Going, J.E., Farrell, T.M. (2013). Explosion protection with metaldust fuels: new experimental evidence. In: Seventh International Seminar on Fire & Explosion Hazards (ISFEH7),pp. 820-829, Providence, Rhode Island, USA2. Taveau, J. (2013). Explosion protection for metal fuels. Presentation to NFPA 484 Technical Committee onCombustible Metals and Metal Dusts, June 17th, Quincy, Massachusetts, USA3. Taveau, J. (2014). Combustible metal dusts: a particular class. 17th Mary Kay O’Connor Process SafetyCenter International Symposium, 594-606, College Station, Texas, USA4. Taveau, J., Vingerhoets, J., Snoeys, J., Going, J., Farrell, T. (2015). Suppression of metal dust deflagrations.Journal of Loss Prevention in the Process Industries, 36, 244-255. Taveau, J., Seidel, R. (2015a). Explosibility and venting tests with 4 metal powders. NFPA 484 committeemeeting, Knoxville, USA6. Taveau, J. (2015b). Scaling-up metal dusts explosion severity. Presentation to the NFPA 68 TechnicalCommittee on Explosion Protection Systems, September 9th, Quincy, Massachusetts, USA7. Taveau, J. (2015c). Metal dusts explosibility testing in 20-l sphere and 1-m3 vessel. Presentation to ASTME27 technical committee, November 19th, Tampa, Florida, USA8. Taveau, J.R., Hochgreb, S., Lemkowitz, S., Roekaerts, D. (2018). Explosion hazards of aluminium finishingoperations. Journal of Loss Prevention in the Process Industries, 51, 84-939. Taveau, J., Lemkowitz, S., Hochgreb, S., Roekaerts, D. (2018). Scaling up metal dusts deflagration severity.12th International Symposium on Hazards, Prevention, and Mitigation of Industrial Explosions, Kansas City, USA10. Taveau, J., Lemkowitz, S., Hochgreb, S., Roekaerts, D. (2019). Metal dusts explosion hazards and protection.Chemical Engineering Transactions, Volume 77, 7-12


7 of 13 7/6/2020, 2:56 PM

Related Item

• Public Input No. 68-NFPA 484-2019


Submitter Full Name: Jerome Taveau

Organization: Jensen Hughes

Street Address:

City:

State:

Zip:

Submittal Date: Wed May 06 13:10:27 EDT 2020

Committee: CMD-CMM


8 of 13 7/6/2020, 2:56 PM

Public Comment No. 14-NFPA 484-2020 [ Section No. 9.7.3.2 ]

9.7.3.2

Explosion protection systems shall incorporate one or more of the following methods of protection:

(1) Oxidant concentration reduction in accordance with NFPA 69

(2) Deflagration venting in accordance with NFPA 68

(3) Deflagration venting through listed flame-arresting devices in accordance with NFPA 68

(4) Deflagration pressure containment in accordance with NFPA 69

(5) Deflagration suppression system in accordance with NFPA 69

(6) Dilution with a noncombustible dust to render the mixture noncombustible

[ 652: 9.7.3.2]

Explosion protec on systems such as ven ng, flameless ven ng, suppression and isola on, that are intended to beused in processes handling metal dusts, must be tested and cer fied under realis c deflagra on condi ons involvingthe same metal dust that is handled in the process to be protected and at a volume representa ve of the actualapplica on.


Rationale: There is a growing amount of evidence that metal dust deflagrations pose more severe challenges to explosion protection systems than organic dusts that are traditionally used for the testing and certification of such devices. And therefore, that conventional explosion protection systems may fail to mitigate metal dust deflagrations, resulting in unmitigated hazards and catastrophic losses [Refs 1-11]. For example, vent panels may experience fragmentation (due to metal dusts higher rates of pressure rise and temperatures), flameless venting devices and suppression systems may not be able to quench the expanding fireball (due to metal dusts higher heat release rates) and isolation systems may not activate fast enough to isolate a propagating metal dust deflagration (due to metal dusts higher flame speeds). Also, a scaling issue related to the venting of aluminum dust deflagrations has been identified in [Refs 9 and 11], with higher than expected Preds as the volume to be protected increases, which has been attributed to the effect of thermal radiation (which can be an order of magnitude greater for metal dusts compared to common organic dusts), and raises doubts concerning the adequate protection of industrial-scale equipment using current venting correlations.Therefore, a specific testing and certification path is required for explosion protection systems used to mitigate metal dust hazards. Testing using the same metal dust and at a volume representative of the actual application is crucial to be able to certify explosion protection systems. Explosion protection systems intended for metal dusts must not be tested and certified using an organic combustible dust, such as cornstarch, which exhibits weaker combustion characteristics.This proposed text supplements information and warnings already available in A.11.2.4.4.1, A.11.2.4.4.11.2, A.11.2.4.4.11.4, A.11.2.4.4.15.6, A.11.5.1.6, A.11.6.1.2.2 of NFPA 484, 2019 edition about limitations ofconventional explosion protection systems when dealing with metal dusts.

References:1. Taveau, J.R., Vingerhoets, J., Snoeys, J., Going, J.E., Farrell, T.M. (2013). Explosion protection with metaldust fuels: new experimental evidence. In: Seventh International Seminar on Fire & Explosion Hazards (ISFEH7),pp. 820-829, Providence, Rhode Island, USA2. Taveau, J. (2013). Explosion protection for metal fuels. Presentation to NFPA 484 Technical Committee onCombustible Metals and Metal Dusts, June 17th, Quincy, Massachusetts, USA3. Taveau, J. (2014). Combustible metal dusts: a particular class. 17th Mary Kay O’Connor Process SafetyCenter International Symposium, 594-606, College Station, Texas, USA4. Taveau, J., Vingerhoets, J., Snoeys, J., Going, J., Farrell, T. (2015). Suppression of metal dust deflagrations.Journal of Loss Prevention in the Process Industries, 36, 244-255. Taveau, J., Seidel, R. (2015a). Explosibility and venting tests with 4 metal powders. NFPA 484 committeemeeting, Knoxville, USA6. Taveau, J. (2015b). Scaling-up metal dusts explosion severity. Presentation to the NFPA 68 Technical


9 of 13 7/6/2020, 2:56 PM

Committee on Explosion Protection Systems, September 9th, Quincy, Massachusetts, USA7. Taveau, J. (2015c). Metal dusts explosibility testing in 20-l sphere and 1-m3 vessel. Presentation to ASTME27 technical committee, November 19th, Tampa, Florida, USA8. Taveau, J. (2017). Dust explosion propagation and isolation. Journal of Loss Prevention in the ProcessIndustries, 48, 320-3309. Taveau, J.R., Hochgreb, S., Lemkowitz, S., Roekaerts, D. (2018). Explosion hazards of aluminium finishingoperations. Journal of Loss Prevention in the Process Industries, 51, 84-9310. Taveau, J., Lemkowitz, S., Hochgreb, S., Roekaerts, D. (2018). Scaling up metal dusts deflagration severity.12th International Symposium on Hazards, Prevention, and Mitigation of Industrial Explosions, Kansas City, USA11. Taveau, J., Lemkowitz, S., Hochgreb, S., Roekaerts, D. (2019). Metal dusts explosion hazards and protection.Chemical Engineering Transactions, Volume 77, 7-12

Related Item

• Public Input No. 68-NFPA 484-2019


Submitter Full Name: Jerome Taveau

Organization: Jensen Hughes

Street Address:

City:

State:

Zip:

Submittal Date: Wed May 06 13:14:20 EDT 2020

Committee: CMD-CMM


10 of 13 7/6/2020, 2:56 PM



15.2.1.1 3D printers used in industrial additive manufacturing shall be listed and labeled in accordance withUL 2011 Outline of Investigation for Machinery or approved for the application based on a field evaluationconducted by an approved agency.[1:46.3.1].


The 2021 edition of NFPA 1 Fire Code will include a new Chapter 46 on Additive Manufacturing. We understand that no NITNAMs were submitted to that chapter and it has been balloted, affirmative by the NFPA 1 Technical Committee. The requirements are similar to those adopted by the International Fire Code (IFC). This public comment, slightly different from the public input is extracted from the 2021 NFPA 1 Fire Code section 46.3.1. It should be included in NFPA 484 to avoid conflicts where the equipment complies with NFPA 484 but not NFPA 1 or the IFC.

Related Item

• PI 66


Submitter Full Name: Kelly Nicolello

Organization: UL LLC

Street Address:

City:

State:

Zip:


Committee: CMD-CMM


11 of 13 7/6/2020, 2:56 PM


15.3.1 General.

This public comment relates to UL proposal for listing of equipment to UL 2011.

15.3.1.1

All pieces of fixed equipment shall be grounded and bonded in accordance with NFPA 77.

15.3.1.2*

Personnel involved in manually filling or emptying containers or vessels of powders with an MIE value lessthan 30 mJ, sieving, handling open containers of these powders, or cleaning these containers shall begrounded or bonded during such operations.

15.3.1.3*

Control measures shall be employed to minimize the formation of suspended dust clouds during transfer ofpowder.

15.3.1.4*

Where equipment operation requires manual removal of the part, the equipment in proximity of the partremoval location, as determined by the DHA, shall be designed for installation in a Class II, Division 1,Group E location.

15.3.1.5

Portable vacuum cleaners used in additive manufacturing operations shall comply with the requirements inSection 13.4.


UL efforts to develop standard collecting best engineering practices for safety of additive manufacturing is much appreciated by the industry. However, UL 2011 Outline of Investigation for Machinery is not yet an approved ANSI standard and does not appear on OSHA’s NRTL scope. Selectively mandating listing for additive manufacturing machines may adversely affect product development. Adding UL 2011 as a reference in NFPA 484 for voluntary use would serve well as a recognition of UL effort.

Related Item

• UL Proposal to mandate listing to UL 2011


Submitter Full Name: Janusz Pankowski

Organization: Desktop Metal

Street Address:

City:

State:

Zip:

Submittal Date: Wed Feb 26 11:18:11 EST 2020

Committee: CMD-CMM


12 of 13 7/6/2020, 2:56 PM

Public Comment No. 12-NFPA 484-2020 [ Section No. J.1.2.6 ]

J.1.2.6 ASTM Publications.

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

ASTM D378, Standard Test Methods for Rubber (Elastomeric) Conveyor Belting, Flat Type, 2010(reapproved 2016).

ASTM D2240, Standard Test Method for Rubber Property — Durometer Hardness, 2015e1.

ASTM E136, Standard Test Method for Behavior of Materials in a Determining Combustibility of MaterialsUsing a Vertical Tube Furnace at 750°C, 2019 2019a .

ASTM E582, Standard Test Method for Minimum Ignition Energy and Quenching Distance in GaseousMixtures, 2007, reapproved 2013e1.

ASTM E1226, Standard Test Method for Explosibility of Dust Clouds, 2012a 2019 .

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

ASTM E2019, Standard Test Method for Minimum Ignition Energy of a Dust Cloud in Air, 2003, reapproved2019.

ASTM E2021, Standard Test Method for Hot-Surface Ignition Temperature of Dust Layers, 2015.

ASTM E2079, Standard Test Methods for Limiting Oxygen (Oxidant) Concentration in Gases and Vapors,2019.

ASTM E2931, Standard Test Method for Limiting Oxygen (Oxidant) Concentration of Combustible DustClouds, 2013, reapproved 2019.

ASTM F955, Standard Test Method for Evaluating Heat Transfer through Materials for Protective ClothingUpon Contact with Molten Substances, 2015.

ASTM F1002, Standard Performance Specification for Protective Clothing for Use by Workers Exposed toSpecific Molten Substances and Related Thermal Hazards, 2015

ASTM F2621, Standard Practice for Determining Response Characteristics and Design Integrity of ArcRated Finished Products in an Electric Arc Exposure, 2019.


updates

Related Item

• fr20


Submitter Full Name: Marcelo Hirschler

Organization: GBH International

Street Address:

City:

State:

Zip:


Committee: CMD-CMM


13 of 13 7/6/2020, 2:56 PM

Committee Input No. 14-NFPA 484-2019 [ Global Input ]

See attached Word file.

Supplemental Information

File Name Description Approved

NFPA_484_Committee_Input_per_NFPA_499_Proposal_of_20190725.docx


Committee:

Submittal Date: Tue Aug 06 14:54:58 EDT 2019

Committee Statement

CommitteeStatement:

There are two main reasons for this committee input, first to clearly include combustible fibers/flyingsto draw the connection to the NFPA 70 application and second to remove any prescriptive limitationor prohibition for use of the Zone system for classification. A number of paragraphs in the main bodyand the annex specifically call out Division system criteria, and these are updated to either removethe specific Division reference or add the equivalent Zone reference. Lastly the term “electricallyclassified area(s)” has been replaced with “hazardous(classified) location(s)” to more clearly alignwith NFPA 70 terminology.

We have not yet and do not expect to completely agree on a definition for combustible dust becauseof the need to include process-specific atmospheres in NFPA 652 and the commodity standards.This proposal makes the functional usage of the term combustible dust equivalent between NFPA70and the various dust standards.

ResponseMessage:

CI-14-NFPA 484-2019

Ballot Results

This item has not been balloted


1 of 4 7/6/2020, 3:06 PM

ATTACHMENT E

Committee Input to NFPA484-2019

1) Add the definition of ignitible fibers/flyings and annex material, extracted from NFPA652. Theaddition of ignitible fibers/flyings is to clarify the relationship with the electrical definitions, suchthat material forms presenting a flash-fire or explosion hazard will be evaluated as hazardous(classified) locations regardless of particle size. Note that the dust standards reference the sameASTM E1226-2012a, Standard Test Method for Explosibility of Dust Clouds, or ISO 6184-1, Explosionprotection systems — Part 1: Determination of explosion indices of combustible dusts in air, forprocedures for determining the explosibility of dusts.

3.3.x* Combustible Fibers/Flyings. Solid particles, where one dimension is greater than 500 μm in nominal size, which may form an explosible mixture with air at standard atmospheric pressure and temperature [this is the IEC definition with spelling change and replacement of “explosive” with “explosible”]

A.3.3.x Combustible Flyings. As used in this recommended practice, flyings refers to aparticle with a small cross sectional area and a length greater than 500 microns. Flyings is a general term encompassing any particle that can be suspended and that has one or more dimensions greater than 500 microns. Examples of flyings include flat platelet-shaped particulate, such as metal flake, and fibrous particulate, such as particle board core material. To be covered by this recommended practice, the particle must present a flash-fire hazard or explosion hazard when suspended in air. If the smallest dimension of a combustible solid is greater than 500 μm, it is unlikely that the material would be combustible dust or combustible flyings, as determined by test. Finely divided solids with lengths that are large compared to their diameter or thickness usually do not pass through a 500 μm sieve, yet could still pose a deflagration hazard.

Combustible flyings that present a flash-fire hazard or explosion hazard when dispersed in air must first be capable of being suspended in air under typical test conditions. The typical test methods for evaluating a flash-fire or explosion hazard are ASTM E1226-2012a, Standard Test Method for Explosibility of Dust Clouds, or ISO 6184-1, Explosion protection systems — Part 1: Determination of explosion indices of combustible dusts in air, for procedures for determining the explosibility of dusts.

2) NFPA 484 currently includes the extracted combustible dust definition and annex from NFPA 654,which has been transferred to NFPA652. Update the definition extract to reflect the changes inNFPA652 as well as the annex. One change for NFPA484, just as was done in the current edition, isto specify that the Chapter 5 reference in the second paragraph of the annex is Chapter 5 ofNFPA652.

3.3.10* Combustible Dust. A finely divided combustible particulate solid, including combustible fibers/flyings, that presents a flash-fire hazard or explosion hazard when suspended in air or the process-specific oxidizing medium over a range of concentrations.[654, 2017][652-3.3.6]

A.3.3.10 Combustible Dust. The term combustible dust when used in this standardincludes powders, fines, fibers, flyings, etc. This definition also includes consideration ofa process-specific oxidizing medium other than air. A larger particle size material mightnot present a hazard in air, yet could present a hazard in an atmosphere with increasedoxygen concentration. Similarly, a combustible metal might still present a hazard in anatmosphere typically considered inert, such as CO2 or nitrogen.

Dusts traditionally were defined as material 420 μm or smaller (i.e, capable of passing through a U.S. No. 40 standard sieve). For consistency with other standards, 500 μm (i.e., capable of passing through a U.S. No. 35 standard sieve) is now considered an appropriate size criterion. Particle surface area-to-volume ratio is a key factor in determining the rate of combustion. Combustible particulate solids with the smallest a minimum dimension more than 500 μm generally have a surface-to-volume ratio that is too small to pose a deflagration hazard. Flat platelet-shaped particles, flakes, or fibers Fibers/flyings with lengths that are large compared to their diameter or thickness usually do not pass through a 500 μm sieve, yet could still pose a deflagration hazard. Many particulates accumulate electrostatic charge in handling, causing them to attract each other, forming agglomerates. Often agglomerates behave as if they were larger particles, yet when they are dispersed they present a significant hazard. Therefore, it can be inferred that any particulate that has the smallest a minimum dimension less than or equal to 500 μm could behave as a combustible dust if suspended in air or the process specific oxidizer. If the smallest minimum dimension of the particulate is greater than 500 μm, it is unlikely that the material would be a combustible dust, as determined by test. The determination of whether a sample of combustible material presents a flash-fire or explosion hazard could be based on a screening test methodology such as provided in the ASTM E1226, Standard Test Method for Explosibility of Dust Clouds. Alternatively, and a standardized test method such as ASTM E1515, Standard Test Method for Minimum Explosible Concentration of Combustible Dusts, could be used to determine dust explosibility. Chapter 5 of NFPA652 has additional information on testing requirements.……..(annex continues)

3) Modify the definition of combustible metal dust in NFPA 484-2019 to include combustiblefibers/flyings and remove “regardless of particle size or shape”. Delete the duplicative and confusingrepeat sections of its annex (except for the first paragraph, it is a verbatim repeat of the annex forCombustible Dust)

3.3.11.1* Combustible Metal Dust. A combustible particulate metal, including combustible fibers/flyings, that presents a fire or explosion hazard when suspended in air or the process specific oxidizing medium over a range of concentrations, regardless of particle size or shape.

A.3.3.11.1 Combustible Metal Dust. Dust from someprocesses can contain various amounts or concentrations oforganic material. The burning characteristics from the mixtureas determined from testing are used to distinguish between acombustible metal dust and a combustible dust.

Dusts traditionally have been defined as a material

420 microns or smaller (capable of passing through a U.S. No. 40 standard sieve). For consistency with other standards, 500 microns (capable of passing through a U.S. No. 35 standard sieve) is now considered an appropriate size criterion. Particle surface area to volume ratio is a key factor in determining the rate of combustion. Combustible particulate solids with a minimum dimension more than 500 microns generally have a surface to volume ratio that is too small to pose a deflagration hazard. Flat platelet-shaped particles, flakes, or fibers with lengths that are large compared to their diameter usually do not pass through a 500 micron sieve yet could still pose a deflagration hazard. Many particulates accumulate electrostatic charge in handling, causing them to attract each other, forming agglomerates. Often, agglomerates behave as if they were larger particles, yet when they are dispersed they present a significant hazard. Consequently, it can be inferred that any particle that has a minimum dimension of less than 500 microns could behave as a combustible dust if suspended in air. The determination of whether a sample of material is a combustible, explosible, dust should be based on a screening test methodology such as that provided in the draft ASTM E1226, Test Method for Pressure and Rate of Pressure Rise for Combustible Dusts. Alternatively, a standardized test method such as ASTM E1515, Standard Test Method for Minimum Explosible Concentration of Combustible Dusts, can be used to determine dust explosibility. There is some possibility that a sample will result in a false positive in the 20 Liter sphere when tested by the ASTM E1226 screening test or ASTM E1515 test. This is due to the high energy ignition source over-driving the test. When the lowest ignition energy allowed 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 over-driving and thus will provide more realistic results. This possibility for false positives has been known for quite some time and is attributed to over-driven conditions that exist in the 20 liter chamber due to the use of strong pyrotechnic igniters. For that reason, the reference method for explosibility testing is based on 1 m3 chamber, and the 20 L chamber test method is calibrated to produce results comparable to those from 1 m3 chamber for most 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 ....” ASTM E1226 further states, “Because a

number of factors (concentration, uniformity of dispersion, turbulence of ignition, sample age, etc.) can affect the test results, the test 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.” NFPA 68 also recognizes this problem and addresses it, stating “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.” Any time a combustible dust is processed or handled, a potential for deflagration exists. The degree of hazard varies, depending on the type of combustible dust and the processing methods used. 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 minimumexplosible concentration (MEC)(4) Sufficiently powerful ignition source such as an electrostaticdischarge, an electric current arc, a glowing ember,a hot surface, welding slag, frictional heat, or a flameIf the deflagration is confined and produces a pressure sufficientto rupture the confining enclosure, the event is, by definition,an explosion.Evaluation of the hazard of a combustible dust should bedetermined by the means of actual test data. Each situationshould be evaluated and applicable tests selected. The followinglist represents the factors that are sometimes used in determiningthe deflagration hazard of a dust:(1) MEC(2) Minimum ignition energy (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 inASTM E1226-2010(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) ChargeabilityIt is important to keep in mind that as particulate isprocessed, handled, or transported the particle size generally

decreases due to particle 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 percent nitrogen), certain of the above tests should be conducted in the appropriate process specific medium.

4) Update 9.7.1.1 to add Zone Group reference.9.7.1.1 Vigorous sweeping or blowing down with compressed air produces dust clouds and shall be permitted only where the following requirements are met:

(1) Electrical equipment not suitable for Class II, Division Group E or Zone Group IIIClocations and other sources of ignition shall be shut downor removed from the area.

(2) Compressed air shall not exceed a gauge pressure of206 kPa (30 psi), unless otherwise determined to be safeby a documented hazard analysis.

5) Remove NFPA 484 statement 10.8.1 and part of current annex that addresses conflicts incombustible dust definition, as well as 10.8.1.4 that prohibits electrical classification according toarticle 506. Rearrange text and retain relevant portion of current 10.8.1 annex attached to new10.8.1.

10.8 Electrical Area Classification. 10.8.1* The classification criteria in NFPA 70 shall be applied whenever combustible metal particulate meets the definition of combustible metal dust in this standard, not withstanding the definition of combustible dust in NFPA 70.

A.10.8.1 The definition of combustible dust in Article 500 ofNFPA 70 limits particle size and conflicts with the definition ofcombustible metal dust in this standard. Combustible metaldust should be considered Class II, Group E regardless of particlesize. (See NFPA 497 and NFPA 499 for information on electricalarea classification.) Housekeeping can reduce or eliminate theelectrical area classification for a location where combustiblemetal dust is present. Electrical equipment upgrades to meetArticle 500 of NFPA 70 can be costly and users might betterfocus on preventing fugitive dust from escaping equipment andaccumulations to minimize the extent of the hazardous (classified)areas.

10.8.1.1 The identification of the possible presence and extent of Class II hazardous (classified) locations shall be made based on the criteria in Article 500.5(C) Article 500 and 506 of NFPA 70.

A.10.8.1 The definition of combustible dust in Article 500 ofNFPA 70 limits particle size and conflicts with the definition ofcombustible metal dust in this standard. Combustible metaldust should be considered Class II, Group E regardless of particlesize. (See NFPA 497 and NFPA 499 for information on electricalarea classification.) Housekeeping can reduce or eliminate theelectrical area classification for a location where combustiblemetal dust is present. Electrical equipment upgrades to meetArticle 500 of NFPA 70 can be costly and users might betterfocus on preventing fugitive dust from escaping equipment andaccumulations to minimize the extent of the hazardous (classified)areas.

10.8.21.1.1 All areas designated as hazardous (classified) locations shall be documented, and such documentation shall be maintained and preserved for access at the facility.

10.8.31.2 Electrical equipment and wiring within Class II locations shall comply with Article 500.5(C) of NFPA 70.

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

A. 10.8.41.3Finding combustible metal dust or powder withinelectrical equipment and components should warrant morefrequent inspection and cleaning.

10.8.1.4* Zone classification for dusts in accordance with Article 506 of NFPA 70 shall not be permitted.

A.10.8.1.4 NFPA 499 provides guidance for zone classificationto clarify that combustible metal dust is Group IIIC, regardlessof particle size. However, this clarification has not yetprogressed through the NFPA 70 revision cycle.

10.8.1.5 Flashlights and other portable electrical equipment shall be identified for the locations where they are used.

6) Update the annex to 10.9.210.9.2* Where industrial trucks, in accordance with NFPA 505, are not commercially available, a documented risk assessment acceptable to the authority having jurisdiction shall be permitted to be used to specify the fire and explosion prevention features for the equipment used.

A.10.9.2 Diesel-powered, front-end loaders suitable for use inHazardous (classified) locations have not been commercially available. Thefollowing provisions can be used to reduce the fire hazard fromdiesel-powered, front-end loaders used in Class II hazardousareas, as defined in Articles 500 and 506 of NFPA 70:

(1) Only essential electrical equipment should be used, andwiring should be in a metal conduit. Air-operated startingis preferred, but batteries are permitted to be used if theyare mounted in enclosures rated for Type EX hazardousareas.

(2) Where practical, a water-cooled manifold and mufflershould be used.

(3) Loaders that are certified to meet the Mine Safety andHealth Administration (MSHA) criteria (formerly Schedule31) found in 30 CFR 36, “Approved Requirements forPermissible Mobile Diesel-Powered Transportation Equipment,”are also acceptable in lieu of A.10.9.2(1) andA.10.9.2(2).

(4) The engine and hydraulic oil compartments should beprotected with fixed, automatic dry-chemical extinguishingsystems.

(5) Loaders should have a high degree of maintenance andcleaning. Frequent cleaning (daily in some cases) of theengine compartment with compressed air could be necessary.Periodic steam cleaning also should be done.(6) Loaders should never be parked or left unattended in thedust explosion hazard or dust fire hazard area.

7) Update Annex to 15.715.7* Machining, Fabrication, Finishing and Media Blasting.

A.15.7 Section 15.7 applies to operations where metals ormetal alloys are subjected to processing or finishing operations.The operations can include, but are not limited to, grinding,buffing, polishing, sawing, and machining of solids. Mediablasting operations include, but are not limited to, abrading,etching, applying an anchor pattern, wheel blast, centrifugalwheel blast, sand blast, grit blast, air blast, airless blast, siphonblast, suction blast, abrasive shot blast, peening, and shot peeningof solids……..

The control of ignition sources is paramount in maintaining

a fire-free environment. The following measures provide guidance for controlling ignition sources: (1) Open flames and smoking should be prohibited.

(2) Cutting and welding in the vicinity of fines, dust, andflammable lubricants should be prohibited.

(3) Electrical equipment, wiring, and lighting in the areashould be Class II, Division 1 or Zone 20/21 explosion proof, conforming to NationalElectricalManufacturers Association (NEMA) rating class II,Group E, as defined in Guide for Classification of All Typesof Insulated Wire and Cable.

(4) Blowers and exhaust fans should be suitable for theapplication. Maintenance should be provided to ensureclearance between the blades and casing…..

8) Update section 16.6.2.2.2 to include Articles 505 and 506.

16.6.2.2.2* Wet solvent milling areas or other areas wherecombustible or flammable liquids are present shall be classified,where applicable, in accordance with Article 500, 505, or 506 ofNFPA 70 with the exception of control equipment meeting therequirements of NFPA 496.

A.16.6.2.2.2 See NFPA 499 for information on electrical areaclassification.

Substantiation

There are two main reasons for this committee input, first to clearly include combustible fibers/flyings to draw the connection to the NFPA 70 application and second to remove any prescriptive limitation or prohibition for use of the Zone system for classification. A number of paragraphs in the main body and the annex specifically call out Division system criteria, and these are updated to either remove the specific Division reference or add the equivalent Zone reference. Lastly the term “electrically classified area(s)” has been replaced with “hazardous(classified) location(s)” to more clearly align with NFPA70 terminology.

We have not yet and do not expect to completely agree on a definition for combustible dust because of the need to include process-specific atmospheres in NFPA652 and the commodity standards. This proposal makes the functional usage of the term combustible dust equivalent between NFPA70 and the various dust standards.

Committee Input No. 18-NFPA 484-2019 [ Section No. 2.4 ]

2.4 References for Extracts in Mandatory Sections.

NFPA 51B, Standard for Fire Prevention During Welding, Cutting, and Other Hot Work, 2019 edition.

NFPA 68, Standard on Explosion Protection by Deflagration Venting, 2018 edition.

NFPA 69, Standard on Explosion Prevention Systems, 2014 edition.

NFPA 91, Standard for Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Particulate Solids,2015 edition.

NFPA 221, Standard for High Challenge Fire Walls, Fire Walls, and Fire Barrier Walls,2018 2021 edition.

NFPA 652, Standard on the Fundamentals of Combustible Dust,2019 2022 edition.

NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing,and Handling of Combustible Particulate Solids, 2017 edition.

NFPA 921, Guide for Fire and Explosion Investigations,2017 2021 edition.

NFPA 1250, Recommended Practice in Fire and Emergency Service Organization Risk Management,20152020 edition.

NFPA 1451, Standard for a Fire and Emergency Service Vehicle Operations Training Program, 2018edition.


Committee: CMD-CMM


Committee Statement

CommitteeStatement:

The extracts from these documents will be updated at the Second Draft meeting, becausethey are still in revision cycles.

ResponseMessage:

CI-18-NFPA 484-2019

Ballot Results



2 of 4 7/6/2020, 3:06 PM

Committee Input No. 22-NFPA 484-2019 [ New Section after 13.3.1 ]

13.3.2 Storage of Powders.

1) Store ordinary combustible materials necessary for the processes in designated areas that are effectivelyseparated from the combustible metal dust/powder storage areas,

2) Store all the combustible powder containers on flat, level locations (e.g. shelves, storage racks, floors,etc.),

3) Stack all the containers to ensure stability (i.e. no leaning) and limit stacking of containers to no morethan two high,

4) Limit the storage height to 2.0-feet below the ceiling or sprinkler head deflectors,

5) Store all combustible powder containers inside of segregated hazardous material safety storagecabinets,

Annex - Currently, no cabinets or similar storage devices have been specifically designed to storecombustible dusts. However, hazardous material safety cabinets are designed for storage of flammableand pyrophoric solids, which more closely resemble the composition and hazards associated withcombustible dusts.

6) Limit the number of containers stored on racks or inside of cabinets to no more than 80% of thedesigned load capacity of each shelf,

7) Conspicuously mark or label each of the storage cabinets and/or storage racks to ensureincompatible and reactive metals or chemicals are not stored near one another,

Annex - Safety instruction signs should be posted on the front of the affected storage cabinets or racks,and should contain at least the following information: "WARNING (INSERT SPECIFIC METAL NAME)METAL ONLY — FIRE OR EXPLOSION CAN RESULT WITH OTHER METALS."

8) Inspect all the containers for signs of damage at the time the shipment is received, and at leastmonthly thereafter.

9) Powder transfer operations to occur in a room separate from storage


Committee: CMD-CMM

Submittal Date: Wed Aug 07 12:23:18 EDT 2019

Committee Statement

CommitteeStatement:

The committee is adding this heading as a reserved section at the First Draft stage. Thecommittee will rework the attached language and consider adding it at the Second Draft stage.

ResponseMessage:

CI-22-NFPA 484-2019

Ballot Results



3 of 4 7/6/2020, 3:06 PM

Committee Input No. 21-NFPA 484-2019 [ Section No. J.3 ]

J.3 References for Extracts in Informational Sections.

NFPA 652, Standard on the Fundamentals of Combustible Dust, 2019 2022 edition.

NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacture, Processing, andHandling of Combustible Particulate Solids, 2017 2020 edition.


Committee: CMD-CMM


Committee Statement

CommitteeStatement:

These extracts will be updated at the Second Draft meeting, because the documents are ina revision cycle.

Response Message: CI-21-NFPA 484-2019

Ballot Results



4 of 4 7/6/2020, 3:06 PM

Name Question Title Response Comments

Affirmative with Comment

I believe the thermite reaction is most often referred to as oxidation-reduction, as opposed to reduction-oxidation.

Samuel A. Rodgers FR-28, Section No. 11.2.4.4.2, See FR-28 Affirmative with Comment

Samuel A. Rodgers FR-2, Section No. 1.1.6.2, See FR-2

As the text currently stands, 4 mJ is too low a threshold for non-conductive dusts. IEC 60079-32-1 applies a 30 mJ threshold for this situation. The addition of a requirement to be static-dissipative for conductive dusts is appropriate.

Samuel A. Rodgers FR-35, Section No. 11.2.4.4.15.4, See FR-35 Affirmative with Comment

The remaining phrase "as per regulatory requirements" is not helpful to the user.

Samuel A. Rodgers FR-46, Section No. 11.2.4.4.11.2, See FR-46 Affirmative with Comment

The 2nd paragraph of A.13.2.4.4.11.2 should be appended instead to the section 13.2.4.4.11.2 as a whole, not to Oxidant control.


17.4.16 Drying of Powder (remove Niobium) 17.4.16.3 We should add a definition of oxidizing temperature in Chapter 3. It should be consistent with the values quoted in A.17.4.16.1 for niobium, zirconium, and hafnium. Can we specify the test method used for those determinations?

Robert G. Zalosh FR-25, Section No. 11.2.3.6.7, See FR-25 Affirmative with Comment

Robert G. Zalosh FR-51, Global Input, See FR-51

Suggest adding the following sentences to the required paragraph 11.2.3.6.7 because it clarifies what is required. A dry-type AMS requires one or more spark removal or extinguishing devices between it and the ignition-producing dust source to mitigate the spark entry hazard. The effectiveness of the removal or extinguishing device should be verified during the DHA. I don't know why paragraph 13.2.3.6.8* is needed in view of the suggested revision to the previous paragraph.

ATTACHMENT F

http://submittals.nfpa.org/TerraViewWeb/FormLaunch?id=/TerraView/Content/484-2019.ditamap/2/C1565205782038.xml&viewmode=nfpa/xslt/nfpaviewmode.xsl









Robert G. Zalosh FR-29, Section No. 11.2.4.4.4.3, See FR-29 Affirmative with Comment

Chnage "of dust less than 500 microns" to "combustible metal dust" since that is more straightforward and the scope of the standard.

Robert G. Zalosh FR-33, Section No. 11.2.4.4.15.9, See FR-33 Affirmative with Comment

Change "of material greater than 500 microns with a maximum of 0.45 kg (1 lb) of material less than 500 microns for an aggregate of 5 kg (11 lb) total" to "of combustible metal dust" since that is simpler and is the scope of the standard.


Since centralized vacuum systems apparantly are not listed, I suggesting changing "equipment used for cleaning shall be listed for use in a Class II, Group E atmosphere" to "portable vacuums used for cleaning shall be listed for use in a Class II, Group E atmosphere."

Robert G. Zalosh FR-23, Chapter 13, See FR-23 Affirmative with Comment

Robert G. Zalosh FR-4, Section No. 9.6.3, See FR-4

Paragraph 15.2.3.2.3. I don't know of any NFPA 69 explosion protection system that will initiate automatic shutdown on any of the three conditions specified in 15.2.3.1. If there is such a system, we should identify it. If there is no such system, we should delete







this paragraph. Paragraph 15.3.5.3.1 should not be applicable to inert gas transfer or to short gravity transfers. The paragraph is probably unnecessary in most cases. Paragraph 15.3.6.1.1* The inert gas environment is not really needed for powder binder jet printers, so we should have an exception paragraph for these printers and others that are deemed by the DHA to not require inerting. 15.3.6.2 Powder Bed Printing. We should add a short annex paragraph to clarify that this section is applicable to both Powder Bed Fusion printers and to Directed Energy Deposition printers with a smaller and shorter time duration powder bed. Paragraph 16.3.6.4.6: Suggest changing "remove a majority of the residual trapped powder" to remove most of the residual trapped powder Paragraph A.15.3.6.3. Besides cold spray printers, this section should also be applicable to material jetting printers in which the metal particles are sprayed in a liquid that evaporates soon after reaching the printing surface. Paragraph A.15.3.6.4.6 Besides gloves, small hand-held tools are used to dislodge and remove residual powder.

Steve James

Barwin FR-28, Section No. 11.2.4.4.2, See FR-28 Negative Information provided Sam Rogers in the email thread referenced below indicates this topic needs to be revisited. From: Rodgers, Sam (Process Safety) [mailto:[email protected]] Sent: Thursday, August 8, 2019 9:56 AM To: Moreno, Laura < [email protected]> Subject: FW: [External] RE: NFPA 484 First Revision on Filter Media

Steve James

Barwin FR-4, Section No. 9.6.3, See FR-4 Negative Suggested alternate wording: Due to the inherent hazards associated with the use of centralized and portable vacuum cleaning systems, equipment used for cleaning shall be consistent with the electrical area classification where the equipment is used.






Negative Section 15.2.3.2 comments: Remote manual emergency shutdown devices seem unnecessary. I’m unaware of a credible scenario where an operator would need a remote shutdown device to mitigate a dust hazard. An alternative could be to change 15.2.3.2.5 to say: ‘Shutdown or loss of power shall deactivate the affected printing operations without creating additional hazards’ Then the remote manual emergency shutdown could simply be a disconnect (or similar device) installed by the user of the equipment. Section 15.2.3.2.6 comment: Add: Unless the system can be maintained below the LOC per NFPA 69 until temperatures are less than the hot surface ignition temperature of the dust. Section 15.3.1.4 comments: Change wording to ‘shall be consistent with the electrical area classification where the equipment is used.’ Section 15.3.6.1.3 comments: Inerting per 13.5.2.4 is not possible since some materials like titanium require very low levels of oxygen to achieve chemistry for the printed material Minimum conveying velocities per 15.5.2.8 cannot necessarily be maintained since dust has to accumulate in the powder bed. Section 15.3.6.2.5.1 comment: The requirement in this section seems repetitive of 15.3.6.1.3. Consider deleting. Section 15.4.1 comment: Change wording to ‘shall be consistent with the electrical area classification where the equipment is used.’

Ashok Ghose

Dastidar FR-19, Chapter 2, See FR-19 Affirmative with Comment

Steve James

Barwin FR-23, Chapter 13, See FR-23

please note that ASTM E1226, Standard Test Method for Explosibility of Dust Clouds, 2012a is undergoing balloting. a new version may be out before 2020. A change in the second round of balloting may be required.

Ashok Ghose

Dastidar FR-4, Section No. 9.6.3, See FR-4 Negative Forces all vacuums to be electrical. Pneumatic vacuums that can be used don't have an electric motor for the Class II Group E rating. Additionally, pneumatic vacuums are not governed by the NEC (NFPA 70) or NFPA 499.







Ashok Ghose

Dastidar FR-38, Section No. A.3.3.45, See FR-38 Affirmative with Comment

Please note that testing MIE without inductance simulates a spark discharge from an electrostatic source. If trying to ascertain ignition likelihood or sensitivity from an electronic or electrical source (like a switch or sensor) MIE testing WITH inductance is required. MIE determination w/ and w/o inductance in the circuit can vary the test results greatly.


it should be noted here that there is experimental evidence that for some metals (i.e. metals with adiabatic flame temperatures greater than 3000°C) the 20-L volume is too small to give accurate results and a 1-m³ chamber should be used. We should caution users to this fact. If they try to develop an explosion protection strategy based on 20-L volume data for Pmax, KSt, MEC and LOC they may be under sizing their systems.

Ashok Ghose

Dastidar FR-54, Section No. A.5.4.4, See FR-54





technical committee on combustible metals and …

Documents