Report of the Committee on

Boiler-Furnace Explosions

James u. Lafontaine, Chairman Pennsylvania Electric

courmey D. Alvey, Lutherville, M'D ~tt'illiam H. Axtman: Manassas, VA' Herbert L. Betmmh Caltex Services Corp.

Pep. American Petroleum Institute James R. Bosttck, Bailey Controls Co. Paul L Cloffl, Babcock & Wilcox William E. C,,,~nh~hnm. United Engineers & constructors Dale E. Dressel, M~nsafito Co. Shelton Ehrlich, Electric Power Research Institute Robert S. Elek, Kemper Group

Rep. The Alliance of American Insurers Humphrey Fedorak, E I duPont deNemours & Co. Frank H. Fishlock, Fenwal Safety Systems, Inc.

Pep. Fire Suppression Systems Assoc. Ronald E. Fringeli, M&M Protection consultants Thomas B. Hamilton, Hamilton Consulting Services Warren G. Hudson, Union Carbide Corp. Masaakl Kinoshlta, Mitsubishi Heavy Industries, Ltd Albert L. Lake, Int'l Union of Operating Engineers Kenneth N. Lawrence, Honeywell Inc.

Rep. Nat'l Electrical Manufacturers Assoc. Donald J. L. Lin, Qilin Inc. Robert M. Lundberg, Los Altos, CA Peter B. Matthews, Hartford Steam Boiler Imp & Ins Co. Russell N. Mosher, American Boiler Manufacturers Assn.

rr~J. Moskal, Combustion Engineering Inc. ael C. Polagye, Factory Mutual Research Corp.

Robert P. Richmond, Baton Rouge, LA James L. Sherman, Baltimore Gas & Electric Co. Robert F. Tomczak, Tampa Electric Co.

Pep. Electric Light Power Group/Edison Electric Institute Enno Toomsaln, Underwriters Laboratories Inc. ames O. Toutz, Forney Engineering eter J. Gore Wlllse, Indust?ial Risklnsurers

Henry K. Wong, Foster Wheeler Energy Corp.

Alternates

john c. deRuyter, E I duPont deNemours & Co. (AlL to H. Fedorak)

John Jazesko, Industrial Risk Insurers (AlL to P.J.G. Willse)

Dennis P. Jehkins, Kemper National Insurance Cos. (Alt. to R. S. Elek)

Paul Karadi, Combustion Engineering Inc. (Alt toJ.J. Mos~)

Richard F. Murphy, Exxon Research & Engr Co. (Alt. to H. L. Berman)

J. c. Waung, Babcock & Wilcox Co. (AlL to P. L. Cioffi)

Subcommittee on Single Bunter BoRer-Furnaces

Humphrey Fedorak, Chairman E I duPont deMenours & Co.

Dale E. Dremel, V/c, Chairman Monsanto Company

Courtney D. Alvey, Lutherville, MD • William H. Amman, Manassas, VA

Ian M. Clark, ABB Combustion Engineering, Inc. Thomas C. Clayton, Black & Veatch John M. DeLacy, The Coen Co. Robert J. Gross, Babcock & Wilcox James I,L Lafontalne, Pennsylvania Electric Kenneth N. Lawrence, Honeywell, Inc.

Pep. Nat'l Electrical Manufacturers Assn. Enno Toomsalu, Underwriters Laboratories Inc. ames C. W'flliams, American Risk Management Corp. eter J. Gore Willse, Industrial Risk Insurers

Nonvoting

Russell N, Mosher, American Boiler Manufacturers Assn.

Sucommlttee on Pulverized Fuel Systems

Thomas B. Hamilton, Cha/rman Hamilton Consulting Services

Courtney D. Alvey, Lutherville, MD William H. Axtman, Manassas, VA John N. Cannon, Brigham Young University, UT

Robert Christtmmon, Stone & Webster Engineering Corp. Thom~ C. Clayton, Black & Veatch Thomas A. Collette, Commonwealth Edison David A. Cowdrick, Tampa Electric Co. John C. deRuyter, E I duPont deNemours & CO. Mike Doherty, American Electric Power Service Corp. Kenneth L. Gardner, Kennedy Van Saun corp. Paul Hunt, Stock Equipment Co. Walter E. Keiser, Georgia Power CO. Allan E. Kukoski, Foster Wheeler Energy Corp. James K. Lafontalne, Pennsylvania Electric DanielJ. Lee, Bailey controls Co. Kiran R. Patel, RileyStoker Corp. Robert Piepho, Babcock & Wilcox Co. AlanJ. Selbert, ABB Combosdon Engineering Gary D. Taylor, Duke Power Co.

Alternates

Domdd Dougnn, Babcock & Wilcox Co. (Alt. to R. Piepho)

Joel Vatsky, Foster Wheeler Energy (Alt. to A. E. Kukoski)

Nonvoting

Frank H. Fishlock, Fenwal Safety Systems, Inc. Russell N. Mosher, Ame .rican Boiler Manufacturers Assn..

StaffLiaison: C ~ C. Grant

This list represents the membershi]~ at the time the committee was balloted on the text of this edinon. Since that time changes in the membership may have occurred.

The Report of the Committee on Boiler combustion System Hazards is presented for adoption in 3 parts.

, Part I of this Report was prepared by the Technical committee on Boiler Combustion SystemHazards and proposes for adoption partial amendments to NTPA 85A, Standard for the Prevention of Furnace Explosions in Fuel Oil- and Natural Gas-Fired Single Burner Boiler- Furnaces. NFPA 85A is published in Volume 4 o f the 1991 National Fire Codes and in separate pamphlet form.

Part 1 of this Report has been submitted to letter ballot of the Technical Comrmttee on Boiler Combustion System Hazards which consists of S1 voting members; of whom all 31 voted affirmatively.

Part II of this Report was prepared by the Technical Committee on Boiler Combustion System Hazards and proposes for adoption partial amendments to NFPA 85F, Standard for the Installation and Operation of Pulverized Fuel Systems. NFPA 85F is published in Volume 4 of the 1991 National Fire Codes and in separate pamphlet form.

Part II of this Report has been submitted to letter ballot of the Technical committee on Boiler Combustion System Hazards which consists of 31 voting members; of whom all 51 voted affirmatively.

Part HI of this Report waa prepared by the Technical Committee on Boiler Combustion System Hazards and proposes for adoption partial amendments to NFPA 85I, Recommended Practice for Stoker Operation. NFPA 85I is published in Volume 9 of the 1991 National Fire Codes and in separate pamphlet form. ,

Part HI of this Report has been submitted to letter b~diot of the Technical Committee on Boiler Combustion System Hazards which consists of 31 voting members; of whom all 51 voted affirmatively.

4

N F P A 85A ~ A92 T C R

PARTI

85A - 1 - (Foreword): Accept ' SUBMITTER: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Delete the notice under "Origins and Development" and replace it with a "Forward" section as follows:

"Foreword

The technological explosion in recent years, and in particular the pervasiveness of microprocessor based hardware, makes it even more important that only highly qualified individuals be em.ployed in the translation of these gmdelines into operating systems.Eacl~ type of hardware has its own unique features and operational modes. It is vital that the designer of the safety system be completely familiar with the features and foibles of the specific hardware, as wellas possess a thorough understanding of these standards and their intent.

It is not possible for these standards to encompass the specific hardware applications, nor should these be considered a "cookbook" for the design of a safety system.

When applying any type of equipment to a safety system, the designer must carefully consider all of the possible failure modes and the effect that each might have on the integrity of the system and the safety of the unit and personnel. In particular, no single point failure should result in an unsafe or uncontrollable condition or a masked failure of a microprocessor based system that could result in the operator unwittingly taking action that could lead to an unsafe condition.

This document is to be used for the design, instalLation, operation, and maintenance of single burner fire-tube and water-tube boiler- furnaces and their biL,'ner management and combustion contrbl systems. The standard is organized as follows: .

/

1. Introduction and common sections that apply to all fired fuels covered in'this standard (Chapters 1-4).

2. Detailed sections that are specific to the particular operation desdribed. Chapter 5 applies to starting up a cold boiler. Chapter 6 applies to operating systems including automatic recycling and automatic non-recycling systems for both watertube and fire tube boilers, and supervised manual systems for oil or gas fired watertube boilers. Chapter 7 applies to simultaneous firing of fuels. Chapter 8 applies to fuel transferring. Chapter 9 applies to dual atomizers in a stogie burner. Chapter 10 applies to inspection and maintenance.

When using this standard, the common sections should be used in conjunction with the sections covering the specific operation described. The Appendixes are additional useful information but are not mandatory." SUBSTANTIATION: This provides information that addresses burner management system logicfor burner boiler applications. This more appropriately belongs in a "Foreword". COMMITrEE ACTION: Accept.

85A- 2 - (1-1.2, 1-2.S): Accept SUBMITTER: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Move 1-2.3 to Scope (1-1) and renumber as 1-1.2. Reverse the order to the two sentences so paragraph starts: "rhig standard is not retroactive. This standard i s . . . "

SUBSTANTIATION: This paragraph properly belongs in the Scope section. The change also makes this consistent with NFPA 85C." COMMITrEE ACTION: Accept-

85A- 3 - (1-1.3, '1-2.4): Accept SUBMITrER: Subcommittee on Single Burner Boiler-Furnaces

I RECOMMENDATION. Move paragraph 1-2.4 to Scope and renumber as 1-1.3. Renumber subsequent paragraphs accordingly. SUBSTANTIATION: This paragraph properly belongs in Scope

' section and will also match NFPA 85C. COMMITTEE ACTION: Accept-

85A- 4 - (I-1.4, 1-2.5): Accept SUBMIT'rER: Subcommittee on Single Burner Boiler-Furnaces

I RECOMMENDATION: Move paragraph 1-2.5 to Scope and renumber as 1-1.4. Renumber subsequent paragraphs accordingly.

SUBSTANTIATION: This paragraph properly belongs in Scope section and will also match NFPA 85C. COMMITTEE ACTION: Accept-

85A- 5 - (1-1.5 (New)): Accept SUBMITI'ER: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Add a new paragraph I-1.5 as follows:

1-1.5 Revisions to this document reflect the current state of knowledge and do not imply that previous editions were in~idequate. SUBSTANTIATION: This maintains the credence of previous editions of NFPA 85A, and also coordinates with NFPA,85F. COMMYI'IIdE ACTION: Accept.

85A - 6 - (1-2.4 (New)): Accept SUBMITI'ER: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Add a new 1-2.4:

~I'he effect of gas cleanup systems located downstream of the p.ost combustion gas passes of the boiler-furnace is known to be sigmfi- cant. Coordinauon b f the operating procedures and designs of the boiler furnace and air quality system's air/flue gas path is required. ' Such coordination shall include requirements for ensuring a continuous flow path from the forced draft fan inlet through the stacL This standard offers only the general requirements of these systems because of the many variations of the designs," SUBSTANTIATION: This addresses the addition of AQCS systems. COMMITTEE ACTION. Accept.'

85A- 7 - (2-1): Accept S U B ~ Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Change title for 2-1 to "Furnace Explosions". Revise Section 2-1 as follows: "2-1 Furnace Explosions.

2-1.1 The basic cause of furnace explosions is the ignition of an accumulated combustible mixture within the confined space of the furnace or the associated boiler passes, ducts and fans which convey the gases of combustion to the s t a ck . . "

2-1.2 A dangerous combustlble mixture within the boiler-furnace enclosure consists of the accumulation of an excessive quantity of combustibles mixed with air in proportions that will result in rapid or uncontrolled combustion when an ignition source is supplied. A furnace explosion may result from ignition of this accumulation if the quantity of combustible mixture and the proportion of air to fuel are such that an explosive force is created within the boiler-furnace enclosure. The magnitude and intensity of the explosion ~vill depend upon both the relative quantity of combustibles that has accumulated and the proportion of mr that is mixed therewith at the moment of ignition. Explosions, including "furnace puffs," are the result of improper procedures by operating personnel, improper design of equipment or control system, or equipment or control system maLtunction.

2-1.3 Numerous situations can arise in connection With the operation of a boiler-furnace that will produce explosive conditions; the- most common experiences are:

(a) An interruption of the fuel or air supply or ignition energy to the burners, sufficient to result in momentary loss of flames, followed by restoration and delayed reignidon of an accumulation.

(b) Fuel leakage into an idle furnace and the ignition of the accumulation by a spark or other source of igniuon. .

(c) Repeated unsuccessful attempts to lightoffwithout appropriate purging resulting in the accumulation of an explosive mixture.

(d) The accumulation of an explosive mixture of fuel and air as a result of a complete furnace flameout and the ignition of the accumulation by a spark or other ignition source, such as attempting to light burner.

2-1.4 The conditions favorable to a boiler-furnace explosion described in 2-1.S are typical examples, and an examination of numerous reports of boder-furnace explosions suggests that the occurrence of smail explosions, furnace puffs, or near-misses has been fa /more frequent than is usually recognized. It is believed that improved instrumentation, safety interlocks and protective devices,

5

N F P A 8 5 A ~ A 9 2 T C R

prop p , e r o erating sequences, and a clearer understanding of the problemby both designers and operators can gready reduce the risks and actual incidence of furnace explosions.

2-1.5 In a boiler-furnace, upset conditions or control malfunction may lead to an air/fuel mixture that may result in a flameout followed by reignition after a combustible air/fuel ratio has been reestablished. Dead pockets may exist in the boiler-furnace enclosure or other parts of the unit, where combustible mixtures can accumu- late under upset furnace conditions. These accumulations may ignite with explosive force in the presence of an ignition source." SUBSTANTIATION: Revise all of Section 2-1 to match Section 2-1 in ' NFPA 85C (except delete 2-1.3(d) and 2-1.3(0). Also remove the parenthetical "(s)" as used in the wording from NFPA 85C, 2-1.3(e). Renumber this section as required. This provides consistency with NFPA 85C. COMMITrEE ACTION: Accept.

85A- 8 -(2-2): Accept SUBMITIT.Rz Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Revise Section 2-2 to read as follows:

"2-2 Manufacture, Design, and Engineering.

2-2.1 The purchaser or the purchaser's agent shall, in cooperation with the manufacturer, assure that the umt is not deficient in apparatus that is required for proper operation, so far as practical, with respect to pressure parts, fuelburning equipment, an" and fuel , metering, and/ate lighting and maintenance of stable flame.

2-2.2 All fuel systems shall include provisions to prevent foreign substances interfering with the fuel supply to the burner.

2-2.3 An evaluation shall be made to determine the optimum integration of manual and automatic safety features considering the advantages and disadvantages of each trip function.

NOTE: The maximum number of automatic trip feature does not necessarily, provide for maximum overall safety. Some trip actions result m additional operations that increase exposure to hazards.

2-2.4 This standard requires a minimum degree of automation. The trend toward more complex plants or increased automation requires added pi'ovisions for:

(a) Information about significant operating events permitting the operator to make a rapid evaluation of the operating situation. The operator shall be provided with usable displays of variables that will allow the opera~r tO. avoid unsafe conditions. '

(b) In-service maintenance and checking of system functions without impairing the reliability of the overall control system.

(c) An environment conducive to proper decisions and actions.

2-2.5 The burner front piping and equipment shall be designed and constructed to prevent the formation of hazardous concentrations of combustible gases that may exist under normal operating condi- tions." SUBSTANTIATION: Revise Section 2-2 to match NFPA 85C, Section 2-3 (for 2-3.1 through 2-3.5 only, and not including 2-3.6 and 2-3.7). Further modifications include deleting and changing the references used in NTPA 85C, 2-3.4 and changing the wording in 85C, 2-3.4(a) wording, second sentence to ~ 'he operator shall be provided with usable displays of..."

Th~ provides consistency with NFPA 85C. The definition of continuous is not clear and is not appropriate for single burner applications." COMM1TIT, E ACTION: Accept.

85A- 9 - (2-3.1.3): Accept SUBMrrTER: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Change the first sentence of 2-3.1.3 to read:

"The safety interlock system and protective devices shall be jointly tested by the organization...", SUBSTANTIATION; To be consistent with NFPA 85C. COMMrl~IT, E ACTION: Accept.

85A- 10 - (2-4): Accept SUBMITTER: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Revise 2-4 to match NFPA 85C, Section 2-5 as follows: 2.4 Coordination of Design, Construction, and Operation. 2.4.1 Statistics indicate that human error is a contributing factor in the majority of furnace explosions. It is important to c'onslder whether the error was a result of:

(a) Lack of understanding of, or failure to use, proper operating procedures, safeguards, and equipment.

(b) Unfavorable operating characteristics of the equipment or its control.

(c) Lack of functional coordination of the various components of the steam generating system and its controls.

2.4.2 Furnace explosions have occurred as a result of unfavorable functional design. Frequently the investigation has revealed human error and has completely overlooked the chain of causes that triggered the operating error. Therefore, the design, installation, and functional objectives of the overall system of components and their controls shall-be integrated. Consideration shall be given to the ergonomics that will exist during the operating life of the system.

2-4.3 In the planning and the engineering phases of plant construc- tion, design shall be coordinated with operating personnel.

2-4.4 The proper integration of the various components consisting of boiler, burner, fuel and air supply equipment, controls, interlocks and safety devices, operator ana maintenance functions, and commumcation and-training shall be the responsibility of the operating company and shall be accomplished by:

(a) Providing design and operatingpersonnel who possess a high degree of competence in this field andwho are required to bring about these objectives

(b) Periodic ~ to compare the plant to evolving technology so that improvements can be made to make the plants safe and more reliable

(c) Maintaining documentation of plant equipment, system, and maintenance." SUBSTANTIATION: This provides consistency with the NTPA 85 series documents. COMMITrEE ACTION: Accept.

85A- 11 - (Chapter 3): Accept SUBMITIT.R: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION. Add to defimtions:

"Boiler Control System. The group of control systems which regulates the boiler process including the Combustion Control but not the Burner Management." SUBSTANTIATION: To be consistent with NFPA 85C. C O ~ ACTION: Accept.

85A- 12 - (Chapter 3): Accept SUBMITIT.R: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Add definition for:

"Burner Management System. The control system dedicated to boiler furnace safety, operator assistance in the starting and stopping of fuel preparation and burning equipment, and for preventing misope~tion of and damage to fuel preparation andburning equipment. , ~

Types of systems used in this document incmoe: ' At/tomatic (Recycling). A system by which a furnace is purged and a

burner is started, ignited, and stopped automatically andwhich recycles on a preset pressure range. Automatic (Nonrecycling). A system by which a furnace is purged

and a burner is started, ignited, and stopped automatically but does not recycle automatically.

Manual. A system by which a furnace is purged and a burner is started, ignited, and stopped manually.

Supervised Manual. A system by which a furnace ispurged and a burner is started, ignited, and stopped manually, with interlocks to ensure that the operation follows established proper procedures." SUBSTANTIATION: This provides consistency withNFPA 85C. COMMITTEE ACTION: Accept.

N F P A 8 5 A - - A 9 2 T C R

85A- 1S - (Chapter 3): Accept SUBMIITER. Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Add definition of "Combustion Control System" as follows:

"Combustion Control System. The .control system that regulates the furnace fuel and air inputs to maintain air/fuel ratio within the limits required for continuous combustion and stable flame throughout the operating range of the boiler in accordance with demand. This control system includes,the furnace draft control Where applicable." SUBSTANTIATION: To be consistent with NFPA 85C. COMMITTEE ACTION: Accept.

85A- 1'~ - (Chapter 3): Accept SUBMITTER: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Revise as follows: " '

"Fuel OiL Numbers 2, 4, 5, and 6 fuel otis m defined in ASTM I)396, Standard Specifications for Fuel Oils." SUBSTANTIATION: This provides consistency with NFPA 85C. Also, #1 oil is not used in this class of boiler. COMMITTEE ACTION: Accept.

85A- 15 - (Chapter 3): Accept SUBMITIT_.R: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Add for cross reference:

"Furnace Purge - see purge." SUBSTANTIATION: Editorial. COMMITTEE ACTION: Accept.

85A- 16 - (Chapter 3): Accept SUBM1TI'ER: Subcommittee on Single Burner Boiler-Furnace. RECOMMENDATION. Change definition of "inerting" to read:

"Inerting. The dilution of the oxygen content of an air/fuel mixture to a point where it is no longer explosive through the addition c.f an inert gas or vapor." SUBSTANTIATION: The current definition is non-specific. The recommended change matches NFPA 85C. COMMrlTEE ACTION: Accept.

85A- 17 - (Chapter 3): Accept SUBMrITER: Subcommittee on Single Burner Boiler-Furnace,; Rlg COMMENDATION" Add a definition for "Logic System" as follows:

"Logic System. The decision making and translation elements i,~f the burner management system. .(a) Hard wired systems. Individual devices and interconnecting wk'ing. .(b) Micro processor based systems. 1. Computer hardware, power supplies, I / O devices ahd intezcon-

, nections between these. 2. Operating systems and logic software."

SUBSTANTIATION: This addresses the issue of microprocessors. COMMITTEE ACTION: Accept.

85A- 18 - (Chapter 3): Accept " SUBMITTER: Subcommittee on Single Burner Boiler-Furnace~; RECOMMENDATION: Add the following definition:

"Safety Shutdown Trip Relay. An electro-mechanical relay utili::ed to trip all required equipment simultaneously. SUBSTANTIATION: To address the need for positive tripping when using microprocessor based logic systems. COMMITTEE ACTION: Accept.

85A- 19 - (4-1.9 (New)): Accept SUBMrI'FF.R: Subcommittee on Single Burner Boiler-Furnace i RECOMMENDATION: Add: 4 .1 .90i lpiping materials and system ~lesign shall be it/accordance with NFPA 31, Stan .d.d.d.d.ard for the Installation of Oil Burning Equip- ment. SUBSTANTIATION: This change will require material selection and piping design in accordance with nationally recognized standards. COMMITIT.EACTION: Accept. ~ .

85A- 20 - (4-2.6 (New)): Accept SUBMITI'ER: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Add: 4-2.6 Gas piping materials and system design shall be in accordance with NFPA 54, National Fuel Gas Code. SUBSTANTIATION' This change will require material selection and piping design in accordance with nationally recognized standards. COMMITTEE ACTION: Accept.

85A- 21 ~ (44.1.35: Accept SUBMITrER: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION. Add the following between the first and second sentence:

"An automatic vent valve sfiall be provided between the two valves or gas igniters (see Appendix E). UBSTANTIATION, This includes the valve labeled "C" in

Appendix E. COMMITTIKE ACTION: Accept.

85A- 22 - (4-5): Accept in Principle " SUBM1TrER: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Insert a new section 4-5 as follows and renumber subsequent sections accordingly: "4-5 Burner Management System, Logic. The intent of this section is to provide guidance in the use of logic systems in burner manage- ment.

4.5.1 General Requirements. A logic system provides outputs in a particular sequence in response to external inputs and internal logic. The logic system for burner management shall be specifically designed so that a single failure in that system shall not prevent an appropriate shutdown. . .

4-5.2 Specific Requirements. As a minimum, the following shall be included in the design to ensure that a logic system for burner management meets the intent of these standards.

NOTE: Some items are not applieal~le to specific types of logic systems, e.g., relay.

4-5.2.1 Failure Effects. The logic system designer shall'recognize the failure modes of components when considenng the design applica- tion of the system. As a minimum the following failure effects shall be evaluated and addressed:

(a) Interruptions, excursions, dips, recoveries, transients, and partial losses of power.

(b) Memory corruption and losses.

(c) Information transfer corruption and losses.

(d) Inputs and outputs "fall-on," "fail-off."

(e) Signals unreadable or not being read.

(f) Addressing errors.

(g) Processor fauhs.

4-5.2.2 Design.

(a) Diagnostics shall be included in the design to monitor processor logic functionability.

(b) Logic system failure shall not preclude proper operator intervenuon.

(c) Logic shall be protected from unauthorized changes.

(d) Logic shall not be changed when the associated equipment is in operation.

(e) System response time (throughput) shall be sufficiently short to prevent negative effects on the application. .

(f) Noise immunity shall be adequate to prevent false operation.

(g) A single component failure within the logic system shall not prevent a mandatory safety shutdown trip.

N F P A 8 5 A - - A 9 2 T C R

(h) The operator shall be provided with (a) dedicated manual switch(es) that shall independently and directly actuate the safety shutdown trip relay.

/

4-5.2.S Requirement for Independence: The logic system perform- ing the safety functions for burner management and borer control systems shall not be combined with anyother logic system. These burner management safety functions shall include, but not be limited to, proper purge interlocks and timing, mandatory safety shutdowns, trial timing for ignition, and flame monitoring. SUBSTANTIATION: This provides information that addresses burner management system logic for single burner. COMMITTEE ACTION: Accept in Principle. Accept the new proposed secnon 4.5 except by revising the first

sentence of 4.5.2.3 as fonows: "The logic system performing the safety functions for burner

management and boiler control systems shall not be combined with any other logic or control system." COMMrrTEE STATEMENT: This prevents combining with other analog controls.

(LOg # 2 ) 85A- 23 - (5-1, 5-2, and 5-3): Accept in Principle SUBMITTER: Humphrey Fedorak, DuPont Co. RECOMMENDATION: Add 5-1 General.

Present 5-1 becomes paragraph 5-1.1 Present 5-2 becomes paragraph 5-1.2 Add 5-2 Gas Fired Boilers. Add 5-211 The procedures of Chapter 6 shall be

followed for starting a cold gas fired boiler. 5-3 Oil Fired Boilers , Present 5-3

becomes 5-3.1 and renumber remainder of present .5-3 section as required. Also add to Chapter 5 index

5-1 General 5-2 Gas Fired Boilers 5-3 Oil Fired BoRers

SUBSTANTIATION: Style of 5-1 to 5-3 do not match remainder of document. Also there is no.clear reference on how to start a cold gas fired boiler. COMMrt-rt;Ig ACTION: Accept in Principle.

1. Add 5-1 General 2. Renumber 5-1 and 5-2 to 5-1.1 and 5-1.2. 3. Insert a new section 5-2 as follows: 5-2 Gas Fired Boiler. The procedures of Chapter 6 shall be

followed for starting a cold gas fire boiler. 4. Insert a new heading in 5.3 as "Oil Fired Boilers."

COMMrrTEE STATEMENT: This meets the intent of the submitter but conforms to the NFPA Manual of Style. The index will be revised automatically by NFPA staff prior to final release of the document. ,

85A - 24 - (6-2.4.1 (a)): Accept SUBMrrTER: Subcommittee on Single Burner Boiler-Furnaces RECOMME~IDATION: Delete "For gas firing, this shall be the down s t r e a m v a l v e . "

SUBSTANTIATION: This conflicts with paragraph 4-2.3, which requires proof of closure on both valves. COMM1TrEE ACTION: Accept.

(Log # 6) 85A- 25 - (6-2.4.1(h)): Reject SUBMITFER: Ma.maki Kinoshita, Mitsubishi Heavy Industries, Ltd. RECOMMENDATION: Revise the last sentence of (h) as follows:

"Purge airflow shall reach no less than 25 percent of the airflow..." SUBSTANTIATION: To be consistent with NFPA 85B and D. If the requirement of 70 percent of the airflow does not have any technical background, it should be the same as 85B and D. COMM1TFEE ACTION: Reject. COMMITIT.E STATEMENT: Extensive Committee deliberations and [3ersonal Committee ex. perience . . . . indicate that the current reqmrements, are ap.p ropnate. In this .instance' consmency wtth muluple burner boilers is not appropriate.

(Log # 7) 85A- 26 - (6-2.4.1(i)): Reject ° SUBMHWER: Masaaki Kinoshita, Mitsubishi Heavy Industries, Ltd. RECOMMENDATION: Revise the first sentence of (i) as follows:

(i) The purge shall be suffident for ai least five air changes. SUBSTANTIATION: To be consistent with NFPA 85B and D. Same as 6-2.4.1 (h). COMMrITEE ACTION: Reject. COMM1TIT~ STATEMENT: Refer to action on 85A-25 (Log #6).

85A- 27 - (6-2.4.6): Accept SUBMrI 'rER: Subcommittee on Single Burner Boiler.Furnaces RECOMMENDATION: Revise as follows:

"For automatic (recycling) boilers, the high steam, pressure, high water temperature, or low water level (not determined by the auxiliary low water cutout) shall accomplish a normal shutdown, and the burner shall be allowed to recycle when steam pressure, water temperature, or water level has dropped to within the preset operating range." SUBSTANTIATION: Low water cutouts are described and shown for firetube boilers but were omitted for watertubes. COM~II'I'I'/~E ACTION: Accept.

(Log # S) 85A. 28 - (6-4.2.2(c)): Accept in Principle SUBMITr~R: Masaaki Kinoshita, Mitsubishi Heavy Industries, Ltd. RECOMMENDATION: Add the following to the end of (c):

Wor gas igniters vent the gas piping between igniter safety shutoff valves to- atmosphere." SUBSTANTIATION: To be consistentwith 6-2.4.2(c) and safe consideration. COMMrrFEE ACTION: Accept in Principle. Accept the submitters change to 6-4.2.2(c). Also add a new 4-2.6 as

follows: 4-2.6 The disch ..m'ge from atmospheric vents shall be located so that

there is no 13ossibiltty of the dischargedgas being drawn into the air intake, venulating system, or windows of the borer room or adjacent buildings and shall be extended sufficiently above the boiler and adjacent structures so that gaseous discharge does not present a fire hazard. There shall be no cross connection between venting systems of different boilers. COMMITTEE STATEMENT: The submitters proposal has pointed. out the lack of specific information on venting to the atmosphere. The new 4-2.6 correlates with paragraph 6-3.1.8 of NFPA 85C and provides the hecessary criteria.

(Log # 9) 85A- 29 - (6-4.2.7(a), (b)): Accept SUBM1TIT.R: Masaaki Kinoshita, Mitsubishi Heavy Industries, Ltd. RECOMMENDATION: Add "power failure" to item (a) and (b). SUBSTANTIATION: To be consistent with 6-2.4.8 and safe consideration. COMMFFrEE ACTION: Accept.

(Log # S) 85A- 30 - (6-6.4): Accept in Principle S U B M r r F F ~ Humphrey Fedorak, DuPont Co. RECOMMENDATION: Insert a new p mTag~_ ph 6-6.4 as follows:

6-6.4 Purge rate, air changes and time shall be not less than requirements of 6-2.4.1.

Renumber existing 6-6.4 and following paragraphs as required. SUBSTANTIATION: The most important startup step to prevent boiler furnace explosions is not specified for supervised manual startup. COMMrFrEE ACTION: Accept in Principle.

For item 4 under qnterlock Functions o f 6-6.4 add: "See 6-9.4.1 (h) and (i)". C O M M I T F ~ STATEMENT: This addresses the concerns of the submitter but provides consistency with the format currently used in NFPA 85A.

85A- 31 - (6-7.4~(New)): Accept in Principle SUBM1TITJ~ Humphrey Fedorak, DuPont Co.

(Log # 4)

. 8

NFi?A 85A '--- A92 TCR

RECOMMENDATION: Insert a new paragraph 6-7.4 as follow;: SUBSTANTIATION: This change will make Appendix G more 6-7.4 Purge rate, air changes and time shall be not less than consistent with safety shutdown requirements described in Chapters 6

requirements of 6-4.2.1. and 7; Renumber 6-7.4 and following paragraphs as required., COMMrlWEE ACTION: A~cept.

SUBSTANTIATION: The most important startup step to prevent boiler furnace explosions is not specified for supervised manua[ starmp. COMMrrTEE ACTION: Accept in Principle. . 85A- 38 - (Figure G-l): Accept

For item 3 under "Interlock Functions" o f 6-7.4 add: "See 6-2.4:.1 (h) SUBMITI 'F .~ Subcommittee on Single Burner Boiler-Furnaces and (i)." RECOMMENDATION: 1. For item P description, "interlock" should COMMITTEE STATEMENT: Refer to action on NFPA 85A-30 (Log be one word. #3). 2. In the diagram - remove line connectin~ the two squares that

represent the operating device on the two oil safety shutoffvaives (Item A). SUBSTANTIATION: This change will make Appendix G more

(Lob¢# 10) consistent with safety shutdown requirements described in Chapters 6 85A- 32 - (9-2(d), (e)): Reiect " and 7. SUBMITTER: Masaaki Kinoshita, Mitsubishi Heavy Industries, Ltd. • COMbIIT1W, E ACTION: Accept. RECOMMENDATION: Perform step (e) prior to step (d). SUBSTANTIATION: Current procedure may cause the drop of boiler load.

With the proposed procedure, it is easier to maintain the boiler (Log # 5) load. Fuel-richcondition can still be prevented by careful change- 85A- 39 - (Appendix H): Accept in Principle over of the valves. SUBMI'rrER: William E. Cunningham,,United Engineers & COMMrrrEE ACTION: Reject. . Constructors COMMITrEE STATEMENT: Current procedure is correct because RECOMMENDATION: Add a new appendix as follows: it lessens the chance for human error. When properly executed'., minimal change in boiler load should be experienced. "Appendix H

General Considerations for Control Logic

85A- 33 - (10-4.1 (b)): Accept SUBMITrF.~ Subcommittee on Single Burner Boiler-Furnace.,, This Appendix is not a part of the requirements of this NFPA

I RECOMMENDATION. Change "Low water level cutout and al;u'm" document, but is included for information purposes only. to "Low water level cutouts andassociated alarms." SUBSTANTIATION: NFPA 85A requires two low water cutouts. H-1 Requirement for Independence. The logic system performing COMMxt-I't2EACTION: Accept. the safety functions for burner management safety funcuons shall

includehut not be limited to, proper purge interlocks and timing and flame monitoring.

85A- 34 - (Figure E-l): Accept ~ H-2 A control system shall be designed to permit a' safe shutdown of SUBMrrrER: Subcommittee on Single Burner Boiler-Furnaces the system, ira failure should occur within the system.

[ RECOMMENDATION: Add "(NC)" after description of item V. SUBSTANTIATION: This provides consistency with other portions of H-3 Simulation and testing of the system should he completed before the document. • , the boiler start up. The testing and simulation should be completed COMMITTEE ACTION: Accept. on the entire system to ensure proper coordination between

, ~ functional logic systems.

H-4 The system should furnish the operator critical information 85A- 85 - (Figure F-l): Accept through alarms or alarm outputs. SUBM1TrERt Subcommittee on Single Burner Boiler-Furnaces , RECOMMENDATION. Delete: "Low boiler (steam and hot wat,:r) H-5 The system logic designer should take into consideration two out- water level interlocks (two required)" . of three logic for master fuel trips.

Delete: "Purge air-flow switcl~" Delete: "Forced draft fan discharge pressure switch and fan damper H-6 If CRT/Keyboard Control is used in the design of the logic

position switch (alternative to purge air-flow switch)" system, the following should be considered. Add: "Auxiliary low water cut-off (one required)" Add: "Combustiofi air supply interlock"

SUBSTANTIATION: This change will make Appendix F more *'A hard-wired push button(s) to trip the system. consistent with safety shutdown requirements described in Chap1 ers 6 and 7. * A redundant CRT and keyboard should be considered during the COMMITTEE ACTION: Accept. design.

• The system outputs should be hard-wired to devices required to trip on,a master fuel trip.

85A- 36 - (Figure F-1 and Figure G-l): Accept SUBMrr rER~ Subcommittee on Single Burner Boiler-Furnaces * Inputs which furnish data which may cause a master fuel trip RECOMMENDATION: Change "Safety Controls not Shown" to should also be hard-wired. "SafetyShutdown Interlocks (not shown): SUBSTANTIATION. This clarifies the items not shown in these • Communication with other systems should be limited to data illustrations by using defined terms, required for graphics, data and start/stop. Backup hard- COMMrrFEE ACTION: Accept:. wired trips should also be included.

-H-7 A single,component failure within the logic system should not prevent a mandatory master fuel trip or any individual safety related,

85A - 37 - (Figure G-l): Accept subsystem trip. , SUBMrr I 'ER: Subcommittee on Single Burner Boiler-Furnaces RECOMMENDATION: Delete: "Low boiler (steam and hot water) H-8 The designer may consider redundant logic for large boiler logic water level interlocks (not required)" systems. The logic will have to transfer to the redundant logic and

Delete: "Purge air-flow switch" - should be so designed to permit transfer back to the prime logic. Delete: "Forced draft fan discharge pressure switch and fan dam?er The redundant logic shall be designed so that the backup system will

position switch (alternative to purge air-flow switch)" cause a master fuel trip upon logic failure of the prime and redun- Add: "Auxiliary low water cut-off (one required)" dant modules. Add: "Combustion air supply interlock

N F P A 85A ~ A92 T C R

H-9 The designer should consider first out logid to permit an ease of trouble shooung, after a trip."

SUBSTANTIATION: The NFPA should furnish an AnDendix H General Considerations for Control Systems. " " The draft is indeed in a rough format but offers a few ideas. Today,

anyone can purchase a low price control system and program it. The purpose to the Appendix would be to offer a few guidelines. COMMITTEE ACTION. Accept in Principle. No Action. COMM1TrF~ STATEMENT. The concerns.of the submitter are primarily addressed with existing text or with other proposals mcludedin this report. The following is a summary response to the submitters proposal:

.1. H-l: Covered by 4-5.2.3, proposal 85A-22; 2. H-2: Covered by 4-3.1 and 4-5.2.2(b), proposal 85A-22; 3. H-3: Covered by 2-3.1.3 of NFPA 85A; 4. H-4: Covered'by 2-2.4(a) of NFPA 85A; 5. H-5: This is too design specific and is not appropriate for a

minimum standard; 6. H-6(a): Covered by 4-5.2.2(h); 7. H-6(b): This is too design specific and is not appropriate for a

minimum standard; 8. H-6(c): Covered by 4-5.2.2(h). Also, this is too design specific

and is not appro~priate for a minimum standard; 9. H-6(d): This is too design specific and is not appropriate for a

minimum standard; 10. H-6(e): This is too design specific and is not appropriate for a

minimum standard;

11. H-7: Covered by 4-5.1 and 4-5.2.2(g), proposal 85A-22; 12. H-8: This is not appropriate for a single burner boiler. Also,

this is too design specific andis not appropriate for a minimum standard;

,13. H-9: This information is desirable but is not within the scope of NFPA 85.4.

(Log # 1) 85A- 40 - (Appendices): Accept in Principle SUBMITrE~ Dale E. Dresse], Monsanto Co. RECOMMENDATION: Revise numbering ofappendicesA through G as indicated below:. Add asterisks in body of document to reference appendix material.

Reorder appendices based on new labelling. Correct references as required.

Appendix A

This Appendix is not a part of the requirements of this NFPA document, but is included for information purposes only.

A-6-1 Manual Systems for Watertube Boilers. The manual systems are not recommended; however, it is recognized that with adequate and uninterrupted supplies of fuel and air, certain operating functions can be pefformedby a qualified operator as weIias by control devices.

I. Controls and Interlocks.

A. Interrupted or Intermittent Igniter.

B. Safety shutoffvalves, as follows:

(a) Gas Firing. Two automatic safety shutoff valves, spring closing, in gas line to the main b'urner, with intermediate spring opening automatic vent valve.

(b) Oil Firing. Two automatic spring<losing safety shutoffvalves in oil line to burner.

CAUTION: Means shall be provided to prevent or relieve excess pressure between these valves.

(c) Gas Fired Igniter. Two spring closing automatic safety shutoff valves in the gas line to the igmter, with intermediate, spring opening automatic vent valve.

C. Manual shutoffvalve(s) in the fuel line(s) adjacent to the burner. For gas firing this shutoffvalve should be proved closed before the spark to the igniter can be energized and the igniter and main gas safety shutoff valves can be opened.

D. Changes in firing rate are made by the simultaneous adjustment of fuel and air supplies at a preestablished optimum air/fuel ratio by the manipulation of a single control device.

E. Limits on fuel and air to prevent reducing furnace input below the point of stable burner operation are provided. The mfnimum and maximum points of stable burner operation are defined by the burner manufacturer and verified by operating investigation.

F. Safe.ty shutdown interlocks include the following:

(a) Low oil pressure.

(b) High gas pressure.

(c) Low gas pressure.

(d) Loss of combustion air supply.

CAUTION: Excessive recycling to achieve a burner light-off can lead to accumulation of a hazardous amount of fuel in the furnace and should be avoided.

G. Where oll heating is provided the following conditions sound an alarm:

(a) Low oil temperature.

(b) High oil temperature.

A-2-7.3.1 The term fuel oil refers to liquid fuels with widely differing characteristics. A fuel oll burning system is designed for a specific range ofoil characteristics. Attempting to burn an oil whose characteristics differ widely from those for which the system was designed can cause serious operatin~ difficulties and potential safety hazards. Hence, care must be exerosed to ensure that oils received at a plant are within the specific ranges of the fuel handling and , burning equipment.

/

II. The more important characteristics of fuel oils are defined in ASTM D396, Standard Specifications for Fuel Oils. Thus it is relativel~simp~e to identify oils that require special provisions for storing, l~eatin , umping, atomizin. .~,etc. Generaily speakin , des 1, 2, t L v e lower scostues and less . ter and se ,ment than grades 5 or 6; hence they require fewer special provisions to ensure proper handling and burning. However, most power boiler fuel oil systems are destgned for the heavier grades 5 and 6; hence such systems include provisions for preheating these usually viscous fuels. Furthermore, more care is required in design and operation of fuel oll systems supplied with .gt'-ade 6 oil than with the other ASTM grades, to avoid flameouts attributed to interruptions or pulsation of the fuel supply, or plugging of strainers, or burner tips.

III. All of the following characteristics may have a bearing upon the problem of properly and safely burning fuel oils.

A. Fuel oil is a complex mixture of hydrocarbons of differing molecular weights, bollin~ and freezing points. When.fuel oil is subjected to sti~iciently high temperature it will partially decompose or vaporize, thus creating new liquid, gaseous, and solid fuels with unpredictable properties.

B. Fuel oil is introduced into the furnace as an extremely fine mist to intimately mix with the combustion air in order to burn quickly and completely. In power boilers this is accomplished by spi'aying through small orifices with high pressure drops (mechanical atomization) o r by using ste .am or air to break up small oil streams. Viscosity and volatility ar-e characteristics of the oil that indicate ease of atomization.

C. Flash point is an indicator of volatility and, thus, of potential for flammable vapors. It is a function of pressure and fuel composition.

D. Some fuel oils contain constituents which, when overheated, may decompose, forming solids, or may solidify when exposed to low ambient temperature. The presence of such solids in the fuel may cause interruptions.

(a) When storing, handling, or burning fuel oils that may have flash points below 100°F (38°C) (Class I liquids as defined in NFPA 30, Flammable and Combustible Liquids Code) or that may be heated above their flash point, consideration should be given to electrical instaUations in areas where flammable vapors or gases may be present in the atmosphere. Typicai locations areburner areas, fuel handling equipment areas, fuel storage areas, pits, sumlSs, and low spots wher/~

10

N F P A 8 5 A - - A 9 2 T C R

fuel leakage or vapors may accumulate. Article 500 of NFPA 70, National Electrical Code", provides for classifying such areas and defines requirements for electrical installations in the areas so classified.

E. Purging the burner atomizer before removal will minimize the probability for hazardous concentrations of flammable vapors at the burner front during maintenance operations. With such provisions, the burner front is not normally classified more restrictively than Class I, Division 2.

F. The operating company is responsible for classifying areas where fuel is stored, handled, or burned, and for revising the classification if conditions are changed. Installations should conform to NFPA 30, Flammable and Combustible Liquids Code; NFPA 31, Standard for the Installation of Oil Burning Equipment; and NFPA 70, National Electrical Code. Guidance can be obtained from API-RP 500, Recommended Practice for Classification of Areas for Electrical Installations in Petroleum Refineries.

A-2-7.1 Low NO, Operation - Special Problems.

I. Air pollution control regulations require that new installations meet NO, emission limits lower than emissions now obtained from many of the presenfly installed firing systems and furnace designs using past operating procedures. In addition, air quality regulations in some local areas require a reduction of NO. emissions from existing boilers, i

II. In order to achieve these reductions, one or more df the following methods are used.

l

A. Low excess air firing, i.e., less than the"normal" 10 percent to 25 percent excess air.

B. Multistage air admission involving the introduction of combus- tion air in two or more stages partly at-the fuel nozzle (may be less than stoichiometric air) and partly by independent admission through (I) special furnace ports, (9) a second stage of air admission within the same burner housing.

C. Flue gas recircuiation into all or a portion of the secondary air.

D. Reduced secondary air temperature.

E. Fuel Staging.

F. On new units, the equipment manufacturers may also introduce new burner and furnace designs.

Ill. The effect of all of these methods is generally to produce lower flame temperatures and longer, less turbulent flames, which result in lower NO~-. - ,

A-2-7.2 Hazards of LOw NO, Firing Methods.

I. These methods may have important implications with regard to furnace safety, particularly for existing units, and may introduce unacceptable risks if proper precautions are not taken.

A. Fuel firing systems designed to reduce NO emissions tend to reduce the margins formerly available to prevent or minimize accumulations of unburned fuel in the furnace during combustion upsets and /o r flameouts. Thus, it is important to trip fuel on loss of flame.

B. These methods may narrow the limits of stable flames produced by the burner system. The tests specified in 4-4.9.3 should be repeated on ems fing units when any of these methods are employed.

C. When flue gas recirculation is used, equipment should be provided to assure proper mixing and uniform distribution of recirculated gas and the combustion air. When flue gas recirculation is introduced into the total combustion air stream, equipment should be provided to monitor either the ratio of flue gas to air or the oxygen content of the mixture. When flue gas recirculation is introduced so that only air and not the mixture is introduced at the burner, proper provisions should be made to ensure the prescribed distribuuon of mr and the recirculadng flue gas/air mixture.

D. All of the methods tend to increase the possibility of an unstable flame and unburned combustibles throughout the umt and ducts; therefore, recommendations of the boiler, burner, and instrument manufacturers should be followed, or tests to verify operating margins should be conducted.

II. Any change in flame characteristics to reduce NO emissions may require changing either or both the type and Iocatio~Cof flame detectors on existing units.

A-6-2.4.8 Supplemental Recommendations and Precautions.

I. Excessive recycling to achieve a burner light-offcan lead to accumulation of a hazardous amount of fuel in the furnace and should be avoided.

II. Recovering from a Fuel-Rich Furnace Condition. If an air deficiency should develop while flame is maintained at the burners, reduce the fuel until the normal air/fuel ratio has been restored. If fuel flow cannot be reduced, slowly increase air flow until normal a i r / fuel ratio has been restored.

HI. It should be recognized that fuels available today contain unexpected constituents. Therefore, engineering systems and material designs must take into consideration these potential variables.

A-4~.I.3 Heavier-than-Air Gases.

I. Gas-Fired Igniters. Many oil-fired boilers are equipped with propane or .other liquefied petroleum gas-(LPG)fired igniters. Special precautions are required in locating the vent pipe from the automatic bleed valve so that heavier-than-alr, vented gases do not accumulate in depressions or in confined areas. An alternative to the automatic venting of heavier-than-air gases is to eliminate the igniter vent valve from between the two igniter safety shutoffvalves.

A-4-2.3 Main Burner Gas Supply. Most natural gas supplied to boilers typically is lighter than air andpresents no special pro~blems in atmosphere over and above those addressed in this standard. Because of developingenergy cost considerations, many boilers are using a gas or a mLxture of gases with heavier-than-air characteristics. These heavier-than-air gases, such as propane/a i r mixtures and refinery l~ases, etc., require special consideration in storing, handling, and venung to prevent accumulations in depressions or in confined areas.

An alternative to the automatic venting of heavier-than-air gases is to eliminate the vent valve from between the two main gas safety shutoffvalves.

A-4.2 For additional information, see NFPA 54, National Fuel Gas Code, and NFPA 58, Standard for the Storage and Handling of Liquefied Petroleum Gases.

(SEE HGURE A.4-4.1 NEXT PAGE)

(SEE HGURE A-4-2.3 FOLLOWINGHGURE A-4-4.1)

(SEE HGURE A-4-1.8 FOLLOWING FIGURE A-4-2.S)

SUBSTANTIATION: Appendices are not numbered per NFPA'$ Manual of Style. Revise numbering to comply. COMMITrEE ACTION: Accept in Principle.

1. Place the following notice at the beginning of the standard: NOTICE: An asterisk (*) following the number or letter designat-

ing a paragraph indicates explanatory material on ~ a t paragraph in Appendix A . -

9. Accept thesubmitters proposed changes but rearrange the "submitters Appendix A paragraphs in the proper sequence and revise the numbering in accordance with the NFPA Manual of Style as requi.red.

3. Revise 2-7 as follows: 2-7 Gas and Oil Firing - Special Problems. Common hazards are

involved in the combustion of solid, liquid, or gaseous fuels. Each of these fuels has special hazards related to its physical characteristics. Refer to A-2-7 for further information.

4. Delete 9-7.1. Move sections 2-7.9 and 2-7.3 to Appendix A as A-9- 7(A) and A-9-7(B), under a heading "A-2-7 Gas and Oil Firing - Special Problems". Reletter the submitters proposed .4.-2-7.1 as A-2- 7 (C), and A-2-7.9 as A-2-7 (D). Add and renumber the submitters A-2- 7.3.1 asan extension of A-2-7(B).

5. Delete section 10-4, add an asterisk after Chapter I0, and add the following new Appendix A material:

11

Natural Gas Supply

N F P A 85A - - A92 T c R

H

T

N

S Vent to Atmosphere

- - - - -~C

/ \ I g n i t e r

A Safety shutoff valve, spring closing (NC) C Vent valve, spring opening (NO)'(optional) H Gas strainer J .Constant gas pressure regulator N Drip leg S Pressure gage T Manual shutoff valve

Light Oil Pilot Supply

0

T !><!

v

'Igniter

O Igniter oil strainer S Pressure gage T Manual shutoff valve V Pilot oil safety shutoff valve, spring closing Y Pilot oil pressure regulator (optional)

Note: NC = normally closed, deenergized NO = normally open,.deenergized

Figure A-4.4.1 ;rypicai Ignition Systems for Gas/Oil-Fired Burner.

A-10 Inspection and Maintenance.

I. Maintenance, Inspection, Training, and Safety.

A. The objective of a maintenance program is to identify and correct conditions relating to the safety, continued reliable operation, and efficient performance of equipment. A program shouldbe provided for maintenance of equipment at intervals consistent with the type of equipment, service requirements, and manufacturers recommendations.

B. As a minimum, the maintenance program should include the following:

1. In service inspections to identify conditions requiring" corrective action or further study.

2. Detailed, knowledgeable planning to allow use of qualified personnel, procedures, and equipment for an efficient safe repair or modification.

3. Use of comprehensive equipment history that records conditions found, maintenance work done, changes made, and date of each.

4. Written comprehensive maintenance procedures incorpo- rating manufacturer's instructions to define tasks and skills reqmred. Any special techniques, such as non-destructive testing or those tasks requiring special tools shall be defined. Special environmental factors shall be covered, such as temperature limitations, dusts, contaminated or oxygen-defident atmosphere, and limited access or confined space requirements. (See H-4.S).

5. Shutdown maintenance inspections, comprehensive in scope, to cover all problem areas.

6. Adequate spare parts available meeting manufacturer's specifications to provide reliable service without necessitating makeshift repairs.

C. In-service inspection of equipment should be established and followed.

D. Operation, set points and adjustments should be verified by periodic testing and the results documented. .

E. Defects should be reported, corrected and r~airs documented.

F. System configuration, including logic, set points, and sensing hardware, should not be changed without the effect being evaluated and approved.

12

' f T ,

N F P A 85A - - A92 T C R

Vent to Atmosphere

S R

/

To Ignition System

• Vent to Atmosphere

C Q

A I ( ~ " X ( ~ / S

D T

~ [ D ~ ~ T ~ M a i n

, Burner

A Safety shutoff valve, spring closing (NC) C Vent valve, spring opening (NO) D Gas flow control valve H Gas strainer I Closed position interlock on valves safety shutoff J Constant gas pressure regulator valve K Vent line manual shutoff valve for leakage testing ,(locked or sealed open) L Leakage test connection M Gas meter (optional) N Drip leg Q High gas pressure switch R Low gas pressure switch S Pressure gage T Manual shutoff valve X Low fire start switch

Safety Controls not Shown Flame detector(s) Purge air-flow switch Forced draft fan discharge pressure switch and

fan damper position switch (alternative to purge air-flow switch)

Excessive steam pressure interlock '(excessive water temperature and pressure interlock for hot water boilers)

Low boiler (steam and hot water) water level interlocks (two required)

Note: NC = normally closed, deenergJzed NO = normally open, deenergized

Figure A-4-2.3 Typical Fuel Supply Systems and Safety Controls for Gas Burner.

G. Inspections, adjustments, and repairs should be performed by trained personnel using tools and instruments suitable for the work. Maintenance and repairs should be performed in accordance with the manufacturer's re.commendations and applical~le standards and codes.

H. It is not practical to pre-establish a single schedule for all installations. Therefore, the following typical schedule isa guide only, subject to adjustment according to specific plant operation mid equipment involved. (See 10-2.1 and 10-2.2).

1. DAILY (a) Flame failure detection system (b) Low water cutoffs and alarms

2. WEEKLY (a) Igniter and burner operation

3. MONTHLY (a)' Fan knd airflow interlocks (b) Fuel safety shutoffvaives for leakage (c) Low fire'start interlock (d) High steam pressure interlock (e) For oil: fuel pressure and temperature interlocks (f) For gas:

1. Gas strainer and drip leg 2. High and low fuel pressure interlocks

4. SEMIANNUALLY OR ANNUALLY as required (a) Igniter and burner components (b) Combustion air supply system (c) Flame failure system components (d) Piping, wiring, and connections of all interlocks and

shutoffvalves (e) Combustion contrbl system (f) Calibration of indicating and recording instruments

5. AS REQUIRED for oil firing (a) Atomizers (b) Strainers

II. Training

. A. Operator Training.

1. A formal training programshould be established to prepare personnel to safely and effectively operate equ{pment. This program can consist of review of operating manuals, videotapes, programmed instruction, testing and field training, among others. The training program should I~ consistent with the type of equipment and hazards involved. " .

i ,

2. Operating procedures should be established that cover normal and emergency conditions. Start-up and shutdown proce- dures, normal operating conditions, and lockout procedures should be covered in detail.

13

Supply

Atomizing T Z Medium ~ , Supply

Alternate • T Z A t o m ,z, n g T.=...4,,~.I~Z 1 ~ J Medium . . . . Supply

N F P A 8 5 A - - A 9 2 T C R

, Clearing Line Z T

S R U F

~ "J I' rner

Y

T r a P ~ Drain

A Safety shutoff valve, spring closing (NC) B Oil recirculation valve (NO)

(optional for unheated oil) D Oil flow control valve F Low oil temperature switch (not al3plicable for unheated oil) I Closed position interlock on safety shutoff valve J Atomizing meal=urn dffferent=al control valve L AutomaUc atomizing meal=urn shutoff valve M Oil meter (optional) N Low atomizing medium pressure sw=tch O Oil strainer P Atomizing medium flow in terlock differential switch, or pressure interlock switch R Low pressure sw=tch S Pressure gage T manual shutoff valve U Oil temperature gage (optional for unheated oil) W Atomizing med=um strainer X Low fire start switch Y Atomizing medium flow orifice Z Check valve

Safety Controls not Shown Flame detector(s) Purge air-flow switch Forced draft fan discharge pressuer switch and fan damper •

position switch (alternative to purge air-flow switch) Excessive steam pressure ~nterlock Low boder (steam and hot water) water

level interlocks (not required)

"Caution: Means shall be prov=ded to prevent or relieve excess pressure between lhe.qe valves

Figure A-4-1.8 Typical Fuel and Atomizing Medium Supply Systems and Safety Controls for Oil Burner.

3. Operating procedures should be directly related to the atmosphere, internal pressure, and limited access or confined space equipment revolved and consistent with safety requirements and requirements should be included. manufacturer's recommendations.

4. Procedures should be periodically reviewed to keep them current with changes in equipment and personnel.

B. Maintenance Training.

1. A formal maintenance training program should be established to prepare personnel to safely and effectivelyperform any reRulred maintenance tasks. This program can consist of review of maintenance manuals, videotapes, programmed instruction, testing, field training and equipment r~antffacture- r training amons~ others_ The training program should be specific to the equipment revolved and to potenual hazards.

2. Maintenance procedures should be established to cover routine and special techniques. Any potential environmental factors such as temperature, dust, contaminated or oxygen-deficient

3. Procedures should be consistent with safety requirements and manufacturer's recommendations.

4. Procedures should be periodically reviewed to keep them current with changes in equipment and personnel.

III. Housekeeping.

A. Good housekeeping is essential for safe operation and preven- tion of fires or explosions; therefore, provision should be made for periodic cleaning of horizontal ledges or surfaces of buildings and equipment to prevent the accumulation of appreciable dust deposits.

B. Creation of dust clouds should be minimized during cleaning. Compressed air should not be used to dislodge soot or dust accumu- lations; water washing or vacuum cleaning methods are preferred.

14

N F P A 85A - - A92 T C R

IV. Safety.

A. General Safety Precautions. Protective clothing, including but not limited to hard hats and safety glasses, shouldbe used by personnel during maintenance operations.

B. Special Safety Precaution.~. " i

1. Welding and Flame Cutting (See also N'I~A 51, Oxygen- Fuel Gas SDtems for Welding, Cutt ingand Allied Procedures, and NFPA 51B, Fire Prevention in Use of Cutting and Welding Processes.

(a) Fire-resistant blankets or other approved methods should be used in such a manner as to confine weld spatter or cutting sparks.

(b) A careful inspection of all areas near where welding or cutting has been done, including the floors above and below, should be made when the job is finished or interrupted and such areas patrolled for a p e n o d long enough to make certain that no smolder- ing fires have developed. .

2. Where flammable dus~ or dust clouds are present, sparking electrical tools must not be used. All lamps must be suitable for Class II, Division 1 locations as defined in NTPA 70, National Electrical Code.

3. Either ground fault protected or specially approved low voltage (6 or 12 volt) extension cords and lightingmust be used for all confined spaces and where moisture may be ahazard.

4. Explosion-operated tools and forming techniques should not be used where flammable dust or dust clouds are present. When these operations become necessary, all equipment, fi//ors, and walls should be cleaned and all dust accumulation removed by an approved method. A careful check should be made to be sure that no cartridges or charges are left in the work area.

C. Confined Space.

1. A confined space is" any work location or enclosure in which any of the follovang may exist:

(a) The dimension~ are such that a person 6 ft (1.8 m) tall cannot stand up in the middle of the space or extend his arms in all directions without hitting the enclosure.

(b) Access to or from the enclosure is by manhole, hatch, port, or other relatively small opening that limits ingress and .egress to one person at a time.

(c) Confined spaces may include bu t are not limited to ducts, heaters, windboxes, cyclones, dust collectors, furnaces, bunkers or bins.

2. Specific procedures should he developed and used for personnel entering confined space which must:

(a) Positively prevent inadvertent introduction offuel, hot air, steam or gas.

- (b) Positively prevent inadvertent starting or moving of mechanical equipment or fans. -

(c) Prevent accidental closing of access doors or hatches.

(d) Include tags, permits or locks to cover confined space entry.

(e) Determine need for ventilatiori or self-contained breathing apparatus where the atmosphere" may be stagnant, depleted o f 0xygen, or contaminated With irritating or combustible gases. Tests for an explosive or oxygen deficient atmosphere shall be made.

(f) Provide for a safety attendant. The safety attendant shall remain outside of the confined space with appropriate rescue equipment and shall be in contact (preferably visual contact) with those inside. ,

(g) Provide foi" use of proper safety belts or harnesses, which shall be properly tied offwhen such use is practical.

15

N F P A 85F u A92 T C R

PART H

85F- 1 - (1-1.5 (New)): Accept SUBMITFER: NFPA 85F Subcommittee RECOMMENDATION: Add a new paragraph 1-1.5 as follows:

1-1.5 Revisions to this document recognize the current state of knowledge and do not imply that previous editions were inadequate. SUBSTANTIATION: Thin maintains the credence of prior editions of NFPA 85F. COMMITTEE ACTION: Accept.

(Log # 1) 85F- 2 - (1-1.5 (New)): Reject SUBblrI-I~R: Karl Klebenow, Chagrin Falls, OH RECOMMENDATION: Add new text:

1-1.5 Those systems with a nominal throughput of 8 lbs per hr or less are excluded from this standard.' SUBSTANTIATION: The scope of this standard makes no mention

-of pulverized fuel system capacity. The standard, however, has limited applicability to smaller (both dimensionally, and in terms of .fuel throughput) systems, which are analytical or laboratory oriented m nature. COMMITTEE ACTION: Reject. COMMrtTt;E STATEMENT: Insufficient information has been provided on how NFPA 85F has limited applicability to smaller systems. The submitter is requested for further information on what sections of NFPA 85F are causing compliance difficulties. Its recognized that this public proposal is associated with Formal Interpretation 85F-89-01, which did not pass letter ballot of the NFPA 85F Subcommittee.

[ 85F- 7- (1-4): Accept SUBMYITER: NFPA 85F Subcommittee RECOMMENDATION: Make "Dusttight" two separate words in the definition of"Valve. Dusttight Valve." Also make this change throughout the document.

SUBSTANTIATION: Both spellings are used throughout NFPA 85F. This change is made for conststency. C O M M 1 T r ~ ACTION: Accept.

85F- 8 - (2-3.4): Accept SUBMrrTER: NFPA 85F Subcommittee RECOMMENDATION: Revise as follows:

2-3.4 All piping system coml:/onents shall be capable of being cleared of pulverized fuel using transport air. SUBSTANTIATION: The term "trarisport air" more clearly addresses the intent of this paragraph rather than "avaiLable primary air velocities." COMMrrrEE ACTION: Accept.

85F- 9 - ( Figure 2-5.1 (a)): Accept SUBMITrER. NFPA 85F Subcommittee RECOMMENDATION: Revise as follows:

(SEE FIGURE 2-5.1 (a) NEXT PAGE)

SUBSTANTIATION: This editorially clarifies this illustration. COMMITrEE ACTION: Accept.

85F- 3- (1-2.3): Accept SUBMrrTER: NFPA 85F Subcommittee RECOMMENDATION: Change the date from ",June 1, 1987" to

une 15, 1992". . STANTIATION: This is the new expected date of issuance for

NFPA 85F. COM311t-rt~E ACTION: Accept.

85F- 4- (1-3.2.1.10): Accept SUBM1TrER: NFPA 85FSubcommittee RECOMMENDATION: Revise the second sentence as follows:

~I'his may be due to insufficient drying indicated by too low a pulverizer outlet mixture temperature,-design, or conditions of wear." SUBSTANTIATION: This is an editorial correction. COMMITTEE ACTION: Accept.

85F- 5 - (1-3.3.3): Accept SUBMITTER: NFPA 85F Subcommittee RECOMMENDATION. Revise the beading "Transporting and Distributing the Pulverized Fuel" to be in bold type. SUBSTANTIATION: Typographical. COMMITTEE ACTION: Accept.

85F- 6- (1-4): Accept SUBMrrrER: NFPA 85F Subcommittee RECOMMENDATION: Revise the three indicated definitions as follows:

Damper. Shutoff Damper. A close-fitting damper to minimize air or flue gas passinginto any system component.

Exhauster. The fan used to draw the pulverizer air throught the pulverizer and to deliver the air/fuel m-ixture to the burne~(s) or other apparatus.

Igniter. A device which provides adequate ignition energy to immediately light off the main burner. See NFPA 85C, Standard for the Prevention of Furnace Explosions/Implosions in Multiple Burner Boiler-Pumaces. SUBSTANTIATION: The word "flue" was inserted in the definition of "Shutoff. Damper" to clarify the type of gas involved.

The definition of"Exhauster" was smaplified since the fan can be located at other than the pulverizer outlet. A reference was added t0 the definition of"Igniter" for clarity.

COMMITrEE ACTION: Accept.

85F- 10- (2-5.1(b)): Accept SUBMITFER: NFPA 85F Subcommittee RECOMMENDATION: Revise as follows:

(SEE FIGURE 2-5.1 (b) FOLLOWING HGURE 2-5.1 (a))

SUBSTANTIATION: This editorially clarifies this illustration. COMMITIT, E ACTION: Accept.

85F- 11 - (2-5.1(c)): Accept SUBMrt-rt:R: NFPA 85F Subcommittee RECOMMENDATION: Revise as follows:

(SEE FIGURE 2-5.1 (c) FOLLOWING FIGURE 2-5.1 (b)

SUBSTANTIATION: This editorially clarifies this illustration. COMMITrEEACTION: Accept. .

85F- 12- (2-5.1(d)): Accept SUBMITrER: NFPA 85F Subcommittee RECOMMENDATION: Revise as follows:

(SEE FIGURE 2-5.1 (d) FOLLOWING FIGURE 2-5.1 (c)

SUBSTANTIATION: This editorially clarifies this illustration. COMMITTEE ACTION: Accept.

85F- 13. (2-5.1(e)): Accept SUBMITrER: NFPA 85FSubcommittee RECOMMENDATION: Revise as follows:

(SEE HGURE 2-5.1 (e) FOLLOWING HGURE 2-5.1 (d)

SUBSTANTIATION: This editorially clarifies this illustration. COMMIT tt;]E ACTION: AccepL

85F- 14- (2-5.1(0): Accept SUBMrrTER: NFPA 85F Subcommittee RECOMMENDATION: Revise as follows:

(SEE HGURE 2-5.1 (0 FOLLOWING HGURE 2-5.1 (e)

16

H SI [~

Hi C( D;

Te Ai Dz

R a w - !

Con t ro l Damper Exhauster i-uels

Feeder discharge Pip ing

ght

on .ace

NFPA 85F - - A92 TCR

Figure 2-6.1(a) Direct-Firing Pulverized Fuel E xhauster System for Pressure Furnace.

SUBSTANTIATION: This editorially clarifies this illustration. C O M M 1 T ~ ACTION: Accept.

85F- 15 - (2.6.1.1): Accept SUBMrrTERa NFPA 85F Subcommittee RECOMMENDATION: Revise as follows:

(SEE FIGURE 2-5.1.1 FOLLOWING FIGURE 2-5.1 (f)

SUBSTANTIATION: This editorially clarifies this illustration. COMMITTEE ACTION: Accept.

(Log # 2) 85F- 16- (2.6.1.2.1): Reject S U B ~ Masaaki Kinoshita, Mitsubishi Heavy Industries, Ltd. RECOMMENDATION: Delete the second sentence of 2.6.1.2.1. SUBSTANTIATION: In case of suction furnace, one ba_,-rier valve is sufficient if sealing air is introduced at the oudet of the valve when it is closed. Necessity of two valves in series should be re-examined' considering the actual example of fire and explosions related to only one valve. C O ~ ACTION: Reject. COMMI"rrEE STATEMENT: The second valve is felt to be needed for personnel safety. Refer to action on 85F-17.

85F- 17- (2.6.1.2.1): Accept SUBM1TTER: NFPA 85F Subcommittee RECOMMENDATION: Revise as follows:

2-5.1.2.1 For a suction furnace that can be fired by other main fuels or is connected to two or more pulverizers or exhausters, valves shall be installed to isolate all burner lines [see Figures 2-6.1.1 (c), (d), (e), (0, (g), (h), and (i) ]. This requirement can be met with one dust tight and one barrier valve, or two dust tight valves. A dustt ight valve shall be installed in the burner pipe as close the furnace as practi- cable. The second valve shall be installed as close to the pulverizer as practicable. The valves shall be closed prior to entering a pulverizer, exhauster, or fuel piping. See also 2-5.1.2.8. SUBSTANTIATION: This more clearly describes the intent of this

P c ~ a ~ ' ~ E ACTION: Accept.

85F- 18 - ( 2 - 5 . 1 . 2 . 2 ) : Accept SUBMrrIT.R: NFPA 85FSubcommittee RECOMMENDATION: Revise the second and third sentences as follows: "In addition, a second dust tight valve shall be installed as close to

the furnace aspracticable. Both valves shall be closed prior to entering a pulverizer, exhauster, or fuel piping." SUBSTANTIATION: This more clearly descnbes the intent of this

~ r a ~ ACTION, Accept.

17

N F P A 8 5 F - - A 9 2 T C R

Raw Fuel Bunker

I

Hot A i r S h u t - O f f

H o t - A i r Or Flue Gas

Hot A i r Control Dal

Temper ing Control Oa

Temper ing A i r Shut O f f Damper

Auxd ie ry Control Da

Auxi l i~ Shut 0

Pri C¢

Pulverizer

Figure 2-5.1 (b) Direct-Firing Pulverized Fuel for Suction Furnace.

85F- 19- (2-5.1.2.3): Accept S U B ~ NFPA 85F Subcommittee RECOMMENDATION: Delete the last sentence. SUBSTANTIATION: This is covered by the revisedparagraphs 2- 5.1.2.1 and 2-5.1.2.2. Refer to acdon on 85F-17 and 85F-18. COMMITTEE ACTION: Aci:ept.

(Log # 3) 85F- 20 - (9-5.1.2.4): Accept in Principle S U B M r I I ~ R : Masaaki Kinoshita, Mitsubishi Heavy Industries, Ltd. RECOMMENDATION: Delete the whole text o f 2-5.1.2.4. SUBSTANTIATION: First sentence of 2-5.1.2.4 contradict to 2- 5.1.2.8.

Regarding the second sentence, see my proposal on 2-5.1.2.1. COMMITTEE ACTION: Accept in PrinCiple. Accept the submitters recommendat ion.

COMMITTEE STATEMENT. The information of 2-5.1.2.4 is addressed by the revised 2-5.1.2.1. Refer to action on 85F-17.

85F- 21 - (2-5.1.2.5): Accept SUBMITI'ER: 'NFPA 85FSubcommit tee RECOMMENDATION: Revise as follows:

=Two dust tight valves or one dust tight waive and one barrier valve, shall be provided in each burner pipe if one or more pulverizers is connected to more than one sucuon furnace at a time [see Figures 2- 5.1.1(g) and (h)]." "

SUBSTANTIATION: This ciarifies the intent o f this paragraph. COMMI'rI 'EE ACTION: Accept.

85F- 22 - (2-5.1.2.6): Accept SUBMITI'ER: NFPA 85F Subcommittee RECOMMENDATION. Revise as follows:

~ r h e n one or more pulverizer(s) is connected to two or more pressure furnace(s) at the same time, valve requirements of 2-5.1.2.2 shall apply [see Figure 2-5.1.1 (1)]." SUBSTANTIATION. This clarifies the intent o f this paragraph. C O M M I T F ~ ACTION: Accept.

85F- 23 - (2-5.1.2.7 and 2-5.1.2.8 (New)): Accept SUBMrrFER: NFPA 85F Subcommittee RECOMMENDATION: 1. Revise 2-5.1.2.7 as follows:

=Two dust tight valves or one dust tight valve and one barrier valve shall be installed in the burner piping when the discharge pipes from separate exhausters or pulverizers are connected to the same burner nozzle of a suction furnace [see Figure 2-5.1.1 (i)]."

2. Insert a new 2-5.1.2.8 as follows, and renumber subsequent p2.5.a~.2phs accordingly: . '

.8 Two dust ught valves shall be installed in the burner piping when the discharge pipes from separate exhausters or pulverizers are connected to the same burner nozzle of a pressure furnace [see Figure'2-5.1.1 (k) ]."

1 8

NFPA. 85F - - A92 T C R

Raw Fuel Bunker

Raw Fuel Gate

P~ux iliary A i r Shutoff Damper

\ Aux ihary A i r ~ ~ ~ " l ' - ~ l ~ ' J -

f

Tempering Ai r Shutoff Damper I

F o r c e d ~ II

Tempering Ai r

Temp. Air Control Damper

Feeder D ischarge Piping

Raw F uer Feeder. Burner

Auxi l iary Ai r Control Damper

/ \

I I Dust I Tight I yalve

Exhauster

Air Heater Hot Air Hot Air Shutoff Control Damper Damper

To Furnace

" Puiver=zer " Other Fuels

Primary Air Control Damper

Pressure Furnace

Figure 2-5.1 (c) Direct-Firing Pulverized Fuel Exhatister System for Pressure Furnace.

SUBSTANTIATION: This clarifies the intent of the old paragraph 2- 5.1.2.7. This section is more appropriately divided into two separate paragraphs: one for suction furnaces and one for pressure furnaces. C O M M I T r ~ ACTION: Accept.

85F- 24 - (2-5.1.2.9, Note): Accept SUBMITTEPa NFPA 85F Subcommittee RECOMMENDATION: Revise the Note as follows:

NOTE: No valves are required between the pulverizer and' the bu.,'ners for a single pulverizer or exhauster connected to one or more burners in a furnace that cannot be fired by any other main fuel, provided that the combustion air to individual burners cannot be shut off [see Figures 2-5.1.1 (a) and 2- 5.1.1 (b) ]. If combustion air can be shutoff to individual burners, see 2-5.1.2.1 and 2-5.1.2.2.

SUBSTANTIATION-' The words "main fuel" have replaced "means" because it more appropriately addresses the type of fuel. The last sentence was addedto account for the situation when combustion air can be shutoff to individual burners. COMM1TFEE ACTION: Accept.

85F- 25 - (2-5.1.3): Accept SUBMrrrER: NFPA 85F Subcommittee RECOMMENDATION: Revise the heading to "Air Supply Isolation Requirements". ° SUBSTANTIATION: This more accurately reflects the information contained within section 2-5.1 3. COMMITTEE ACTION: Accept.

85F- 26'- (2-5.1.3.I): Accept S L r B ~ NFPA 85F Subcommittee RECOMMENDATION: Make "pulverizer" plural the first two times it appears in 2-5.13.1. SUBSTANTIATION: Editorial. ' C O ~ ACTION: Accept.

85F- 27- (Figure 2-5.2.1.1(a) and (b)): Accept SUBMITrER: NFPA 85F Subcommittee RECOMMENDATION- Separate and revise these two illustrations as, follows:

(SEE FIGURE 2-5.2.1.1 (a) FOLLOWING FIGURE Figure 2-5.1.1)

19

N F P A 85F - - A92 T C R

R a w Fuel Burner / R a w Fuel Gate

Aux i l i a ry A i r S h u t o f f Damper

A u x i l i a r y A i r Contro l Damper

A u x i l i a r y Air

Burner

R a w Fuel Feeder / ~ - - " ?

Tempering Tempering Air Air Shu to f f Contro l Damper Damper ~ ~ I ~

Forced - ~ \ p I Dra f t Fan ~ \ p I

. ~ ~ rimary i~ L ~ ~ Air Fan I I 71

- esecdhear r g e

P" A'r Tempering Air / / , I ~ ^;. rumary = ' / /~1 ~ ' " Control Damper

Air Heater / V l \ "1 Hot A i r Control Damper

I TO Furnace - Hot Air S h u t o f f Damper

Dust Tight Valves

Dust Tight Valves

Pulverizer

Pressure Furnace

Other Fuels

Figure 9-5.1 (d) Direct-Firing Pulverized Fuel Hot Primary Air Fan System for Pressure Furnace.

(SEE FIGURE 9-5.9.1.1 (b) FOLLOWING FIGURE 2-5.9.1.1 (a))

SUBSTANTIATION: This editorially separates and clarifies these two illustrations. COMMtrt tJg ACTION. Accept.

85F- 98 - (Figure 2-5.221.9 (a)): Accept SUBMITTER= NFPA 85F Subcommittee RECOMMENDATION: Revise as follows:

(SEE FIGURE 2-5.2.1.2(a) FOLLOWING FIGURE 2-5.9.1;1 (b))

SUBSTANTIATION: This editorially clEifies this illustration. CoMMrI'rE£ ACTION: Accept.

85F- 29 - (Figure 9-5.2.1.9 (b)): Accept S U B ~ NFPA 85F Subcommmee RECOMMENDATION: Revise as follows:

(SEE FIGURE 2-5.2.1.2(b) FOLLOWING FIGURE 2-5.2.1.2(a)

SUBSTANTIATION: This editorially clarifies this illustration. COMMITTEE ACTION: Accept.

/

85F- 30- (Figure 2-5.2.1.2(c)): Accept SUBMITrER: NFPA 85F Subcommittee. RECOMMENDATION: Revise as follows:

(SEE FIGURE 2-5.2.1.2(c) FOLLOWING FIGURE 2-5.2.1.2(b)

SUBSTANTIATION: This editorially clarifies this illustration. COMMITTEE ACTION: Accept.

85F- 31 - (Figure 2-5.2.1.2(d)): Accept SUBMITTER: NFPA 85F Subcommittee RECOMMENDATION: Revise as follows:

(SEE FIGURE 2-5.2.1.2(d) FOLLOWING FIGURE 2-5.2.1.9(c)

SUBSTANTIATION: This editorially clarifies this illustration. COMMITTEE ACTION: Accept.

20

N F P A 85F - - A92 T C R

Raw Fuel Storage Bunker

Raw Fuel Gates

Primary A i r Control Damper

Tempering Air Control

Secondary Damper

] Tempering ~ A i r Shutoff mper

rners Forced Draf t Fan /

Hot A i r C o n t r o l ~ - - - - - - - -~ Damper

Temper ing ~ - " A i r

Feeder Discharge Piping

Hot A i r

Valves [ X

' "~ Other Fuels

Hot A i r Shutoff Damper

Primary Air Heater

Primary Air Fan

Figure 2-5.1 (e) Direct-Firing Pulverizer Fuel Cold Primary Air Fan System for Pressure Furnace.

85F- 32 - (2-5.2.4.3(f)): Accept SUBMITTER: NFPA 85F Subcommittee RECOMMENDATION: Revise as follows:

(f) Check valves (when required) shall be located as near as . practicable to the source of possible reverse flow into the system. SUBSTANTIATION: An editorial change was made by changing "or" to "of". COMMITIT, E ACTION: Acc~pt.

85F- 38 - (2-6.1.8): Accept SUBMITrER: NFPA 85F Subcommittee RECOMMENDATION: Revise the list of items in 2-6.1.8 as follows:

(a) Lock hoppers; (b) Circulaung fans; (c) Transport systems; (d) Pulverized fuel feeders; (e) Primary air fans handling fuel-laden air; or (0 Vent fans if not located downstream of a dust collector vented

in accordance with 2-6.1.9.

SUBSTANTIATION: This corrects the concerns addressed by Formal InteLrp, retation 85F-90-01,. which did not pass letter ballot of the NFPA 851~ Subcommmee. COMMrrrEE ACTION: Accept.

f

85F- 34- (2-6.1.9): Accept SUBMITI'ER: NFPA 85F Subcommittee

I RECOMMENDATION. Change "... in accordance with NFPA 68 . . ,. ." to " . . . as described in NFPA 68. . . " .

• SUBSTANTIATION: Its improper in the NFPA system for a standard (NFPA 85F) to have a mandatory reference to a Guide (NFPA 68). COMMITTEE ACTION: Accept.

21

N F P A 85F - - A92 T C R

Secondary

~.......i Air Heater ~ ~ rrler$

Forced [

Tem A it,

Raw Fuel Storage Bunker

Raw Fuel Gate

Primary A i Control Damper I V

A i r Shuto f f Damper /Raw Fuel Feeder

Temping Air Contro l Damper

A ir

Valve

~ Feeder Discharge -'1 Piping

Pulvertzer

Hot Air Control Damper

Hot Aw Shuto f f Damper

Prnmary Air Heater

Primary A i r Fan

Dust T ight Burner Valv° , ~ / •

I._,,~ / Suct ion / Furnace

Fuels

Figure 2-5.1 (f) Direct-Firing Pulverized Fuel Cold Primary Air Fan Systems for Suction Furnace.

85F- 35 - (2-6.2.1): Accept SUBMFrTER. NFPA 85F Subcommittee RECOMMENDATION: Change "13.6" at the end of the paragraph to "3.4". SUBSTANTIATION: This coordinates with the criteria of paragraph 2-6.1.1. This change was inadvertently omitted when paragraph 2- 6.1.1 was changed at the Fall 1987 NFPA meeting dunng the last revision cycle of NTPA 85F. COMMI'rTEE ACTION: Accept.

85F- 36- (2-6.6.1): Accept SUBMITI'ER: NFPA 85F Subcommittee RECOMMENDATION: Revise as follows:

2-6.6.1 Materials used to meet strength requirements shall be ferrous materials and shall satisfy the strength requirements of 2.6.1 at temperatures normally encountered in the service of the equip- m e n t . " SUBSTANTIATION: Further guidance is required to use materials (i.e., ferrous materials) that will meet s t reng~ requirements but will not succumb to elevated temperatures. COMMITFEE ACTION: Accept.

(Log # 4) 85F- 37 - (2-6.8.1): Reject SUBM1TTEI~ Masaaki Kinoshita, Mitsubishi Heavy Industries, Ltd. RECOMMENDATION: Revise 2-6.8.1 as follows:

"Pulverizers and pulverized fuel storage systems for those fuels with high reactivities w~th a volatile content of more than 25 percent on dry basis shall be equipped with an inerting system..." SUBSTANTIATION: From our experience, fire and explosions occurred only in case of high reactive coal with a volatile content /nore than 3Opercent. I believe that fires and explosions for low reactive coal w~th volatile content of less than 25 percent have never occurred in U.S. either. COMMITTEE ACTION: Reject. COMMITTEE STATEMENT: Explosions have occurred on all types of bituminous coal.

(Log # 5) 85F- 38 - (3-3.3.1 (a)): Accept in Principle SUBM1TTER: Masaaki Kinoshita, Mitsubishi Heavy Industries, Ltd. RECOMMENDATION: Revise (a) as follows:

"(a) Reduce pulverizer output to the load as recommended by the system designer and establish..." SUBSTANTIATION: Current wording of "not less than of rated pulverizer capacity" does not have any technical background and too restrictive.

22

I

NFPA 85F - - A92 TCR

NO VALVES

Single Source Of Fuel No Individual BurnersOff (See 2.5.1.2.9)

Note ~ S_ingle' Pulverizer Or Exhauster

( a ) 0 - / /

~ - - - //

I // n / / s u c t , o Furnace

(b)

. . . . - K ×

Pressure Furnace

SUCTION-FURNACE

Multiple Source Of Fuel

~ 7 Divider

Exhauster

(d) --/~/

,e) . I z } -

Barrier Valves

One Or More Burners Of f Connection To More Than One Furnace Or Mult iple Connection To One Burner

(f) ..n~ -- ~

~ Other Fuels

( g )

VVVV

(h) \ / \ . /

Other Fuels

h)

Valves interlocked

PRESSURE-FURNACE

Multlpte Source Of Fuel

(J ) _ _ - -

I - !

, "Ou, t , ;

(k)

(I) ~ •

Oust Tight Valves"

Figure 2-5.1.1 Direct-Firing Pulverized Fuel Systems Valve Requirements in-Burner Piping.

COMMITrEE ACTION: Accept in Principle. " Revise (a) as follows: (a) Reduce pulverizer output and establish required combustion

system condiuons for shutdown (see NFPA 85C, Standard for the ' Prevention. of Furnace Ex p losions/Im p losions in Multi p le Burner Boiler-Furnaces)". COMMI'rrEE STATEMENT: Tills more clearly states the intent of this paragraph and meets the intent of the submitter. Also, NFPA 85Chas replaced NFPA 85E.

(Log # 6) 85F- 39 - (3-3.3.1 (d)): Accept SUBMITTER: Masaaki Kinoshita, Mitsubishi Heavy Industries, Ltd. RECOMMENDATION: Revise (d) as follows: "(d) Shut the pulverizer down after pre-dctcrmincd time as

required to empty the pulverizer." SUBSTANTIATION: It is not possible to confirm that the pulverizer is empty when the mill is running. COMMITTEE ACTION: Accept.

(Log # 7) 85F- 40 - (3-4.9.2.1 (c)): Accept in Principle SUBM1TTER: Masaaki Kinoshita, Mitsubishi Heavy Industries, Ltd. RECOMMF..NDATION: Revise (c) as follows:

"When pulverizer is operated for pre-determined time to empty the fuel and is cool..." SUBSTANTIATION: It is not.possible to confirm that the pulverizer is empty when the mill is running. COMMITTEE ACTION: Accept in Principle.

Revice (c) as follows: (c) After pulverizer is operated for pre-determined time sufficient

to be empty of fuel and is cool, shut it down. COMMITTEE STATEMENT: This is the same as what the submitter has proposed but with editorial corrections.

85F- 41 - (Appendix C): Accept SUBMITTER: NFPA 85F Subcommittee RECOMMENDATION. Replace Appendix C with the following:

Appendix C Maintenance, Inspection, and Training

2 3

NFPA 85F - - A92 TCR

Feeder Discharge Piping Raw-Fuel

] Bunker Vent

Hot Air Cont, o l \ ~ ~ r E Damper ~ \ / Raw- Cyclone ~ I \

I \ \ IF::: N ' Or FlueOas I \ ~ ~ ~_._1_~ k,.,/

Tempering "xX~- \ ,1 F Raw- ~¢-"~ / Air Control 'l~ \ ~1 I ,Fuel \ / / ~

Pulverizer Ai ~ / Pulverized Control Damper ~ Pulverizer Fuel Pump

1 Pulverizer Air Fan

Note: Pulverizer Fan Or Vent Fan May Not Be Required.

Pulverized Bin Vent Fuel Bin /

V e n ,

/ ~ - ' L _ _ I Burner

' ' / k / Furnace

Vent Dust ~ / t ~ . Collector \ / P u I v . 7~ I~1

/ F u e l ~ / \ / F e e d e r , T J ~rri~.r / ~ 9 ~ __..__.1 ~ Barrier Valve

? ~ Pcro:taro~ DAi:rnper Primary. Air Fan

Figure 2-5.2.1.1 (a) Pulverized Fuel Storage Firing System.

Pulverized Fuel Bin

_ - - Pulv. Burner " ~ Fuel " ~ IV*

\ / jGato ~r$ Pressu re Lo ck ~ , , , , ~ k ~ d l ~ PUleierlzer ~ ~E ; ;eSnSUr:

Primary.ir =~ ~- -H , ~ - - I ~ .or A.r Control Damper ( | 3 " --.~1~ ~ ~/~ttCon~oyi Dampe r

• - J / A I I I Dust Tight Valves / ~. I (interlocked) / ~I I ~ _ Forced

Tempering Air. 7 w ~ .ql_._ L U M P - - D raft Control Damper / "~ - - J Fan

Tempering Air

Figure 2-5.2.1.1 (b) Pulverized Fuel Storage Firing System.

24

N F P A 85F - - A92 T C R

V e n t Va lve (Con t ro l l ed )

Ho t A i r S h u t o f f Damper

Ho t A i r Con t ro l Damper

T e m p e r i n g A i r Cen t re Damper

PulVer izer At r . Con t ro l Damper"

Raw Fuel

Pulver izer A i r Fan

Pulver izer Feeder Discharge Piping

Flaw Fuel Bunker

Raw Fuel Gate

V e n t Dust Co l lec tor

Pulver ized Fuel B in

V e n t Fan

Cyc lone A i r Discharge Lines

Check Va lve Pulver izer Fuel B in V e n t A n d

~, ] / . D u s t Co l lec to r

Stack /

77,,

Suct ion Furnace

Pressure Lock

Pulver ized Fuel P u m p

Pr imary A i r Fan

Barr ier Valve

Pulver ized Fuel Feeder

P r imary A i r Con t ro l Damper

Pulver ized Fuel Gate

Figure 2-5.2.1.2(a) Pulverized Fuel Storage FiringSystem (Partial Recirculation re.Vented Air to Stack). '

C-1 Maintenance and Equipment Inspection.

G-I.1 The objective of a maintenance program is to identify and correct conditions that adversely effect the safety, continued reliable. operation, and efficient performance of equipment. A program should be provided for maintenance of equ.ipment at intervals consistent with the type of equipment, semce requirements, and manufacturers recommendations.

C-1.2 As a minimum, the maintenance program should include the following:

(a) In service inspections to identify conditions requiring corrective action or further study.

(b) Detailed, knowledgeable plarining for effecting repair or modifications using qualified personnel, procedures, and equipment.

(c) Use of comprehensive equipment history that records conditions found, maintenance work done, changes made, and date of each.

(d) Written comprehensive maintenance procedures incorporat- ing manufacturer's instructions to define tasks and skills required." Any special techniques, such as non-destructive testing or those tasks requiring special tools, should be defined. Special environmental factors should be 'covered, such as temperature limitations, dusts, contaminated or oxygen-defi~:ient atmosphere, and limited access or confined space reqmrements.

(e) Shutdown maintenance inspections, comprehensive in scope, to cover all areas.

(f) Adequate spare parts available meeting specifications that will provide reliable service without necessitating makeshift repairs.

• G-I.S An inspection and maintenance schedule should be established and followed.

C-1.4 Operation, set-points, and adjustments should be verified by periodic testing and the results documented.

G-1.5 Defects should be reported and corrected and the repairs documented.

C-1.6 System configuration, including logic, set-points, and sensing hardware, should not be changed without the effect being evaluated and approved.

G1.7 Inspections, adjustments, and repairs should be performed by trained personnel, using tools and instruments suitable for the work. Maintenance and repairs should be performed in accordance with the manufacturer's recommendations and applicable standards and codes.

C-2 Training.

C-2.1 Operator Training.

25

N F P A 8 5 F - - A 9 2 T C R

Raw Fuel Bunker

Hot A i r Shu to f f Damper

Hot A i r Contro l Damper

Tempering Ai r

Tempering Air / Contro l D a m p e r - -

Primary A i r Contro l Damper

Vent Contr l Valve

Feeder Discharge Piping

Hot A i r

. \ Cyclone Air D i s c h a r g e ~ Line

Raw Fuel Gate

Vent Dust Col lector ~

Pulver izer Fan

='•=• I Pulverized Fuel Pump

~ yclone

Raw-Fuel Feeder

Pulverizer Note: Vent Dust Col lector May Be Omit ted.

Au tomat ic A u x Ai r In let

Vent Fan Pulverizer Fuel Bin Vent And Dust Col lector

Pressure / I Lock / / . / ? l v e r , z e d Fue lB in

- - ~i~ / Pulver,zed tl / F u e l Feeder

Suction Furnace

Check Valve X "

\ Primary Air Fan

Barrier Valve

Fi~.re 2-5.2.1.2(b) Storage Firing System (Parual Recirculation --Vented Air to PA Fan).

Raw Fuel Bunker

Automatlc Jux Air lolet

Hot Air Shutoff Damper Hot Air

Hot Air Control

Tempering A ir.-~

Tampering Air ~ Control Damper

Primary Air J Control Damper

Vent Control Valve

Feeder - Discharge Piping

Pulverizer Fan

Cyclone Air Discharge Line

__

Raw-Fuel Feeder

Note' Vent Dust Collector May Be Omitted.

Raw Fuel Gate /

Vent Dust Collector ~

Pulverized Fuel Pump

Cyclone

Pulverizer

Vent Fan Pulverizer Fuel Bin Vent And Dust Collector

Pressure ~u Y Lock #~, / Iverlzed Fuel Bin

Pulverized Fuel i Feeder

Suction Furnace

Primary Air Fan Barrier Valve

Check Valve

Figure 2-5.2.1.2(c) Storage Firing System (Partial Recirculation --Vented Air to Furnace).

26

N F P A 8 5 F - - A 9 2 TCR

R a w Fuel Bunker

Raw Fuel Gate ,

R aw Fuel Feeder

Feeder Discharge Piping

V e n t Control Valve

Pulverizer Air Control Damper

T e m p e r ing Air Shutof f Damper

t[7 ;

Hot Air Control Dam

AUX i~iary Air

\ Automat ic Auxlhary Air Inlet

Vent Fan / Vent

Exhauster

Pulver izer Fuel Bin Vent And Dust Collector

• \

Pulverized Fuel Gate

Pu(verlzed Fuel Feeder

f Cyclone

Pressure Lock ~

~,~Pressure Lock Burner'

Barrier Valve

V e n t Dust / S Collector Fuel Discharge Piping

P( imary / ,A i r Shutof f

Damper

Primary Air Con Damper

Tempering Air

" ~ Hot ALr _ Temper tng Air

Control Dampers

Hot Air Shutof f Damper

' Air Heater

Vent Dust ' Collector

Suct ion Furnace

,~ Forced Draf t

• Fan

I

Figure 2-5.2.1.2 (d) Storage Firing System (Partial Recirculation).

C-2.1.1 A formal training program should be established to prepare personnel to safely and effectively operate equipment. This program can consist of review of operating manuals, vadeotapes, programmed instruction, testing, and field trmning, am6ng others. The training program should be consistent with the type of equipment and hazards involved. '

G-2.1.2 Operating procedures should be established that cover normal and emergency conditions. Start-up and shutdown proce- dures, norrhal operating conditions, and lockout procedures should be covered in detail.

G-2.1.30peratingprocedures should be directly applicable to the equipment involvedand consistent with safety requirements and manufacturer's recommendations.

C-2.1.4 Procedures should be periodically reviewed to keep them current with changes in equipment and personnel.

G-2.2 Maintenance Training.

G-2.2.1 A formal maintenance training program should be estab- lished to prepare personnel to safely and effectively perform any. re uiredma[ntenance tasks This program can consist of review of maintenance manuals, ,adeotapes, programmed mstrucuon, tesung, field training, and equipment manufacturer training, among others.

The training progr'am should be spedfic to the equipment involved and to potential hazards.

C-2.2.2 Maintenance procedures should be established to cover routine and special techniques. Any potential environmental factors such as temperature, dust, cont,~minated oi" oxygen-deficient . atmosphere, internal pressures, and limited access or confined space requirements should be included.

C-2.23 Procedures should be consistent with safety requirements and manufacturer's recommendati6ns.

C-2.2.4 Procedures should be periodically reviewed to keep them current with changes in equipment and personnel.

SUBSTANTIATION: This is useful information that addresses potential combustion hazards due to maintenance, inspection, and tr~aining. This is consistent with similar information contained within NFPA 85C. The appendix C that is being replaced did not contain any useful informauon. C O M M I T T E E ACTION' , Accept. - '

2 7

N F P A 8 5 F - - A 9 2 T C R

85F- 42. (Entire Document): Accept SUBMITrER: NFPA 85F Subcommittee RECOMMENDATION: Editorially revise the numbering of NFPA 85F as foUows~

i . Number the second paragraph of 1-3.1.2 as 1-5.1.3 and , renumber subsequent paragraphs accordingly.

2. Insert a new heading as follows: 1-3.2.1.6' Transport Air, Renumber the current 1-3.1.6 as 1-3.2.1.6.1 and 1-3.2.1,6.1 as 1-

5.2.1.6.2.

3. Combine 1-5.2.1 into 1-3.2. Renumber 1-3.2.1.1 through 1-5.2.1.17 as .1-3.2.1 through 1-3.2.17.

4. Renumber items (a), (b), and (c) of 1-3.5.1 as 1-3.5.1.1, 1- 3.5,1.2, and 1-5.5.1.3.

5. Combine 2-4,1 into 2-4. I

6. Combine 2-6.2.1 into 2-6.2. Renumber 2-6.2.1.1 through 2-6.2.1.8 as 2-6.2.1 through 2-6.2.8.

7. Combine 2-6.3.1 into 2.6.3.

8. Combine 2-6.4.1 into 2-6.4.

9. Renumber 2-6.5.3.1 to 2-6.5.4.

10. Renumber 2-6.6.3.1 and 2-6.6.4 to 2.6.6.4 and 2-6.6.5.

11. Combine 3-3.1.1 into 3-3.1,

12. Combine 3-3.3.1 into 3-3.3.

13. Combine 3-4.1.1.1 into 3-4.1.1.

14. Combine 3-4.1.3.1 into 3-4.1.3.

15. Combine 3-4.2.1.1 into 3-4.2.1.

16. Combine 3-4.2.2.1 into 3-4.2.2.

17. Combine 4-1.1 into 4-1.

18. Combine 4-3.2.1 into 4-3.2,

, 19. Combine 4-3.4.1 into 4-3.4.

20. Provide a heading for Appendix A as "Direct-Firing Circular-' ing System. Delete A-1. Revise'the Appendix A numbering as follows:

(a) A-l-1 becomes A-1

(b) A-2-1 becomes A-2

(c) A-2.1.1' becomes A-2-1

(d) A-2-1.2 becomes A-2-2

(e) A-2.1.2.1 becomes A-2-2.1

(f) A-2-1.2.2 becomes A-2-2.2

(g) A-2-1.3 becomes A-2-3

(h) A-2-2 becomes A-3

(!) A-2-2.1 becomes A-3-1

(j) A-2-2.2 becomes A-3-2

(k) A-2-2.2.1 becomes A-3-2.1

(1) A-2-2.2.2 becomes A-3-2.2

(m) A-2-2.3 becomes A-3-3

21. Provide a heading for Appendix B as "Direct-Firing System for Firing Zinc-Fuming Furnace." Delete B-1. Revise the Appendix B numbering as follows:

(a) B-1-1 becomes 13-1

(b) 13-1-1.1 becomes B-1-1 °

(c) B-1-1.2 becomes B-1-2

(d) B-l-2 becomes B-2

(e) I?,-1-3 becomes 13-3

(f) B-l-4 becomes 13-4

(g) B-1-4.1 becomes B-4.1

(h) 13-1-4.2 becomes 13-4.2

(i) B-1-4.3 becomes B-4-3

(j) 13-1-5 becomes 13-5

SUBSTANTIATION: These are editorial changes to the numbering system of NFPA 85F made to conform with the NFPA Manual of Style. COMMITTEE ACTION: Accept.

2 8

N F P A 85I - - A92 T C R

PART III

851- 1 - (1-1.4): Accept SUBMH'rER: NFPA85I Task Group RECOMMENDATION: Revise 1-1.4 as follows:

1-1.4 Requirements for auxiliary fuel firing equipment and interlocks should follow NYPA 85A and NFPA 85C.

Exception No. 1: The purge requirements of NFPA 85A and NFPA 85C are not required when the stoker is firing and the boiler is on- line. In those cases, if no cooling air is being provided to the auxiliary, burners, a purge of their associated air supply ducts should be prowded. '

Exception No. 9: When firing oil or gas in a supervised manual system in accordance with NFPA 85A, the excessive steam pressure interlock is not required (see 6-5.5). SUBSTANTIATION: Changes have been made for clarity and to emphasize the criteria by using exceptions•

Exception No. 9 was added because the application of the excessive steam pressure interlock is not desired because it could create an

Set condition that should be avoided. MMrrTEE ACTION: Accept.

851- 9 - (1-9.1): Accept SUBIVItt-r~R: NFPA851 Task Group RECOMMENDATION: Revise the date from "December 198ff" to "July 15, 1999." SUBSTANTIATION: This properly revises the effective date.

- COMMITTEE ACTION: Accept.

85I- 3 - (1-9.2 (New)): Accept SUBM1TI'ER: NFPA 851 Task Group RECOMMENDATION: Insert a new 1-9.9 as follows:

1-2.2 No document can be promulgated that will guarantee the • elimination of boiler combustion hazards.. Technol%,y in this area is under constant development, which will be reflected in revisions to this document. The user of this document must recognize the complexity offirlng fuel with regard to the type of equipment and the characteristics of the fuel. Therefore, the designer is cautioned that the document is not a design handbook. The document does not do away with the need for the engineer or for competent engineeringjud, gment. It is intended, that a designer. .capable of .

applying more complete and ngnrous anaiym to special or unusual problems shall have latitude in the development of such designs. In such cases, the designer is responsible for demonstrating the x~idity of the approach• " SUBSTANTIATION: This is an important statement that provides flexibility for new and unusual technologies. This is also consistent with the other NFPA 85 series documenfs. COMMrrrEE ACTION: Accept.

85I- 4 - (1-9.3 (New)): Accept in Principle SUBM1TTER: NFPA 85I Task Group RECOMMENDATION: Insert a new 1-2.3 as follows and renumber subsequent paragraphs accordingly:

1-9.3 Revisions to this docume'nt do not imply that previous editions were inadequate. SUBSTANTIATION. This maintains the credence of prior editions. COMMITTEE ACTION. Accept in Principle.

Insert a new 1-9.3 as follows and renumber subsequent paragraphs accordingi~:

1-9.3. Revisions to this document reflect the current state of knowledge and do not imply that previous editions were inadequate. COMMITTEE STATEMENT: This is consistent with changes being made to NFPA 85A and NFPA 85F.

85I- 5 - (9-1.3(d) (New)): Accept 8 U B M r r Y F ~ NFPA 85I Task Group RECOMMENDATION: Insert a new (d) and reletter subsequent items accordingly as follows:

(d) Utilization of high volatile fuels such as gasoline for ignition s°ses.

TANTIATION: This is consistent with the caution statement of

ACTION: Accept.

85I- 6- (3-1 (New)): Accept SUBMITIT~ NFPA 85I Task Group RECOMMENDATION: Insert a heading 3-1 as follows:

3-1 These definitions apply to this Recommended Practice. SUBSTANTIATION: This clarifies the correlation between NFPA 85I and the other NFPA 85 series documents. "COMMITI'EE ACTION: Accept.

• \

85I- 7 - (Chapter 3): Accept in Principle SUBMITYE~ NFPA 85I Task Group _ RECOMMENDATION: 1. Add the following definitions:

"Air. Seal Air. Air supplied to any device at pressure for the specifiedpurpose of minimizingcontamination. Boiler• A closed vessel in which water is heated, steam is generated,

steam is superheated, or any combination thereof by the application of heat from combustible fuels, in a self-contained or attached furnace.

Boiler Control System. The group of control systems that regulates the boiler process including the Combustion Control.

Boiler-Furnace Enclosure. The physical boundary for all boiler pressure parts and the combustion process.

Combustion Control System. The control system'that regulates the furnace fuel and air inputs to maintain air/fuel ratio within the limits required for continuous combustion throughout the operating range of the boiler in accordance with demand. This control system includes the furnace draft control where applicable.

Logic System. The decision making and translation elements of the stoker management system.

(a) Hardwired Systems: Individual devices'and interconnect- ing wiring. , (b) Microprocessor Based Systems: 1. Computer hardware, power supplies, I / O devices, and interconnections between these. 2. Operating system and logic software.

Open Flow Path. A continuous path for movement of an air stream fro/n the forced draft fan inlet to the stack.

Mass Burning Stoker. See Overfeed Stoker. . " Recommended Practice. A document similar in content and

structure to a code or standard but containing only nonmandatory provisions using the word "should" to indicate recommendatons in the body of i.he text."

9. Delete the definition for "Fuel Discharge Stoker" and "Stable F l a l T l e " .

3. Create a new definition heading"Stoker". Move the following definitions so that they become subheadings under "Stoker."

Chain Grate Stoker Dump Grate Stoker Forced Draft Stoker Front Discharge Stoker Gate Stoker

• Mass Burning Stoker' (New) Mechanical Stoker ' ' Multiple Retort Stoker Overfeed Stoker ' Rear Discharge Stoker Reciprocating Grate Side Dump Stoker Single Retort Stoker Spreader Stoker Stationary Grate Traveling Grate Stoker Underfeed Stroker Water Cooled Stoker

,4. Revise the definition of "overfeed stoker" as follows: "overfeed Stoker. A stoker in which fuel is fed onto grates above

the point of air admission to the fuel bed. overfeed stoker grates include:

Front Feed, Inclined Grate. Fuel is fed from the front onto a grate inclined downwards toward the rear of the stoker.

Chain or Traveling Grate. A moving endless grate that conveys fuel into and through the furnace where it is burned, after which it discharges the refuse. ¢Vibraun~. An inclined vib~tin~ gra. te in which fuel is conveyed into

and throffgh the furnace where i~ is burned, after which it discharges the refuse."

5. Revise the definition of "Spreader Stoker" as follows: "Spreader Stoker. A stoker that distributes fuel into the furnace

from a location above the fuel bed with a portion of the fuel burned in suspension and a portion on the grates. Spreader stoker grates include:

Stationary Grate. A grate in which fuel is fed onto a fixed position grate.

29

N F P A 85I m A92 T C R

Dump Grate. A grate in which fuel is fed onto a non-movlng grate that is arranged to allow intermittent discharge of refuse through tilting action of the grate bars.

Continuous Discharge or Traveling Grate. A grate which continu- ously discharges the refuse from the end after burning the fuel. SUBSTANTIATION: 1. Definitions have been addedbecause they are used in NFPA 85I and are consistent with NFPA 85C.

2. The definition for Fuel Discharge Stoker was deleted because it is redundant with the definition for Front Discharge Stoker. Also, "Stable Flame" is not used.

3. The "Stoker" heading was added for clarity. 4. The definition of "Overfeed Stoker" was revised for clarity. 5. The definition of "Spreader Stoker" was revised for clarity.

COMMrr lXE ACTION: Accept in Principle. Accept theproposed changes, but revise the last word of the

definition of"Boiler" from "furnace" to "combustion chamber". COMMrt-rtJg STATEMENT. This is consistent with changes being made to NFPA 85H.

85I- 8 - (4.1.4 (New)): Accept . SUBI~I£rI'KR" NFPA 85I Task Group RECOMMENDATION'. Insert a new Section 4-1.4 as follows:

4.1.4 Coal Special Problems. 4.1.4.1 The term coal refers to solid fuels with widely differing

characteristics. A°coal burning fuel system is designed for a specific range of coal characteristics. Coals that differ widely from the design range of characteristics can cause serious operating difficulties and become a potential safety hazard. The coal as mined, transported, and delivered to the plant can vary in size and in impurities to a degree that exceeds the capability of the 131ant equipment. When coals are received from more than one source, care must be exercised to make sure that all coals received are within the specific range of the coal handling and coal burning equipment.

4.1.4.9 To ensure that the type o f coal and itspreparation are suitable for the equipment, there must be a quality definition that is acceptable to the equipment designer, the purchasing agency responsible for procuring the fuel, and the operating department that burns the fuel. Volatility, moisture and ash content, size of raw . coal, and other characteristics must be given close attention: All of the following factors have a bearing upon the problem: ,

(a) Coal is an abrasive and corrosive substance. Equipment maintenance therefore may be several orders of magnitude greater than with liquid and gaseous fuels: (b) Coal changes when it is exposed to the atmosphere. It is

common practice to ship and stockpile coal without protection from the weather. The properties of stored coal may change. This may require special considerations. Coal with high surface moisture may freeze in shipment or in storage. This may require special handling equipment. (c) Since coal has a high ash content, special attention must be

given to problems associated with slag and ash deposits. (d) Coal is capable of spontaneous combustion and, self-heating

from normal ambient te .mperature.' This tendency increases radically when the temperature is increased. Blended or mixed coals may heat more rapidly than an7 of the parent coals.

(e) Volatile matter is given offby the coal. This volatile matter is a gaseous fuel that causes additionalhazards. SUBSTANTIATION: This is useful information that correlates with NFPA 85C. COMMITTEE ACTION: Accept.

85I- 9- (4-7 (New)): Accept SUBMITrER: NFPA 851 Task Group RECOMMENDATION: Insert a new. 4.7 as follows:

4.7 Special Considerations. For special problems in handling refuse fuels, refer to NFPA 850. SUBSTANTIATION: This provides recognition of the new alterna- tive fuels criteria included in NFPA 850., COMMITTEE ACTION: Accept.

85I- 10- (5-1.3): Accept SUBMITrER: NFPA85I Task Group RECOMMENDATION: Revise as follows: I 5-1.3 Ash Subsystem. A dump grate is used to deposit ash into an ash pit. Ash is typically manually removed from the ash pit through ash doors on the front of the unit. SUBSTANTIATION: This clarifies this paragraph and eliminates the

recognition of the dangerouspractice of removing ash through a fire door as opposed to an ashpit door. COMMITTF~ ACTION: Accept.

851- I I - (5-2): Accept SUBMITrER: NFPA 851 Task Group RECOMMENDATION: Revise as follows:

"5-2 Overfeed Mass Burning Stoker. Overfeed mass burning stokers include not only chain and traveling grate stokers for..." SUBSTANTIATION: Editorial. COMMITTEE ACTION: Accept.

85I- 12- (Figure 5-1(b)): Accept SUBMrt-rKR: NFPA 85I Task Group RECOMMENDATION: Revise Figure 5-1 (b) as follows:

Dump Grate

Figure 5-1 (b) Multiple Retort Underfeed Stoker Showing Components. (Reprinted with Permission

of Detroit Stoker Company)

SUBSTANTIATION: This clarifies this illustration. COMMITTEE ACTION: Accept.

85I- 13 - (Figure 5-2.10): Accept SUBMITFER: NFPA 85I Task Group RECOMMENDATION: In caption, indicate "(Reprinted with Permission of Detroit Stoker Company)" SUBSTANTIATION: Detroit Sto~:er Company now owns LacLede Stoker Company. COMMITTEE ACTION: Accept.

85I- 14- (Figure 5-3): Accept SUBM1TFER: NFPA 85I Task Group RECOMMENDATION: Revise Figure 5-3 as follows:

(SEE FIGURE 5-3 NEXT PAGE)

SUBSTANTIATION: This clarifies this illustration. COMMrITEE ACTION: Accept.

85I- 15 - (5-Z6): Accept' SUBMrI'TER~ NFPA 85I Task Group RECOMMENDATION: Revise to:

"The as-fired total moisture in the coal should be a maximum of 20 percent by weight." . - SUBSTANTIATION. This changes "ash-fired" to "as-fired", which is a

Ographical error. MMITTEE ACTION. Accept.

3O

Coal Hopper

Feeder

Ash Hopper

71f-

Overhre Air

Overfire Overthrow Air Rotor

Air Seal Air Seal

Stoker Travehng Grate

Z T

Figure 5-3 Side View of a Spreader Stoker with Traveling Grate. (Reprintedwith Permission of

Detroit Stoker Company)

85I- 16 - (5-2.10): Accept SLrBMITI3~R~ NFPA 85I Task Group RECOMMENDATION: Revise the first sentence of the second paragraph as follows:

"These stokers are mainly used for medium-sized industrial boilers with heat inputs from 40,000,000 Btu /h r (11,720 kW) to 170,000,000 Btu /hr (49,800 kW)." SUBSTANTIATION: This uses the same units as used by the documents scope statement. COMMITTEE ACTION: Accept.

851-17- (5-2.11): Accept SUBMrITER: NFPA 85I Task Group RECOMMENDATION: Revise the first sentence of the third ' paragraph as follows:

"These stokers are mainly used for medium-sized industrial boilers with heat inputs from 70,000,000 Btu /hr (20,500 kW)" to 140,000,000 Btu /h r (41,000 kW)." SUBSTANTIATION: This uses the same units as used by the documents scope statement. COMMrrIT.~ ACTION: Accept.

851- 18 - (5-2.12): Accept SUBMITITd~: NFPA 85I Task Group RECOMMENDATION: Revise the first sentence of the first paragraph as follows:

"The grate of an inclined stoker resembles a staircase that is used to move refuse from the feed end of the furnace to the ash discharge end." SUBSTANTIATION: This is a more appropriate description of this ~eMMITI , E E O f stoker.

ACTION: Accept.

85I- 19- (5-2.12): Accept SUBMI'TrER: NFPA 85I Task Group RECOMMENDATION: Revise the first sentence of the fourth para~'raph as follows: "

"This stoker is currently used for medium-sized boilers with heat inputs from 30,000,000 Btu /hr (8,800 kW) to 340,000,000 Btu /hr (99,600 kW). SUBSTANTIATION: This uses the same units as used by the documents scope statement. COMM1TFEE ACTION: Accept.

NFPA 851 - - A92 TCR

85I- 20 - (5-3.1): Accept SUBMITTER: NFPA 85I Task Group RECOMMENDATION: Delete "for one" from the last sentence of the first paragraph. SUBSTANTIATION: Editorial. COMM1TIT..E ACTION: Accept.

85I- 21 - (5-3.1): Accept SUBMI'ITER: NFPA 85I Task Group I RECOMMENDATION: Revise the first sentence of the sixth paragraph as follows:

"Spreader stokers are utilized on boilers having heat inputs from 30,000,000 Btu /hr (8,800 kW) to 820,000,000 Btu /hr (240,300 kW), depending upon the fuel and type of spreader stoker grate."

SUBSTANTIATION: This uses the same units as used by the documents scope statement. COMMII - t /~ ACTION: Accept.

851- 22- (5-4.2.3(b)3.): Accept SUBMITTER: NFPA 851 Task Group RECOMMENDATION: Add a sentence at the end of the paragraph as follows:

"See NFPA 850 for additional requirements." -" SUBSTANTIATION: This provides recognition for NTPA 850 which includes criteria on this subject. COMMrrrEE ACTION: Accept.

85I- 23 - (5-4.2.3(c)2.): Accept SUBMIITt:R: NFPA 85I Task Group RECOMMENDATION: Revise as follows:

"Properly placed observation ports should be provided to permit inspection of the furnace and grate. Refer to Section 9-9." SUBSTANTIATION: This ibrovides reference to Secdon 9-9 which contains further requirements on this subject. COMMITI'EE ACTION: Accept.

851- 24- (5-4.2.3(c)4.): Accept SUBMITI'ER: NFPA 851 Task Group ' . RECOMMENDATION: In the third and fourth paragraph, replace "NFPA 85G" with "Chapter 5 of NFPA 85C". SUBSTANTIATION: NFPA 85G has been incorporated into NFPA 85C. COMMITFEE ACTION: Accept.

85I- 25: (5-5.1.2): Accept ' SUBMrlq'ER: NFPA 85I Task Group RECOMMENDATION: Revise the ~ieginning of the paragraph as follows:

"The combustion control subsystem should control furnace inputs and their relative ..." SUBSTANTIATION: This clarifies the !ntent of this paragraph. COMMITTEE ACq'ION: Accept.

r

85I- 26 - (6-1 (New)): Accept SUBMITTER: NFPA 85I Task Group RECOMMENDATION: Insert a new 6-1 as follows and renumber subsequent paragraphs accordingly:

6-1 General. This chapter addresses typical stoker operation. In all cases, manufacturers recom.mendations should be consulted and followed. SUBSTANTIATION: This re-emphasizes criteria already shown in

ACTION: Accept. ' "

85I- 27 - (6-1.1, 6-1.2, 6-1.3 and 6-1.4): Accept SUBMITrER: NFPA 85I Task Group RECOMMENDATION: Renumber 6-1.1, as 6-2, 6-1.2 as 6-2.1, 6-1.3 as 6-2.2,.and 6-1.4 as 6-2.3.

Renumber subsequent par'agraphs accordingly.

31

N F P A 85I - - A 9 2 T C R

Revise the heading of 6.1.1 (now 6-2) as'follows: 6-2 Start Up Procedures (Cold Start). The cold start procedure is as

follows: SUBSTANTIATION: This should be a separate section from "Start- ~PoGeneral."

MMrlWEE ACTION: Accept.

85I- 33 - (7-2): Accept SUBMITTER: NFPA 85I Task Group RECOMMENDATION: Revise as follows:

"7-2 Maintenance Programs. As a minimum, the maintenance program should include the following:" SUBSTANTIATION: Editorial. COMMITr~S ACTION: Accept.

85I- 28 - (6-2.4): Accept in Principle SUBMITrER: NFPA 85I Task Group RECOMMENDATION: Revise as follows:

• "Fuel should be fed to maintain an even depth of ash. As the percent of ash in the fuel changes, it may be necessary to make adjustments. It is necessary to observe this condition from the depth of ash at the discharge end of the grates." SUBSTANTIATION: These changes editorially clarify this par'a.

ra h. ~ ) P ~ I ' T E E ACTION: Accept in Principle. Accept the changes, but revise the last sentence to "It is necessary to

observe the depth of ash at the disch .a~e end of the grates'. COMMIt t t ;E STATEMENT: This editorial change makes the last sentence more readable.

85I- 2 9 - (6-3(e) and 6-3(g)): Accept SUBMI'IWER: NFPA 85ITask Group RECOMMENDATION: 1. Revise 6-3(e) as follows:

(e) After fuel feed ceases and the fire is burned out, the overflre air and forced draft fan can be shut off or left running depending on the desired rate of boiler cool-down. However, the overflre air fan should be left running until the furnace and boiler are sufficiently cool to prevent damage to the overflre system from a back flow of hot gases.

2. Delete 6-3(g) and reletter subsequent paragraphs accordingly. SUBSTANTIATION: This clarifies this section and combines items (e) and (g) which deal with the same subject. COMMITI'EE ACTION: Accept.

85I- 30 - (6-5.2): Accept SUBMI'ITER: NFPA 85I Task Group RECOMMENDATION: Revise the last sentence to:

*The operator should manually open fire doors above the grate only if there is sufficient furnace draft. " - SUBSTANTIATION: Editorial. COMMITTEE ACTION: Accept.

85I- 31 - (6-5.5): Accept SUBMITFER: NFPA 85I Task Group RECOMMENDATION: Revise Sectlgn 6-5.5 as follows:

6-5.5 Critical Emergency Situations. Critical emergency situations requiring action are:

(a) Low Drum Level. 1. Stop all fuel feeds. 2. Stop fan(s) that supply combustion air to the unit. 3. Continue running 113 fan with combustion air damper at

minimum setting. This is recommended to limit continued combustion of the residual fuel bed.

(b) High Operating Steam Pressure. 1. Stop all fuel feed(s). 2. Decrease combustion air to minifi~um and maintain furnace

draft. 3. When steam pressure is in normal operating range, start fuel

feed and place combustion air for normal air/fuel rauo. SUBSTANTIATION: This provides editorial clarification of this section. COMMITTEE ACTION: Accept.

85I-34-(7-3.1 through 7-3.5 (New)): Accept S U B ~ NFPA 85I'Task Group RECOMMENDATION: Insert new paragraphs as follows and renumber subsequent paragraphs accordingly:

7-3.1 An inspection and maintenance schedule should be estab- lished and followed.

7-3.2 Operation, set-points, and adjustments should be verified by periodic testing and the results documented.

7-3.3 Defects should be reporte8 and corrected and the repairs documented.

7-3.4 System configuration, including logic, set-points, and sensing hardware, should not be changed without the effect being evaluated and approved.

7-3.SInspections, adjustments, and repairs should be performed by trained personnel, using tools and instruments suitable for the work. Maintenance and repairs should be performed in accordance with the manufacturer's recommendations and applicable standards and codes. SUBSTANTIATION: This is useful information and provides consistency with N'FPA 85(3. CoMMrlWEE ACTION: Accept.

85I- 35 - (9-2.2): Accept SUBMITTER: NFPA85I Task Group RECOMMENDATION: Revise to read as follows:

"9-2.2 Specific procedures should be developed and used for personnel entering confined spaces and should: SUBSTANTIATION: Editorial. COMMITTEE ACTION: Accept.

85I- 36. (9-7 (New)): Accept in Principle SUBMITTER: NFPA 85I Task Gi'oup RECOMMENDATION: Insert a new Section 9-7 as follows and reunumber subsequent paragraphs accordingly:

9-7 Explosion-Operated Tools. Explosion-operated tools and forming techniques should not be used where flammable dust or dust clouds are present. When these operations become necessary, all equipment, floors, and walls should be cleaned and all dust accumu- lation removed by an approved method. A careful check should be made to be sure that no cartridges or charges are left in the work area. SUBSTANTIATION: This is useful information and provides consistency with NFPA 85C. COMMITTEE ACTION: Accept in Principle. Accept the proposed change but change "flammable" to "combus-

tible'. Also, addat the endU(see 9-4.2)". COMMITTEE STATEMENT: Modifications have been made for clarity.

85I- 37 - (9-9, 9-9.1 and 9-9.2): Accept SUBMITI'ER: NFPA 85I Task Group RECOMMENDATION: Insert "or observation ports" after "acess doors" in three places. SUBSTANTIATION: Observation ports need to be specifically addressed in addition to access doors. COMMITTEE ACTION: Accept.

85I- 32 - (6-8 and 6.8.1): Accept SUBMI'IWER: NFPA 85I.Task Group RECOMMENDATION: Combine 6-8 and 6-8.1 to read:

"6-8 Purge Cycle. Dual fuel fired boilers with stoker and auxiliary burners may require purge cycles under certain..." SUBSTANTIATION: Editorial. COMMrrIT, E ACTION: Accept.

85I-38- (9-10.3 (New)): Accept . '

SUBMITTER: NFPA 85I Task Group RECOMMENDATION: Insert a new paragraph as follows:

9-10.3 Vertical lifting ashpit doors shouldbe securely blocked open prior to personnel entry. SUBSTANTIATION:This is a significant safety concern that should be addressed for ash hopper access doors, just as it is addressed in 9- 7.2 for the feed gate on overfeed mass burning stokers. COMMITI'EE ACTION: Accept,

3 2

N F P A 85I - - A92 T C R

85I- 39 - (Endre Document): Accept SUBMITTER: NFPA 851 Task Group RECOMMENDATION: Editorially revise the numbering system of NFPA 851 as follows:

1. Revise 2-3(a), 2-3(b), and 2-3(c) to 2-3.1, 2-3.2, and 2-3.3.

2. Insert the following heading for 4-6.2.1 as follows:

4-6.9.1 Bagasse. • Renumber the two paragraphs of 4-6.2.1 as 4--6.2.1.1 and 4-6.2.1.2.

3. Insert the following heading for 4-6.2.2 as follows: 4--6.2.2 Refuse-Derived Fuel Renumber the three paragraphs of 4--6.2.2 as 4-6.2.2.1, 4,-6.2.2.2, and

4-6.2.2.3.

4. Leave 5-2.10 as a heading, and renumber the three paragraphs of 5-2.10 as 5-2.10.1, 5-2.10.2, and 5-2.10.3.

5. Leave 5-2.11 as a heading, and renumber the four paragraphs of 5-2.11 as 5-2.11.1, 5-2.11.2, 5-2.11.3, and 5-2.11.4.

6. Leave 5-2.12 as a heading, and renumber the six paragraphs of 5- 2.12 as 5-2.12.1 through 5-2.I2.6.

7. Insert the'following heading for 5-3.1 as follows: 5-3.1 General. Renumber the six paragraphs of 5-3.1 as 5-3.1.1 through 5-3.1.6.

8. Number the second, third, and fourth paragraphs of 5- 4.2.S(c) (4) as (5), (6), and (7).

9. Renumber items (a) through (g) of Secdon 5-5.2 as paragraphs 5- 5.2.1 through 5-5.2.7. SLrBSTANTIATION: These editorial numberin~ changes ~ e made for clarity and to conform to the NFPA Manual of Style. COMMITTEE ACTION: Accept.

33