The Report of the Committee on Ovens and Furnaces Rep. NEMA · recent change to definition of...

Report of the Committee on Ovens and Furnaces

3. M. Simmons, Chairman Factory Mutual Research Corp.

James T. Blackmon, J r . , Professional Loss Control Inc. 3oseph G. Coutu, Industr ia l Risk Insurers Gust A. Dadas, LTV Steel Co. Christopher B. Fink, Honeywell Inc.

Rep. NEMA Lawrence H. Fournler, Al lstate Insurance Co.

Rep. AISG John C. Herron, Electric Furnace Co. Alan W. Hoagland, Inland Steel Co.

Rep. AISI Fred K. Jensen, Jensen Oven Co. Inc. William R. Jones, Vacuum Furnace Systems Corp. Kenneth R. Keska, St., C A L i tz ler Co. Inc. Richard G. Marco, United Technology Corp.

Rep. AIA Davis C. Mclntosh, Lindberg Heat Treating Co. Raymond Ostrowski, Protection Controls Inc. Wayne F. Parker, Maumee, OH William L. Pingry, Maxon Corp. Richard C. Riccardi, North American Mfr. Co.

Rep. IHEA Paul N. Rick, Ford Motor Co. 3. William Sheppard, General Motors Corp. Rep. NFPA IFPS

Nicholas L. Talbot, Pompano Beach, FL Rep. !RM Insurance

W. P. Thomas, Jr . , Kemper Group Rep. AAAI

Robert H. Timmlns, Reynolds Metals Co. Algirdas Underys, A. Finkl & Sons. Co. Philip L. Young, Jr. , Union Carbide Corp.

Alternates

James L. Bender, Texas Instruments Inc. (Alternate to C. Fink)

John M. Berger, Maxoh Corp. (Alternate to W. L. Pingry)

John R. Hensley, Inco A]loys In t l Inc. (Alternate to Huntington Al loys Inc.)

Gerald G. Hoeft, Ca te rp i l l a r Tractor Co. (Alternate to CTC Rep.)

Jeffrey 3. K rou t i l , IRM Insurance (Alternate to N. L. Talbot)

Edward K. Lack, Protection Controls Inc. (Alternate to R. Ostrowski)

Glen R. Mortensen, Kemper Group (Alternate to W. P. Thomas)

David S. Rohrbaugh, Drever Co. (Alternate to R. C. Riccardi)

A]lan Sordelett , Reyno]ds Metals Co. (Alternate to R. H. Timmins)

Peter J. Gore Wil lse, Industr la l Risk Insurers (Alternate to 3. G. Coutu)

Nonvoting

F. 3. Thornton, Standards Assn. of Austra l ia

Staff Liaison: Casey C. Grant

This l i s t represents the membership at the time the Committee was bal loted on the text of th is ed i t ion. Since that time, changes in the membership may have occurred.

The Report of the Committee on Ovens and Furnaces is presented for adoption.

This Report was prepared by the Technlca] Committee on Ovens and Furnaces and proposes for adoption amendments to NFPA 86-1985, Standard for Ovens and Furnaces. NFPA 86-1985 is published in Volume 4 of the 1988 Natlonal Fire Codes and in separate pamphlet form. The number of th is document is being changed from NFPA 86 to NFPA 86AB.

This Report has been submitted to l e t t e r ba l lo t of the Technical Committee oh Ovens and Furnaces which consists of 26 vot ing members; of whom 23 voted a f f i rmat i ve ly , 1 negatively (Mr. Fink), and 2 bal lots were not returned (Messrs. Hensley and Rick).

Mr. Fink voted negatively for the fo l lowlng reason: "NEHA is very concerned with certain safety issues

out l ined in 3-5 Oxygen Enhanced Fuel Fired Units (4-16) and 4-8 Fuel Gas-Mtx|ng Mach]nes (page 32-33). These sections are attempting to have a national safety standards organization provide approval of oxygen f i red or enrichment systemS, however, no approved test agency or insurance body, i . e . , American Gas Association, Underwriters Laboratories, Inc. (UL 296-0i l , U/L 795 Gas), Factory Mutual, Industr ia l Risk Insurers have an approved safety control relay, safety controls or safety shutoff valves for oxygen services.

Mr. Simmons voted a f f i rmat ive with the fol lowlng comment :

"Paragraph 4-2.2 Exception and Note. The l i s ted requirement is too r e s t r i c t i v e and

should be approved. Ins ta l la t ions which are approved can be and have been designed and are operat lonal. These were the requirements needed for th is service, redundancy and sel f c l i ck ing have been provided. Listed devices e i ther do not ex is t or only one or two might be considered in th is category."

Mr. Parker voted af f i rmat ive with the fol lowing commen t :

"Reference Page 9 - Genera] (Controls, Fuel Safety) Remove the words "Combustible gas detectors" from this de f in i t i on m Reason: To be consistent with new revised 86 Standard where - in the Committee voted to remove'"combustibles gas detectors" from a l ] other sect ions."

Mr. Sheppard voted a f f i rmat ive with the fol lowing comment:

"While I vote Af f i rmat ive, two points need further c l a r l f i c a t l o n : 1. 4-2.2(b) Exception - Note: The word "approved" should be u t i l l z e d rather than " l i s t e d . " 2. 4-2.13(d) The inclusion of th is paragraph w i l l now contradict 4-2.13(c) as presently proposed.

Mr. Thomas voted a f f i rmat ive with the fol lowlng commen t :

"1. The high temperature l i m l t switch in Figure 4-6.4.1(b) appears to be drawn incor rec t ly . 2. In the note under Figure 4-6.4.1(b) in the las t sentence of the f i r s t paragraph "should" should be "shut -o f f . "

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86- I - (T i t le ) : Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Change the t i t l e of document to:

"NFPA 86A/B, Standard for Ovens and Furnaces." SUBSTANTIATION: The designation A/B wi l l be a quick clue for the reader that this document covers Class A as well as Class B ovens. Similar designations have already been done for NFPA 86C which covers Class C ovens (special atmospheres) and NFPA 86D which covers Class D ovens (vacuum atmospheres). COMMITTEE ACTION: Accept.

86- 2 - (Forward): Accept ~IJI).~I_T_T._E_~: Technical Committee on Ovens and Furnaces RECOMMENDAUJ~J: Change f i r s t sentence to read:

" . . . fuel f i red, electr ic and other heat . . ." ~_UB~TANTIAT_T_!_ON: The change is necessary to account for other types of heating systems such as solar drying and l iquid heat transfer systems. COMMITTEE ACTION: Accept.

86- 3 - ( I - I ) : Accept SUBMITTER: Technical Committee on Ovens and Furnaces ~-~C_O_MMEND_D_~LT_~.~I: Delete " . . . and heating systems for furnaces having a l iquid heat transfer medium."

Put a period af ter the word "systems." SVBSTANTIATION: Information on these systems wil l be added to the standard. The section wi l l cover organic heat transfer systems. COMMITTEE ACTION: Accept.

86- 4 - ( I -3) : Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Delete the last sentence. Replace with:

"Chapter 9, Inspection and Maintenance, and Section I-6, Operation and Maintenance Personnel Training, shall apply to al l operating furnaces." SUBSTANTIATION: The change wi l l highlight the

importance of following the requirements in the referenced sections for existing, as well as new furnaces. COMMITTEE ACTION: Accept.

86- 5 - ( I -4) : Accept SU_BMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add:

Air, Purge. See Purge Air. SUBSTANTIATION: The cross reference is necessary to make the document easier to use. COMMITTEE ACTION: Accept.

86- 6 - ( I -4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Change the t i t l e of the def in i t ion "Analyzer Fuel Gas" to "Analyzer, Gas" with the following def in i t ion:

"An instrument which measures the concentrations of gases or vapors comprising gaseous mixtures." SUBSTANTIATION: The addition of heating gas to the def ini t ion separates Fuel Gas Analyzer from Continuous Vapor Concentration Indicator and Controller.

This c lar i f ies the existing d e f i n i t i o n . COMMITTEE ACTION: Accept.

86- 7 - ( I -4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add def in i t ion as follows:

Aspirator, Proportioning. See Mixers, Air Jet. SUBSTANTIATION: This provides consistency with the recent change to def in i t ion of Inspirator, Atmospheric (Venturi) which now refers to mixers, gas je t . COMMITTEE ACTION: Accept.

(Log # I) 86- 8 - ( I -4) : Accept in Principle SUBMITTER: James J. Houston, Industrial Heating Equipment Association RECOMMENDATION: Burner, Nozzle Mixing.

Delete "gas" af ter " fuel" in the f i r s t sentence. SUBSTANTIATION: Editor ial . COMMITTEE ACTION: Accept in Principle. ~OMMITTEE STATEMENT: Also delete second sentence since i t does not app!y.

86- 9 - ( I -4) : Accept S U ~ : Technical Committee on Ovensand Furnaces RECOMMENDATION: For the def in i t ion of "Burner (or Nozzle)" change "fuel gas" to " fuel" at the beginning of the second sentence. SUBSTANTIATION: To be consistent with Proposal 86-8 (Log #I). COMMITTEE ACTION: Accept.

86- 10 - ( I -4) : Accept SUB_tLI_I~T__~R: Technical Committee on Ovens and Furnaces RECOMMENDATIQI~: Add the following to the definit ions of Continuous Vapor Concentration Indicators and Controllers and Controller, Continuous Vapor Concentration.

Insert the word "solvent" af ter the word "continuous" in both def ini t ions. Replace "measure and indicate" with "measure, indicate and control" in both defini t ions. S U B S T A ~ : The word solvent makes the def ini t ion more precise as to what these devices are to look at. The word control was added to make i t certain that items also "control" the process. COMMITTEE ACTION: Accept.

86- II - ( I -4) : Accept SUBMIT TER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Replace the def in i t ion of Fume Incinerator as follows:

Fume Incinerator. A fume incinerator is any separate or independent combustion equipment or device which entrains the process exhaust (particulate matter, dust, fumes, gas, mist, smoke or vapor, or any combination thereof) for the purpose of thermal decomposition with or without heat recovery. SUBSTANTIATION: The def in i t ion is more precise than the current wording. I t wi l l also make this document more consistent with NFPA 86C, Special Atmospheres. COMMITTEE ACTION: Accept.

86- 12 - ( I -4) : Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add the following def in i t ion to Section I-4:

Hazardous Material. Any material possessing a re lat ive ly high potential for harmful effects on persons, property, or process. A material having one or more of the following characteristics.

(a) Has a closed-cup flash point below 140°F (60°C) or is subject to spontaneous-heating.

(b) Has a threshold l imi t value below 500 parts per mil l ion in the case of a oas or vapor or below 500 mg/cu M for fumes, and below 25 mppcf in the case of a dust.

(c) Has a single dose oral LD 50 below 500 mg/kg. (d) Is subject to polmyerization with the release of

large amounts of energy. (e) Is a strong oxidizing or reducing agent. ( f ) Causes first-degree burns to skin in short-time

exposure, or is systemically toxic by skin contact; or (g) In the course of normal ope'rations, may produce

dusts, gases, fumes, vapors, mists, or smokes which have one or more of the above characteristics. SUBSTANTIATION: The def in i t ion of Hazardous Material is more correct. Reference to a toxic material by the revision to paragraphs 2-1.4.2, 5-I.6(a) and 5-I.? is

n o t as precise. The def in i t ion of and reference to a hazards material wi l l be easier to understand. COMMITTEE ACTION: Accept.

273

86- 13 - (I-4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: For the definit ion of "Heater, Indirect - Fired" delete the last part of this definition which states ", heating being accomplished by radiation or connection from the tubes or muffles". SUBSTANTIATION: The Subcommittee notes there are other methods of indirect heating available. COMMITTEE ACTION: Accept.

86- 19 - ( 1 -4 ) : Accept ~ : Technical Committee on Ovens and Furnaces RECOMMENDATION: Add the f o l l o w i n g d e f i n i t i o n :

Safety I n t e r l o c k . A device requ i red to ensure safe s t a r t - u p , safe ope ra t i on , and/or cause safe equipment shutdown. SUBSTANTIATION: The d e f i n i t i o n is necessary so tha t one may asce r ta i n e x a c t l y what the sa fe t y i n t e r l o c k is to accomplish. COMMITTEE ACTION: Accept.

86- 14 - (I-4): Accept ~ : Technical Committee on Ovens and Furnaces RECOMMENDATION: Remove definitions for "Inspirator, Proportioning", "Inspirator, High Pressure" and "Inspirator, Low Pressure." SUBSTANTIATION: The definitions are not useful or necessary. COMMITTEE ACTION: Accept.

86- 15 - (I-4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Remove definit ion of "Insplrator, Atmospheric (Venturi)" and replace with:

"See Mixers, Gas 3et (Atmospheric Inspirator Mixer)." Also, move Figure I-4.27 after "Mixers, Gas Jet

(Atmospheric Inspirator Mixer)" and change caption to read "Example of an Atmospheric Inspirator Mixer." SUBSTANTIATION: This provides consistency with the definitions. COMMITTEE ACTION: Accept.

86- 16 - (I-4): Accept S_UBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add the following cross references:

Lower Explosive Limit (LEL). See Range, Explosive. Upper Explosive Limit (UEL). See Range, Explosive. Also, for the definit ion of "Range, Explosive (Limits

of Flammability)" add a new sentence after the second sentence that says "The highest flammable concentration is the upper explosive l imi t (UEL)." SUBSTANTIATION: The cross reference is needed so one doesn't have to search for these definitions. COMMITTEE ACTION: Accept.

86- 17 - (I-4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add the following definit ion:

Programmable Controller. A d ig i ta l l y operating electronic system designed for use in an industrial environment, which uses a programmable memory for the internal storage of user-oriented instructions for implementing specific functions such as logic, sequencing, timing, counting and arithmetic to control, through digi tal or analog inputs and outputs, various types of machines or processes. SUBSTANTIATION: The Committee feels that the definition is necessary since they have included specific language for requirements of the devices. COMMITTEE ACTION: Accep t .

86- 20 - (I-4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add definit ion as follows:

Switch, Limit. A switching device which actuates when an operating l imi t has been reached.

Also, add a cross reference in Section I-4 as follows: Limit Switch - See Switch, Limit.

SUBSTANTIATION: The definit ion For this device is required in the standard. COMMITTEE ACTION: Accept.

86- 21 - (I-4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RE_ COMMENDATION: Change the current definit ion as follows:

Valve, Electric, Manual-Opening, Automatic-Closing Safety Shutoff. A valve which can be opened only manually after the valve solenoid coi l , or other holding mechanism, is energized. The valve closes automatically when the holding mechanism is deenergized. The manual opening means is designed so that i t cannot prevent the valve from closing when deenergized. ~UBSTANTIATIOFF: This new definit ion is more precise than the current definit ion. COMMITTEE ACTION: Accept.

86- 22 - (I-4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add the following definition:

Ventilation, Proven. Uti l izat ion of l isted devices to assure that proper ventilation exists throughout operating periods.

Correct the cross reference for Proven Ventilation to read "see Ventilation, Proven".

Also add a cross reference: "Proper Ventilation. See Ventilation, Proper".

SUBSTANTIATION: The cross references and definitions are needed for c lar i ty . COMMITTEE ACTION: Accept.

86- 23 - (I-5.1): Accept $UBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add:

"For application of programmable controllers, also see Section 4-2." SUBSTANTIATION: Special guidance to the particular section where these requirements occur is necessary. COMMITTEE ACTION: Accept.

86- 18 - (I-4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATIOn: Under definit ion of Purge, Inert Atmosphere delete:

. . . i .e . , 50 percent of the lower explosive l imi t (LEL) or < l percent oxygen." S__U_~_S]_AN~: This change wi l l make the document consistent with the definit ion as found in NFPA 86C, Ovens and Furnaces, Special Atmospheres. COMMITTEE ACTION: Accept.

86- 24 - (1 -5 .3 Note (New)): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add the f o l l o w i n g note:

NOTE: The Nat ional E l e c t r i c a l Code is ind ica ted as reference source for safe practices and wiring methods. Where i t is considered that variation from the recommended wiring methods as currently specified in the Natlonal Electrical Code is necessary to provide greater safety of the instal lat ion, such variations are required to meet with the approval of al l parties having jurisdiction and are required to be the sole responsibility of the parties in i t ia t ing such variation.

274

SUBSTANTIATION: The purpose of the note is to make the user aware that, in some cases, the NEC may not be sufficient for determining wiring requirements for the unit. COMMITTEE ACTION: Accept.

86- 25 - (I-6.4(f) (New)): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add new item (f).as follows:

(f) Handling and processing of hazardous materials; SUBSTANTIATION: Some oven and furnace operations may require the operator to be exposed to or be within the v ic in i ty of a process involving a hazardous material. COMMITTEE ACTION: Accept.

86- 26 - (2-1.4.2): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Change the word "toxic" to "hazardous" in section 2-1.4.2. SUBSTANTIATION: Reference to a toxic material is not precise. COMMITTEE ACTION: Accept~

86- 27 - (2-1.4.5): Accept _~_UBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Delete current wording and replace with:

2-I.4.5 Corrosion. Equipment shall be located with consideration to potential adverse effects of external corrosion in the environment.

NOTE: Fumes or materials from adjacent processes or equipment which are not normally corrosive may produce corrosive conditions when introduced into a furnace environment. (See NFPA 325M, Fire Hazard Properties of Flammable Liquids, Gases, and Volatile Solids.

SUBSTANTIATION: The new wording including the note is intended to highlight problems which may come about as a result of a unit being placed in a corrosive environment. COMMITTEE ACTION: Accept.

SUBSTANTIATION: The most common practice of oven manufacturers to this date is to provide explosion rel ief venting in the form of access doors with special latches. Although Factory Mutual has approved the latches that are used, the fact remains that the present practice is dangerous. The doors open and usually prevent major damage to the oven, but the doors represent a hazard to nearby employees (as in one accident in 1984 in Minnesota where a worker was fatal ly injured when struck by a door that opened as a result of a deflagration within the oven). Moreover, the f irebal l that discharges through the open doors can cause serious injury to personnel in front of the oven even i f they are beyond the arc of the doors. COMMITTEE ACTION: Reject. C~MMITTEE STATEMENT: The Committee feels that the current wording of Notes 2 and 3 suff iciently address this issue.

86- 30 - (2-2.3.3.1, Note 4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add at the end of the note:

"for an oven structure rated at 1 pslg." SUBSTANTIATION: To add further clar i f icat ion. COMMITTEE ACTION: Accept.

86- 31 - (2-2.4): Accept ~LU~_M~TTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Delete the word "oven" from the subtit le. ~UBSTANTIATION: The term "oven" is not useful in the t i t l e . COMMITTEE ACTION: Accept.

86- 32 - (2-2.4.13): Accept ~_UBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Delete "by the user." SUBSTANTIATIOn: A suitable system needs to be supplied. In some cases, the responsibility for this may rest with the manufacturer rather than the user. COMMITTEE ACTION: Accept.

(Log # 4) 86- 28 - (2-1.4.6 (New)): Accept in Principle SUBMITTER: Ken Bibby, Ken Bibby Industries Inc. RECOMMENDATION: Add new 2-1.4.6 as follows

2-I.4.6 Building Make-up Air. A sufficient quantity o f tempered make-up air shall be admitted to oven rooms and buildings to prevent oven ventilation fans from being starved of ai'r thus reducing the required safety volume. SUBSTANTIATION: This is becoming more important with modern well insulated and 'sealed' buildings. COMMITTEE ACTION: Accept in Principle.

Insert a new section as follows: 2-2.8 Building Make-up Air. 2-2.8.1 A sufficient quantity of make-up air shall

be admitted to oven rooms and buildings to provide the air volume required for safe operation of oven ventilation and combustion air fans. COMMITTEE STATEMENT: The Committee agrees with the suhmitter but feels that i t is more appropriately located as section 2-2.8 and worded as indicated.

86- 33 - (2-2 .7 , 2-2 .7 .1 , 2-2 .7 .2 and 2-2.5 .5 (New)): Accept ~U~_.M_ITTER: Technical Committee on Ovens and Furnaces RECOMH~T_jT~O_ff: Relocate existin 9 section 2-2.7.2 t e a new section 2-2.5.5 and delete 2-2.7 and 2 . . . . 2 7 1 ~ I A T I ~ : Paragraph 2-2.7.2 is appllcable to al l moving parts of the unit and not just the fans and thus belongs in section 2-2.5. The rest of section 2-2.7 is already covered by Chapter 4 and is unnecessary. COMMITTEE ACTION: Accept.

86- 34 - (3-1(a) and (b)): Accept ~_UBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Remove the let ter "(a)" at the beginning of the f i r s t sentence and delete paragraph (b). SUBSTANTIATION: Paragraph 3-1(b) is not considered useful or necessary. COMMITTEE ACTION: Accept.

(Log # 3) 86- 29 - (2-2.3.3.1 Note 3): Reject SUBMITTER: Robert L. Moison, Robert L. Moison & Associates, Inc. RECOMMENDATION: Revise Note 3 as follows:

NOTE 3: Explosion rel ief vents, where possible, shall be placed in the top of the furnace or in the side walls and located so that employees wi l l not be exposed to injury. Where explosion rel ief unavoidably exposes employees to injury, e.g., when access doors are designed to relieve, the area in the v ic in i ty of the doors should be restricted by means of signs, ropes, barricades, etc. whenever the oven or furnace is in operation.

86- 35 - (3-3) : Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Revise t i t l e to :

"Fuel Gas-Fired Units." ~LUB.~TANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

275

86- 36 - (3-3.1(a) and (b)): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: For paragraphs (a) and (b) of 3-3.1, make these paragraphs 3-3.1.I and 3-3.1.2. SUBSTANTIATION: To conform with the NFPA Manual of Style. COMMITTEE ACTION: Accept.

86- 37 - (3-3.4.3.4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Revise sentence as follows:

"Vents from fuel gas pressure switches, but no other devices, may be vented into the fuel regulator vent lines provided that switch or regulator diaphragm failure shall not backload the regulator." SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

86- 38 - (3-3.4.3.4 Exception): Accept ~B_~_(IT_gE: Technical Committee on Ovens and Furnaces RFGC.QtII~FJ~IP_A~LOJ~: Insert "Fuel gas" at the beginning of the sentence and add the following sentence at the end:

"This exception shall not apply to oxygen-enrlched al r . " SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

86- 39 - (3-3.5.1): Accept ~ILB.H_LT.If~R: Technical Committee on Ovens and Furnaces RECOMMENDATIOn: Add "(oxygen enriched air or oxygen)" after "combustion a i r . " SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

86- 44 - ( 3 - 3 . 7 . 2 ) : Accept SUBHITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: I n s e r t " c o n t r o l " be fo re "va l ves " in the third l ine. SUBSTANTIATION: Editorial. COMMITTEE ACTION: Accept.

86- 45 - ( 3 - 3 . 8 . 2 ) : Accept ~UBHITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: De le te "be assured of" and add:

"provide for." SUBSTANTIATION: Editorial. COMMITTEE ACTION: Accept.

86- 46 - (3-3.9): Accept .~LU~I~T.I~B: Technical Committee on Ovens and Furnaces RECOMMENDATION: Revise t i t l e to"

"Fuel Gas-Air Mixing Machines." SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

86- 47 - ( 3 - 3 . 9 . 2 ) : Accept SUBMI~IER: Technical Committee on Ovens and Furnaces ~ _ Q . ~ I ~ : Change the term "gas-mlxlng machines" to "fuel gas-alr mixing machines" and add the word i i I I I I l i t l i fue l be fore gas in the term "gas-a r mixtures. SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

86- 40 - (3-3.6.1.1): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add new 3-3.6.1.1 as follows and renumber subsequent paragraphs accordingly:

"This section shall pertain only to mixtures of fuel gas with air, and not to mixtures of fuel with oxygen or oxygen-enriched air. Oxygen shall not be introduced into air-fuel gas mixture piping, fuel gas mixing machines, or into mixing blowers." SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

86- 41 - (3-3.6.1.6): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add "fuel" before the word "gas." SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that this is now paragraph 3-3.6.1.7 instead of 3-3.6.1.6 per Proposal 86-

86- 42 - (3-3.6.3.1): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Change the term "gas-mlxing machines" to "fuel gas-air mixing machines." SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

86- 43 - (3-3.6.3.2): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add "fuel" before the word "gas" in three places.

86- 48 - (3-3.9.3): Accept S__UBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Change the term "gas-mixing machines" to "fuel gas-air mixing machines" and add "fuel" before the word "gas" in each of the other places i t appears. SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

86- 49 - (3-3.9.4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Change the term "gas-mixlng machines" to "fuel gas-air mixing machines" and add the word "fuel" before "gas" in each of the other places i t appears. SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

86- 50 - (3-3.10.2): Accept SUBHITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Delete " . . . in sufficient quantity, and . . . " from this section. SUBSTANTIATION: I t is necessary to have a source'of "sufficient quantity" in order for ignition to occur. COMMITTEE ACTION: Accept.

86- 51 - ( 3 - 4 . 4 . 3 ) : Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: I n s e r t " o i l " be fore " s h u t o f f " in t i t l e . SUBSTANTIATION: This recognizes new technology i n v o l v i n g oxygen enr iched burners . COMMITTEE ACTION: Accept.

276

86- 52 - (3-4.4.3.1): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Insert "o i l " before "shutoff." SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

86- 53 - (3-4.7.1.1): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Change to read:

"The burner shall accept fuel oi l of the proper grade which has been preconditioned properly for combustion." S U ~ A T I Q N : The wording as currently exists is awkward to understand. The new wording simplifies the requirement. COMMITTEE ACTION: Accept.

86- 54 - (3-4.7.1.2): Accept S UBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Change to read:

3-4.7.1.2 The burner shall maintain stable self sustained combustion throughout i ts f i r ing range. SUBSTANTIATION: The new wording more precisely defines the intent of the Committee. COMMITTEE ACTION: Accept.

86 - 55 - (3-5): Accept ~UBMITTER: Technical Committee on Ovens .and Furnaces RECOMMENDATION: Insert new Section 3-5 as follows and renumber subsequent sections:

3-5 Oxygen Enhanced Fuel Fired Units. 3-5.1 Scope. This section pertains to combustion

systems using oxygen (oxy-fuel) or oxygen-enriched air with gas or l iquid fuels. The requirements shall be in addition to those in articles 3-3 (fuel gas burners), 3-4 (oil burners), and in Chapters 4 and 8. (Also see Appendix H).

3-5.2 Combustion Systems Uti l iz ing Oxygen. 3-5.2.1 Oxygen storage and delivery systems shall

comply with NFPA 50, Bulk Oxygen Systems at Consumer Sites.

3-5-2.2 Oxygen shall not be introduced into inlet or discharge piping of a i r compressors or blowers that are internally lubricated with petroleum oi ls, greases, or other flammable substances.

3-5.3 Oxygen Piping and Controls. 3-5.3.1 Design, materials of construction,

instal lation and tests of oxygen piping shall comply with applicable sections of ANSI B31.3, Code for Pressure Piping, Chemical Plant and Petroleum Refinery Piping.

3-5.3.2 Oxygen piping shall comply with Sections 3, 4 and 5 of the Compressed Gas Association Pamphlet G-4.4, Industrial Practices for Gaseous Oxygen Transmission and Distribution Piping Systems.

NOTE: Referenced publication specifies gas maximum velocity cr i ter ia, materials of construction, instal lation methods, joining methods, metering methods, use of f i l te rs , and specifications for oxygen-compatible sealing materials, gasket materials, thread sealants.

3-5.3.3 Oxygen piping shall be cleaned prior to admitting the gas, using methods prescribed in Section 5 of Compressed Gas Association Pamphlet G-4.4.

3-5.3.4 Air that can be used to cool burner internals when theburner is not f i r ing but is s t i l l exposed to elevated furnace temperature, shall be free of o i l , grease, and other flammable material.

NOTE: This art ic le is intended to prevent contamination of surfaces that must be clean for oxygen service by the o i l normally present in plant compressed air.

3-5.3.5 An oxygen shutoff valve shall be installed in the oxygen supply main to interrupt the flow of oxygen to the affected area in case of an emergency. I t shall be situated so that fires and other hazardous conditions at the furnaces cannot impede access to the valve.

3-5.3.6 Emissions of oxygen and fuels from pressure r e l i e f devices and purge out lets shall not be released into pipes or manifolds where they can mix. The emissions shall be released where they do not create safety hazards.

3-5.3.7 Means shall be provided to prevent reverse flow of oxygen into fuel or a i r l ines, fuel into the oxygen or a i r l ines, and a i r into oxygen or fuel l ines, i f i t is possible for oxygen, fuel o r . a i r to intermix in burner supply l ines due to valve leakage, burner plugging, or other system malfunction.

NOTE: I t is usually impractical to i ns ta l l reverse flow check valves in the discharge pipel ines from large combustion a i r blowers. However, a l l parts of the combustion a i r system which can po ten t ia l l y be contacted by oxygen or oxygen-enriched a i r must be free of o i l , grease, and other flammable materials.

3-5.3.8 Oxygen piping shall be inspected and maintained as prescribed in Section 6 of Compressed Gas Association Pamphlet G-4.4.

3-5.3.9 Glass tube f l o ~ e t e r s shall not be used in oxygen service.

3-5.3.10 Piping fed from a cryogenic supply source shall be designed to contain the maximum design pressure at the lowest possible temperature that can enter i t . A l te rna t i ve ly , the p ipel ine may be protected from excessive cooling by means of an automatic, low-temperature shutoff device.

CAUTION: Commercial grade carbon steel pipe exhib i ts a marked reduction in impact strength when cooled to sub-zero temperatures. Consequently i t is vulnerable to impact fracture i f located downstream of a l i qu id oxygen vaporizer running beyond i t s rated vapor izat ion capacity, or at very low ambient temperatures.

3-5.3.11 Piping downstream of an oxygen pressure reducing regulator shall be able to withstand the maximum potent ia l upstream pressure, or be 'protected from overpressurlzation by means of a sui table pressure r e l i e f device.

3-5.3.12 Means shall be provided to readi ly depressurize and disconnect fuel and oxygen supply l ines from the furnace, al lowing for safe entry by maintenance and other personnel.

NOTE: This requirement is intended to f a c i l i t a t e compliance with procedures for entering confined spaces. ANSI Zl17.1, "Safety Requirements for Confined Spaces," l i s t s acceptable methods for i so la t ing a confined space (e.g. a furnace).

3-5.4 Oxygen Flow Control Valves. 3-5.4.1 Flow control valves of appropriate size and

design shall be used to modulate the flow rate of pressurized oxygen or oxygen-enriched a i r ;

. 3-5.4.2 Where the minimum and/or the maximum flow of oxygen or oxygen-enriched a i r is c r i t i c a l to safe operation of a burner, the oxygen/oxygen-enriched a i r flow control valve shall be equipped with an appropriate l im i t i ng means and locking device to prevent an unintentional change in the set t ing.

3-5.4.3 An oxygen pressure regulator shall be furnished whenever the plant oxygen supp]y pressure exceeds that required for proper burner operation, or whenever the plant supply pressure is subject to excessive f luctuat ions. An automatic flow control valve shall f u l f i l l th is requirement, so long as i t can compensate for the ful l range of expected supply pressure variations and complies with paragraph 3-5.4.2.

3-5.5 Oxygen-Enriched Combustion Air. 3-5.5.1 Filters shall be installed in the air blower

intake to minimize contamination of the oxygen-enriched air main.

3-5.5.2 Oxygen-enriched combustion air shall not be introduced into a burner before the oxygen has been uniformly mixed into the air stream.

3-5.5.3 Branching of the enriched-air piping shall not be permitted before a uniform mixture of oxygen and air has been attained.

3-5.5.4 Devices, such as diffusers, used to disperse oxygen into an air stream shall he designed to prevent je t impingement of oxygen onto inter ior surfaces of the air piping.

NOTE: Diffusers are commonly used to disperse oxygen into an air stream effecting rapid and complete mixing of the oxygen into the air. High velocity impingement of oxygen is a potential f i re hazard.

277

SUBSTANTIATION: This recognizes new technology involving oxygen enhanced fuel f i red units. COMMITTEE ACTION: Accept.

86- 56 - (3-5.2.1): Accept ~_UBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Delete " . . . those o f the . . ."

Relocate "types" to the end of the sentence. SUBSTANTIATION: Edi tor ia l . COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that this is now paragraph 3-6.2.1 instead of 3-5.2.1 per Proposal 86-55.

86- 57 - (3-5.2.2.4): Accept ~ : Technical Committee on Ovens and Furnaces RECOMMENDATION: Change to read:

" . . . be constrained from motion induced by thermal stress which could . . ."

Remainder of this section to remain the same. SUBSTANTIATION: Editor ial . COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that this is now paragraph 3-6.2.2.4 instead of 3-5.2.2.4 per Proposal 86-55.

86- 58 - (3-6): Accept ~_UBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Change t i t l e from "Steam Heating Systems" to "Fluid Heating Systems." SUBSTANTIATION: This allows recognition of organic heat transfer systems. COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that this is now Section 3-7 instead of 3-6 per Proposal 86-55.

86- 59 - (3-6.1): Accept ~ : Technical Committee on Ovens and Furnaces RECOMMENDATION: Revise 3-6.1 to read (keep existing note):

"Scope. This section includes al l types of heating systems where water, steam or heat transfer f lu ids are the source of heat through the use of heat exchangers supplied from a central heater or generator. Heat transfer f lu ids are nonwater media which have a high boil ing temperature, a high flash point, and are thermally stable and noncorrosive." SUBSTANTIATION: This allows recognition of f lu id heat transfer systems. COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that this is now paragraph 3-7.1 instead of 3-6.1 per Proposal 86-55.

86- 60 - (3-6.2.1): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Revise "Code for Power Piping ANSI B31.l" to "Code for Pressure Piping ANSI B31". SUBSTANTIATION: Edi tor ia l . COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that this is now paragraph 3-7.2.] instead of 3-6.2.1 per Proposal 86-55.

86- 61 - (3-6.3.] (New) and 3-6.3.2 (New)): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add new sections 3-6.3.] and 3-6.3.2 as shown:

3-6.3.1 System equipment shall be operated within the temperature and pressure l imits specified by the supplier or manufacturer of the heat transfer media and by the manufacturer of the equipment.

3-6.3.2 On circulating l iquid systems, l imi t switches in addition to the low l iquid level cutoff shall be provided to shut o f f the heater automatically i f l iquid temperature is excessive or i f circulation rate is low.

SUBSTANTIATION: These new paragraphs provide requirements for f lu id heat transfer systems. The current text does not cover this. COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that these new paragraphs wi l l be 3-7.3.1 and 3-7.3.2 instead of 3-6.3.1 and 3-6.3.2 per Proposal 86-55.

86- 62 - (3-6.3): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Remove the word "steam." S U B S T A ~ : This paragraph needs to include other heat t rans fe r systems. COMMITTEE ACTION: Accept.

86- 63 - (3-6.4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Remove the word "steam." SUBSTANTIATION: This paragraph needs to include other heat transfer systems. COMMITTEE ACTION: Accept.

86- 64 - (3-6.5): Accept ~UBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Remove the word "steam." ~U_B_STANTIATION: This paragraph needs to include other heat transfer systems. COMMITTEE ACTION: Accept.

86- 65 - (Chapter 4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Remove the word "approved" from al l of Chapter 4, excluding the new Section 4-2. SUBSTANTIATION: The term "approved" is misused in this section. COMMITTEE ACTION: Accept.

86- 66.- (4-1.1.1): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Provide a new 4-1.1.1 as follows and renumber subsequent paragraphs:

"All safety devices shall be l is ted for the service intended. Safety devices shall be applied and installed with established safe practices and manufacturers instructions. When such devices are not l isted for the service intended and l isted substitutes for similar service are .not available, the selected device shall require approval by the authority having jur isd ic t ion. " SUBSTANTIATION: The addition of this information wil l elaborate on the importance of using l isted equipment. COMMITTEE ACTION: Accept.

86- 67 - (4-1.1.2): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Provide a new 4- I . I .2 as follows and renumber subsequent paragraphs:

4 - I . I .2 Section 4-2 concerning the application of programmable controllers shall apply to a l l safety controls included in a l l chapters of this standard. SUBSTANTIATION: I t is necessary to point out that specific requirements for programmable controllers exist in Section 4-2 of the standard. COMMITTEE ACTION: Accept.

86- 68 - (4-1.2( f ) ) : Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Modify to read:

( f ) Water, steam, electr ic and heat transfer f luids. SUBSTANTIATION: The addition wi l l recognize the f lu id heat transfer systems which wi l l be covered by revisions to Section 3-6. COMMITTEE ACTION: Accept.

278

86- 69 - (4-1.2(g) (New) and (h) (New)): Accept ~_U_BMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Revise by adding:

(g) Oxygen and oxygen-enriched combustion air. (h) Oxygen pressure, temperature and velocity.


86- 70 - (4-2): Accept SUBMITTER: ~echnical Committee on Ovens and Furnaces RECOMMENDATION: Add a new Section 4-2 as follows and renumber subsequent sections accordingly:

4-2 Programmable Controllers. 4-2.1 When a programmable controller is used, the

following requirements shall apply: (a) In the event of a power failure, the

programmable controller (hardware and software) shall not prevent the system from reverting to a safe condition. A safe condition shall be maintained upon " I the restoration of power.

(h) The control system shall have a separate manual emergency switch, independent of the programmable controller, that wi l l cause the system to revert to a safe condition.

(c) The software for the programmable controller shall reside in some form of nonvolatile storage (memory that retains information on loss of system power).

(d) The programmable controller shall have the capability of detecting failures and unprogrammed logic changes of i ts safety dependent inputs and outputs and, upon detection of same, shall annunciate and cause the system to revert to a safe condition.

(e) Application software that contains safety logic shall be separate from all other programming. Application software that interacts with safety logic or detection logic for input/output devices shall also be separate from all other programming. Application software that contains safety logic or detection logic shall not be modified in any manner that does not comply with this standard. The authority having jurisdiction shall be notified, in writing for permanent documentation, of any changes.

(f) System operation shall be verified for compliance with this standard whenever the programmable controller is replaced, repaired, or updated.

(g) The internal status of the programmable controller shall be monitored. In the event of a programmable controller fai lure, the system shall annunciate and cause the system to revert to a safe condition.

(h) The supplier of tile application software for the programmable controller shall provide the end user and the authority having jurisdict ion with documentation needed to verify that al l related safety devices and safety logic are functional before the programmable controller is placed in operation.

( i) The system access shall be limited by incorporating measures to prevent remote or local instructions to the programmable controller that could result in hazards to personnel or equipment.

( j) Only approved programmable controller-based systems meeting the above requirements shall be used to control the equipment as l isted under 4-1.1.

NOTE: Other programmable controller-based systems may be used only to monitor.

4-2.2 When a programmable controller is used in conjunction with the combustion safety circuitry, the following additional requirements shall apply: I

(a) Failures that create a hazard shall cause the I system to revert to a safe condition. (b) Combustion safety interlocks, combustion

safeguards and excess temperature l imits shall be wired to directly de-energize the safety shutoff valves and their operation shall result in a safe system condition.

Exception: Programmable controller-based systems listed for combustion safeguard service may be directly applied.

NOTE: Programmable controllers not l isted for combustion safeguard service may be used only to monitor equipment, except that isolated I programmable controller contacts (not direct ly connected to a power source) may be wired in series with the above safety circuits.

SUBSTANTIATION: This new section on programmable controllers wi l l provide the necessary requirements for the use of this equipment. COMMITTEE ACTION: Accept.

86- 71 - (4-2.1.2): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: In the f i rs t l ine, delete "direct f i red." SUBSTANTIATION: This requirement is applicable to a11 furnaces and not just the direct fired type. COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that this is now paragraph 4-3.1.2 instead of 4-2.1.2 per Proposal 86-70.

86- 72 - (4-2.1.3(c)): Accept ~BMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Remove the word "combustion." SUBSTANTIATION: Section 4-2.1.3 applies only to the shutdown of the recirculating and/or exhaust fans. COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that this is now paragraph 4-3.1.3(c) instead of 4-2.1.3(c) per Proposal 86-70.

86 - 73 - (4-2.2-(New)): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add a new paragraph as follows:

4-2.2 A natural draft purge shall be permissible when no combustion air blower or exhaust blower is available, provided al l of the following conditions are satisfied:

(a) A furnace door or cover is secured in the fully-open position to admit air, and the flue damper ( i f any) is secured fu l ly open to vent a i r or other atmosphere from the furnace. These conditions prevail from start to end of the preignition purge and l ight-of f processes.

(b) The open positions of the door or cover and damper ( i f any) is verified at al l times by al l persons engaged in the l ight-of f process, and closing of either causes an alarm.

(c) The purge interval is timed and is long enough to rel iably reduce the flammable vapor or gas concentration in the combustion chamber to 25 percent or less of the lower explosive l imi t of the fuel in air and less than 21 volume pe(cent oxygen.

(d) The purge time required to ventilate the combustion chamber, as prescribed in item (c) has been measured using combustible gas analyzers and oxygen analyzers by the party responsible for commissioning the burner system. This measurement has been conducted at a time when the furnace is at normal ambient temperature. Confirming calculations and measurement data are available for review at the request of authority having jurisdict ion. ~_~BSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that this is now paragraph 4-3.2 instead of 4-2.2 per Proposal 86-70.

86 - 7a - (4-3): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Delete ". . . by the user." in the f i rs t sentence. SUBSTANTIATION: The user or the manufacturer may have to provide this system. COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that this is now paragraph 4-4 instead of 4-3 per Proposal 86-70.

86 - 75 - (4-5.1): Accept ~UBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Insert "shutoff" before "valve". SUBSTANTIATION: This provides c lar i ty .

279

COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that this is now paragraph 4-6.1 instead of 4-5.1 per Proposal 86-70.

86 - 76 - (4-6.2.2.1, Exception No. 2): Accept ~UBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Remove Exception No. 2. SUBSTANTIATION: This is an unsafe practice. COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that this is now paragraph 4-7.2.2.1 instead of 4-6.2.2.] per Proposal 86-70.

(Log # 2) 86- 77 - (4-6.2.2.1 Exception Nos. 3 and 4 (New)): Reject SUBMITTER: 3ames O. Houston, Industrial Heating Equipment Association RECOMMENDATION: Add Exceptions No. 3 and 4.

Exception No. 3: Spring loaded solenoid valves may be used as the primary safety shutoff valve with fuel flow up to 400,000 Btuts (I17 kw) per hour, or as the secondary safety shutoff valve with the double safety shutoff valve provided:

(a) The sealing force of the spring is a minimum of five pounds, exclusive of "dead weight" of the assembly and fuel pressure exerted.

(b) Their use does not necessitate any abnormal settings of either the high or low gas pressure switches to counter any transient pressure fluctuations created by sudden operations of the valve.

Exception No. 4: Other solenoid valves, not meeting the above specifications may be used when al l three of the following conditions prevail:

(a) The flow is less than 150,000 Btu's (44 kw) per hours.

(b) The valve size is 3/4 in. or less. (c) The gas pressure is five psig (34 kPa), or less.

SUBSTANTIATION: This standard has been a part of the previous codes. The definit ion of the "safety shutoff valve" is as yet unclear and in practice includes these solenoid valves. Also, with the deletion of the vent valve, the need for a second safety shutoff valve is questionable. COMMITTEE ACTION: Reject. COMMITTEE STATEMENT: The Committee feels that this is beyond the scope of this standard and is the responsibility of l i s t ing agencies.

86 - 78 - (4-6.4): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Delete the current text of 4-6.4 and replace with the following:

4-6.4 Combustion Safeguards (Flame Supervision). 4-6.4.1 Each burner flame shall be supervised by an

approved combustion safeguard, having a nominal flame response timing of 4 seconds or less, interlocked with the safety circuitry.

Exception No. I: I t is permissible to supervise flames at the intersection of the main burner flame and the p i lo t flame rather than provide supervision equipment for both.

Exception No. 2: Neither interrupted p i lo t nor second flame sensor are required for self-piloted burners, as defined in Section I-4.

Exception No. 3: Supervision of the main burner flame may be accomplished by either a second sensor applied to the main flame only, or by interruption of the main burner ignition pi lot .

Exception No. 4: Multiple burners, where combustion safeguards for each burner are too numerous to be practical, can use continuous line-burner-type pilots for groups of burners (see 3-3.5.2). A combustion safeguard shall be provided at the far end of each line-burner-type p i lo t , away from the p i lo t fuel source, with sensing element located at the junction of the flame paths of both p i lo t and last main burner, The p i lo t safety shutoff valve must be i n i t i a l l y opened by a manual momentary push button.

Exception No. 5: Where two premix burners, which w i l l r e l l a b l y i gn i t e one from the other, are used, i t shal l be permissible to use a s ingle approved combustion safeguard, supervis ing one of the burners; the supervised burner shal l burn cont inuously at a f i r i n g rate at a l l times s u f f i c i e n t to r e l i a b l y i gn i te the unsupervised burner,

Exception No. 6: Burners fo r d i r e c t - f i r e d heating systems which supply a furnace at a fuel rate not exceeding 150,000 BTU/hr (44 kw) may be equipped with heat-actuated combustion safeguards or safety p i l o t s . For small equipment under constant attendance, approaching in size the household gas range or very small labora tory tes t furnace, combustion safeguards may be omitted, subject to approval of the au tho r i t y having j u r i s d i c t i o n .

Exception No. 7: In general, for greatest secur i ty , a l l burners should be protected with combustion safeguards as out l ined in the foregolng sections. When th is is not p rac t ica l from an engineering standpoint, the maximum prac t ica l p ro tec t ion shal l be furnished by prov id ing a r e l i a b l e source of i g n i t i o n at each burner, and/or operat ing burners on high- low flame, and by i n s t a l l i n g devices (pressure switches and safety shutof f valves) to assure, where p rac t i ca l , closure of a l l i nd iv idua l burner cocks [see Figures 4-6 .4 .1(a) , (b), (c) and (d) ] before the main burner safety shutof f valve can be opened, and shutof f a l l fuel in case of high and low fuel pressure and low a i r pressure, where a i r pressure is necessary fo r operat ion of burners and controls subject to the approval of the au tho r i t y having j u r i s d i c t i o n .

Exception No. 8: Radiant tube heat ing systems u t i l i z i n g exp los ion- res is tan t tube construct ion do not require combustion safeguards. However, a su i tab le means of i g n i t i o n shal l be provided.

Exception No. 9: On furnace zones, when a combination of burners with and without flame supervision exists, i t is permissible to switch the flame supervision out of the safety circuit for that zone when the zone temperature is at or above 1400°F (760°C). The burners without flame supervision shall be interlocked to prevent their operation until the zone temperature is at or above 1400°F (760°C). The flame supervsion shall become part of the safety c ircui t when the zone temperature drops below 1400°F (760°C).

NOTE: A method of assuring closure of a l l i nd iv idua l fuel gas burner cocks before the main burner fuel gas safety shutof f valve can be opened is the supervis ing cock and fuel gas safety control system. A typ ica l p ip ing and wi r ing arrangement using the pneumatic-type supervis ing cock is i l lustrated in Figure 4-6.4.1(a) and (b)'. (See Section I-4, Supervisory Cock.) The number and location of pressure switches, arrangement of tubing and other details wi l l vary with the individual instal lat ion. In the i l lustrat ion, the main burner safety shutoff valve cannot be opened until the supervisory cocks are closed, combustion air pressure is normal, and normal fuel gas pressure is present in the p i lo t burner manifold. Power failure, loss of combustion air, and/or gas pressure failure during normal f i r ing wi l l shut and lock out the main burner and pi lot safety shutoff valves. Once the in i t ia l check has been completed and the main burner safety shutoff valve is opened, the low fuel gas pressure switch downstream from the safety should valve shunts the checking pressure switch so that, after l ighting the pilots, the supervising cocks can be opened to l ight-off .

A typical piping and wiring arrangement for the electric interlocking-type supervislng cock is also i l lustrated in Figures 4-6.4.1(c) and (d). The main burner safety shutoff valve cannot be opened until al l supervising cocks are closed (cock switch contacts in series are al l closed), ventilation fans operating, preventilation purge completed and other interlocks satisfied.

280

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~...=.o~o..~oo=~/~ow=:..==o.~=w,~=. i TEMPERATURE i BUTT F =,~T~ =,UTO,, V , , V ~ . ~ \ \~,T=O~ VA.VE i r E, .~ w~w <T~.~,.,

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Figure 4-6.4.1(a) Example of a Supervising Cock and Fuel Gas Safety Control System - Pneumatic

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120/I/60 / HOT

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Figure 4-6.4.1(b) Example of A Supervising Cock and Fuel Gas Safety Control System - Pneumatic

Type (E lect r ica l ) .

281

TO BURNERS

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Figure 4-6.4.1(c) Example of a Supervising Cock and Fuel Gas Safety Control System - Electric

Interlock Type (Piping).

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Figure 4-6.4.1(d) Example of a Supervising Cock and Fuel Gas Safety Control System - Interlock

type (Electr ical ) .

2 8 2

4-6.4.2 Line burners, pipe burners, and radiant burners, when installed immediately and adjacent to one another or connected with suitable flame propagating tubes/devices shall have at least one approved flame safeguard installed so as to sense flame presence at the furthest end of assmebly from source of ignition within the tr ial-for-ignit ion period. (See also 4-6.4.3)

4-6.4.3 Automatic relight after unintentional flame failure shall be prohibited.

4-6.4.4 Trial for ignition of pilots or main burners shall not exceed 15 seconds.

Exception: Longer time, up to a maximum of 60 seconds, may be permitted for ignition provided:

(a) Written request for extension of tr ial for ignition is filed with the authority having jurisdiction and

(b) I t is determined that 25 percent of the lower explosive l imit will not be exceeded in the extended time. SUBSTANTIATION: The new text provides a much better description of the combustion safeguards. COMMITTEE ACTION: Accept. COMMITTEE STATEHENT: Note that this is now Section 4-7.4 instead of 4-6.4 per Proposal 86-70.

86 - 79 - (4-7): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Change t i t l e to "Fuel Gas-Air Mixing Machines". SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept. COMMITTEE STATEMENT: Note that this is now Section 4-8 instead of 4~7 per Proposal 86-70.

PILOT SHUTOFF COCK -~P ILOT REGULATe7 f PILOT SAFETY SHUTOFF VALVE

/ / F HIGH GAS PRESSURE SWITCH

~ ~ , ~ F -PILOT BURNER

SAFETY sHPu~FGVALVE ,I AS - - - ~ T E S , T TAP C ~ O ~ C ~ ~ M P A I L N O ~L;LMAEM-Es-ESNEs~GN~LEELMEEMNETN7

MAIN SHUTOFF C O ~ / : V ~ . v. ~ ~ T ~ S T COCK CONTINUOUS LINE BURNERS

GAS PRESSURE REGULATOR --j LSAFETY SHUTOFF VALVE ~2

I. Approved main gas safety shutoff valve. Manual-opening automatic-closing valve or automatlc-opening automatic-closing valve, to suit f ir ing method used.

2. Permanent and ready means for making periodic checks of main gas safety shutoff valve. 3. Approved pilot gas safety shutoff valve. 4. Pilot flame-sensing element. 5. Main flame-sensing element.

Figure 4-6.4.2(a) Example of an Approved Combustion Safeguard Supervising a Pilot For a Continuous Line Burner During Lighting-0ff and the Main

Flame Alolle During Firing

283

PLOT U T O U; /PLOT Y U T O V LV

PILOT G A S ~

SAFETY SHUTOFF VALVE . I j / ~ E S T TAP COCK~///-HIGH GAS PRESSURE SWITCH ¢

LOW GAS PRESSURE SWITCH _ _ - - ~ / ~ [ ~ ~j~

~ S H U T 0 ~?i cPKR E S S USRA; ER:;U~22:2F F VAL VEX 2 ~- TEST COCKCK

FLAME SENSING ELEMENT-~

///e LRADIANT CUP BURNERS

I. Approved main gas safety shutoff valve. Manual-opening automatic-closing valve or automatic-opening automatic-closing valve, to suit f i r ing method used. 2. Permanent and ready means for making periodic tightness checks of main gas safety shutoff valve. 3, 4.

Approved p i lo t gas safety shutoff valve. Main flame-sensing element.

Figure 4-6.4.2(b) Example of an Approved Combustion Safeguard Supervising a Group of Radiant-Cup Burners

Having Reliable Flame-Propagation Characteristics From One to the Other by,Means of Flame-Propagation Devices

86 - 80 - (4-8): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Insert a new Section 4-8 after the section on "Fuel Gas-Mixlng Machines" as follows and renumber subsequent sections:

4-8 Oxygen Safety Devices. 4-8.1 General. Refer to Appendix H for precautions

and safe practices concerning oxygen. 4-8.2 Scope. These articles augment, but do not

replace other articles in this chapter concerning fuel safety devices, except where noted.

4-8.3 Oxygen Safety Devices. 4-8.3.1 An oxygen shutoff valve shall be installed

in the oxygen supply main to interrupt the flow of oxygen to the affected area in case of an emergency. I t shall be situated so that fires and other hazardous conditions at the furnaces cannot impede access to the valve.

4-8.3.2 Two safety shutoff valves in series shall be provided in the oxygen supply line when the burner system has a heating capacity equal to or exceeding 400,000 BTU/hr. A single safety shutoff valve shall suffice i f the p i lo t or main burner capacity is less than 400,000 BTU/hr. A f i l t e r or fine-mesh strainer shall precede the upstream safety shutoff valve.

4-8.3;3 When oxygen is added to a combustion air line, the oxygen and air flows shall be interlocked to prevent the in i t ia t ion of oxygen flow prior to establishment of a i r flow.

4-8.3.4 Oxygen and fuel flows to an oxy-fuel burner shall be shutoff automatically, and an alarm activated, in the event of a fuel flow interruption, an oxygen flow interruption, flame failure, interruption by the excess temperature l imi t controller or other safety device.

4-8.3.5 Oxygen and fuel flows to an oxygen-enriched burner shall be shutoff automatically, and an alarm activated, in the event of a fuel flow interruption, an oxygen flow interruption, flame failure, interruption by the excess temperature l imi t controller or other safety device.

Exception: The flow of fuel may continue when there is no interruption in the flow of combustion air, so long as the control system can automatically revert back to a safe air-fuel ratio before a hazard due to a fuel-rich flame is created.

4-8-3.6 There shall be a high oxygen flow l imit and a high fuel flow l imi t on the burner supply that automatically cause the oxygen and fuel to be shutoff and an alarm activated, when the flow is excessive.

4-8.3.7 There shall be low-oxygen-flow l imi t and a low-fuel-flow l imi t on the burner supply that automatically cause the oxygen and fuel to be shutoff and an alarm activated, when the flow is not sufficient for safe furnace operation.

Exception: The flow of fuel may continue when there is no interruption in the flow of combustion air, so long as the control system can automatically revert back to a safe air-fuel ratio before a hazard due to a fuel-rich flame is created.

NOTE: Low flow controls prevent low oxygen flow or low fuel flow which may result in fuel-rich or oxygen-enriched conditions, and burning outside the combustion section.

4-8.3.8 Burner systems employing water or other l iquid coolants to cool the burners shall be equipped with coolant flow or excess temperature safety interlocks. The interlocks shall cause the oxygen flow and the fuel flow to be shutoff and activate an alarm, i f the coolant flow is interrupted or diminishes to an unsafe flow rate, or i f an abnormal coolant temperature rise indicates insufficient cooling.

284

4-8.3.8.1 The sensors or devices used to monitor the coolant flow or temperature shall be insta l led on the coolant l ine downstream of the burner.

4-8.3.8.2 Coolant piping systems shall be protected from freezing and over-pressurlzat ion. ~BSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept. ~ T E E STATEMENT: Note that th is w i l l be new Section 4-9 instead o f 4-8 per Proposal 86-70.

86 - 81 - (4-9.1, Exception): Accept SUBMITTER: Technical Committee on Ovens and Furnaces P~E_COMMENDATION: Change "avoid" to "void". SUBSTANTIATION: Ed i to r ia l . C_O_M_H~_T!EE ACTION: Accept. .COMMITTEE STATEMENT: Note that this is now paragraph 4-11.1 instead of 4-9.1 per Proposals 86-70 and 86-80

86 - 82 - (5-1.6(a), 5-1.7): Accept ~ : Technical Committee on Ovens and Furnaces RECOMMENDATION: Replace the word " tox ic" in these paragraphs with the word "hazardous". ~ A T I O N : The word hazardous has a broader meaning which is what these paragraphs need to address. COMMITTEE ACTION: Accept.

86 - 83 - (5-1.7(c)) : Accept SUBMITTE_R: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add the fol lowing to item (c):

"Dual purpose fans are not allowed, i . e . , rec i rculat ion and exhaust." ~_U_BSJANT_~_T_!_O~: This statement w i l l h ighl ight the prohib i t ion on the use of one fan to accomplish oven exhaust and rec i rcu lat ion. COMMITTEE ACTION: Accept.

86 - 84 - (5-1.7(c), Note): Accept J ~ : Technical Committee on Ovens and Furnaces RECOMMENDATION: Replace exist ing Note with the fol lowing:

NOTE: Radial blade fans are more e f fec t ive in d i r t y appl icat ions, as they are less subject to accumulation of deposits.

SUBSTANTIATION: This note provides necessary information to users and designers. The exist ing note contradicted with (d). COMMITTEE ACTION: Accept.

86 - 85 - (5-1.7(d), Note): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Delete wording a f te r "exhaust fan". SUBSTANTIATION: The discharge of individual oven . exhaust fans into a common exhaust system is considered less desirable. COMMITTEE ACTION: Accept.

86 - 86 - (5-1.9.1): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Remove the word " ind i rec t " from this sect ion and change to read:

• . . in a heating system . . ." SUBSTANTIATION: This requirement is applicable to an ind i rect and d i rect f i red heating system. COMMITTEE ACTION: Accept•

86 - 87 - (5-1.9.2): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Change the word "adequate" to "proper".

SUBSTANTIATION: "Proper" ven t i la t ion is a well defined term and is more precise. COMMITTEE ACTION: Accept•

86- 88 - (5-1.11 Note 2 and Note 3 (New)): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECQMMENDATI_!Ip_N: Change ex is t ing note to "Note I" and add the fol lowing:

NOTE 2: Temperature correction of volume does not compensate fo r reduced safety caused by increased temperature reducing the concentration at LFL (LEL). NOTE 3: Al l volumes and volumetrlc flow values should indicate temperature and pressure conditions, eq: 100 c u f t per minute at 300°F and ambient pressure.

~ U ~ T _ ~ _ O N : This helps to eliminate the confusing volumes at d i f fe ren t dryer locations. By defining temperatures and pressure the tota l mass is f ixed. COMMITTEE ACTION: Accept.

86 - 89 - (Table 5-2): Accept ~ : Technlcal Committee on Ovens and Furnaces RECOMMENDATION: Revise Tables 5-2, English and Metric, as fol lows:

( table shown on fol lowing page) SUBSTANTIATION: To provide consistency with updated information from NFPA 325M. COMMITTEE ACTION: Accept.

86 - 90 - (5-2.1, Exception No. 2-(New)): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATIOn: Add the fol lowing new Exception:

Exception No. 2: In the case of a multizone oven having solvent evaporating zones operating above 25 percent LEL, each zone shall also have solvent vapor concentration analysis unless i t can be shown that they could not exceed-25 percent LEL in the case of an accidental increase in solvent input, ~UBSTANTIATION: An exception and necessary requirements fo r multizone ovens is needed in th is paragraph. In a mul t izone oven, some zones may have to operate above 25 percent LEL. Depending upon arrangement, l a t e r zones may not need so lven t vapor concent ra t ion ana lyzers . COMMITTEE ACTION: Accept.

86- 91 - (5-2.1 Exception): Accept SUBMITTER: Technical Committee On Ovens and Furnaces RECOMMENDATION: Add the word "solvent" in the exception to read:

". . . continuous solvent vapor concentration . . ." SUBSTANTIATION: Ed i to r ia l . COMMITTEE ACTION: Accept.

86 - 92 - (5-3.1): Accept S__UBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add " in each batch" a f te r the word "vo la t i l es " in the f i r s t sentence. SUBSTANTIATION: I t is very important to real ize that this requirement is for each batch. Although Note I does state th is , i t is c r i t i ca l to the use of this calculat ion and should be flagged as such. COMMITTEE ACTION: Accept.

86 - 93 - (5-3.3): Accept ~ : Technical Committee on Ovens and Furnaces RECOMMENDATION: Add a heading fo r this section:

"Temperature Mu l t i p l i e r " . SUBSTANTIATION: The temperature mu l t i p l i e r is needed for operating temperatures of greater than 250°F. The new heading wi l l draw the users at tent ion to th is . COMMITTEE ACTION: Accept.

285

T a b l e 5 -2 T a b l e o f P r o p e r t i e s o f C o m m o n l y U s e d F l a m m a b l e L i q u i d s

I n E n g l i s h U n i t s

The data in this table have been obtained from NFPA 325M, 1984, Fire Hazard Properties of Flammable Liquids, Gases, and Volatile Solids. Available figures from numerous sources will be found to vary over a wide range in many instances, depending on the purity or grade of samples and on the test conditions prescribed by different observers. The figures presented are for information and general guidance only and are not to be regarded as official standards.

The importance of obtaining precise data on the rate ofevaporsticn by actual tests on particular paint formulations in use needs to be emphasized. Some af these multicomponent preporaticne may contain several solvents with widely different values of "lower explosive limit," "specific gravity," and "vapor density." Until such determination s are made, the operation should be on the side of safety. Therefore, the individual solvent, whose data result in the largest required volume of air per gallon, should be used as the basis for sale ventilation. Corrections and factors of safety for fi hal ventilation values are to he ap plied as indicated in the footnotes.

A B C Molecular Flash Ign.

Weight Point Temp. DeS. F. Des. F.

Acetone 58 - 4 869 n-Amyl Acetate 150 60 680 sec-Amyl Acetate 130 89 Amyl Alcohol 88 91 "572

Benzine (Petroleum Ether) Mix < 0 550 Benzene (Benzol) 78 12 928 n-Butyl Acetate 116 72 797 n-Butyl Alcohol 74 90 650 No.Butyl Alcohol 74 75 761

Butyl Cellosolve 118 148 472 (Glycol monobutyl Ether)

Butyl Propionate I~[} 90 799 Camphor 152 150 871 Carbon Disulphide 76 - 22 194 Cellosolve 90 106 460

(Ethylene Glycol Monoethyl) Cellmolve Acetate 132 124 715

(Ethylene Glycol Monoexhyl Ether Acetate)

Chlorobenzene-mono I I 3 02 1099 Cottonseed Oil Refined Mix 486 650 m or p Cresol 108 187 1038

Cyclohexane 84 - 4 475 Cyclohexanone 98 l I I 788

p.Cymene 134 117 817

Denatured Alcohol Mix 60 750 Dibutyl Phthalate 278 315 757

o.Dich]orobenxene 147 151 1198

Diethyl Ketone ' 86 55 842 N.Dhnethyl Formamide 73 , 186 838 .

p-Dioxane (Diethylene Dioxide) 88 54 356 Ethyl Acetate 88 24 800 Ethyl Alcohol 46 55 685 Ethyl Ether 74 - 49 356 Ethyl Lactate 118 I 15 752

Ethyl Methyl Ether 60 , - 35 374 Ethyl Propionate 102 54 824 Ethylene Dichloride 99 56 775 Gasoline Mix - 45 495 Hexane 86 - 7 487 Kerosene (Fuel Oil No. I) Mix 110-162 410 Linseed Oil - Raw Mix 452 650 Methyl Acetate 74 14 850 Methyl Alcohol 32 52 867 Methyl Carbitol 120 205 465

(Diethylene Glycol Methyl Ether) Methyl Callos~lve 76 105 551 Methyl Cello~olve Acetate 110 -111 . Methyl Ether 46 Gas "662 Methyl Ethyl Ketone 72 16 759 (2.Butenone) Methyl Lactate 104 121 725

Mineral Spirits No. I0 Mix 104 473

Naphtha (V,M. & P. Regular) Mix 28 " 450

Naphthalene 128 174 979 Nitrobenzene 123 190 900

Nitroethane 75 82 778 Nitromethane (a) 61 95 785 1 .Nitropropane 89 96 789 2.Nitropropane 89 75 802 paraffin Oil Mix 444 . . . . Perch]oroethylerte 106 None None petroleum Ether Mix <0 550

. Propyl Acetate 10'2 55 842

Propyl Alcohol 60 74 775 ~u~o.Propyi Alcohol 60 53 750

n.Propyl Ether 102 70 370 p y r i d l n e 70 68 900 Resin Oil Mix 266 648 Soy Bean Oil Mix 540 838 Toluene 92 40 898 Turpentine 138 95 488 Vinyl Acetate 86 18 788 o-Xylene I0~ 90 867

J D E F G H I "Appmx~nate Cu. Ft.

ExpIo. Limil.~ Specif. Vapor Boiling Lb~. Cu. Ft. of Vapor of Air rendered barely % by Volume Gravity Density Point Per Per Gal. Per Lb. explosive per

Lower Upper (Wate r= I) (Air= I) Deg. F. Gal. Liquid Liquid gal. of Solvent

2.8 18 0,8 2.0 135 6.7 44.4 6.63 1780 I .I 7.6 0.9 4.5 800 7.5 22.2 5.04 2000

. . . . 0.9 4.5 249 7.2 22.2 8.09 'i.2 10.0 o.s 3.0 200 6.0 29.6 4.80 2440

@212 I.I 5.9 0.6 2 5 95-140 5.4 26.7 4.94 2400 1.5 7.9 0.9 2.8 176 7.$ 35.7 4.89 2710 1.7 7.6 0.9 4.0 260 7.3 25.0 3.42 1450 1.4 11.2 0.8 2.6 248 6.7 34.2 5.10 2410 1.7 9.8 0.6 2.6 201 6.7 34.2 5. I0 1980

@212 @212 . . . . . . . . 0.9 4. I 340 7.5 24.4 5.25 . . . .

0.9 4.5 205 7.3 22.2 3.o4 . . . . o.s ' s : 5 1.0 5.2 899 8.2 21 2 2.58 . . . . I .$ 50,0 1.3 2.6 115 10.5 55.5 5.29 4210 2.6 15.7 0.9 3.1 275 7.8 52.2 4.13 1210

1.7 . . . . 1.0- 4.7 318 8. I 22.8 2.82 1320

1.3 9.6 l.l 3.9 270 9.2 31.8 3.41 2360 .... 0.9 .... 7.7

l . f . . . i .o . . . . s�s' 8.6 291~ ~i~d 26~d @SO2

I.S "8" ' 0.8 2.9 178 6.5 80.6 4.71 2320 I.I 9.4 0.9 8.4 $15 7.9 29.4 3.72 2640

@212 0.7 8.6 o.9 4.6 ~19 7.2 21.7 3.02 3080

@212 o.s 1.6 175 6.7 55.5 8.29 . . . . 6~ iiii 1.o, .... ~ 8.7 . . . . . . . . . . . .

@456 2.2 9.2 I.$ 5.1 356 I0.9 28.8 2.60 1260

1.6 .... 0.8 3.0 217 6.8 29.6 4.56 1820 2.2 15.2 o.9 2.5 807 7.8 40.0 5.13 1780

@212 2.0 22. 1.0 + 8.0 214 8.97 37.0 4.13 "1810 2.0 I 1.5 0.9 3.0 171 7.5 83.3 4.44 1680 3.3 19." 0.8 1.6 173 6.6 55.5 8.41 1650 1.9 $6. 0.7 2.6 95 5.9 29.9 5.07 1540 1.5 .... 1.0+ 4.1 309 0.5 27.1 $.19 1780

@212 2.0 10.1 0.7 2.1 51 6.1 37.0 6.06 1810 1.9 I1. 0,9 3.,5 210 7.4 28.6 5.80 1480 6.2 16. 1,3 3.4 183 7.4 42.5 5.74 640 1.4 7.6 0.8 3-4 100-400 7.0 25.4 3,63 1790 I. I 7.5 0.7 3.0 156 5.5 25.9 4.71 2350 0.7 5. <1 . . . . 804-574 7.5 . . . . . . . . . . . .

0.9 600+ 7.7 s . f i61 o.9 2 . s 14o 7.7 ~17 ~164 ii2o 6.0 36. o.8 11 147 6.6 80.8 12.2 127o 1.38 9~.7 1.0. 4.14 379 8.5 27.4 3.22 1990

. . . . . . . . 1.0- 2.8 255 8.1 40.9 5.08 . . . . 1.7 8 ° 1.0 4.07 292 8.3 27.3 3.29 . . . . 3.4 27,0 . . . . 1.8 - 11 8.3 48.8 8,84 . . . . 1.4 11.4 0.8 2.8 178 8.7 25.8 5.30 2540

@2oo @200 2.2 . . . . 1.1 3.6 298 9.1 33.9 8.73 1510

@212 0.8 . . . . " 0.8 3.9 ~ 6.7 22.8 1.72 2830

@212 0.0 6.0 0,8 <1 212-320 6.2 24.0 3,87 ....

O.9 5.0 I.I 4.4 424 9.7 27.8 2.86 3060 1.8 . . . . 1.2 4,3 412 10,0 81.0 3.10 1690

@2OO 3,4 . . . . 1,1 2.6 237 8.7 47,0 5,40 1340 7.3 . . . . 1.1 2.1 214 9.4 58.2 6.19 740 2,2 1.0 3.1 268 8.3 55.8 4,32 1580 2.6 I'1.()' l . i l - 3.1 248 8.2 35,8 4.37 1340

7.1-7.3 . . . . . . . . . . . . None . . . . 1.8 5.8 250 13.0 . . . . . . . . . . . .

1.1 5.9 0.8 2.8 95-140 0.4 26.7 4.94 2400 1.7 0. 0.9 2.5 21g 7.5 28.0 8.81 1850

@100 2.2 13.7 0.8 2.1 207 8.7 42.3 6.32 1920 2.0 12.0 0.8 2.1 101 6.6 42~ 6.41 2070

@200 1.3 7.0 0.78 3.f~ 194 6.1 23.6 3.87 1820 1.8 12A 1.0- 2.7 239 8.2 41.1 8.02 2240

. . . . . . . . 1.0 . . . . >680 8-2 . . . . . . . . . . . . . 0.9 . . . . . . . . 7.7 . . . . . . . . . . . .

% " ' ~ 0.9 0.1 . 1 7-2 82~ 4 . ~ . . 0~ . . . . <1 . . . . 300 7-2 . . . . . . . . 2.8 13.4 0.8 8.0 161 7.7 ~ 4.33 1250 1.0 7.0 0.9 2.7 292 7.3 27.0 3.70 2670

Note: Column J gives the cubic feet of air rendered barely ecplosive by I gallo n of solvent. However, for most practical calculations, this value is close enough to the actual volume of the vapor-air mixture.

* For final required safety ventilation values in each particular oven operation these figure~ are multip]icd by the folluwing factors as they apply:

.(I) Temporature--Vohime Conversion (see Table 5-1,11).

2 8 6

(2) Standard factor of safety of 4 for continuous process ovens (see 5-2.1). (3) L.E.L. Correetian factor for hetoh ovens between 250"F. and 500"F. multiply by 1A (see

5-3.3). (4) The ma:dmum number of ganors of solvent evaporated per unit of time on the basis of

maximum possible loadings.

(a) Classified as a potentially explosive chemical.

Table 5-2 Table of Properties of Commonly Used Flammable Liquids

In Metric Units

The data in this table have been obtained from NFPA 325M, 1984, Fire Hazard Properdsa of Flammable Liquids, Gases, and Volatile Solids. Available figures from numerous eourcea will be found to vary over a wide range in many instances, depending on the purity or grade of samples and on the test conditions prescribed by different observers. The figures presented are for in forc~ation and general guidance only and are not to be regarded as ofi~cial standards.

The im!~ortance ofohtaining precise data on the rate of evaporation by actual tests on particular paint formulations in use needs to be emphasized. Some of these muhicomponent preparations may contain several solvents with widely different values of "lower explosive limit," "specific gravity," and "vapor density." Until such determinations are made, the operation should be on the side of safety. Therefore, the individual solvent, whose data result in the largest required volume of air per gallon, should be used as the basis for safe ventilation• Corrections and factors of safety for final ventilation values are to be applied as indicated in the footnotes.

A B C Molecular Flash Ign.

Weight Point Temp. Deg. C. Deg. C.

Acetone 58 - 20 468 Amyl Acetate 180 16 560 • ,ec-Amyl Acetate 130 32 Amyl Alcohol 88 33 300

Benzine (Petroleum Ether) Mix < - 18 288 Benzol (Benzene) 78 - 11 498 n-Butyl Acetate 116 22 425 n-Butyl Alcohol 74 37 343 see-Butyl Al~ohol 74 24 405

Butyl CeUomlve 118 64 244 (Glycol Monobutyl Ether)

Butyl Propionate 130 32 426 Camphor 152 66 4456 Carbon Disdphlde 76 - 30 . 9O C, dlomlve 90 41 238

(Ethy~ C e U , : ~ ) (Ethylene Glycol M o n ~ y l )

~ l v e Acetate 132 (Ethylene Glycol Monoethyl

Acetate) Chlombenzene-mono l 13 28 593 Cottonseed Oil (Refined) Mix 252 343 m or p Cresol 108 86 558

Cyck)hexane 84 - 20 " 245 Cydohexanone 98 44 420

p*Cymene 154 47 436

Denatured Alcohol Mix 16 399 " Dibutyl phthaixte 278 157 402

o-Diehlorobenzene 147 66 648

Diet hyl Ketone 86 13 450 N.Dhnethyl Formamide 73 58 445

p.Dioxane (Dlethylene Dioxide) 88 12 180 Ethyl Acetate 88 - 4 426 Ethyl Alcohol ~6 13 363 Ethyl Ether 74 - 45 180 Ethyl Lactate 118 46 400

Ethyl Methyl Ether 60 - 3 7 190 (See Methyl Ethyl Ether)

Ethyl Propionate 102 12 440 Ethylene Dichloride 99 1 S 413 Gasoline Mix - 43 257 Hexane n 88 - 22 228 Kerosene Mix 43-72 210 Linseed O i l - Raw Mix 222 343 Methyl Acetate 74 - 10 454

• Methyl Alcohol 32 I I 484 Methyl Carbltol 120 96 240

(Diethylene Glycol Methyl Ether) Methyl Cellosolve 76 41 289 Methyl Cellosolve Acetate I 18 -38 . .

(Ethylene Glycol Methyl Ether Acetate) Methyl Ether 46 Gas 350 Methyl Ether Ketone 72 - 9 404 ~2.Butanone) Methyl Lactate " 104 49 385

Mineral Spirits No. 10 Mix 40 245

Naphtha (V~M. & P. Regular) M=x - 2 232

Naphthalene 128 79 526 Nitrobenzene 123 88 482

Nitroethane 75 28 414 Nitromethane (a) 61 35 418 1.Nitropropane 89 36 421 2-Nitropropane 89 24 428 paraffln O il Mix 229 . . . .

Perchloroethylene 106 None None Petroleum Ether Mix < - 18 288 Propyl Acetate 102 13 450

Propyl Alcohol 60 23 412 tso.Propyl Alcohol 60 12 399

n.Propyl Ether I02 21 188 Pyridine 79 20 482 Rosin Oil Mix 130 342 Soy Bean Oil Mix 282 445 Toluene 92 4 480 Turpentine 138 35 253 Vinyl Acetate 80 - 8 402 o-Xylene 108 32 463

D E E G' Explo, Limits Specif. Vapor Boiling % by Volume Gravity Density Point

Lower Upper (Water= 1) (Air= I) Deg. C.

2.5 13 0.8 2.0 56 l . l 7.5 0.9 4.5 149

0.9 4.5 121 1.2 iolo 0 8 3 0 138

@10o 1.1 5.9 0.6 2.5 35-60 1.3 7.9 0.9 2,8 80 1.7 7.6 0.9 4.0 127 1.4 11.2 0.8 2.6 117 1.7 9.8 0.8 2.6 94

' ' @19O @19O . . . . . . 0.9 4.1 171

0.9 4.5 146 o.6 3.~ l.O 8.2 2o4 1.8 50.0 1.3 2.6 46 2.6 15.7 0.9 3.1 135

, H I Kg. Cu. Meters of Vapor Per Per dmS Per Kg.

dm' . Liquid Liquid

0.823 0.333 0.404 0.875 0.166 0.190 " 0.863 fi.166 0.193 - 0,815 0.222 0.272

0.647 0.200 0.309 0.875 0.287 0,306 0.875 0.187 0.214 0.803 0.256 0.314 0.803 0.256 0.319

0.844 0.183 0.203

0.875 0.166 0.190 0.982 0.160 0,163 1.258 0.416 0.331 0.954 0.241 0.259

J Approx., Cu. Meters of Air

rendered barely ex plcelve per

d m = of Solvent

13.32 14.92

is.2s

17.98 20.27 10.81 18.03 14.80

31.58 9.51

81 380 1.7 . . . . 1.0- 4.7 187 0.970 0.172 0.177 9.95

1.3 9.6 I.I 3.9 132 1.102 . . 0.9 . . . . . . . . 0.922

i~ 10 .... 201 10so @150

1,3 8.0 0.8 2.9 82 0.779 1.1 9.4 0.9 3.4 156 0.946

@lgo 0.7 5.6 0.9 4.6 176 0.862 @100 . . . . . . 0.8 1.6 79 " 0.80~ 0.5 . . 1.0+ . . . . 540 1.042

@235 2.2 9,2 1.3 S.l fso i.so6

16 0 8 3 0 103 0 8 i s 2.2 i512 0.9 2.5 153 0,934

@too 2.0 22. 1.0 3.0 I01 Ii075 2.0 11.5 * b 9 3.0 77 0.899 3.3 19. 0.8 1.6 78 0•790 i 9 36.0 0.7 2.6 35 0.707 1.5 . . . . l.O 'E l 154 l .Oi8

@to0 2.0 lO.l 0.7 2.1 II 0.730

1.9 I I. 0.9 3.5 99 0.886 6.2 16. 1.3 3.4 84 0.886 1.4 7.6 " 0.8 3.4 38-204 0839 1.1 7.5 0.7 3.0 69 0.659 0.7 5. • l . . 151-301 0.899

0.9 316 0.922 ~.l i61 0.9 ~.8 60 0.922 6.0 "36. 0.8 1. I 64 0.790 1.38 22.7 1.9+ 4.14 192 1.018

1.0- 2.8 124 0.970 "1'.7 8.2' 1.0 4.07 144 0.994

3.4 27.0 1.6 - 24 0.659 1.4 11.4 "0 .'8" 2.5 80 0•805

@93 @93 2.2 . . I.I 3.6 145 1.090

@to0 0.8 0.8 3.9 149 0.803

@ioo 0.9 6.0 <I .... 100-160 0.743

0.9 5.9 I.I 4.4 218 1.162 1.8 . . . . 1.2 4,3 211 1.198

@93 3.4 . . . . . I. I 2.6 114 1.042 7.3 .... l.l 2.1 101 1.126 2.2 1.0 3.1 131 0.994 2.6 1110 1.0' 3.1 120 0.982

0 5O . . . . . . . . . . . . . . . . . . . . 0 ~ 9 9 None None 1.63 5.3 121 1.029

1.1 0.9 0.0 2.5 35-60 0.647 1.7 8.0 0.9 3.fi 102 0.999

@38 2-2 13.7 0.8 2.1 97 0.803 2.0 12.0 0.3 2.1 83 0,791

@93 1.3 7.0 0.78 3.53 90 0.731 1.3 12.4 1.0 2.7 110 0.982

. . . . . . . . 1.0 . . . . >360 0.982

. . . . . . . . 0.9 . . . . . . . . 0.922 i-2 7.1 0.9 3.1 IIi 0.86,3 0*8 . . . . .1 . . . . 149 0 ~ 3 2.8 13.4 0.9 3.0 72 0.922 1.0 7.0 0.9 3.7 144 0~75

0.235 0.213 17.86

0.229 0.295 17.39 0.220 0.283 19.78

0.163 0.189 28.12

0•416 0•518 "....

0.212 0.162 9.42

0.222 0.272 I$.65 0.299 0.321 13.29

0.277 0.258 13.57 0.250 0.278 12.25 0.416 0.526 12.19 0.224 0.317 II.57 0.203 0•199 18.85

0•277 0.380 I$.57

0.214 0.241 II.05 0.318 0.359 " 4.81 0.190 0.227 10.38 0.194 0.294 17.44

o.26:~ o.:,9o s .~ 0.605 0.766 9.48 0.205 0.201 14.90

0.310 0.320 . . . . 0•204 0.206 ....

0.364 0,552 0•266 0.331 10.oo

0.254 0.233 II.29

0.171 0,212 21.20

0.180 0.242 19.82

0.208 0.179 22.90 0.232 0.194 12.66

0.352 0'.337 10.0fi 0.436 0.387 99.20 0.268 0,270 II.91 • 0.268 0.273 10.04

0-2~1t4 0.143 . . . . 0.200 0.309 17.98 0.214 0.238 12.37

• 0.317 0.393 14.41 0.317 0.401 15.53

0.177 0.242 17.70 0.,,~08 0.314 18.80

0.241 0.280 19.34 0.173 0.,200 21.45 0,2,60 0.271 0.37 0.202 0.231 20.00

Note: Column J gives the cubic meters of air rendered harely explosive by i liter of solvent• However, for moat practical calculations, tbJs value is close enough to the actual volume of the vapor-air mixture.

* For final required safety ventilation values in each particular oven operation these figures are multiplied by the following factors as they apply:

(1) Temperature--Volume Conversion (see Table 5-1.11). 287

(2) Standard factor of safety of 4 for continuous process ovens (see 6-2.1). (3) " L.E.L. Correction factor for batch ovens between 121"C., and 260"C., multiply by 1.4 (see

5-3.3). (4) The maximum number of liters of solvent evaporated per unit of time on the basis of

maximum possible loadinge.

(a) Classified as a potentiafiy explosive chemical.

86 - 94 - (5-3.3, Note l ) : Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: At the end of Note I add:

"(see Appendix D)". ~UBSTANTIATION: This provides c lar i f i ca t ion. COMMITTEE ACTION: Accept.

86 - 95 - (5-4.1): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Replace the existing 5-4.1 and Note with:

5-4.1 Where the safety vent i lat ion rate in the oven has been designed to result in vapor concentrations between 25 percent and 50 percent of the lower explosive l imi t , a continuous vapor concentration indicator and control ler shall be provided. The system shall be arranged to alarm and prevent operation in excess of 50 percent of the lower explosive l imi t . SUBSTANTIATION: Tbis provides additional information important for this subject. COMMITTEE ACTION: Accept.

86 - 96 - (5-4.2): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Replace existing 5-4.2 with:

5-4.2 The continuous vapor concentration indicator and control ler system shall have the following characteristics ( refer also to Appendix E):

(a) Calibration is valid for the oven application and al l of the solvents to be used. A record of calibration data is maintained.

NOTE: Where a variety of.formulations are used, I the solvent producing the lowest control ler true signal is the primary cal ibration; a l l other solvents may read higher than true value.

(b) Malfunction alarms indicate any sample, flow, c i rcui t or power fa i lures.

(c) A maximum LEL l imi t operating in the fa i lsafe mode immediately sequences to reduce the dryer solvent load to a minimum. "I

NOTE: The sequence may include the following: open exhaust and fresh a i r dampers, shut down heaters, stop the conveyor or web, stop the coating process; stop or remove the coating material.

(d) Prevent conveyor web or process from restarting unti l the vapor concentration has been restored to a safe level and the operator has manually reset the

system. I (e) The sensor and the sample system are maintained

at a temperature that prevents condensation. ( f ) Response time is suf f ic ient to in i t i a te oven

shutdown without exceeding the lower explosive l imi t on a sudden, predictable oven upset or fa i lure.

(g) The system is secured against unauthorized adjustment. SUBSTANTIATION: This provides additional information which is important for this subject. COMMITTEE ACTION: Accept.

86 - 97 - (5-4.3, Note): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: .Remove "and prompt renewal of filaments when necessary are" and replace with " is" . SUBSTANTIATION: The revised wording is more general. COMMITTEE ACTION: Accept.

"A bleed stream ( l ine 2) is processed by a solvent recovery system. A coolant ( l ine 3) acts to condense the solvent which is discharged to storage ( l ine 4). With solvent removed, the gas stream is returned to the oven." SUBSTANTIATION: Present wording refers to the bleed stream as 1 percent of the recirculation flow, which is deleted as too rest r ic t ive. Cooling by vaporization is also deleted as too restr ic t ive. Other wording is c lar i f ied. COMMITTEE ACTION: Accept.

86 - 99 - (6-7.3 (New)): Accept ~U_BBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add a new paragraph as follows:

6-?.3 Piping which contains cryogenic l iquids, or is installed downstream of a cryogenic gas vaporizer and is used to convey safety purge gases, shall be constructed of metals which retain adequate strength at cryogenic temperatures.

Caution: Commercial grade carbon steel pipe exhibits a marked reduction in impact strength when cooled to sub-zero temperatures. Consequently i t is vulnerable to impact fracture i f located downstream of a vaporizer running beyond i ts rated vaporization capacity, or at very low ambient temperature. SUBSTANTIATION: This addresses cryogenic systems.

COMMITTEE ACTION: Accept.

86 - 100 - (6-8.2): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Remove "(see Appendix C)". SUBSTANTIATION: Clar i f icat ion. COMMITTEE ACTION: Accept.

86 - lOl - (6-8.3): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Remove "oxygen". SUBSTANTIATION: Editor ial . COMMITTEE ACTION: Accept.

86 - 102 - (Chapter 7): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Change t i t l e as follows:

Chapter 7 Fume Incinerators (Afterburners) and Heat Recovery Applications for Class A Ovens

~V~TANTIATION: More descriptive of material in t e x t . COMMITTEE ACTION: Accept.

86 - 103 - (7-1.1 and Figure 7-1.1-(New)): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add the following to 7-I.1:

"Figure 7-1.1 shows a solvent fume incinerator with heat recovery."

Add a new Figure 7-1.1 as Follows: (f igure on following page)

SUBSTANTIATION: The new figure wil l give an example of this type of incinerator. COMMITTEE ACTION: Accept.

86 - 98 - (Figure 6-I, Note): Accept SUBMITTER: Technical Committee on Ovens and Furnaces I RECOMMENDATION: Revise last 3 sentences of Note to read:

288

Solvent Fume Incinerator w/ Heat Recovery (After Burner)

Exhaust

Incinerator ~ ~ - ~ m

k

, . ~ , / F u e l Supply

11/Heat Exchanger

- - , _ _ ~ -7 ~Burnar --" ~--~ I l t---~ 7- 1 J

TIC I I • T/C Hi Temp. Control Limit Switch

- - Oven V Fume Exhaust Single or Multiple

Pass Heat Exchanger ov0-TJ~.--]

Figure 7-1.1 Solvent. Fume Incinerator (Afterburner) with Heat Recovery

86 - 104 - (Figure 7-2(e)-(New)): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add new Figure 7-2(e) as shown: SUBSTANTIATION: The new figure wi l l give an example of a heat recovery application. COMMITTEE ACTION: Accept.

After Burner With Low Effectiveness Heat Exchanger

System ~ ] Burner Exhaust" F II \ ~ ./

m l I ~ ~ . Combustion I l m m , / • . Chamber IAI

,i i I TAfter 2~n~; Con,,o I Ill

'1 II I l Exhaust

. { " - - ~ G u m e C o n t r o l T ' VolumeContro' " l I ~ Damper Operated by ~ Damper Operated by

I I Volume I I Zone Temp. Control Zone Temp. Control

• F , L _ I ~_5 I H ~ : q

/ , . iI l ~ Zone Temp. I P --el Zone Temp, \ / ~ -- Control E{ement ~ - C°ntro' Element ~

Figure 7-2(e) Example of Typical Heat Recovery Application

1 289

86 - 105 - (8- I ) : Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Remove "shal l" from f i r s t sentence and add at the end of the paragraph:

"(see Appendix H)." SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

8-2.7 0xy-fuel burners instal led on arc-metal heating furnaces shall be exempt from requirements of Chapters 3 and 4 requiring:

(a) Burner flame pi lo ts or igni ters; (b) Combustion safeguards (flame supervision).


86 - 106 - (8-2.3): Accept JBU~_ILTE_R: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add following to l i s t of required interlocks:

(m) Safety shutoff valves on oxygen and fuel lines supplying burners are proved closed. ~UBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

86 - 108 - (Appendix C): Accept SUBMITTER: Technical Committee on Ovens and Furnaces R_E~0MMENDATION: In Appendix C under Regular Shift Checklist, change "gas" to "solvent vapor" in three places. SUBSTANTIATION: These changes are more descriptive. The concern is with a vo la t i l e solvent which may or may not be a "gas". To some this might imply a fuel. COMMITTEE ACTION: Accept.

86 - 107 - (8-2.6-(New) and 8-2.7-(New)): Accept SUP~!!EB: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add the following:

8-2.6 0xy-fuel and oxygen-enriched a i r burner controls shall be interlocked for burner igni t ion with the arc furnace controls. An isolated contact on the arc furnace controls shall be available for interconnecting the burner management system to establish that enough current is flowing through the secondary leg of the power transformer to maintain a strong arc in the furnace.

Exception: Operation of a burner need not be halted in the event of a momentary interruption of the arc, nor after arc heating has been intent ional ly discontinued, so long as the contents of the furnace are incandescent or are otherwise known to be at a temperature in excess of 1400°F (760°C). The arc, hot furnace walls, and molten metal close to the burner outlets may be considered dependable igni t ion sources.

86- I09 - (Appendix C; Figure C-l): Accept SUBMITTER: Technical Committee on Ovens and Furnaces I RECOMMENDATION: Replace exist ing Figure C-I with the following: S__UBSTANTIATI0_N: This provides c la r i f i ca t ion . COMMITTEE ACTION: Accept.

FLAME ROD OR UV OETECTOR- / so.E,o,o VALV? A,R FLOW SW, TCH\ /

• / \ / /K PILOT SHUTOFF COCK-~ I~ J~ \ \ \ k

SMHAuNoFF COCK-i o LOWGAS TEST TAP COCK ( ~ ~. _ . ~ ~ z. l :: ..... ' THERMOCOUPLE

GAS INLET-- ~ L : i ~ ~IIHAUSR TX RKI ; E C ~ E C R U L A T I O N ~ / ~ CONTROL VALVE J TEMPERATURE CONTROLLER X

Figure C-] Example of a Gas Piping Diagram.

290

86 - II0 - (Appendix E): Accept SUBMITTER: Technical Committee on Ovens and Furnaces R__E~QMMENDATION: Remove existing Appendix E and replace with the following:

Appendix E Continuous Solvent Vapor Concentration Indicator and Controller,

I. Solvent Vapor Analyzer Systems. A solvent vapor concentration indicator is a measurement system used to determine the solvent vapor concentration in a Class A oven, expressed as percent of the lower explosive l imi t (% LEL), also called lower flammable l imi t (% LFL). I t is required for safe operation of ovens at solvent concentrations above 25% LEL. The measurement system consists of three integral parts:

1. The gas sample system which delivers the oven gas sample to the analyzer.

2. The solvent vapor concentration analyzer. 3. The safety logic system which is activated by the

analyzer. The oven gas should be sampled at a point which best

represents the average concentration of solvent vapor in the oven or oven zone. Usually this is at the oven exhaust point. Care must be taken to provide suf f ic ient turbulence within the oven to avoid signif icant pockets of high solvent concentration. The sample system consists of a sample pickup tube, sample l ine, sample pump and f i l t e r or other sample conditioning devices. The volume of the sample system should be as small as possible ahd the sample flow rate maximized for fast response of the system. Special precautions such as heating the sample lines and analyzer to prevent condensation of volat i les in the sample system may be required. The length of the sample l ine should be minimized by locating the analyzer, close to the sample point.

The solvent vapor concentration analyzer may be one of several types. The choice of the appropriate type depends on factors such as the solvent composition, whether calibration for more than one solvent is required, necessary response time of the measurment system, ab i l i t y to handle contaminants, oxygen content etc. The following types of analyzers are used:

1. Catalytic Combustion. Combustion of solvent vapor occurs on a heated catalyst surface, such as a platinum wire. The heat of combustion causes a change in electr ical resistance which is calibrated in terms of percent LEL. Because the measurement is based on combustion, the calibration does vary signi f icant ly for d i f ferent solvents. However, contamination of the catalyst with silicones can cause a calibration shi f t .

2. Infrared. The sample is passed through a measurement cell where infrared energy is absorbed by the solvent vapor and compared with the energy.absorbed in a reference cell containing background gas. Contamination by sil icone is not a problem with this type of analyzer, but the calibration is specific to certain classes of solvents and may vary considerably for various solvent types. I ts area of application is for single solvent systems where sil icone poisoning may be a problem.

3. Flame Temperature. This is a combustion type analyzer in which solvent vapor in the sample is burned as i t passes through a chamber containing a small constant-burning flame. A temperature sensor is located immediately above the flame. The temperature varies with the amount of solvent burned in the flame, and is calibrated in percent LEL. Contamination by silicones is not a problem, and calibration is re lat ive ly constant {or various solvents.

4. Flame Ionization. Ionization of solvent vapor in contact with a hydrogen flame causes a change in electr ical properties which can be measured and calibrated in percent LEL. This method is also used to measure very low concentrations of solvent vapor. Very rapid response can be obtained, but the calibration can vary for some types of solvents.

All of the various types of analyzers must be routinely calibrated using zero and span gas. Standards require i n i t i a l calibration for the specific solvents being measured.

The safety logic system involves high-l imit contacts in the analyzer and/or recorder which wil l stop the conveyor or other means of solvent introduction and actuate dampers or fan motor drives to provide maximum makeup a i r and exhauEt. Other parts of the analyzer logic system include flow meters and pressure switches to ver i fy the proper operation of the sample system.

The solvent vapor concentrat ion analyzer may also be u t i l i z e d to contro l the percent LEL in the oven by modulation of the makeup a i r or exhaust.

I t cannot be emphasized too s t rong ly that the solvent vapor concentrat ion measurement system must. have a very fas t response time so that co r rec t i ve act ion can be taken in response to upsets such as excessive , i n t roduc t ion of solvent in to the oven. Response times as l i t t l e as 5 seconds may be required in some cases.

I I . LEL Values and Ca l i b ra t i on Concerns. Proper operat ion of a continuous solvent vapor concentrat ion analyzer requires careful c a l i b r a t i o n fo r the correct LEL values of the p a r t i c u l a r solvent or solvent mixtures, and fo r response of the analyzer to the p a r t i c u l a r so lvents.

1. LEL Values and Temperature Correct ions. LEL values fo r many conmonly used solvents are given in Table 5-2. Add i t iona l data may be found in NFPA 325M, "F i re Hazard Proper t ies of Flammable L iquids, Gases, and V o l a t i l e So l i ds . "

Most of the LEL values are reported at 25°C " (77°F), although several are given at IOOOC (212°F). The LEL value decreases at higher temperature, so i t is necessary that the LEL value fo r the p a r t i c u l a r solvent be corrected fo r the operat ing temperature of the oven. Bureau of Mines B u l l e t i n 627 suggests tha t the LEL value be corrected fo r temperature according to the f o r m u l a :

L~ = L~ 5 [1-0.000784(t-25°C)] w~ere ~ = oven temperature, °C. Using th is formula, LEL values fo r operat ing

temperatures above 25°C need to be corrected by the fo l l ow ing fac to rs :

Oven Temperature LEL CQrrective Factor 77°F (25°C) 1.00

212°F (100°C) 0.94 300°F (149°C) 0.90 400°F (204°C) 0.86 500OF (260°C) 0.82

The temperature cor rec t ion fac to r can also be expressed approximately as a 5 percent reduct ion in the LEL value fo r each lOOUF r ise in temperature above 77OF.

For mixtures of so lvents , the LEL of the mixture may be ca lcu la ted by formula:

LEL Mixture = . . . . I00 . . . . PI/LI + P2/L2 + .. Pn/Ln

WhereP1 2 n = % by volume of component i ,2 . .n, LI 2 ' - '~ the LEL value of each solvent

I I .2 'Ih~rument Calibration Factors. The solvent vapor analyzer systems described in Appendix E, Section I respond d i f ferent ly to various solvent vapors. Instrument calibration to the specific solvent vapor or solvent mixture vapor is required both before i n i t i a l operation of the instrument, and on some routine schedule af ter i n i t i a l operation.

II.2A In i t i a l Calibration. The instrument shall be i n i t i a l l y calibrated with the solvent vapor or solvent mixture vapor used in the oven application. A label describing this calibration shall be aff ixed to the instrument. Perma6ent record of this calibration shall be included with records for the instrument.

The user must understand how the instrument wil l respond to vapors for which the instrument is not calibrated, including: other solvent vapors or mixtures of solvent vapors present in the sample; and vapors whose relat ive response data is not known. The instrument manufacturer should be consulted for guidance in these cases.

The i n i t i a l calibration shall be based on "worst case" considerations, including the fo l l ow ing .

I. I f a variety of mixture of solvent vapors wil l be present, the instrument shall be calibrated for the solvent vapor that produces the lowest instrument signal. All other solvent vapors wil l indicate a meter value greater than the actual concentration, so that any error in reading is alwaYs in a safe-early warning-direction.

2. Solvent mixtures containing minor components may be calibrated withut the minor components when the estimated error produced is less than three percent of meter reading.

3. When calculating the LEL Value and Oven Temperature Correction as defined in Appendix E, Section I I , Part l , the maximum oven temperature shall be used.

291

II.2B Field Calibration. Solvent vapor analyzer systems require f ield calibration checks during normal operation to verify the accuracy of the system. The manufacturer shall supply the user with a recommended schedule for calibration checks. This schedule shall be contained in the operating instructions for the specific instrument used.

I t is recommended that f ield calibrations be made using a known concentration of the actual solvent vapor present in the process.

Field calibration may also be performed using a known concentration of reference test gas in situations where use of the actual solvent vapor present is not possible.. This reference test gas may be used as a substitute for the actual solvent vapor, and meter reading adjustments may be made based on test gas response data supplied by the instrument manufacturer.

The use of relative response data in making f ield calibration checks is not recommended.

Certain materials, including but not limited to silicones, su|fur compounds, phosphorus compounds, chlorinated compounds and halogenated hydrocarbons have a "poisoning" or inhibit ing effect on some solvent vapor analyzers. These materials can produce a loss in sensit ivity in certain instruments. I f the presence of desensitizing materials in the sample is known or suspect, instrument f ield calibration checks shall be performed on a more frequent basis. Consult the instrument manufacturer for guidance on calibration frequency in these situations. SUBSTANTIATION: This new material reflects the current state-of-the-art on this subject. COMMITTEE ACTION: Accept.

86- 111 - (Appendix H (New)): Accept SUBMITTER: Technical Committee on Ovens and Furnaces B_~_C_O~_~NDATION: Add a new Appendix H as follows:

H-I Using oxygen to augment or to substitute for combustion air in industrial furnace heating systems presents new safety hazards for users acquainted only with air-fuel burners.

One group of hazards arises from the exceptional reactivity of oxygen. I t is a potent oxidizer; therefore, i t accelerates burning rates. I t also increases the flammability of substances that are generally considered nonflammable in air. A f i re fed by oxygen is d i f f i cu l t to extinguish.

Special precautions are needed to prevent oxygen pipeline fires; that is, fires in which the pipe i tse l f becomes the fuel. Designers and installers of gaseous oxygen piping must familiarize themselves with standards and guidelines referenced in this code on pipe sizing, materials of construction, and sealing methods. Gaseous oxygen must flow at relat ively low velocity in pipelines bui l t of ferrous materials, because fr ic t ion created by particles swept through steel pipe at high speed can ignite a pipeline f i re. For this reason copper or copper-based alloy construction is customary where the oxygen velocity must be high., such as in valves, valve trim areas, and in orif ices.

Oxygen pipelines must be scrupulously cleaned to rid them of o i l , grease, or any hydrocarbon residues before oxygen is admitted. Valves, controls and piping elements that wi l l be in contact with oxygen must be inspected and certi f ied "clean for oxygen service." Thread sealants, gaskets and seals, and valve trim must be oxygen-compatible; otherwise they may in i t ia te or promote f ires. Proven cleaning and inspection methods are described in Compressed Gas Association Guidelines l isted among the references.

Furnace opera to rs and o the r persons who i n s t a l l or service oxygen piping and controls must be indoctrinated in the precautions and safe practices for handling oxygen. For example, someone smoking or striking a welding arc in an oxygen-enriched atmosphere could touch off a f i re. Gaseous oxygen has no odor and is invisible, so places where there is a potential for leaks must be "off l imits" to smokers and persons doing hot work. Such places must be posted. Persons who have been contacted with oxygen must be aware that their clothing is extremely flammable until i t has been aired out. Equipment or devices that contain oxygen must never be lubricated or cleaned with agents that are not approved for oxygen service.

Oxygen suppliers are sources of chemical material safety data sheets (MSDS) and other precautionary information for use in employee training. Users are urged to review the safety references in this standard and adopt the recommendations.

Another group of hazards arises from the nature of oxy-fuel and oxygen-enriched air flames. Because they are exceptionally hot, these flames can damage the burners, ruin work in process and furnace internals, and even destroy refractory insulation that was intended for alr-fuel heating. Oxygen burner systems and heating controls must have quick-acting, reliable means for controlling heat generation.

Air that has been enriched with oxygen wi l l pause fuel to ignite unusually easily because added oxygen widens the flammability range of air-fuel mixtures. Therefore preignition purging is cr i t ica l when oxygen is used.

Oxygen is also a hazard for persons entering furnaces to perform inspections or repairs. Strict confined space entry procedures must be implemented. They must include analyses for excess oxygen (oxygen contents in excess of 20.9 percent), in addition to the ususal atmosphere tests for oxygen deficiency and flammability. ~_~LBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

86- 112 - (Appendix M-2 (New)): Accept SUBMITTER: Technical Committee on Ovens and Furnaces RECOMMENDATION: Add new Appendix H-2 as f o l l o w s : H-2 Oxy- fue l burners are o f ten u t i l i z e d in

con junct ion wi th arc me l t ing furnaces to augment e l e c t r i c hea t ing . Some o f these burners u t i l i z e a i r as w e l l . S ta t i ona ry burners are at tached to the furnace she] l and/or cover. Moveable burners , normal ly not at tached to the furnace, are suspended from s t r u c t u r a l members ou ts ide a furnace door. They are manipulated from the opera t ing f l o o r , and the oxygen and fue l are in t roduced i n to the furnace through long, concent r ic p ipes.

Convent ional f lame safeguards are imprac t i ca l in con junc t ion wi th oxy fue l burners in arc furnaces because o f the rad io f requency noise assoc ia ted wi th the arcs. The e l e c t r i c arc is a r e l i a b l e means of i g n i t i o n f o r the burners, once i t has been es tab l i shed . A f te rwards , the high tempratures ins ide an arc furnace prevent s i g n i f i c a n t amounts o f oxygen and fuel from accumulating without ignition. SUBSTANTIATION: This recognizes new technology involving oxygen enriched burners. COMMITTEE ACTION: Accept.

292

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