toj.j. - nfpa · 2010-06-22 · bed ~ and pr.opmes for adoption amendments on nfpa 8504- 19c~,...

Report of the Committee on

Boiler Combustion System Hazards

Technical CorrelafiRg Comminee

Dale E. Dremel, Chair Monsanto Co., MO

Courmey D. Alvey, Lutherville, MD W'dliam H. Axtmaa, Gray Gull Assoc.. Inc., VA ohnay W. ( B m ~ m , Forney Int'l Inc., TX

Bos~k, Bailey Controls Co., OH us Bukowski, Underwriters Laboratories Inc., [L

Paul L. Cioffi, Babcock & Wilcox, OH WiUtam E. Cuaaingham,Jr., Raytheon Engr & Consu~ctors, MA John C. deRuyter, The DuPont Co., DE Robert S. ~ Kemper Nat I Insurance Cos., OH Ronald E. I~riagell, M&M Protec~on Consultants, OH MusaakiKinos~im, Mitsubishi Heavy Industries Ltd, Japan James g. Lafomalne, Pennsylvania ElectriC, PA DomddJ. L. Lin, Q~lin Inc., TX FrancisX. Mmkol, Honeywell Inc., PA Peter B. Matthews, Hartford Steam Boiler Imp & Ins Co., CT Russell N. Mosher, American Boiler IVlf~. Assn., VA

J. Moskal, ABB Combustion Engr, Inc., CT L Sherman, Baltimore Gas & Electric Co., MD

bert F. Tomc~ak, Tampa Electric Co., FL Rep. Electric Light Power Group/Edison Electric Inst.

PeterJ. Gore W'dlse, Industrial Risk Insurers, CT Rep. Industrial Risk Insurers

Henry K. Wong, Foster Wheeler Energy Corp., NJ

Alternates

Temuya Fujino, Mitsubbhi Heavy Industries America, Inc., CA (Alt. to M. Kinoshita)

Gordon G. Gaetke, Union Carbide Chemicats & Plastics Inc., WV (Vot. Alt. to UCCP Pep.)

/ Dennis P. Jenkins, Kemper Nat'i Insurance Cos., NC (Alt. to P,. S. Elek) " .

Kenneth N. Lawrence, Honeywell Inc., PA (Alt. to F. X. Maskol)

W. Scott Matz, Fomey lnt'l Inc., "IX (Alt. tO.]. W. Bass)

Richard F. Murphy, Exxon Research & Engr, Co., (Vot. Alt. to API Rep.)

John P. O'Rourke, ABB Combustion Engr, Inc., CT (Ale toJ.J. Moskal)

S. Sam P/~gadala, M&M Protection Consultan~ IL (Alt. tO l~ F-. Fringeli)

RichardJ. Wachter, Industrial Risk Insurers. CT (Alt. to P.J.G. Willse)

J. C. Waung, Babcock & Wilcox Co., OH (AlL tO P. L. Cioffi)

Nonvoting

Shelton Ehrlich, Palo Alto, CA Thomas B. Hamilton, Hamilton Consulting Services, NC Robert M. Lundberg, Los Altos, CA, Michael C. Polagye, Factory Mutual Research Corp., MA

Committee Scope: This Committee shall have primary responsibib ity for documents coveting the reduction of combustion system hazards in single and multiple burner boilers with a heat input rate of 12~500,000 Btu/hr and above. This indudes all fuels. Also respons~le for documents covering the reduction of hazards in pulverized fuel systems, fluidized bed boilers, heat recovery steam generators, and stoker]fired boilers, at any heat input rate.

Technical Committee on

Fluidized Bed Boilers

Shelton Ehrlich, Chair Palo Alto, CA

W'dllam H. Axtman, Gray Gull Assoc., Inc., VA David D. Cole, Texas-New Mexico Power Co., TX Arnold (Red) Coared, Nova Scotia Power Corp., Canada .[oselph N. _Dmgam~ Sargent & Lundy, IL ]robert IL Eag, Foster W~eeler Energy Corp., NJ

307

Robert Fleck, Montana-Dako~ Utifities, ND ~ . Geackea , Stone & Webster Engr, Corp., MA

O. Gold~ch, Combustion Powe~ Co., CA RobertM. Hemd~ma, ABB Combustion Engr, CT DonaldJ. gaotah Black & Veatch, MO David I2 Kraft, Babcock & W'dcox 05., OH James K. Lafontaiae, Penmytvania Electric, PA Leonard L Htde, Riley Stoker Corp., MA Donald L. Lueckenotte, Burns & McDonnell, MO Peter B. Mmdaemh Hartford Steam Boiler Imp & Ins Co., CT Thomm M. Mcgee, U.S. Generaeng Co., MD Bobert H. Melvia, AC Power ACE Operation, CA Thomas Modradk, Raytheon Engr and Constructors, PA Russell N. Mosher, American Boiler Mfrs. Assn., VA Johu A. Nero, IBEW, MN

Int'l Brotherhood of Electrical Workers O'l~'ies, Tennessee Valley Authority, AL

eel C. Polwffe, Factory Mutual Research Corp., MA Robert S. ItJmd,-Bailey Cone~ols, OH

L. ~ , Ahbtrom Pyropower Corp., CA re terJ . Gore WHIm, Indusuial Risk Insurers, CT

Rep.~mdnstrial Risk Insurers James M. W'm, Jr., Southern Co. Services Inc, AL

Alternates

ThomusJ. ~ Electric Power Research hast., NC (Ah.to $. Elfi4ich)

Douglm J. Campbei~ Nova Scotia Power, (AlL to A. Conrod)

Joe Comim, Tennessee Valley Authority, KY (Alt.to W. B. O'Brien)

Steven L. gdward~ Black & Veatch, MO (Alum D.J. Knom)

Blair E. ~ , Riley Stoker Corp., MA (Alt. to L. E. Little)

(C~t.F.. Normaa, ABB CombmtionEngr, CT to R. M. Herdman)

JamesJ. Utt, Ahlstrom Pyropuwer, CA (Alt to D. L Wletzke)

Staff Liaison, Merton W. ~ k - ~ , Jr.

~on t&~ao/t~sa~6oL S/n~Jhat t/~ cha,~sin ~s~rsh/p may haw o~-urr~

Committee Scope: This Committee shall have primary responsibil- ity for documents covering the operation and re~iuction of combustion sy~..em hazards and ~e orevention of boiler furn~, e explosions offlmdized bed boilers. This indudes all fuels at any heat input rate.

The Report of the Technical Committee Report of the Committee on Boiler Combustion System Hazard is presented for adoption.

This Report was prepared by the Techakal Committee on Fluidized Bed ~ and pr.opmes for adoption amendments on NFPA 8504- 19c~, &umdanl me Aimogpherie lquidtzed-Bed Boiler Olmmdon. NFPA 8504-1995 is published in Volume 9 of the 1995 National Fire Codes and in separate pamphlet form.

This Report has been submitted to letter ballot of the Teclmical Committee 6u Fluldized lied Boilers, which consists of 27 voting members. Ttie results of the balloting can be found in the report.

Mr. Rand voted altimmtive on all proposals with the following comment:

"At the March 6, 1995 meeting.., I pro p ~ that Sections 7-8 and 8-8 be deleted from this standard because th~ey are inappropriate for application to fluidized-bed boilers and are uns~e for use on ffmdized-bed boilers that are ot~ecated-from control robras. The committee rejected my propos/d. However, the letter ballot does not indicate this gction.

I have determined that the NFPA 8502 committee has taken strong action on these sections and believe pay~proposal should be revisitea. Refer to NFPA 8502, A95 ROP (Log #172), page 124 and 125. As a minimum, we should adopt the position of NFPA 8502,

"Section 6-8 shall not beappliedto new construction, Section 6-8 shall apply to existing boil-e/s with boiler frout control and to alterations to manuaT boilers." (Same for Section 7-8)."

This Report has also been submitted to letter ballot of the Teclmical Correlating Committee on Boiler Combustion System Hazards which consists of 24 voting members; of whom 17 voted affirmatively and 7 ballots were not returned (Messrs. Ciol~, Cunningham, Lafontaine, Moskal, Murphy, Tomczak, and W'dlse).

N F P A 8 5 0 4 - - A 9 6 R O P

(Log #36) 8504- 1 - (Title): Reject SUBMITrER: Shelton Ehrlich, Ehrlich Assodates RECOMMENDATION: NFPA 8504 Standard on : . t , , w v L ~ , ~ Fluidized-Bed Boiler Operation. SUBSTANTIATION: The 1993 edition of 8504 did not discuss combustion hazards that are peculiar to pressurized fluidized bed combustion (PFBC) systems. Thejnst if icat ion for the proposed new text is: 1. Several PFBC plants are now in operation and several are being constructed. More PFBCs are anticipated to be constructed. Anecdotal evidence exists on the problems discussed in this proposal. For example, t h e r e has been at least one i n d d e n t in which a fuel line failure led to a back flow of red hot solids which then contacted the fuel also escaping f rom the ruptured fuel line. While no explosion occurred the wording. COMMITTEE ACTION: Reject. COMMITIT, E STATEMENT: It is ne i ther timely nor appropriate to include Pressurized Huidized Bed Boilers in this standard. NUMBER OF COMMI'FIT.,E MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMrITEE ACTION:

AFFIRMATIVE: 19 NOT RETURNED: 8 Axtman, Conrod, Darguzas, Goldbach,

Knotts, Matthews, McKee, O'Brien

(Log #37) 8504- 2 - (1-1.1): Reject SUBMITTER: Shelton Ehrlich, Ehrlich Associates RECOMMENDATION: 1-1.1 This standard applies to boilers with a fuel input rating of 12,500,000 B tu /h r (3663 kW) or greater. This standard applies only to boilers using ,,t,;,G~t,i,~, ~ fluidized bed combustion. SUBSTANTIATION: The 1993 edition of 8504 did not discuss combustion hazards that are peculiar to pressurized fluidized bed combustion (PFBC) systems. The justification for the proposed new text is: 1. Several PFBC plants are now in Operation and several are being constructed. More PFBCs are anticipated to be constructed. Anecdotal evidence exists on the problems discussed in this proposal. For example, there has been at least one incident in which a fuel line failure led to a back flow of red hot solids which then contacted the fuel also escaping f rom the ruptured fuel line. While no explosion occurred the wording. COMMITIT, E ACTION: Reject. COMMITTEE STATEMENT: It is ne i ther timely nor appropriate to include Pressurized Fluidized Bed Boilers in this standard. NUMBER OF COMMITIT.E MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:


Knotts, Mao_hews, Mcgee, O'Brien

(Log #33) 8504- 3 - (1-1.4): Reject SUBMITTER: Robert M. Herdman, ABB Combustion Engineering RECOMMENDATION: Revise text as follows:

1-1.4" This standard is no t retroactive. This s tandard is applicable to new installations, and to major alterations or extensions that are contracted subsequent to the effective date of this standard. A-l-l .4 In existing units, it is not always practical to strictly apply

the provisions of this standard. Physical limitations may require disproport ionate effort or expense with little increase in protection. In such cases, the Authority Having Jurisdiction must be satisfied that reasonable protect ion is assured.

In existing units it is in tended that any condit ion that represents a serious boiler combustion system hazard be mitigated by application of appropriate safeguards. It is not in tended to require modification for conditions that do no t represent a significant threat, even though such conditions are not literally in conformance with these requirements. SUBSTANTIATION: Provide additional definition of "Major Alteration". COMMI'VrEE ACTION: Reject. C O M M I ~ STATEMEN'I~: The proposal was offered to conform to changes being proposed in NFPA 8502 (85C) but the existing language in the current edit ion of NFPA 8504 is clear and adequate. NUMBER OF C O M M I ~ MEMBERS ELIGIBLE TO VOTE: 97 VOTE ON COMMITTEE ACTION:



(Log #1 ) 8504- 4 - (2-9.8(g) (New)): Reject Note: This proposal appeared as comment 85H (8504)-47 which

was he ld for fur ther study f rom the Annum 93 TGD, which was on

~ roposal 85H (8504)-12. UBMITrER: Robert M. Lundberg, Los Altos, CA

RECOMMENDATION: Add new text as follows: "Steam can at operating bed temperatures initiate gasification

reactions within the bed." SUI~TANTIATION: The reactions due to tube leaks can cause both exothermic and endothermic reactions that are capable of unit destructions.

Such reactions were utilized commercially to produce hydrogen. COMMITrEE ACTION: Reject. COMMrrrEE STATEMENT: Gasification reactions are theoreti- cally possible within an operat ing FBC that is operating with a normal charge of carbon within the bed. However, the concentration of carbon in the bed is usually in the 0.1 percent to 1 percent range. In purpose-built fluidized bed gasifiers, the concentrat ion is in the range of 10 percent to 50 percen t

Tube leaks have occurred within FBC's equipped with CO and hydrocarbon detectors. There are no reports of near explosive concentrat ions of CO and hydrocarbons from these plants.

The caution in 2-9.8(c) adequately covers the avoidance of high carbon loading in beds. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:



(Log #38) 8504- 5 - (2-10 (New)): Reject S U B b l I ~ Shelton Ehflich, Ehrlich Associates RECOMMENDATION: 2-10 Pressurized Huidlzed-Bed Combus- tion---Special Hazards

(a) Pressurized system components are subject to rapid corrosion where certain conditions obtain: relatively high SO9 concentration and relatively cool metal temperatures. The reaction, SO 2 + 1/9 0 2 > SO3 is favored by high pressure (and the high excess 02 typical of part load operation), ff a pressure boundary metal surface is cool, as in a startup, sulfuric acid could condense on the meta l surface and initiate a rapid chemical attack. •

(b) Some PFBC plants use coaxial piping for the hot air and hot gas flowing from and to the pressure vessel. Failure of the internal insulation in the pipe filled with high pressure gas at near 1,500°F may cause the p ipe to fail.

(c) Failure of a coal feed line may lead to substantial back flow of hot solids from the pressurized bed while coal also flows out of the break.

(d) Sophisticated controls systems are required to coordinate the safe startup, normal operation, normal shutdown and emergency shutdown of the combustion process, the steam turbine a n d t h e gas turbine. SUBSTANTIATION: The 1993 edition of 8504 did no t discuss combustion hazards that are peculiar to pressurized fluidized bed combustion (PFBC) systems. The justification for the proposed new text is: 1. Several PFBC plants are now in operation and several are being constructed. More PFBCs are anticipated to be constructed. Anecdotal evidence exists on the problems discussed in this PwhrOposal. For example, there has been at least one incident in

ich a fuel line failure led to a back flow of red hot solids which then contacted the fuel also escaping f rom the ruptured fuel line. While no explosion occurred the wording. COMMITrEE ACTION: Reject. COMMITTEE STATEMENT: It is nei ther timely nor appropriate to

• include Pressurized Fluidized Bed Boilers in this standard. NUMBER OF COMMIT'IT, E MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:


Knotts, Mauhews, McKee, O'Brien

(Log #24) 8504- 6 - (3-1 Alteration, Extension, Repair (New)): Accept in Principle SUBMITrER: Robert M. Herdman, ABB Combustion Engineering RECOMMENDATION: Add new definitions as follows:

Alteration. A change or modification in a boiler system or subsystem that results in a deviation from the original design specifications or criteria.

308

N F P A 8 5 0 4 m A 9 6 R O P

Extension. An addi t ion to the boiler system or addit ional t subsystems such as, bu t not l imited to, air quality control.

i Rel)air. A process that re turns the boiler system or subsystem to its original design specifications or criteria. SUBSTANTIATION: The addit ion of these definit ions is also relevant to NFPA 8504 and provides consistency between these documents . COMMI1~rEE ACTION: Accept in Principle.

Add new definit ions as follows: Alteration. A change e r modification in a boiler system or

subsystem flaat results in a deviation f rom the original design specifications or criteria.

Extension. An addit ion to the boiler system or additional subsystems.

Repair. A process that re turns the boiler system or subsystem to its original design specifications or criteria. COMMITI 'EE STATEMENT: Examples in the definit ion of "extension" were removed because they were inappropriate for FBC's. NUMBER OF COMMI'Iq'EE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVE: 18 NEGATIVE: 1 N O T RETURNED: 8 ~Mitman, Conrod, Darguzas, Goldbach,

Knotts, Matthews, McKee, O 'Br ien EXPLANATION OF NEGATIVE:

COLE: The defini t ions in Proposal 8504-6 do no t add any clarity to the text in 1-1.4 bu t rather increase the possibility of confusion in interpretat ion.

Often the "...original design specifications or criteria." is no t a per t inent descript ion o f the "as built" plant. [

The text in 1-1.4 presendy includes "..-.existing e q u i p m e n t for the I preparat ion and bu rn ing of fuel...", the phrase "boiler system or subsystem" in he definit ions is a broader-s ta tement and could include sys tems/subsystems that are not within the scope of the p resen t wording.

Additionally, commit tee action on proposal 8504-3, a rejection , was substanf ia tedwith the s t a tement "...the e- xisting l anguag6 in the cur ren t edit ion of NFPA 8504 is clear and adequate . ' . Why add to what has been d e e m e d "clear and adequate" in ano the r proposal that addresses the same :article.

(Log #2) 8504- 7 - (3-1 Ambien t Tempera tu re (New)): Accept in Principle Note: This proposal appea red as c o m m e n t 85H (8504)-52 which

was he ld for fur ther study f rom the Annua l 93 TCD, which was on

~ roposal 85H (8504)-12. UBMITTER: Robert Herdman, ABB Combust ion Engineer ing

RECOMMENDATION: Add definit ion of: Ambien t Tempera ture . T he design air t empera ture of the plant, as

def ined by the purchaser , the manufacturer , and the "authori ty havingjurisdicfion." SUBSTANTIATION: AJa a s sumed value for ambien t tempera ture is required in many s ta tements o f this s tandard. A definit ion of what value dais represents is therefore required. COMM]TYEEACTION: Accept in Principle. COMMITTEE STATEMENT: Refer to Commit tee Action and Sta tement on Proposal 8504-11 (LOg #25). NUMBER OF COMMITYEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVE: 19 N O T RETURNED: 8 Axtman, Conrod, Darguzas, Goldbach,

Knotts, Matthews, McKee, O 'Br ien

(Log #39) 8504- 8 - (3-1 Atmospher ic Fluidized Bed Combust ion, Pressurized Fluidized Bed Combus t ion (New)): Accept in Part SUBMITTER: Shel ton Ehrlich, Ehrlich Associates RECOMlVIENDATION: 3-1 Definit ions

Atmospher ic Fluidized Bed Combust ion. Fuel firing technique us ing a t luidized bed opera t ing at nea r a tmospher ic pressure on the fire side.

Pressurized Fluidized Bed Combust ion. Fuel f ir ing technique us ing a fluidized bed opera t ing at elevated pressure on die fire side. SUBSTANTIATION: The 1993 edition of 8504 did no t discuss combust ion hazards tha t are peculiar to pressurized fluidized bed combust ion (PFBC) systems. -The justif ication for the proposed new text is: 1. Several PFBC plants are now in opera t ion and several are being constructed. Moth. PFBCs are anticip-ated to be constructed. Anecdotal evidence exists on the p rob lems discussed in this proposal. For example, there has been at least one inc ident in whic- h a fuel line failure led to a back flow of red hot solids which then contacted the fuel also escaping f rom the rup tured fuel line. While no explosion occurred the wording.

309

COMIVIITTEE ACTION: Accept in Part. Add a new definit ion as follows: Atmospher ic Fluidized Bed Combust ion. Fuel f ir ing technique

us ing a fluidized bed opera t ing at near a tmospher ic pressure on the fire side. COMMITrEE STATEMENT: The definit ion of Pressurized Huidized Bed Boilers is unnecessary, because it is beyond the scope of this standard. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVE: 19 N O T RETURNED: 8 Axtrnan, Conrod, Darguzas, Goldbach,


(Log #3) 8504- 9 - (3-1 Loop Seal (New)): Accept in Principle Note: This proposal appeared as c o m m e n t 85H (8504)-89 which

was he ld for fur ther study f rom the Annual 93 TCD, which was on

~ roposal 85H (8504)-12. UBM]TTER: Peter Matthews, Hartford Steam Boiler

RECOMMENDATION: Definition for Loop Seal n e e d e d such as: "U o r J shaped device tha t conducts solids f rom the bot tom of the

cyclone back to the furnace and acts as a pressure seal." SUBSTANTIATION: I want to recognize a loop seal as men t ion of accumula t ion of material with blockage needs to be men t ioned in Appendix or text. See later comment . COMMITIT, E ACTION: Accept in Principle. COMMITTEE STATEMENT: Refer to Commit tee Action an d Sta tement on Proposal 8504-43 (Log #20). NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:



(Log #4) 8504- 10 - (3-1 Purge Rate): Accept in Principle Note: This proposal appea red as c o m m e n t 85H (8504)-98 which

was he ld for fu r ther study f rom the Annua l 93 TCD, which was on proposal 85H (8504)-12. S U B ~ l ~ Robert Herdman, ABB Combus t ion Engineer ing RECOMMENDATION: Add the following to the definit ion of Purge Rate:

"The full load volumetric airflow shall be calculated on the basis of ambien t pressure and temperature ." SUBSTANTIATION: The definit ion as worded does not sufficiently define what volumetric air flow is to be used. As vo lume as pressure and t empera tu re dependen t , fur ther criteria are necessary to define the in tent of t h e p a r a g r a p h . COMMITrEE ACTION: Accept in Principle. COMMITFEE STATEMENT: Refer to Commi t tee Action an d Sta tement on Proposal 8504-11 (Log #25). NUMBER OF COMMITrEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:



(Log #25) 8504- 11 - (3-1 Purge Rate, Coal., Purge Rate, Gas/Oil) : Accept in Principle SUBMITTER: Robert M. Herdman , ABB Combus t ion Engineer ing RECOMMENDATION: 1. Revise file definit ions as follows:

Purge Rate, Coal. A cons tant flow of not less than 25 percent nor more than 40 percent of the full load mass airflow.

Purge Rate, Gas/Oil . A cons tant flow of no t less than 25 percent of the full load mass airflow.

2. Revise '~volumetric airflow" to "airflow" in paragraph 6-2.2.6. SUBSTANTIATION: Provide consistency between 85C and 8504. COMMITrEE ACTION: Accept in Principle.

1. Revise the definit ion of Purge Rate as follows: "Purge Rate. A cons tant flow of no t less than 25 percen t of the full

load mass airflow with the bed in a semifluidized or fluidized condition."

2. Add a defini t ion of Semifluidized as follows: "Semifluidized. A state where a un i fo rm flow of air which is less

than tha t necessary to fluidize the bed is admit ted and is f ound to be sufficient to adequately remove gaseous combust ibles as agreed between the manufac tu re r and the authori ty having jurisdiction."

N F P A 8 5 0 4 - - A 9 6 R O P

COMMITrEE STATEMENT: This change meets the intent of the submitter. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVE: 18 NEGATIVE: 1 NOT RETURNED: 8 Axtman, Conrod, Darguzas, Goldbach,

Knotts, Matthews, McKee, O'Brien EXPLANATION OF NEGATIVE:

LITTLE: I object to the use of the word "semi-fluidized" because in the context in which it is used ("less than that necessary to fluidize'...), it would permit a collapsed bed, for which "semi-fluidized" would be confusing.

Also, for distributed (non-uniform) particle sizes, "fluidized" has never been defined adequately. (For non-uniform particle sizes, the smaller particles can be fluidized with the larger particles unfluidized.) To be meaningful for distributed particle sizes, one must quantify something like >_95 percent of the bed by volume fluidized to be called "fluidized", as measured by bench scale test. >_95 percent of bed fluidized could be point of minimum fluidization.

Also, "uniform" flow of air is hard to obtain and needs fur ther definition.

Recommendation: Revise definition of Purge Rate as follows: Purge Rate. A constant t low of not less than 25 percent of full load

mass air flow and of flow sufficient to remove gaseous combustibles as agreed between the manufacturer and the Authority Having JuriSdiction.

(Log #26) 8504- 12- (4-3.2.1): Accept SUBMITTER: Robert M. Herdman, ABB Combustion Engineering RECOMMENDATION: Add new text:

(h) Relay coil failure. (i) Relay contact failure. (j) Timer failure.

SUBSTANTIATION: These are other likely failure modes which should be addressed and to provide consistency with 85C. COMMITTEE ACTION: Accept. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:



(Log #27) 8504- 13- (4-3.2.3): Accept in Principle SUBMITTER: Robert M. Herdman, ABB Combustion Engineering RECOMMENDATION: Add new text to read:

4-3.2.3.1 The burner management system shall be provided with independen t logic, independen t inpu t /ou tpu t systems, and independen t power supplies, and shall be functionally and physically separate from other logic systems (i.e., boiler control system).

4-3.2.3.2 The same hardware tyjae shall be permit ted to be used for Burner Management Systems as is used for o ther logic systems.

4-3.2.3.3 Data highway communications between the Burner Management System and other systems shall be permitted. Signals that initiate mandatory master fuel trips shall be hardwired. SUBSTANTIATION: Consistency with 85C. Better deft nition of the committee 's requi rement for independence . COMMITTEE ACTION: Accept in Principle. Add new text to read as follows: 4-3.2.3.1 The burner management system shall be provided with

independen t logic, independen t i npu t /ou tpu t systems, and independen t power supplies, and shall be functionally and physically separate from other logic systems (i.e., boiler control system).

4-3.2.3.2 The same hardware type shall be permit ted to be used for Burner Management Systems as is used for other logic systems.

4-3.2.3.3 Data highway communications between the Burner Management System and other systems shall be permitted, however, signalk that initiate mandatory master fuel trips shall be hardwired. COMMITrEE STATEMENT: The change to 4-3.2.3.3 clarifies the Section and satisfies the intent of the submitter. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVE: 18 ABSTENTION: 1 NOT RETURNED: 8 Axtman, Conrod, Darguzas, Goldbach,

gaaotts, Matthews, McKee, O'Brien EXPLANATION OF ABSTENTION:

MELVIN: 4-3.2.3.3 Data highway communicat ions between the Burner Management System and other systems shall be permitted, however, sicnals that initiate mandatory master fuel trins shall be hardwired, v

I unders tand the s tatement but am concerned as to the intent. At what level in the logic system do hard wired trips start. I believe the statement, "sicnals that initiate mandatory master fuel trios shall be ~ " could be interpreted in several ways, leading to confusion on the part of the designer/user .

(Log #29) 8504- 14- (4-3.2.4 (New)): Accept SUBM][TTER: Robert M. Herdman, ABB Combustion Engineering RECOMMENDATION: Add new text:

4-3.2.4 Logic sequences or devices in tended to cause a safety shutdown, once initiated, shall cause a burner or master fuel trip, as applicable, and shall require an operator action prior to resuming operation of the affected burner(s) . No logic sequence or device shall be permit ted that allows momentary closing and subsequent inadvertent reopening of main or ignition fuel valves. SUBSTANTIATION: A. Consistency with 85C.

B. Prevent readmission of fuel without overt operator action. COMMITrEE ACTION: Accept. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:



(Log #5) 8504- 15 - (4-5.2.9): Accept in Principle Note: This proposal appeared as comment 85H (8504)-130 which

was held for fur ther study from the Annual 93 TCD, which was on

~ roposal 85H (8504)-12. UBMIqFrER: ILS. Rand, Bailey Controls Co.

RECOMMENDATION: Replace Section 4-5.2.9 with "Flue gas oxygen and combustibles analyzers shall be provided for use as an operation guide." SUBSTANTIATION: Flue gas analysis for both oxygen and low range combustibles is required to moni tor fluidized bed combustion. These measurements are needed to determine if a fuel rich bed condition exists. These measurements are also needed to insure safe operation of individually fired warm-up burners when used. COMMITrEE ACTION: Accept in Principle. Add a new Appendix A item as follows: "A-4-5.2.9 Accumulated Fuel In Bed. Fluid bed combustors under

certain abnormal operating conditions can accumulate significant quantities of unburn t fuel without obvious indication of abnormality. Such conditions can occur when the fuel input exceeds the available air for combustion over an extended period of time. This condition is a particular concern when nonhomogeneous fuel of widely varying heating value is fired. The combustion control system is presently required to include features to reduce the likelihood of this occurrence. The continuous indication of critical process variables referred to

in Section 2-3.4(a) and described more thoroughly in Section 4-8 is a key aid to tile operators in avoiding ongoing operation with fuel input greater than air input.

Oxygen analyzers are required for fluidized bed combustion in order to keep the fuel input calibrated to true air demand for comparison to actual air input. The oxygen analyzers also advise the operator when air input rate relative to fuel input falls below the acceptable range.

Combustibles analyzers are r ecommended in a Note associated with Section 4-5.1.3 and in Section 4-5.2.9 as an aid in avoiding excess fuel operation. Combustible analyzers provide valuable data in addit ion to the previously described measurements and information. The deficiency of air may not always deplete flue gas oxygen before high levels of combustible products are observed. Particularly in the event of inadequate bed mixing, flue gas oxygen and flue gas combustibles may co-exist and actually present a more difficult situation than a purely air deficient circumstance. COMMITTEE STATEMENT: An appendix item was deemed more appropriate than a mandatory requirement. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMM1TrEE ACTION:

AFFIRMATIVE: 19 NOT RETURNED: 8 Axtrnan, Conrod, Darguzas, Goldbach,


310

N F P A 8 5 0 4 - - A 9 6 R O P

(Log #34) 8504- 16- (4-6.1.9, 4-6.1.10 (New)): Accept in Principle SUBMITTER: Robert M. Herdman , ABB Combus t ion Engineer ing RECOMMENDATION: Revise 4-6.1.9 as follows:

4-6.1.9 The discharge f rom a tmospher ic vents shall be located so tha t there is no possibility of the discharged gas being drawn into the air intake, venti lat ing system, or windows of the boiler room or adjacent buildings and shall be ex tended sufficiently above the boiler a n d adjacent s tructures so tha t gaseous discharge does no t present a fire hazard.

Vents shall be sized according to Table 4-6.1.9.

Table 4-6.1.9 Vent Line Sizes

Fuel Line Diameter Vent Line Diameter

-<1 1 /2 3 / 4 2 1

2 1 / 2 t o 3 l 1 /4 3 1 /2 1 1 /2 4 t o 5 2

5 1 / 2 t o 6 2 1 / 2 6 1 /2 to 7 1 /2 3

8 3 1 /2 >8 15% of the cross sectional area of the

pipe.

Insert a new paragrapb 4-6.1.10 as follows: 4-6.1.10 The ven t lines f rom the individual burners shall be

permi t ted to be mani fo lded together. The vent lines f rom the individual igniters shall be permi t ted to be manifo lded together. The cross-sectional area of the mani fo lded line shall no t be less than the largest ven t line plus 50 percen t of the cross-sectional area of the addit ional vent lines.

Exception No. 1: Burner vents shall no t be manifo lded with igniter vents or lance vents in any combinat ion.

Exception No. 2: Header vents shall only be manifolded with o ther header vents.

Exception No. 3: Vents of headers being served f rom different pressure reduc ing stations shall no t be manifolded.

Exception No. 4: Vent systems of different boilers shall not be manifolded.

Exception No. 5: Vents of systems operat ing at different pressures shall no t be manifolded.

Exception No. 6: Vents of systems using different fuel sources shall no t be manifolded.

A 4-6.1.9 Atmospher ic vent valves located between shutoffvalves are in tended to relieve zany gas pressure which may build up due to failure of the first (upst ream) shutoff valve. This minimizes the potential for leakage into an idle furnace. To per form properly, these valves shou ld be large e n o u g h to relieve gas to a tmosphere at a rate equal to the potential leakage rate. In absence of o ther justification, vent pipe sizes and vent valve port diameters should conform to Table 4-6.1.9. SUBSTANTIATION: 1. Consistency with 85C.

2. Fur ther direction on vent sizing and manifo ld ing criteria. C O M M I T r E E A C T I O N : Accept in Principle.

1. Revise 4-6.1.9 as follows: 4-6.1.9 The discharge from atmospher ic vents shall be located so

that there is no possibility of the discharged gas being drawn into the air intake, venti lat ing system, or windows of the boiler room or adjacent buildings and shall be ex tended sufficiently above the boiler and adjacent s tructures so that gaseous discharge does not present a fire hazard.

Vents shall be sized according to Table 4-6.1.9.

Table 4-6.1.9 Vent Line Sizes

Fuel Line Diameter Vent Line Diameter

<_1 1 /2 2

2 1 /2 m 3 3 1 /2 4 t o 5

5 1 /2 to 6 6 1 /2 to 7 1 /2

8 >8

3 / 4 1

1 1 /4 1 1 /2

2 2 1 /2

3 3 1 /2

15% of the cross sectional area of the pipe.

2. Insert a new paragraph 4-6.1.10 as follows: 4-6.1.10 The ven t lines f rom the individual burners shall be

permi t ted to be mani fo lded together. The vent lines f rom the individual igniters, shall be permitted, to be manifolded, together. The cross-sectmnal area of the mani fo lded line shall no t be less than the largest vent line plus 50 pe r cen t of the sum of the cross-sectional areas of the addit ional vent lines.

Exception No. 1: Burner vents shall no t be manifolded with igniter vents or lance vents in any combinat ion.

Exception No. 2: Header vents shall only be permit ted to be manifo lded with o ther header vents only where they are operated and tr ipped in parallel.

Exception No. 3: Vents of headers being served f rom different pressure reducing stations shall no t be manifolded.

Exception No. 4: Vent systems of different boilers shall no t be manifolded.

Exception No. 5: Vents of systems operat ing at different pressures shall no t be manifolded.

Exception No. 6: Vents of systems using different fuel sources shall no t be manifolded.

A 4-6.1.9 Atmospher ic vent valves located between shutoffvalves are in tended to relieve any gas pressure which may build up due to failure leakage of the first (upst ream) shutoff valve. This minimizes the potential for leakage into an idle furnace. To per form properly, these valves should be large e n o u g h to relieve gas to a tmosphere at a rate equal to the potent ia l leakage rate. In absence of o ther justification, vent pipe sizes and vent valve port diameters should conform to Table 4-6.1.9.

3. Change Section 4-6.1.11 to read as follows: "Gas piping materials and system design shall be in accordance with ANSI B31.1, Code for Power Piping."

4. In Section 7-2(d), delete the following: "(See NFPA 54, National Fuel Gas Code.)"

5. In Section 7-2(g), delete the following,: "(See NFPA 54, National Fuel Gas Code . ) ' C O M M I T r E E STATEMENT: Changes m a d e for consistency with NFPA 85C (8502). These changes satisfy the in tent of the submitter. NUMBER OF COMMITTEE MEMBERS ELIGIBLE T O VOTE: 27 VOTE ON COMMITTEE ACTION:



(Log #6) 8504- 17- (5-4.2.2(d)4): Reject Note: This proposal appea red as c o m m e n t 85H (8504)-163 which

wax held for fur ther study f rom the Annual 93 TCD, which was on proposal 85H (8504)-12. SUBMITTER: Michael C. Polagye, Factory Mutual Research Corp. RECOMMENDATION: Add "and gas recirculation fan(s)" to en d of second sentence. SUBSTANTIATION: Gas recirculation fans shou ld be tripped. COMMITTEE ACTION: Reject. COMMITTEE STATEMENT: It is p ruden t to keep the recirculation fan operat ing u n d e r the circumstances described in Section 5- 4.2.2. (d)4, in order to prevent the possible backflow of gasses. NUMBER OF COMMITTEE MEMBERS ELIGIBLE T O VOTE: 27 VOTE ON COMMITTEE ACTION:



(Log #7) 8504- 18 - (5-5.2(b) and Note (New)): Reject Note: This proposal appea red as c o m m e n t 85H (8504)-167 which

was he ld for fur ther study f rom the Annual 93 TCD, which was on proposal 85H (8504)-12. SUBMITTER: Michael C. Polagye, Factory Mutual Research Corp. RECOMMENDATION: Revise (b) and add Note:

(b) Pluggage of the sens ing tap or o ther maloperat ion of r e d u n d a n t transmitters within the furnace pressure control system.

Note: Due to the small changes in furnace pressure at the control point dur ing normal operation, a deviation a larm a m o n g the transmitters may no t be a reliable indicat ion of a problem. Other means, such as a cons tant furnace pressure being recorded at one sensor over a limited period of t ime may be a better indication. SUBSTANTIATION: If two of three taps plug the correct pressure may be disregarded. Plugged taps may not be sensed by deviation checks. C O M M r r r E E ACTION: Reject.

311

N F P A 8 5 0 4 m A 9 6 R O P

COMMITrEE STATEMENT: It is impractical to provide this level of technology, given the p resen t state of the art. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVE: 19 NOT RETURNED: 8 Axtlnan, Conrod, Darguzas, Goldbach,


(Log #8) 8504- 19- (6-1.3): Reject Note: This proposal appea red as c o m m e n t 85H (8504)-173 which

was he ld for fu r ther study f rom the Annua l 93 TCD, which was on

~ roposal 85H (8504)-12. UBMITTER: Robert M. Lundberg , Los Altos, CA

RECOMMENDATION: Revise text as follows: 1. Revise (a) and (b) to read as follows: (a) For various reasons, it is desirable that the start ing and

shutdown sequences for fluidized bed boilers preserve the temperature of the bed material and refractory while providing proper operat ing conditions.

( b ) Asia result, the r e c o m m e n d e d warm-up cycle for cold start-up and lint restart as well as the shutdown sequence may be different f rom other coal, oil or gas fired boilers an~l no t be identical to previous NFPA procedures.

2. Delete (c). 3. Revise (d) to read as follows: (d) The objective is to mainta in bed tempera ture and protect the

refractory against sudden tempera tu re change by reduc ing the cooling effect f rom high volumes of air.

4. Delete or revise (e). SUBSTANTIATION: 1. The fo rmer paragraph is no t just if ied with backup material.

2. Add c o m m a after agreed. Move up nex t paragraph. In 85C coal fired s tandard, there is reference to a bottled up condition. I will r e c o m m e n d tha t it be dele ted f rom 85C.

3. Delete 613(c). Multi beds at different air flows are no t as desirable as all beds at same condit ions of flow and tempera ture . A severe fire was caused by dais condition.

4. Delete first sen tence of 613(d) "boiler manufac tu re r migh t allow •. ." How can NFPA sponsor this without data or justification?

5. Delete 613(e) for the followinl~ ' reasons: a. "Provided average t e m p e r a t u r e ' . . . This cannot be measu red

reliably without fow. Will they show us how? As units grow very large, it may be difficult to tell if the bed contains some hot material and perhaps some colder material.

b. Volatile mat ter is no t the onlyact ive material in the bed(s). An ignition source may exist in the stationary bed in the form of ho t carbon particles or even red ho t l imestone particles tha t will be blown into an ignitable mixture above the bed if the bed is fluidized. Tbe 85 series of s tandards already recognizes the basic problem, tha t is, the possibility tha t changes in air flow can induce an explosion by "stirring up embers" that provide an ignition source. (See for example, 85C-1991, 2-13(0.)

c. After the master fuel trip, which is des igned to stop the bu rnou t of the active material, a set procedure mus t be provided. It mus t take into account that the trip may occur for different reasons. P ruden t individuals shou ld want to proceed slowly.

Conclusion: The paragraph 613 reads as an economic goal and is no t entirely

true unless severely restricted. It is inconsis tent with NFPA general practice.

There are inconsistencies elsewhere in the A93-TCR that this paragraph ignored.

Wi thout specifics, dais paragraph appears to tacitly g ran t approval for any p rocedure or none . COMMITrEE ACTION: Reject. COMMITTEE STATEMENT: T he present wording is sufficient. The s tandard requires that the bed t empera tu re be measu red with airflow (fluidized bed). NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITrEE ACTION:



(Log #9) 8504- 20- (6-1.5.1(b)): Reject Note: This proposal appea red as c o m m e n t 85H (8504)-183 which

was he ld for fu r ther s tudy f rom the Annual 93 TCD, which was on

~ roposai 85H (8504)-12. UBMITTER: Robert M. Lundberg , Los Altos, CA

RECOMMENDATION: Revise text as follows: 1. Retain first sentence.

2. Delete second sentence. 3. Add "If bed material is already on the bed, purge the bed(s)

while in the fluidized or semifluidized condition." SUBSTANTIATION: Do no t add materials to a uni t which hasn ' t been purged. Static electricity or a spark can create an explosion. COMMITTEE ACTION: Reject• COMMITrEE STATEMENT: See Commit tee Action an d Sta tement on Proposal 8504-21 (Log #10). NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVE: 19 NOT RETURNED: 8 Axtmma, Conrod, Darguzas, Goldbach,


(Log #10) 8504- 21 - (6-1.5.1(c)): Reject Note: This proposal appea red as c o m m e n t 85H (8504)-185 which



RECOMMENDATION: Add new text as follows: "ff no material was on the bed(s), add such non-f lammable

material to the beds, preferably at purge rate." SUBSTANTIATION: Cont inua t ion o f good practice r e c o m m e n d e d in changed 6-1.5.1 (b). COMMITrEE ACTION: Reject. COMMITrEE STATEMENT: There have not been any repor ted t~lroblems with the addit ion of bed material causing ignition within

e furnace. The s tandard already prohibits the addit ion of fuel ruMBior to a purge.

ER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:



(Log #11) 8504- 22 - (6-2.1.2(d)): Reject Note: This proposal appea red as c o m m e n t 85H (8504)-207 which


~ roposal 85H (8504)-12. UBMITTER: Gordon L. Johnson , Bechtel Corp.

RECOMMENDATION: Insert between (c) and (d), r e n u m b e r subsequen t paragraphs accordingl)~

"ff manufac tu re r does no t require a specific level of material on tile air grid, p roceed with start ing up the furnace as a simple gas or oil fired furnace with the primary air fan o f f o r d a m p e r closed to stop air flow th rough the grid." SUBSTANTIATION: Present wording in (f) "purge the bed" is confusing i r a bed doesn ' t exist, f f fu rnace is opera t ing as described above or with a bed but no primary air pressure u n d e r the bed, the burners mus t be t r ipped with a slight positive pressure in the furnace for a sus ta ined period >10 seconds. If they are no t tripped, ho t flue gas will flow down th rough the bed (if it exists) and t h ro u g h the grid, creating a situation like the Morgantown incidenL COMMITrEE ACTION: Reject. COMMI'VrEE STATEMENT: This present wording is sufficient. The submi t te r ' s substant iat ion is no t in accordance with the cur rent unde r s t and ing of the referenced incident. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:


Knotts, Ma~hews, McKee, O 'Br ien

(Log #CP3) 8504- 23- (6-2.2.6): Accept SUBMITTER: Technical Commit tee on Fluidized Bed Boilers RECOMMENDATION: Revise Section 6-2.2.6 to read as follows:

"Total airflow shall no t be reduced below 25 percent of full load airflow. Airflow shall no t be reduced below that required to maintain stable fluidization condit ions within active beds or bed compart- ments ." SUBSTANTIATION: To provide consistency between NFPA 8502 and NFPA 8504. Also refer to Commit tee Action and Sta tement on Proposal 8504-11 (Log #25). COMMrI[TEE ACTION: Accept. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27

312

N F P A 8 5 0 4 - - A 9 6 R O P

VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 19 NOT RETURNED: 8 Axtman, Conrod, Darguzas, Goldbach,


(Log #12) 8504- 24- (6-2.4): Reject Note: This proposal appeared, as c o m m e n t 85H (8504)-239 which

was he ld for fu r ther study f rom the Annual 93 TCD, which was on


RECOMMENDATION: Revise text as follows: CAUTION: It is possihle to accumula te combust ible t h roughou t

the uni t inc luding the windbox and ductwork. T he procedures for post purge and normal shutdown will aid in dis turbances tha t will effect min imiz ing and mixing of combustibles and air. SUBSTANTIATION: 85C procedure of 30 years - refer to Kessler's paper. COMMITrEE ACTION: Reject. COMMITTEE STATEMENT: The present Caution Note adequately provides warning to the user of the s tandard. There is insufficient informat ion to genera te a more detai led Caution Note.

The submit ter is encouraged to provide copies of the referenced paper in order to fu r the r substantiate the r e c o m m e n d e d changes. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:



(Log #l 3) 8504- 25- (Table 6-2.5.1 (a)): Accept in Principle Note: This proposal appea red as c o m m e n t 85H (8504)-269 which

was he ld for fur ther study f rom the Annua l 93 TCD, which was on

~ roposal 85H (8504)-12. UBMITTER: Henry K. Wong, Foster Wheeler Energy Corp.

RECOMMENDATION: Revise condi t ion for mandatory automat ic fuel trip by adding the following under l ined phrase.

(f) Bed tempera tu re below value specified in 6-2.2.5 and warm-uo bu rne r f lame no t oroven." SUBSTANTIATION: Original s ta tement does no t agree with original in ten t nor Figalre 9-3.1 (b) Boiler Trip Logic.

I COMMITrEE ACTION: Accept in Principle. Revise Table 6-2.5.1 (a) to r e a d a s follows: (f) Bed tempera tu re belowvalue specified in 6-2.2.5 when main

fuel is being admi t ted to bed and no s t m ' t " ~ 3~¢.1~..¢~ bu rne r is established. COMMITTEE STATEMENT: The te rm "warm-up" is the proper terminology. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:



COMMrITEE ACTION: Accept. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:



(Log #14) 8504-28- (6-2.5.4 t h rough 6-2.5.6 (New)): Reject Note: This proposal appea red as c o m m e n t 85H(8504)-273 which

was he ld for fur ther study f rom the Annual 93 TCD, which was on proposal 85H (8504)-12. SUBMITllgPa Robert M. Lundberg , Los Altos, CA RECOMMENDATION: Insert new 6-2.5.4 - 6-2.5.6 as follows:

6-2.5.4 Procedure for Purg ing after an Emergency Shutdown. Fans that are operat ing after the master fuel trip shall be con t inued in service. Do no t immediate ly increase the airflow be deliberate manua l or automat ic control action, f f t h e airflow is above purge rate, it may gradually be decreased to this value for a post-firing purge, f f t he airflow is below purge rate at the t ime of the trip, it shall be con t inued at the existing rate for five minu tes and t hen gradually increased to purge rate airflow and held at this value for a post-firing purge.

6-2.5.5 W h e n the emergency trip was caused by loss of draft fans, or draft fans have also tripped, close gas recirculating fan dampers and slowly open all dampers in the air and flue gas passages of the uni t to the wide open position in order to create as m u c h natural draft as possible to ventilate the unit. Open ing fan dampe r s shall be t imed or controlled to avoid excessive positive or negative furnace pressure t ransients dur ing fan coast-down. Maintain this condi t ion for a per iod of no t less than 15 minutes . At the end of this period, start the fan(s) in accordance with NFPA 85C, Chapter 5, "Furnace Implosion Protection." Gradually increase airflow to purge rate and complete a post-firing uni t purge.

6-2.5.6 ff it is impossible to restart for some ex tended period of time, a flow of air t h rough the uni t shall be main ta ined to prevent accumula t ions of combustible gases. SUBSTANTIATION: Minimize dis turbance of air flow in critical period. COMMITrEE ACTION: Reject. COMMITI'EE STATEMENT: 1. Section 6-2.5.4: After emergency shutdown as a result of a low water condition, it is p ruden t to secure all airflow to prevent damage to pressure parts. Refer to Section 6- 2.5.3.

2. Section 6-2.5.5: The proposed wording is inconsis tent with Hot Restart as described in Section 6-2.4. Fluidized bed boilers are substantially different f rom mult iple bu rne r boilers as described in NFPA 85C (8502).

3. Section 6-2.5.6: For the situation described, users should follow requ i rements of Section 6-2.3. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMrFFEE ACTION:



(Log #CP4) 8504- 26 - (Table 6-2.5.1 (a)): Accept SUBMITTER: Technical Commit tee on Fluidized Bed Boilers RECOMMENDATION: Change Table 6-2.5.1(a), line (e) to read as follows:

"(e) Whenever the total airflow drops below the purge rate by 5 percen t of full load airflow". SUBSTANTIATION: "To provide consistency between NFPA 8502 and NFPA 8504. Also see Commit tee Action and Sta tement on Proposal 8504-11 (Log #25). COMMIq['rEE ACTION: Accept. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMM1TT]Z ACTION:

AFFIRMATIVE: 19 N O T RETURNED: 8 Axtman, Conrnd, Darguzas, Goldbach,


(Log #CP2) 8504- 27 - (6-2.5.3): Accept SUBMITTER: Technical Commi t tee on Fluidized Bed Boilers RECOMMENDATION: Change "low, low" to read as "low-low" in Section 6-2.5.3. SUBSTANTIATION: Editorial.

(Log #16) 8504- 29 - (6-4.1): Reject Note: This proposal appea red as c o m m e n t 85H (8504)-278 which

was he ld for fur ther study f rom the Annual 93 TCD, which was on proposal 85H (8504)-12. SUBMITTER: Robert M. Lundberg , Los Altos, CA RECOMMENDATION: Add new text.

A suggest ion tha t the possibility of iner t ing the forced draft ducts be considered. 85C and 85F have material on iner t ing and fuel clearance.

Steam canno t be used. A t t h e tempera tures involved it is an active reagent. SUBSTANTIATION: Tbe volumes of inerts necessary for this apparatus, it may be p roduced slowly th rough a small inert genera- tor.

Purging fuel with air without inert gases separat ing the fuel f rom the air is a complicated procedure and often becomes the prelude to an explosion. COMMI'ITEE ACTION: Reject. COMMITrEE STATEMENT: It does not appear ei ther necessary (based upon experience) or practical to inert forced draft fan ductwork.

Also see 8504-30 (Log #15). NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27

313

N F P A 8 5 0 4 - - A 9 6 R O P

VOTE ON COMMITTEE ACTION: AFFIRMATIVE: 19 NOT RETURNED: 8 Axtman, Conrod, Darguzas, Goldbach,


(Log #15) 8504- 30 - (64.4 (New)): Accept in Principle Note: This proposal appearedas comment 85H (8504)-276 which

was held for further study from the Annual 93 TCD, which was on

~ roposal 85H (8504)-12. UBMITTER: R.S. Rand, Bailey Controls, Co.

RECOMMENDATION: Add a new item 64.4 as follows: 6-4.4 If the FD fan(s) Irip with fuel in the bed, and an ID fan

remains running, restart a FD fan at a low output sufficient to pressurize the combustion air ducts, a n d / o r decrease the furnace

~ ressure with the ID fan. flail FD and ID fan(s) trip with fuel in the ed, restart an ID fan and establish a lower than normal furnace

pressure. These actions are intended as immediate actions to

~ revent back flow of gaseous combustibles into the combustion azard. Longer term corrective actions shall be taken after an

assessment o f the boiler's situation. SUBSTANTIATION: These are prudent actions to prevent explosions in the combustion air ducts.

COMMITTEE ACTION: Accept in Principle. Add a new item A-6-2.5 as follows: "A-6-2.5 f f the FD fan(s) trip with fuel in the bed and an ID fan

remains running, restart an FD fan at a low output sufficient to pressurize the combustion air ducts, a n d / o r decrease the furnace

~ ressure with the ID fan. If all FD and ID fan(s) trip with fuel in the ed, restart an ID fan and establish a lower than normal furnace

pressure. These actions are intended as immediate actions to Pdrevent back flow of gaseous combustibles into the combustion air

uctwork. Longer term corrective actions shall be taken after an assessment of the boiler's situation." COMMITrEE STATEMENT: This change addresses the intent of the submitter. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:



(Log #CP6) 8504- 31 - (Figure 7-5.1.1(f), (g)): Accept SUBMITTER: Technical Committee on Fluidized Bed Boilers RECOMMENDATION: In Figures 7-5.1.1(f) and %5.1.1(g), change existing reference "Q" to "R" and "R" to "Q".

T M Gas supply [See Figure A-7-5.1 .l(a)]

S Ol S

© I_

R

burner

To remaining burners

Figure A-7-5.1.1(f) Typical fuel gas burner/lance system master flow control valve for multiple burners (automatic).

[See Figure A-7-5.1.1 (a)]

R

'01

~ To bumer

L

y

To remaining burners

v

Figure A-7-5.1.1(g) Typical fuel gas burner / lance system master flow control valve for multiple burners (supervised manual).

314

N F P A 8 5 0 4 - - A 9 6 R O P

SUBSTANTIATION: Editorial. COMMITTEE ACTION: Accept. NUMBER OF COMMITTEE MEMBERS ELIGIBLE T O VOTE: 27 VOTE ON COMMITTEE ACTION:



being continuously moni tored and used for control is more reliable than a separate measurement. Generally, "combustion control" sensors are analog where BMS sensors are temp/f low or press switches. Analog signals can be continuously moni tored for proper function, whereas temp/f low or press switches can only be tes tedby off-line preventive maintenance procedures.

(Log #30) 8504- 32 - (7-5.2.1.2(a)): Accept SUBMITTER: Robert M. Herdman, ABB Combustion Engineering RECOMMENDATION: 1. Revise to read as follows:

7-5.2.1.2(a)* An operational leak test of the fuel header piping system shall be performed in accordance with established procedures while maintaining purge rate airflow. Successful completion of the leak test shall be part of a completed unit purge.

2. Also add A-7-5.2.1.2(a) as follows: A-7-5.2.1.2(a) If a charging valve (required self-closing) on the

main gas supply is furnished, this should be opened to bypass the main safety shutoffvalw:; otherwise open the main safety shutoff valve. Open main fuel control valve as required. Vent the burner header until it is filled with gas. Close burner header atmospheric vent valve. Leave charging or main safety shutoff valve open to establish a nominal pressure on the burner header. Then close the charging or main safety shutoffvalve. It may be concluded that the safety shutoffvalves do not leak ff this pressure remains within def ined limits. SUBSTANTIATION: Consistency with 85C. COMMITTEE ACTION: Accept. NUMBER OF COMMITTEE MEMBERS ELIGIBLE T O VOTE: 27 VOTE O N COMMITTEE ACTION:



(Log #17) 8504- 33 - (9-2.30) Exception No. 2 (New)): Reject Note: This proposal appeared as comment 85H (8504)-462 which

was held for fur ther study from the Annual 93 TCD, which was on proposal 85H (8504)-12. SUBMITTER: Michael C. Polagye, Factory Mutual Research Corp. RECOMMENDATION: Revise text as follows:

1. Add: "No. 1" after "Exception." 2. Add: "Exception No. 2: An auctioneered drum level signal or

furnace draft signal may be used for control and interlock purposes. [See 5-5.2(b) ]" SUBSTANTIATION: These are two cases where the most reliable signal is the signal used for normal control We should not force independence when it results in less reliability of the safety system. COMMITTEE ACTION: Reject. COMMITTEE STATEMENT: The proposed wording is contrary to the intent of Section %2.30) and the requirements for independence. Independence of systems is not a burdensome requirement. NUMBER OF COMMITTEE MEMBERS ELIGIBLE T O V O T E : 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVE: 18 NEGATIVE: 1 NOT RETURNED: 8 Axtman, Conrod, Dargnzas, Goldbach,


RAND: I vote Negative on the Committee Action on 8504-33 (Log #17) because the true intent of NFPA 8502 changes were not brought out. Also, we have revised tltle definition of Purge Air Flow to be Mass

Flow. This will require that the mass air flow be computed in the burner management system under the present separation and independence requirements. We need to revisit this issue. In particular we should consider

exception to separation and independence for the bed temperature, air flow, drum level, and furnace pressure inputs to the burner management system.

f f the "combustion control" is the source of BMS inputs, certain requirements such as "functions impacting trip signals to the BMS shall not be permit ted to be changed while the boiler is being operated" and "signals shall fail-safe on loss of power or micropro- cessor failure" must be imposed on the combustion control.

The 8502 philosophy seems to be twofold, (1) BMS are being configured with inputs from the "combustion control" because it is convent and some BMS equipment can not handle the analog requirements even though 85 series standards require separation; (2) system design engineers feel that a "combustion control" signal

(Log #CP1) 8504- 34 - (Figure 9-3.1 (b)): Accept SUBMITTER: Technical Committee on Fluidized Bed Boilers RECOMMENDATION: In Figure 9-3.1 (b), Block 12, "Change Operator trio" to "Operator Trip"° See Figure %3.1(b) on the following page. SUBSTANTIATION: Editorial. COMMII'TEE ACTION: Accept. NUMBER OF COMMITTEE MEMBERS ELIGIBLE T O VOTE: 27 VOTE O N COMMITTEE ACTION:



(Log #CP7) 8504- 35 - (9-3.3): Accept SUBMITTER: Technical Committee on Fluidized Bed Boilers RECOMMENDATION: In Section 9-3.3, delete the words "a unit purge has been completed and". SUBSTANTIATION: To provide consistency with Section 6-1.3 of dais standard. This change removes redundancy and clarifies the statement. COMMI'I"I'EE ACTION: Accept. NUMBER OF COMMITTEE MEMBERS ELIGIBLE T O VOTE: 27 VOTE ON COMMI'F/'EE ACTION:



(Log #18) 8504- 36 - (9-3.3.1 through 9-3.3.6 and 9-3.3.7): Reject Note: This proposal appeared as comment 85H (8504)-502 which

was held for fur ther study from the Annual 93 TCD, which was on proposal 85H (8504)-12. SUBMITFER: ILS. Rand, Bailey Controls RECOMMENDATION: Revise text as follows:

1. Replace paragraph %3.3.1 with: "Loss of individual warm-up burner flame shall initiate the tr ipping

of the individual burner safety shutoffvalve(s) and its individual igniter safety shutoff valve(s) and deenergize associated sparks."

2. Replace paragraph %3.3.2 with: "Improper warm-up burner header pressure, (high or low) shall

initiate the tripping of the individual burner safety shutoffvalve(s) and its individual igniters safety shutoffvalve(s) and deenergize associated sparks. Burner header pressure shall be moni tored to insure each warm-up burner is being operated within its capacity and stability limits as designated by the burner manufacturer and demonstra ted by test.

3. Delete the Note under paragraph %3.3.2. 4. Replace paragraph %3.3.3 with: "hnproper warm-up burner atomizing media pressure shall initiate

the tripping of the individual burner safety sbutoff valve (s) and its individual igniter safety shutoff valve(s) and deenergize associated sparks." 5. Replace paragraph %3.3.4 with: "Improper warm-up burner combustion air flow shall initiate the

tripping of the individual burner safety shutoffvalve(s) and its individual igniter safety sbutoffvalve(s) and deenergize associated sparks."

6. Replace paragraph %3.3.5 with: "Improper warm-up burner header pressure, improper atomizing

media pressure, inadequate combustion air flow or loss of fan(s) affecting all warm-up burners, shall initiate the tripping of the warm- up burner header safety shutoff valve, the warm-up burner igniter header safety shutoffvalve, all individual burner safety shutoffvalves, all individual igniter safety shutoff valves and deenergize all sparks."

7. Add under new paragraph 9-3.3.5: "Note: Some fuel supply systems for warm-up burners are

configured with sensors and interlock logic for monitoring and tr ipping burners on a per burner basis. Others are configured with sensors and interlocks for monitor ing and tr ipping warm-up burners as a group."

315

N F P A 8 5 0 4 1 A 9 6 R O P

QI ®1 @1 ®1 @1 ®1 @1

Cut back main fuel

I T i_ ! ~ A Loss of ID fan I -

I ~ D - ' ~ Loss of ID fan ] y

Loss of FD fan I ~ A I N___~

Loss of FD fan I ~ D

Drum level low I

Furnace pressure I high

Airflow < 25% [ full load airflow [ v

Loss of boiler [ circulation if applicable

Any coal feeder ] I ' ~ established

Any warm-up bumerl =,.I n l I l r ' I ' I established I

i .._ SET - -

@ [ AdequateAi' fual ,npulStemperatureZero bed F [ ~ ~ ~ . O "~AJ~ ND

®= --°ra,u+ lOW ~ "

@ 1 Warm-up burner not proven

I @ 1 0 p e r a t o r t r i p ,

O R

Reset master fuel trip relay

(from purge logic) (Figure 9-3.2)

Actuate master ? fuel trip relays

Close all individual igniter safety shutoff

valve(s) and deenergize sparks

(Figure 9-3.3)

Close all individual warm-up burner safety

shutoff valve(s) (Figure 9-3.3)

Close all individual lance safety shutoff

valve(s) (Figure 9-3.4)

" - " ~ l (Figures 9-3.3 and 9-3.4)

Close all igniter, warm-up burner, and

lance header safety shutoff valve(s)

Stop all solid fuel and sorbent feed systems

(Figure 9-3.5)

] To purge logic

Trip electrostatic precipitators and fired reheaters

and other sources of ignition energy

Figure 9-3.1(b) Boiler trlp logic.

8. Replace paragraph %3.3.6 with: "A master fuel trip shall initiate the t r ipping of all warm-up bu rne r

safety shutoffvalves, all warm-up bu rne r igniter safety valves, and deenergize all sparks."

9. Add new paragraph 9-3.3.7: "The master fuel trip relay shall directly trip all warm-up bu rne r

safety shutoff valves, trip all warm-up b u r n e r igniter safety shutoff valves, and deenergize all sparks." SUBSTANTIATION: The present s tandard contains 15 different fuel system diagrams for warm-up burners. These revisions are to accommodate all fuel systems. These revisions are based on NOT tr ipping file warm-up header safety shutoff valves unless a combustion safety hazard is detected that affects all burners. It is NOT necessary to trip the warm-up bu rne r header safety shutoffvalve on a loss of all warm-up bu rne r flame. Warm-up burners are in tended to

be used for un i t start-up and as me thod of mainta ining and stabilizing bed tempera ture dur ing upset condit ions in the bed. C O M M r I T E E ACTION: Reject. C O M M I T r E E STATEMENT: The present wording of the s tandard incorporates the submit ter 's proposed changes. NUMBER OF COMMITTEE MEMBERS ELIGIBLE T O VOTE: 27 VOTE ON COMMITTEE ACTION:


Knotts, Matthews, McKee, O 'Br ien EXPLANATION OF NEGATIVE:

RAND: I vote Negative on the Commit tee Actions on 8504-36 (Log #18), 8504-38 (Log #22), and 8504-41 (Log #23) because discussion was deferred on these proposals because of t ime constraints and

316

N F P A 8 5 0 4 - - A 9 6 R O P

because parts of the original proposals were already incorporated in this standard (i.e., it was difficult to review these proposals because they were written as comments to an earlier version of the standard). As I promised at the meeting, I have submitted revised comments

on these sections that should be reviewed by the Committee.

(Log #CP8) 8504- 37 - (9-3.4): Accept SUBMITTER: Technical Committee on Fluidized Bed Boilers RECOMMENDATION:: In Section 9-3.4, delete the words "a unit

~ urge has been completed and,". UBSTANTIATION: To provide consistency with Section 6-1.3 of

this standard. This change removes redundancy and clarifies file statement. COMMITrEE ACTION: Accepe NUMBER OF COMMI'ITEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVE: 19 NOT RETURNED: 8 Axtman, Conrod, Dargnzas, Goldbach,


(Log #22) 8504- 38 - (Figure 9-3.4, 9-3.4, 9-3.4.1 through 9-3.4.4, and 9-3.4.5 (New)): Reject Note: This proposal appeared as comment 85H (8504)-508 which


~ roposal 85H (8504)-12. UBMITI'ER: R.S. Rand, Bailey Controls Go.

RECOMMENDATION: Revise text as follows: 1. Replace paragraph 9-3.4 with: "Lances. Lances shall not be placed in service until a unit purge

has been completed, the master fuel trip relay has been reset and the bed temperature has reached the ignition temperature for the fuel being fired in the lance."

2. Replace paragraph 9-3.4.1 with: "Lance firing depends on fuel ignition by the hot bed material. All

lance safety shutoffvalves shall be closed until the bed temperature has reached the ignition temperature for the fuel being fired in the lance, see 6-1.5.1 (g)."

3. Replace paragraph 9-3.4.2 with: " Improper lance fuel header pressure shall initiate tr ipping of all

lance safety shutoffvalve(s). Lance header pressure shall be moni tored to insure each lance is being operated within its capacity limits as designated by the lance manufacturer."

4. Delete Note under 9-3.4.2. 5. Replace paragraph 9-3.4.3 with: "Bed temperature below the operating limit (per 6-2.2.5) for the

fuel being fired in the lance, after having operated at normal temperature, shall initiate a master fuel trip and the tr ipping of all lance safety shutoffvalve(s). The bed shall be considered to have operated at normal temperature Kit has exceeded 1450 F or exceeded the operating limit by 50 F. K the operating limit for the fuel being fired in the lance is higher than the operating limit for the solid fuel, a master fuel trip is not required if the bed temperature is below the operating limit (per 6-2.2.5) for the fuel being fired in tile lance."

6. Replace paragraph 9-3.4.4 with: "A master fuel shall initiate the tripping of all lance safety shutoff

valves." 7. Add paragraph 9-3.4.5 "The master fuel trip relay shall directly

trip all lance safety shutoffvalves." 8. Replace Figure 9-3.~ "Loss of lance atomizing media" with "Bed

temperature below the operating limit." 9. On Figure 9-3.4 change "device" to "relay," "(Figure 9-3.1 (a))" to

"(Figure 9-3.1 (b))," "combustor" to "bed" and delete numbers at lower right of boxes. SUBSTANTIATION: The text and figure were modified to correspond to tbe requirements for ignition and operating bed temperature limits per 6-1.5.1 (g) and 6-2.2.5.

Lances do not require atomizing media. MFT Relay and Bed are correct terminology. MFT reference is (b). Note: A lance fuel system diagram should be added to Appendix A.

COMMITI'EE ACTION: Reject. COMMITrEE STATEMENT: The present wording of the standard incorporates the submitter 's proposed changes. NUMBER OF COMMI~fTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:



EXPLANATION OF NEGATIVE: RAND: See my Explanation of Negative for 8504-36 (Log #18) and

8504-41 (Log #23).

(Log #19) 8504- 39- (9-3.4.2 Note): Reject Note: This proposal appeared as comment 85H (8504)-513 which

was held for fur ther study from Annual 93 TCD, which was on proposal 85H (8504)-12. SUBMITTER: Thomas M. McKee, Bechtel Power Gort). RECOMMENDATION: Add to end of Note:

"unless pressure drop through the lance is relatively low compared to bed pressure." SUBSTANTIATION: Low fuel pressure to the lance should not be influenced significantly by bed pressure fluctuations. COMMITI'EE ACTION: Reject. COMMITFEE STATEMENT: The present wording of tile standard- sufficiently addresses the concerns of the submitter. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:



(Log #CP9) 8504- 40 - (9-3.5): Accept SUBMITTER: Technical Committee on Fluidized Bed Boilers RECOMMENDATION: In Section 9-3.5, delete the words "a unit purge has been completed and,". SUBSTANTIATION: To provide consistency with Section 6-1.3 of this standard. This change removes redundancy and claiifies the statement. COMMITI'EE ACTION: Accept. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVE: 19 NOT RETURNED: 8 Axtman, Gonrod, Darguzas, Goldbach,


(Log #23) 8504- 41 - (9-3.5 Note and Figure 9-3.5): Reject Note: This proposal appeared as comment 85H (8504)-517 which

was held for fur ther study from the Annual 93 TCD, whicll was on proposal 85H (8504)-12. SUBMITTER: ILS. Rand, Bailey Controls Co. RECOMMENDATION: Revise text as follows:

1. Replace paragraph 9-3.5 with: "Solid Fuel. The solid fuel feed system shall no t be placed in

service until a unit purge has been completed, the master fuel trip relay has been reset and the bed temperature has reached the ignition temperature of the solid fuel being fired."

2. Replace paragraph 9-3.5.1 with: "Solid fuel firing depends on fuel ignition by the hot bed material.

All solid fuel feed systems shall be t r ipped if the bed temperature drops below the ignition temperature for the fuel being fired, see 6-1.5.1 (g)." 3. Add new paragraph 9-3.5.2 with: "Bed temperature below the operating limit (per 6-2.2.5) for the

solid fuel being fired, after having operated at normal temperature, shall initiate a master fuel trip and the tripping of all solid fuel feed systems. The bed shall be considered to have operated at normal temperature if it has exceeded 1450 F or exceeded the operating limit by 50 F." Renumber old paragraph 9-3.5.2 as 9-3.5.6.

4. Replace paragraph 9-3.5.3 with: "A master fuel trip shall initiate the tr ipping of all solid fuel feed

systems." 5. Add paragraph 9-3.5.4: "The Master fuel trip relay shall direcdy trip all solid fuel feeders." 6. ON Figure 9-3.5 change "device" to "relay," "(Figure 9-3.1 (a))"

to "(Figure 9-3.1 (b))," "combustor" to "bed" and delete numbers at lower right of boxes.

7. Add to Figure 9-3.5 a new box "Bed temperature below the operation limit." Add line from this new box to OR for solid fuel tdap.. SI.IBSTANTIATION: Tile text and figure were modified to correspond to the requirements for ignition and operating bed temperature limits per 6-1.5.1 (g) and 6-2.2.5.

M v r Relay and Bed are correct terminology. MFT reference is (b). COMMITrEE ACTION: Reject.

317

N F P A 8 5 0 4 1 A 9 6 R O P

COMMI'VrEE STATEMENT: The present wording of the standard incorporates the submitter 's proposed changes. NUMBER OF COMMITTEE MEMBERS ELIGIBLE T O VOTE: 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVE: 18 NEGATIVE: 1 NOT RETURNED: 8 Axtmaxa, Conrod, Darguzas, Goldbach,


RAND: See my Explanation of Negative for 8504-36 (Log #18) and 8504-38 (Log #22).

( Log #21 ) 8504- 42- (A-2-6.1): Reject Note: This proposal appeared as comment 85H (8504)-538 which


~ roposal 85H (8504)-12. The original comment referenced A-2-8.8, ut this was changed to A-2-6.1 in last revision. This proposal was

modified to reference A-2-6.1. SUBMITTER: Pe te r J . Gore Willse, Induslxiai Risk Insurers RECOMMENDATION: Relocate this to A-2-6 Maintenance Organization and add the following section as part (g).

( g ) It is not practical toprees tabhsh a single schedule for all installations. Therefore, the following typical schedule is a guide only, subject to adjustment according to specific plant operation and equipment involved. (See 10-2.1 a n d 10-2.2.)

( a ) Daily. (i) Flame failure detection system (ii) Low water level cutoffs and associated alarms

(b) Weekly. (i) Igniter and burner operation c) Monthly.

((i) Fan andair f low interlocks (ii) Fuel safety shutoff valves for leakage (iii) Low fire start interlock (iv) High steam pressure interlock (v) For oi1: 1. Fuel pressure and temperature interlocks. (vi) For gas: I. Gas strainer and drip leg 2. High and low fuel pressure interlocks

(d) Semiannually or Annually as Required. (i) Igniter and burner components (ii) Combustion air supply system (iii) Flame failure system components (iv) Piping, wiring, and connections of all interlocks and shutoff

valves (v) Combustion control system (vi) Calibration of indicating and recording instruments

(e) As Required for Oil Firing. (i) Atomizers (ii) Strainers.

SUBSTANTIATION: 2-8.8 is entitled "Additional Problems Requiring Consideration" and this section is on maintenance and Equipment Inspection. We do not indicate a schedule for testing, but do require tests to be conducted (i.e., Leakage testing of the safety shutoff valves). COMMH'rEE ACTION: Reject. COMM1TFEE STATEMENT: The proposal provides excessively detailed information for this standard, and Section A-2-6.1 (I) adequately addresses the submitter 's intent. NUMBER OF COMMITTEE MEMBERS ELIGIBLE T O VOTE: 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVE: 19 NOT RETURNED: 8 Axtman, Conrod, Darguzas, Goldbacb,


(Log #20) 8504-43- (A-2-9.7): Accept in Principle Note: This proposal appeared as comment 85H (8504)-531 which

was held for fur ther study from Annual 93 TCD, which was on

~ roposal 85H (8504)-12. UBMITTER: Peter Matthews, Hartford Steam Boiler

RECOMMENDATION: Add details of the possibility of the entire volume of bed material accumulating in the loop seal, with resultant overload of componen t structures. SUBSTANTIATION: Reported to be a potential hazard and should be discussed in committee as to possible inclusion in appendix material. COMMITTEE ACTION: Accept in Principle. Add a new subsection to 2-9.8 as follows: "(g) Structural load requirements for abnormal accumulations of

a sh /be d material within the boiler furnace enclosure and solids return path."

318

COMMITTEE STATEMENT: This action satisfies the intent of the submitter. NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:



(Log #32) 8504- 44 - (A-5-1 (New)): Accept in Principle SUBMITTER: Robert M. Herdman, ABB Combustion Engineering RECOMMENDATION: Add new appendix material: A-5-1 Furnace Implosion Protection. No standard can be

promulgated which will guarantee the elimination of furnace implosions. Chapter 5 involves a balance between complications of re ihforcement of ecjuipment, limitations and reliability of operating procedures, control systems, and interlocks to minimize the occurrence of the conditions leadingto furnace implosions.

If worst case conditions are assumed (cold air, high head induced draft fan, forced draft fan flow shutoff, induced draft control dampers open with induced draft fan operating), the furnace cannot be pi-otect~d by reasonable structural design. With provisions outlined in Chapter 5, the likelihood of furnace

damage is believed to be remote as long as tile induced draft fan has reasonable head capability. If the induced draft fan head capability is increased significantly, then special consideration of induced draft fan characteristics or special du~t arrangements or special instru- mentat ion or control should be investigated. SUBSTANTIATION: This material provides useful clarification of the intent of this paragraph and its limitations. COMMI]~rEE ACTION: Accept in Principle. Add new appendix material: A-2-2 Furnace Pressure Excursion Protection. No standard can be

promulgated which will guarantee the elimination of furnace implosions. Chapter 5 involves a balance between complications of re inforcement ofeequipment, limitations and reliability of operating procedures, control systems, and interlocks to minimize the occurrence of the conditions leading to furnace implosions.

ff worst case conditions are assumed (cold air, high head induced draft fan, forced draft fan flow shutoff, induced draft control dampers open with induced draft fan operating), the furnace cannot be protected by reasonable structural design. With provisions outl ined in Chapter 5, the likelihood of furnace

damage is believed to be remote as long as the induced draft fan has reasonable head capability, ff the induced draft fan head capability is increased significantly, then special consideration of induced draft fan characteristics or special duct arrangements or special instru- mentat ion or control should be investigated. COMMITI'EE STATEMENT: Paragraph reference change was editorial. NUMBER OF COMMITTEE MEMBERS ELIGIBLE T O VOTE: 27 VOTE O N COMMITTEE ACTION:



(Log #28) 8504- 45 - (A-9-2.3(i)): Reject SUBMITTER: Robert M. Herdman, ABB Combustion Engineering RECOMMENDATION: Change "Mandatory Master Fuel Trip System and Circuits" to "The Burner Management System". SUBSTANTIATION: Existing text incorrectly limits the separation only to MFI" logic, rather than the entire BMS. COMMYVI'EE ACTION: Reject. C O M M I T r E E STATEMENT: The proposed change could be misinterpreted to require more complex changes than are necessary. NUMBER OF COMMITTEE MEMBERS ELIGIBLE T O VOTE: 27 VOTE O N COMMITTEE ACTION:



(Log #CP5) 8504- 46-_.LAt3pendix B): Accept SUBMITTER: Technical Committee on Huidized Bed Boilers RECOMMENDATION: 1. In Section B-l, change the second sentence to read as follows: "The test approaches described in Sections B-3 and B-4 are typical approaches followed by manufacturers to assist in design actiQities for this equipment."

2. AfterSect ion "B-3 Test Set-Up and Measurements" insert new Section to read as "B-3.1 Pilot Test Set-Up and Measurements."

NFPA 8 ~ 0 4 - A96 ROP

& Insert new section B-3.2: B73.2 B e n c h Scale ~ b l l i t ~ Test Set-up. An alternate means of

~establia~. g an initial minimum i~fition temperature by test is mrougn me use of conventional fgnition or flammability tests. The In~nt of these tests is .not so mudi to directly establish a minimum ~gmuo~ temp .~m.re, 10ut rather to allow the manufacturer to extrapolate an ~gm..uon temperature ba~e_ d upon the results of a given test and similar tests on fuels fired at other actual in~allation~ .The correlation between the ignition temperature (flammability indent) yiekied by tests ofvarious fuels at the actual plant and t_tie veriti.ed min~." um ignition temperature established for those plants andthe results of the t.ey~ag performed on the unknown fuel are sumcient to yield an initial setpoint for the unknown fuel. As a minimum, the following are requiredi

(a) A furnace with a Controllable heat source. (b.) Thermocouples to monitor the temperature of the furnace. ,tc) gepresentative samples of the fuel to be fired. The samples

mould be pr.epare~!_ in accordance with normal procedures fdr the test setup to be utilized. ~ed~ Tl~ in ten t is n.~ to require any specific test, but...r~h, er to use

same test on multiple me~ sam~es m oraer to establish a relationship between the unknown fuel and its appropriate minimum ,gnitiou temperature based upon the ~el'au%mhip of other known fuels and their proven ignition temperatures.

4. Add "B-4.!.1 Pilot Test Oi56ration ~ after existing Section B-4.1 5. In existing Section B-4.1 Co), change "B-4.1 (a)" to read as

"B-4.1d (a) ~ . 6. In existing Section B-4.1(c), change "B-4.1 (a)" to read as

"B-4.1.1 (a)" 7. In existing Se_ction.B-4.2, change "Eb4.2 Minimum Permissive

Bed Temperature" to read as "B-4.L2 Minimum Permis~ve Bed Temperature" and change "...that described in B-4.1... ~ to read as "...thht described in B-4.L1... ~

8. Insert a new B-4.2 as follows: "B-4.2 Bench Scale Flammability Test. B-4.~.I Test Procedure. (t~.a~ Stabilize the test f~tmac~e at 100-200°F above the expected

tion temperature ca me ree l (b) Admit a fuel sample.

, (c) If the fuel ignites, repeat the test reducing the temperature of r i l e I u r n a c e .

(d) If the fuel fails to ignite, terminate the test. The ignition temperature of the fuel/hall be the last value which saff~ed (c).

B-4.~.2 Minimum Permissive Bed Tempe rature.q~e initial mi ".mmum ~ e l permj~ive shall be deterfi~ined by correlating the results ot the tests ot me uuxnown fuel sample with similar tests performed for fuels used on other units of sunllar des!~? and the co~espon, ding minimum igni_tion temperatures estabh3hed for those mere in me respective units. It shouldbe notedthat this procedure, like the one described in section B-4.1.1 has a d_egree of uncertainty and appropriate safety ma~gim should be included until the compldtion of teming'on the actual unit can be completed. ~ 9. Change Section B-5to read as follows: , "B-5 Verifying Minimum Temperature at Actual Plant. .The FBC

supplier and the operator should agree to a procedure similar to matfler~ribed in g-4.1.1 for vedfyidg a minifiaum bed temperature xor zuel now start in the full scale p l~ t . A ~ of safety should'be added to any value derived through test. Where fuet sources change toe minimum temperature, the test should be repeat es:L SUBSTANTIATION: Chagg_ es are for consistent/with corr.es~ond- ing text in body of standard. Some changes are editorial. Als~ refer to'Proposal 850647 (Log #31) and 8504-~ (Log #35). COMMITrEE~"YION: Accevt. - NUMBER OF COMMITTEE MEMBERS ELIGIBLE TO VOTE- 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVF_~ 19 NOT RETURNED: 8 AxUnan, Conrod, Darguzas, Goldbach,

Knotts, Malthews, McKee, O'Brien

([.,og#S]) 8504- 47 - (B-3-2 (New)): Accept ha Prindple SUBMIT'rg~ Robert M. Herdman, ABB Combustion Ei~gineering RECOMMENDATION: Renumber existing paragraph B-$ and all subsequent items as ]5-3.1 et~

Insert new section-B-~.2: 13-3.2 An alternate means of establishing an initial minimum

ignition temperature by test is through the use of conventional ignition or flammability tests. The ifitent of these tests is not so much to directly establish a minimum ignition temperature, but rather to allow the manufacturer to extrapolate an ~gr~ition tem.perature based, upon the results of a ~ test arid similar tests on me~ nrea at omer actual Insmllation~ The correlation between the igni~on, temperature (flammability index) yielded by tests of vad'ous fuels at me actual plant and. the verified minimum ignition tem.peramre established for those plants and the results of the

performed on the unknown fuel are sufficient to yield an initiags .etpoint for the unknown fuel. As a minimum, the following are requlreo:

(a) A furnace with a controllable heat source. (b) Thermocouples to monitor the temperature of the furnace. (c) Representa~e samples of the fuel to'be fired. The samples

should fie prepared in accordance with normal procedures for the test .sytup to bi~.utilized. (The intent is not to require any specific test, I~ t rather to use ~ e .same test on multiple fuel samples in order to esta~fisn a relationship between the unknown fuel andits appropriate minimum ignition temperature based upon the relationship of othei" kti~>wn fuels arid their proven ignition temperatu/es), SU]LqrANTIATION: Utilizing a pilot plant as described may not yie~ more accurate minimum permissmes than more conventional Igni~tion (flar~a~tbil" ity) test. Hl0t plmaw, in spite of the criteria listed

me ~ are typically re~acm~ lined or external heated mrougnout the c o ~ h e i g h t . Surface area to volume effects are high in comparimn:with full scale units and energy flux .rates from the walls to individual parg"cles will be ap.precia[ge. Further- more, giventhe corn~exity gnd variability ofUie ~iesi~ns offei-ed by mc~. n~numctarers, it is unlikely that a i/todel pilot l~a~ to the J~el ot detail L~,oposed will be built routinely, ~nd t!ius, the accuracy ozan~ test will be.m:u~ect~not only due to the effects just discussed, out ~so as.a result in me si "_gt~acant differet~ces in di~ign between me pilot plant _and the actual desi~.. Ignition or f l ~ t y tests as con .ventionally performedwill yteld information about various mere wlm respect to one another whic.b may then be correlated with reasoname assurance Wttla operating data to determine a minimum temperature permissive. c O P AcL'rioN: Accept in Prindple. (X)MMITrgg f f r A ~ : Refer to Go~unittee Action and Statement on Propeea18504~Log4K~5) .

OF C ~ M I ~ [ ] [ I ~ IfLIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ALWION: AFFIRMATIVE: 19 NOT RETURNED: 8 AxUnan, Gonrod, Darguzas, Goldbach,

Knot~, Matthews, McKee, O'Brien

(Log #35) 8504- ~ B - 4 ) : Accept in Prindple S ~ Robert M. Herdman, ABB Combustion Engineering RlgCA)MMENDATION: Renumber existing paragraph B3f.l.2 as B-4.1.1, 4-1.2, etc.

Insert new section B-4.2: • 8-4.2 HammabilRyTest.

B-4N.1 Test Procedure. (a) Stabilize the test furnace at 100-200°F above the expected

ignition temperature of the fuel. (b) Admit a fuel sample, (c) If the fuel ignites, repeat the test reducing the temperature of

the furnace. (d) If the fuel fails toignlte, terminate the test. The igni'tion

teml~ranlge of the fugl S-haft be the last value which satisfied (c). B-4.~.2 The initial mininmm fuel permissive shall be determined

b]r corre .19tint the results of the tests of the unknown fuel ~ l e ~ t h ~ tests performell for fuels used on o ~ r units of ,i/nllar ~st~es~H1 ~ ~ e ~ 6 r r ~ g m i n l m u m ~ o n teraperatures • esta ttslied for mose f u ~ ~ the ~ u n i ~ It sfiould be noted that this procedure, 1Eke die'one defcribed in section B-4.1 has a .de~ree of uncertainty and appropriate safety margins should be induded until the comple~on of testing on the a~ual unit can be - complete& S .U~'TANTIATION: Utilizing a pilot plant as described may not yieJ.a more accurate.mininmm pe/'mismves than more conventional .egret/on ( ~ i t y ) test. Pilot plants, in spite of the criteria listed m me sumoam are typically refractory lined or external heated thro.ughout the c o m l ~ e ~ h e l g h t . Surface area to .volume effects are ~ i n c o ~ with full scale units and e n ~ flux rates from the walh. to indi~dual p ~ ' c l e s will be appreciate. Further- more, given me coml31exity/rod varlabi[ity of file desig~ offered by most manufacturers, it is unlikely that a model pilot.plant to the level of de tan... ~ w i t l be built routinely, and thus, the accuracy ot any test w~lrbe'st~pf.ct notonly due to the effects just discussed, . put also as a result in the siRUificant differences in design between the pilot plant and the ac t~ . d e ~ : Ign_ition or f l ~ i l i t y tests

conventionally pertormed will yteld ibformafion about various fuels wire respect to one another which may then be correlated with reasonable assurance with operating data to determine a minimum temperature permissive. COMMITFEE ACTION: Accept in Prindple. COMMrrrEE.$TATEMENT: Refer to Committee Action and Statement on Proposal 8504-46 (Log #CP5). o NUMBER OF COq~4MITrEE M]~4BE]~ ELIGIBLE TO VOTE: 27 VOTE ON COMMITTEE ACTION:

AFFIRMATIVE: 19 NOT RETURNED: 8 Axunan, Conrod, Darguzas, Goldhach,


319

toj.j. - nfpa · 2010-06-22 · bed ~ and pr.opmes for adoption amendments on nfpa 8504- 19c~,...

Documents