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TECHNICAL COMMITTEE ON EXPLOSION PROTECTION SYSTEMS

NFPA 68 & NFPA 69 TIA Discussion Meeting Agenda

September 9-10, 2015 8:00 AM - 5:00 PM EDT NFPA Headquarters, Quincy, MA

1. Call to Order. Larry Floyd, Chair

2. Introductions.

3. Staff Updates. Laura Montville, NFPA Staff

Presentation on NFPA Research resources

4. Minutes of May Meeting

Corrections per Jérôme Taveau dated June 26.

5. Committee Member Recognitions

Larry Britton

John Going

Joe Senecal

6. TIA Discussions

NFPA 68 TIA 1 – 3 address chapter 8 vent sizing flow issues, submitted by S. Rodgers. See 5/13/14 memo from L. Floyd to S. Rodgers, “NFPA 68 (2013), Tentative Interim Amendments (TIA),” attached to meeting agenda.

o It was decided at the May 2015 meeting that he will submit a TIA on paragraph 8.2.2.1

and send to Mitchel Rooker for agreement. The other two proposals did not receive

substantial support from the Committee so they will be addressed in the next revision

cycle.

o Following the May 2015 meeting, it was determined that a correction to paragraph 8.4.1

does not qualify as an erratum. The existing text was accepted in the F2012 ROP. If a

correction to the 2014 edition is desired, it should be included in the TIA submission.

NFPA 68 TIA 4, Fireball Equation, submitted by Brice Chastain and Bill Stevenson. See notes from the 7/31/14 CMD-HAP A2016 meeting in Atlanta, attached to meeting agenda.

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o Larry Floyd was to contact Brice Chastain for additional details about the Georgia Pacific

Incident.

NFPA 68 TIA 5, Paragraph 8.5.5. Submitted by S. Rodgers. See 8/21/14 e-mail attached to meeting agenda.

o Following the May 2015 meeting, it was determined that this correction to paragraph

8.5.5 does not qualify as an erratum. The issue as described has existed since Chapter 8

was rewritten in 2007. If a correction is desired, it should be included in one of the TIA

submissions.

NFPA 68 and NFPA 69 TIA 6, vent ducts for metal dusts, Submitted by Scott Davis and S. Rodgers. See 2/19/15 memo S. Rodgers to L. Floyd “Proposal for NFPA 68 and 69 TIAs on Metal Dusts,” attached to meeting agenda.

o Presentation by Jérôme Taveau

o Task group: Scott Davis, Bob Zalosh, Sam Rodgers, Henry Febo, Alfonso Ibarreta, and

Jérôme Taveau

o Sam Rogers and Bill Stevenson were to submit a TIA on NFPA 68 paragraph 6.1.2 and its

subparagraphs, and NFPA 69 paragraph 6.2.

NFPA 69, submitted by L. Britton. See 10/31/13 memo from L. Floyd to L. Britton, “NFPA 69 2014, Tentative Interim Amendment (TIA),” attached to meeting agenda.

o Larry Britton and Sam Rodgers were to submit a TIA on Figure A.7.7.2.7 and adjusted LOC

values in Table C.1(a).

o Form a task group to incorporate an LOC mixture rule based on Le Chatelier’s formula into

NFPA 69.

Additional items identified at the NFPA 67 Second Draft Meeting held in May:

o Inertia corrections

o Velocity through an explosion vent that exceeds the speed of sound

o Reorganization of NFPA 68 Chapter 7 to clarify applicability of requirements (discussion

lead: Sam Rodgers)

7. Large scale gas explosion testing. David Kirby

8. New Business.

Revision to Figure A.8.5(a) and accompanying text regarding values for K- flow

resistance coefficient (inclusion of appropriate references).

9. Next Meeting.

10. Adjourn.

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Address List No PhoneExplosion Protection Systems EXL-AAA

Laura E. Montville08/26/2015

EXL-AAA

Larry D. Floyd

ChairBASF1379 Ciba RoadMcIntosh, AL 36553-5436

U 7/29/2005EXL-AAA

Luke S. Morrison

SecretaryProfessional Loss Control Inc.PO Box 162Fredericton, NB E3B 4Y9 CanadaAlternate: Alvin Grant Roach

SE 1/1/1987

EXL-AAA

Venkateswara Sarma Bhamidipati

PrincipalPowder Process Solutions1620 Lake Drive WestChanhassen, MN 55317

IM 03/07/2013EXL-AAA

Martin P. Clouthier

PrincipalClouthier Risk Engineering6178 Cedar StreetHalifax, NS B3H 2J7 Canada

SE 10/27/2005

EXL-AAA

Michael Davies

PrincipalPROTEGOIndustriestrasse llBraunschweig, D-38110 GermanyAlternate: Thomas Heidermann

M 1/14/2005EXL-AAA

Randal R. Davis

PrincipalIEP Technologies417-1 South StreetMarlborough, MA 01752-3149

M 7/14/2004

EXL-AAA

Nathan R. Egbert

PrincipalMAC Process LLC7901 NW 107th TerraceKansas City, MO 64153

SE 08/17/2015EXL-AAA

Henry L. Febo, Jr.

PrincipalFM GlobalEngineering Standards1151 Boston-Providence TurnpikePO Box 9102Norwood, MA 02062-9102Alternate: John A. LeBlanc

I 8/5/2009

EXL-AAA

Robert J. Feldkamp

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

M 7/29/2005EXL-AAA

Joseph P. Gillis

Principal29 Hyder StreetWestboro, MA 01581

SE 10/1/1980

EXL-AAA

Dan A. Guaricci

PrincipalATEX Explosion Protection, L.P.2629 Waverly Barn Road, Suite 121Davenport, FL 33897

M 7/1/1991EXL-AAA

Michael D. Hard

PrincipalHard Fire Suppression Systems, Inc.4645 Westerville Road, Suite AColumbus, OH 43231-6050Fire Suppression Systems AssociationAlternate: Kirk W. Humbrecht

M 10/1/1994

EXL-AAA

David D. Herrmann

PrincipalE. I. DuPont de Nemours & Company1007 Market Street, (D12016)Wilmington, DE 19898Alternate: Thomas C. Scherpa

U 10/10/1997EXL-AAA

Alfonso F. Ibarreta

PrincipalExponent, Inc.9 Strathmore RoadNatick, MA 01760-2418Alternate: Timothy J. Myers

SE 3/4/2009

1 of 22



EXL-AAA

Eric R. Johnson

PrincipalSavannah River Nuclear Solutions, LLCSavannah River SiteBldg. 235-11H, Room 10Aiken, SC 29808

U 10/18/2011EXL-AAA

David C. Kirby

PrincipalBaker Engineering & Risk Consultants, Inc.1560 Clearview HeightsCharleston, WV 25312Alternate: James Kelly Thomas

SE 1/1/1983

EXL-AAA

Steven A. McCoy

PrincipalIngredionPO Box 1084Indianapolis, IN 46206NFPA Industrial Fire Protection Section

U 10/10/1997EXL-AAA

Scott W. Ostrowski

PrincipalExxonMobil Research and Engineering4500 Bayway DriveBaytown, TX 77520-2127American Petroleum Institute

U 08/17/2015

EXL-AAA

James O. Paavola

PrincipalDTE Electric Company2000 Second Ave., Room 421 GODetroit, MI 48226

U 1/10/2002EXL-AAA

Stefan Penno

PrincipalRembe GmbH Safety & ControlGallbergweg 21Brilon NRW, D-59929 GermanyAlternate: Gerd Ph. Mayer

M 11/2/2006

EXL-AAA

Samuel A. Rodgers

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

U 4/1/1996EXL-AAA

Mitchel L. Rooker

PrincipalBS&B Safety Systems, LLCPO Box 470590Tulsa, OK 74147-0590Alternate: Geof Brazier

M 10/10/1997

EXL-AAA

Cleveland B. Skinker

PrincipalBechtel Power Corporation5275 Westview DriveFrederick, MD 21703-8306Alternate: David M. Nieman

SE 3/4/2009EXL-AAA

Bill Stevenson

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

M 7/22/1999

EXL-AAA

David R. Stottmann

PrincipalST StoragePO Box 996Parsons, KS 67357Alternate: Keith McGuire

M 11/2/2006EXL-AAA

Stephen M. Stuart

PrincipalHylant Group2401 West Big Beaver Road, Suite 400Troy, MI 48084

I 7/24/1998

EXL-AAA

Jérôme R. Taveau

PrincipalFike Corporation704 SW 10th StreetBlue Springs, MO 64015-4263Alternate: Jef Snoeys

M 03/07/2013EXL-AAA

David E. Trull

PrincipalGlobal Asset Protection Services17804 NE 100th CourtRedmond, WA 98052-3273Alternate: Todd A. Dillon

I 03/03/2014

2 of 22



EXL-AAA

Erdem A. Ural

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

SE 1/16/1998EXL-AAA

Robert G. Zalosh

PrincipalFirexplo20 Rockland StreetWellesley, MA 02481

SE 1/1/1991

EXL-AAA

Geof Brazier

AlternateBS&B Safety Systems, LLC7455 East 46th StreetTulsa, OK 74145Principal: Mitchel L. Rooker

M 3/21/2006EXL-AAA

Todd A. Dillon

AlternateGlobal Asset Protection Services1620 Winton AvenueLakewood, OH 44107Principal: David E. Trull

I 7/16/2003

EXL-AAA

Thomas Heidermann

AlternateBraunschweiger Flammenfilter GIndustriestrasse 11Braunschweig, 38110 GermanyPrincipal: Michael Davies

M 10/23/2013EXL-AAA

Kirk W. Humbrecht

AlternatePhoenix Fire Systems, Inc.744 West Nebraska StreetFrankfort, IL 60423-1701Fire Suppression Systems AssociationPrincipal: Michael D. Hard

M 7/19/2002

EXL-AAA

Edward L. Jones

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

M 7/29/2005EXL-AAA

Jason Krbec

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

M 10/18/2011

EXL-AAA

John A. LeBlanc

AlternateFM Global1151 Boston-Providence TurnpikePO Box 9102Norwood, MA 02062-9102Principal: Henry L. Febo, Jr.

I 8/5/2009EXL-AAA

Gerd Ph. Mayer

AlternateRembe, Inc.3809 Beam Road, Suite KCharlotte, NC 28217Principal: Stefan Penno

M 03/05/2012

EXL-AAA

Keith McGuire

AlternateCST StoragePO Box 996Parsons, KS 67357Principal: David R. Stottmann

M 11/2/2006EXL-AAA

Timothy J. Myers

AlternateExponent, Inc.9 Strathmore RoadNatick, MA 01760-2418Principal: Alfonso F. Ibarreta

SE 10/20/2010

EXL-AAA

David M. Nieman

AlternateBechtel Corporation11720 Plaza America Drive, 10th FloorReston, VA 20190-4757Principal: Cleveland B. Skinker

SE 08/17/2015EXL-AAA

Alvin Grant Roach

AlternateProfessional Loss Control Inc.346 Queen Street, Suite 105Fredericton, NB E3B 1B2 CanadaPrincipal: Luke S. Morrison

SE 08/17/2015

3 of 22



EXL-AAA

Thomas C. Scherpa

AlternateThe DuPont Company, Inc.71 Valley RoadSullivan, NH 03445Principal: David D. Herrmann

U 8/9/2011EXL-AAA

Jef Snoeys

AlternateFike CorporationToekomstlaan 52Herentals, B-2200 BelgiumPrincipal: Jérôme R. Taveau

M 3/21/2006

EXL-AAA

James Kelly Thomas

AlternateBaker Engineering & Risk Consultants, Inc.3330 Oakwell Court, Suite 100San Antonio, TX 78218Principal: David C. Kirby

SE 8/9/2011EXL-AAA

Franz Alfert

Nonvoting MemberInburex ConsultingAugust-Thyssen-Str.1Hamm, D-59067 Germany

SE 7/29/2005

EXL-AAA

Laurence G. Britton

Nonvoting MemberProcess Safety Consultant848 Sherwood RoadCharleston, WV 25314

SE 1/1/1983EXL-AAA

Vladimir Molkov

Nonvoting MemberUniversity of UlsterFireSERT Institute(Block 27)Newtonwnabbey, BT37 0QB Northern Ireland, UK

SE 10/6/2000

EXL-AAA

Laura E. Montville

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

01/06/2015

4 of 22

letter_britton_103113lf.docx Helping Make Products Better ®

Larry Floyd BASF Corporation 1379 Ciba Road McIntosh, Alabama 36553 Telephone (251)436-2747 Fax (251)436-5044 Cell (251)591-2068 [email protected] www.basf.com/usa

October 31, 2013

RE: NFPA 69 2014, Tentative Interim Amendment (TIA)

Laurence G. Britton Process Safety Consultant 848 Sherwood Road Charleston, WV25314 USA Phone: 304-768-8244 [email protected]

Dear Larry,

You recently sent a number of e-mails to Sam Rodgers, Joe Senecal, and Bob Zalosh, members of the Explosion Protection Systems Committee (EXL-AAA).

First, I apologize for the delayed response. My day job prevented a more timely response.

Hopefully, I am correctly summarizing the concerns expressed in your e-mails:

Inerting safety factors for systems not continuously monitored with interlocks are too conservative. Modifications to the figure in A.7.7.2.7 are recommended (Ref. section 7.7.2.7 in the 2014 edition). [1]

Adjusted LOC values in NFPA 69 2008 version table Table C.1(a) that reflect a 2% absolute adjustment from "classical" LOC values are too conservative. You cite work by Zlochower, Green. [2]

The two requirements above will negatively impact existing processing.

NFPA 69 should incorporate an LOC mixture rule based on Le Chatelier’s formula. You again cite Zlochower, Green. [2]

Regarding impact on existing processes please note the 2014 edition requirements are not retroactive unless specifically noted. With respect to comments on LEL and LOC, I believe your comments have merit.

I spoke this afternoon to Barry Chase, our NFPA staff liaison, who confirmed that the closing date for a Notice of Intent to Make a Motion (NITMAM) was August 23, 2013. Therefore, any revisions will be to the 2014 version, which is to be published within a few weeks.

At this time the vehicle for revising the standard will be through the Tentative Interim Amendment (TIA) process. Section 5.1 from NFPA regulations document that describes the procedure is attached. The TIA submission is to include:

(a) The proposed text and/or modification or deletion of existing text.

(b) The technical justification

(c) Justification of the emergency nature of the TIA. What constitutes an emergency is defined in NFPA regulations document [3].

(d) The written agreement of two members of the EXL-AAA committee agreeing with the TIA submission.

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Letter_Britton_103113lf.docx Page 2 of 3

NFPA 69 2014, Tentative Interim Amendment (TIA)

The TIA is submitted to the Standards Secretary to be approved for processing. If approved, then the TIA will be balloted by the EXL-AAA committee for 1) technical merit, and 2) emergency nature.

Depending on the extent of your proposals, and judging from the content of your recent e-mails, I anticipate calling a meeting of the committee to discuss your recommendations prior to balloting. Given the subject matter of your concerns, multiple TIA may well facilitate the discussion and balloting process.

With respect to timing the TIA submission(s), please note that the next standards committee meeting is March 2014.

I am copying Sam, Joe and Bob with the intent of furthering technical discussions and identifying the two committee members who will support the TIA.

I look forward to hearing from you.

Best regards,

Larry D. Floyd BASF Member Process Safety CoE EXL-AAA Committee Chair

Cc: B. Chase, S. Rodgers, J. Senecal, R. Zalosh

attachments

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Letter_Britton_103113lf.docx Page 3 of 3

NFPA 69 2014, Tentative Interim Amendment (TIA)

“5.1 Content of a Proposed Tentative Interim Amendment. Each Tentative Interim Amendment (TIA) shall be submitted to the Standards Council Secretary and shall include the following:

a) Identification of the submitter and his or her affiliation (i.e., Technical Committee, organization, company), where appropriate

b) Identification of the NFPA Standard, edition of the NFPA Standard, and paragraph of the NFPA Standard to which the TIA is directed

c) Proposed text of the TIA, including the wording to be added, revised (and how revised), or deleted

d) Statement of the problem and substantiation for the TIA

e) The signature of the submitter or other means of authentication approved by the Standards Council Secretary

f) Statement of the basis of conclusion that the TIA is of an emergency nature requiring prompt action g) The written agreement of at least two members of the involved Technical Committee or Correlating

Committee to the processing of the TIA. The agreement to the processing of the TIA is for the sole purpose to allow the TIA to be processed and does not necessarily imply agreement with the merits or emergency nature of the TIA.”[3]

References

1. NFPA 69 2nd Draft 2014 Working Draft of Committee Meeting Output, Technical Committee on Explosion Protection Systems, Editor. 2008, National Fire Protection Association: Quincy, Massachusetts. p. 70.

2. Isaac A. Zlochower and Gregory M. Green, The limiting oxygen concentration and flammability limits of gases and gas mixtures. Journal of Loss Prevention in the Process Industries, 2009. 22(4): p. 499-505.

3. NFPA Policy, Regulations Governing the Development of NFPA Standards, in Regulations and Procedures. 2013, National Fire Protection Association: Quincy, Massachusetts. p. 25.

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tia_rodgers_050914lf.docx Helping Make Products Better ®

Larry Floyd BASF Corporation 1379 Ciba Road McIntosh, Alabama 36553 Telephone (251)436-2747 Fax (251)436-5044 Cell (251)591-2068 [email protected] www.basf.com/usa

May 13, 2014

RE: NFPA 68 (2013), Tentative Interim Amendments (TIA)

Barry D. Chase NFPA Staff Liaison 1 Batterymarch Park Quincy, MA 02169‐7471 Office: (617) 984‐7259 [email protected]

Dear Barry,

Sam Rodgers is recommending an edit and three TIAs:

Edits

1. Place §8.4 “Effects of Initially Elevated or Subatmospheric Pressure” before §8.2.5.

2. Label §8.2.5 “Effects of Turbulence”.

TIA 1: Eliminate §8.2.2.1 criteria

§8.2.2.1 “Equation 8.2.2 shall apply to initial pressures before ignition of 1 bar-abs ± 0.2 bar.”

Problem: In all pressure cases the initial vent area, Av0, must be calculated using equation 8.2.2:

Av0 is subsequently used in equation 8.4.1 in §8.4.1 to determine the vent area for pressures outside of the 1 bar-abs ± 0.2 bar:

Substantiation: The initial pressure limits imposed by §8.2.2.1 are no longer needed as adjustment for a pressure outside of the limits is now addressed in §8.4. §8.2.2.1 is a source of confusion and should be deleted.

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TIA_Rodgers_050914lf.docx Page 2 of 3

NFPA 68 (2013), Tentative Interim Amendments (TIA)

TIA 2 and 3: §7.2.1 and §7.2.6

1. Remove the default values for u, Gu, and b under 7.2.1, leaving the definitions of the terms. 2. Remove the definition for u under 7.2.6.1 because it is used already in 7.2.1 3. Remove the default values for u, and au under 7.2.6.1, leaving the definitions of the terms.

Add new paragraphs

1. 7.2.1.1* It shall be permitted to assume u = 1.2 for flammable gases with stoichiometric concentrations less than 5 vol% and an initial temperature of 20oC

2. A7.2.1.1 Parameters for gases and gas mixtures at various initial pressures and temperatures can be estimated using thermodynamic tools such as GASEQ and CHETAH.

3. 7.2.1.2 It shall be permitted to assume Gu = 230.1 kg/m2‐s for an enclosure initial temperature of

20oC

4. 7.2.1.3 It shall be permitted to assume b = 1.25 [this value is not as conservative as the original 1.1 – 1.2 range and should be discussed]

5. 7.2.6.1.2 It shall be permitted to assume u = 1.8E‐05 kg/m‐s for gas concentrations less than 5 vol% at ambient concentrations. (See also A7.2.1.1)

6. 7.6.1.2.3 It shall be permitted to assume au = 343 m/s for gas concentrations less than 5 vol% at ambient conditions (See also A7.2.1.1)

Best Regards,

Larry D. Floyd BASF Process Safety CoE NFPA EXL-AAA Committee Chair Cc: EXL-AAA Committee

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TIA_Rodgers_050914lf.docx Page 3 of 3

NFPA 68 (2013), Tentative Interim Amendments (TIA)

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Subject Fw: NFPA 68 Chapter 8 Vent Sizing Flow Issues

From Larry Floyd

To [email protected]

Sent Friday, April 18, 2014 9:31 AM

TIA_Rodgers_051314lf

Larry,Yes – I recommend this for a TIA due to the potential to prevent someone properly applying the vent equations. Av0 must always be calculated to always have an Av1, otherwise the chain falls apart. I also just noticed that there is a typo in paragraph 8.4.1 ‐‐‐ it should say Avep/Av1 to match the equation, not Avep/Av0.

Sam

From: "Rodgers, Sam (Process Safety)" <[email protected]>To: Larry Floyd <[email protected]>Date: 04/17/2014 09:23 AMSubject: FW: NFPA 68 Chapter 8 Vent Sizing Flow Issues

Possible TIA #1 to NFPA 68

From: Rodgers, Sam (Process Safety) Sent: Tuesday, September 03, 2013 10:18 AMTo: 'Jason Krbec'Cc: Bill Stevenson; 'Larry Floyd'; [email protected]: RE: NFPA 68 Chapter 8 Vent Sizing Flow Issues

Jason,I agree with you. We need Av0 in all cases. 8.2.2.1 should be eliminated now that we apply section 8.4 all the time. Paragraph 8.4.5 takes us back to Avep=Av1 if we are in the +0.2 bar initial pressure range.

Larry,The removal of 8.2.2.1 is a potential TIA due to confusion in applications. If you are keeping track of such things, maybe we could have a meeting to discuss errors noted and then consider which ones need a TIA developed. There are some questions about 67 and well as 69 that we could discuss.

We did not feel we had the time to re‐order the chapter at the last meeting, but section 8.4 should be placed before 8.2.5 and I would recommend we label section 8.2.5 to indicate it is “Effects of Turbulence”.

Regards,Sam

From: Jason Krbec [mailto:[email protected]] Sent: Tuesday, September 03, 2013 8:48 AMTo: Rodgers, Sam (Process Safety)Cc: Bill StevensonSubject: NFPA 68 Chapter 8 Vent Sizing Flow Issues

Sam,

One of our engineers came to me with an issue regarding the flow and limitations in Chapter 8 of NFPA 68. The issue centers around the requirement in 8.2.2.1 that limits the applicability of equation 8.2.2.

I attached some notes from my engineer. I spoke with him and was able to explain the process that should be followed. However, after reviewing the document I am in agreement that either 8.2.2.1 should be eliminated or reworded otherwise you cannot apply 8.2.2 which prevents you from developing an Av1 which is required to calculate 8.4.1 for initially elevated or subatmospheric pressures.

When you get a chance please look at this and let us know your thoughts.

Best Regards,

Jason KrbecEngineering Manager

NFPA 68 TIA 1 (S. Rodgers)Friday, April 18, 201412:45 PM

NFPA 68 Page 1

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North America

CV Technology, Inc.15852 Mercantile CourtJupiter, Florida 33478Direct: 561‐318‐4051Main: 561‐694‐9588Mobile: 727‐460‐5519Fax: 561‐694‐9585E‐mail: [email protected]: www.cvtechnology.com

Come visit CV Technology, Inc. at the PTXi show in Houston!!!

This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This message contains confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e‐mail. Please notify the sender immediately by e‐mail if you have received this e‐mail by mistake and delete this e‐mail from your system. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited.

NFPA 68 Page 2

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Subject Fw: NFPA 68 2013 Spreadsheet Update

From Larry Floyd


Sent Friday, April 18, 2014 10:42 AM

Possible TIA #2 and #3 to NFPA 68

From: Rodgers, Sam (Process Safety) Sent: Wednesday, January 15, 2014 9:18 AMTo: Larry Floyd ([email protected])Cc: 'Bill Stevenson'; Tom Scherpa; 'Walter Frank'; Zalosh, Bob ([email protected]); Erdem A. Ural; Bitter, Robert-1Subject: NFPA 68 2013 Spreadsheet Update

Larry,I am sharing my spreadsheet solving the 2013 equations as well as a couple concerns with the current gas equation system. My first concern is that we have a cut‐off for vent release velocity based on a ratio of Pred to Pa. The formula for the velocity is not the issue, rather that the cut‐off based on the Pred/Pa ratio can result in a velocity exceeding the speed of sound. We should have a TIA to correct the formula.

Recommend changing to

Subject RE: NFPA 68 TIA 2, 3: 2013 Spreadsheet Update, Section 7.2.6

From Rodgers, Sam (Process Safety)

To Larry Floyd

Sent Friday, April 25, 2014 5:05 PM

My actual proposal for the ability to adjust gas values is:

Remove the default values for u, Gu, and b under 7.2.1, leaving the definitions of the terms.

Remove the definition for u under 7.2.6.1 because it is used already in 7.2.1Remove the default values for u, and au under 7.2.6.1, leaving the definitions of the terms.

Add new paragraphs

7.2.1.1* It shall be permitted to assume u = 1.2 for flammable gases with stoichiometric concentrations less than 5 vol% and an initial temperature of 20 CA7.2.1.1 Parameters for gases and gas mixtures at various initial pressures and temperatures can be estimated using thermodynamic tools such as GASEQ and CHETAH.7.2.1.2 It shall be permitted to assume Gu = 230.1 kg/m2‐s for an enclosure initial temperature of 20 C.

7.2.1.3 It shall be permitted to assume b = 1.25 [this value is not as conservative as the original 1.1‐1.2 range and should be discussed]

7.2.6.1.2 It shall be permitted to assume u = 1.8E‐05 kg/m‐s for gass concentrations less than 5 vol% at ambient concentrations. (See also A7.2.1.1)7.6.1.2.3 It shall be permitted to assume au = 343 m/s for gas concentrations less than 5 vol% at ambient conditions (See also A7.2.1.1)

From: Larry Floyd [mailto:[email protected]] Sent: Friday, April 25, 2014 5:32 PMTo: Rodgers, Sam (Process Safety)Subject: NFPA 68 TIA 2, 3: 2013 Spreadsheet Update, Section 7.2.6

Sam,TIA’s 2 and 3.Larry

TIA_Rodgers_051314lf

NFPA 68 TIA 2, 3: 2013 Spreadsheet Update, Section 7.2.1, 7.2.6 (Sam Rodgers)Friday, April 18, 20142:16 PM

NFPA 68 Page 3

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My second concern is that the heat capacity ratio for burnt gas is indicated as 1.1‐1.2. GASEQ shows that adiabatic combustion at constant P or V yields a value of closer to 1.25. This yields smaller vent areas and could be a better choice for a permitted value.

Lastly there have been multiple questions about adjusting the permitted values for the gas parameters with increased initial temperature or pressure. I added a tab to provide a method for this adjustment, but the standard does not give any guidance for adjustment. It would be helpful to formally permit adjustment of the parameters for the gas mixture (burned/unburnt).

Feel free to share with the entire Explosion Protection committee, if desired.

Sam[attachment "oledata.mso" deleted by Larry Floyd/NA/BASF] [attachment "image004.wmz" deleted by Larry Floyd/NA/BASF] [attachment "image007.wmz" deleted by Larry Floyd/NA/BASF] [attachment "NFPA 68 2013 Revised 20140112.xlsx" deleted by Larry Floyd/NA/BASF]

NFPA 68 Page 4

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Subject Fw: NFPA 68 (2013), Tentative Interim Amendments (TIA)

From Larry Floyd


Sent Friday, May 16, 2014 1:59 PM

Attachments

From: "Rodgers, Sam (Process Safety)" <[email protected]> Date: 05/16/2014 01:49 PM Subject: RE: NFPA 68 (2013), Tentative Interim Amendments (TIA)

All,If time permits, I would also like to recommend a TIA to change equation 7.2.6.1e to be more appropriate. The current equation for vent velocity can result in velocity exceeding the speed of sound because of the approximate cut‐off based on Pred vs 0.9 bar‐g. As vent velocity goes up so does vent Reynolds number and flame enhancement, thus this leads to larger vent area than necessary.

Sam

Current Equation

Proposed Equation

The above equation has Pa in bar‐g, so it is normally ~0.

OR (assumes ambient at vent is always 0 bar‐g)

From: Larry Floyd [mailto:[email protected]] Sent: Tuesday, May 13, 2014 4:57 PMTo: Chase, BarryCc: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; Rodgers, Sam (Process Safety); [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; john.leblanc%[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]: NFPA 68 (2013), Tentative Interim Amendments (TIA)

Hello Barry,

See attached for recommended TIA to be discussed on 5/19.

Larry

Larry FloydSenior Process Safety SpecialistPhone: (251)436-2747, Mobile: (251)591-2068, E-Mail: [email protected] Address: 1379 Ciba Road, McIntosh, AL 36553BASF, The Chemical CompanyIf you think safety is expensive, try an accident. T. Kletz

NFPA 68 TIA 3 (4), change equation 7.2.6.1eFriday, May 16, 20143:09 PM

NFPA 68 Page 5

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7/31/2014 2:13 PM During CMD‐HAP A2016 meeting Brice Chastain reported on an incident at Georgia Pacific that resulted in two fatalities and multiple injuries resulting from a dust collector venting during a fire event. The personnel fatally injured were emergency responders. He believes that the fireball equations in NFPA 68 may not be sufficiently conservative. That is, the radiant heat flux extended past the radius determined by the NFPA 68 fireball equation that is based on research done by Holbrow, "1. Paul Holbrow, Stuart J. Hawksworth, and Alan Tyldesley, Thermal radiation from vented dust explosions. Journal of Loss Prevention in the Process Industries, 2000. 13(6): p. 467‐476."

Bill Stevenson's advice is to keep people 90ft away from the axial vented area.

From NFPA 68, 7.7 is for vapors, gases and mists,

NFPA 8.9.2 gives fireball dimensions for a dust deflagration

NFPA 68 TIA 4, Fireball EquationThursday, July 31, 20142:12 PM

NFPA 68 Page 6

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Subject Fw: Paragraph 8.5.5

From Larry Floyd


Sent Thursday, August 21, 2014 1:43 PM

Luke,We were initially correct that this paragraph should not prohibit use of the vent duct correction for sub‐atmospheric pressures. The ROC record discusses the addition of sub‐atmospheric pressure and the real concern. Henry Febo object to the sub‐atmospheric correction in the voting saying that this technology was not demonstrated and that venting could actually occur at ambient conditions. His comment reminded me that the real issue for sub‐atmospheric venting is that there is a peak around ‐0.4 bar where the vent area requirement is higher than at atmospheric. Since we know the limits of the sub‐atmospheric correction, at least theoretically, we felt comfortable adding a maximum 10% vent area as a result. We do not have data to substantiate using the vent duct correction along with elevated pressure.

8.4.2 accounted for the peak by saying that for sub‐atmospheric always use the largest factor over the pressure range from operating to ambient, thus including the peak. 8.4.3 also permits just using a 1.1 factor for sub‐atmospheric venting as this is the maximum value. And 8.4.4 says for greater than 0.2 bar there are extra restrictions, specifically vent duct L/D < 1.

All of these are in agreement with Table 8.5.10. Thus Paragraph 8.5.5 is inconsistent and incorrect. It should be:

8.5.5 Equation 8.5.1a shall not be used if the initial pressure exceeds +0.2 barg. [It should NOT be + 0.2 barg]

We forgot to update this paragraph when we added sub‐atmospheric pressure.

Larry – This should be another item for our TIA, because it incorrectly prevents use of the vent duct equations for sub‐atmospheric conditions.

Barry – Luke has somehow gotten removed from the committee list in all three of our documents. Hopefully you can correct this computer glitch.

Best Regards,Sam

08/21/14 TIA, NFPA 68 Paragraph 8.5.5Friday, August 22, 20148:20 AM

NFPA 68 Page 7

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Interoffice Correspondence Colonial Heights, VA

Date: February 19, 2015 From: Samuel Rodgers

Organization: SM Process Safety Engineering

Subject: Proposal for NFPA 68 and 69 TIAson Metal Dusts Location: Technical Center

Mail Stop: 15801 Woods Edge Road To: Larry Floyd Telephone: (804) 520-3706

Fax: (804) 520-

A presentation by Scott Davis of Gexcon illustrated failure of deflagration venting of metal dusts sized on the basis of NFPA-68. The failure was particularly worse for metals with higher burning temperatures and generally adequate for lower burning temperature metal dusts. Additionally it was noted that vent duct predictions were similarly inadequate for hotter burning metal dusts.

Bob Zalosh previously presented information to the committee on the higher KSt exhibited by hotter burning metal dusts in the 1 m3 sphere vs the 20 L sphere, this being the reverse of the trend for organic dusts. Evidence has also been presented to the committee that certain metal dusts present challenges to isolation and suppression systems beyond the common effects of KSt and Pmax.

Given the growing body of work showing incomplete accounting for the effects of metal dust deflagrations, it is recommended that TIA be processed for NFPA 68 to warn of this dangerous situation and provide guidance on testing metal dusts and using the sizing equations until more information is available.

The recommended change to NFPA 68, 8.5.5 is for consistency with the permission of vent ducts for initially sub-atmospheric conditions in Table 8.5.10. It is recommended because the prohibition of vent ducts for initially sub-atmospheric conditions results in an unnecessary business burden and was not intended by the committee.

NFPA 68 TIA Proposal

6.1.2* For dusts, KSt and Pmax shall be determined in approximately spherical calibrated test vessels of at least 20 L capacity per ASTM E 1226, Standard Test Method for Explosibility of Dust Clouds. 6.1.2.1* It shall be permitted to determine KSt and Pmax per ISO 6184/1, Explosion Protection Systems — Part 1: Determination of Explosion Indices of Combustible Dusts in Air. 6.1.2.2 The owner/user shall be permitted to test the dust with moisture content and particle size that deviates from the recommended conditions established by the method described in 6.1.2 or 6.1.2.1, provided a documented assessment acceptable to the authority having jurisdiction has been performed prior to using these KSt and Pmax values to determine vent sizing.

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6.1.2.3* For metal dusts KSt and Pmax shall be determined in both nominal 20 L and 1 m3 calibrated test vessels. A6.1.2.3 Recent testing has shown that certain metal dusts exhibit KSt and Pmax values that are significantly larger in 1 m3 tests than in 20 L tests, the difference increasing with adiabatic flame temperature. Until more information is available, testing in both standard test vessels is intended to provide additional confidence in application of the design methods. 6.1.2.3.1 Testing shall be in accordance with the same test method in both cases, either ASTM E 1226, 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. 6.1.2.3.2* KSt and Pmax values for metal dusts used in this standard shall be the larger of the individual values determined in the two different sized vessels. A6.1.2.3.2 Where both the KSt and Pmax values are higher in the larger 1 m3 calibrated test vessel and the enclosure to be protected is larger than 1 m3, the owner/user should consider vent sizing based on full-scale testing.

8.5.4 Equation 8.5.1a shall not be used if the vent cover is not located at the entrance of the duct. 8.5.5 Equation 8.5.1a shall not be used if the initial pressure exceeds ±0.2 bar-g +0.2 bar-g. 8.5.6 Equation 8.5.1a shall not be used if the vent duct crosssectional area varies by more than 10 percent anywhere along the length. 8.5.7* Equation 8.5.1a shall not be used for metal dusts with adiabatic flame temperature exceeding 2500 K. A.8.5.7 Equation 8.5.1a can be applied for metal dusts with flame temperatures equivalent to iron or lower. This does not mean that vent ducts cannot be used with metal dusts (see 8.5.9). 8.5.7 8.5.8 It shall be permitted to use Equation 8.5.1a for vent ducts equipped with elbows, bird screens, and rain covers as long as the obstructions are properly accounted for through the duct resistance coefficient K. 8.5.8 8.5.9 It shall be permitted to use vent ducts outside the limitations of Equation 8.5.1(a) if designed in accordance with full-scale test data. Renumber subsequent.

NFPA 69 TIA Proposal

Add ASTM E 1226 and ISO 6184/1 to section 2.3.3 and 2.3.4 references, respectively.

6.2 Limitations. The limitations specific to each method shall be considered and are specified in the corresponding chapter for each method. 6.2.1* When using the techniques of Chapters 10, 11, 12 or 13 or of NFPA 68, Standard on Explosion Protection by Deflagration Venting, for metal dusts, KSt and Pmax shall be determined in both nominal 20 L and 1 m3 calibrated test vessels. A6.2.1 Recent testing has shown that certain metal dusts exhibit KSt and Pmax values that are significantly larger in 1 m3 tests than in 20 L tests, the difference increasing with adiabatic flame temperature. Until more information is available, testing in both standard test vessels is intended to provide additional confidence in application of the design methods.

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6.2.1.1 Testing shall be in accordance with the same test method in both cases, either ASTM E 1226, 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. 6.2.1.2* KSt and Pmax values for metal dusts used in this standard shall be the larger of the individual values determined in the two different sized vessels. A6.2.1.2 Where both the KSt and Pmax values are higher in the larger 1 m3 calibrated test vessel and the enclosure to be protected is larger than 1 m3, the owner/user should consider protection based on full-scale testing. 6.2.2 When using the techniques of Chapters 10, 11 or 12 where metal dusts are involved, the system design methodology shall include testing using a metal dust having an adiabatic flame temperature the same or higher than the relevant dust.

Samuel A. Rodgers Process Safety Ldr PMT cc:

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