26 - NFPA · 2012. 8. 20. · reconfirmation of NFPA 491M-1975, Manual of Hazardous Chemical Reactions. NFPA 491M-1975 is published in Volume 7 of the 1984 National Fire Codes and

Report of Committee on Chemicals and Explosives

Correlating Committee

Robert W. VanDolah, Chairman Pittsburgh, PA

Robert P. Benedetti, Secretary National Fire Protection Assn.

(Nonvoting)

William J. Bradford, Brookfield, CT Thomas E. Duke, Fire Prevention & Engineering Bureau of Texas Howard F. Kempsell, Exxon Research & Engineering Co.. Richard Y. LeVine, Olin Corp. Samuel J. Porter, Falls Church, VA William J. Wiswesser, We~d Science Research

Technical Committee on

Electrical Equipment in Chemical Atmospheres

Richard Y. LeVine, Chairman Olin Corp.

Robert P. Benedetti, Secretary National Fire Protection Association

(Nonvoting)

F. D. Alrotb, Underwriters Laboratories Inc. John D. Ca~bell, Brown & Root Inc.

Rep. IEEE James C. Cawley, U S Bureau of Mines Paul M. Fitzgerald, Factory Mutual Research Corp. John T. Higgins, Dow Corning Corp.

Rep. NFPA Industrial Fire Protection Section Ernest C. Magison, Honeywell Inc.

Rep. Instrument Society of America Richard C. Masek, Bailey Controls Robert E. McKenney, Dept of Public Ut i l i t ies William I. Morton, E. I. Dupont De Nemours & Co.

Rep. Chemical Manufacturers Assn, Frank E. Rademacher, Industrial Risk Insurers John E. Rogerson, Cedar Lane Farm R. F. Schwab, Allied Corp. Walter A. Short, Crouse-Hinds Co.

Rep. NEMA George H. St Onge, Exxon Research & Engineering Co.

Rep. American Petroleum Inst.

Alternates

Albert A. Bartkus, Underwriters Laboratories Inc. (Alternate to F. Alroth)

Jane I. Lataille, Industrial Risk Insurers (Alternate to F. E. Rademacher)

Francis J. McGowan, The Foxboro Co. (Alternate to E. C. Magison)

John Rennie, Factory Mutual Research Corp. (Alternate to Fitzgerald)

David B. Wechsler, Union Carbide Corp. (Alternate to J. T. Higgins)

Technical Committee on

Hazardous Chemical Reactions

William J. Wiswesser, Chairman Weed Science Research

Robert P. Benedetti, Secretary National Fire Protection Assn.

(Nonvoting)

Howard H. Fawcett, Wheaton, MD Rep. American Chemical Society

Mark fan Grossman, American Ins. Services Group Inc. Frank O. Lindemann, Allied Corp-Fibers & Plastics Robert W. VanDolah, Pittsburgh, PA

F Technical Committee on

Storage, Handling and Transportation of Hazardous Chemicals

William J. Bradford, Chairman Brookfield, CT

Robert P, Benedetti, Secretary National Fire Protection Assn.

(Nonvoting)

W. S. Chang, Bureau of Explosives Lab John A. Davenport, Industrial Risk Insurers Thomas J. Gilding, Natl Agricultural Chemicals Assn. Mark fan Grossman, American Ins. Services Group Inc. Erskine E. Harton Jr., Hazardous Materials & System L. Paul Herman, NATLSCO William A. Keim, PPG Industries Inc.

Rep. SPI Robert S. Levine, Ctr. for Fire Research Clarence Lowery, EM Science • John F. McAnulty, U S Coast Guard Hdqrts. Chester M. McCloskey, The Norac Co. Inc.

Rep. SPI Harry H. Mclntyre, Harry Mclntyre Assoc. Samuel J. Porter, Falls Church, VA S. F. Sammis, Natl Cargo Bureau Inc. Anthony Santos, Factory Mutual Research Corp. H. M. Shuey, Rohm & Haas Co. Damon W. Snow, Monsanto Co. Robert W. VanDolah, Pittsburgh, PA Ford B. West, The Ferti l izer Institute

Alternates

J. P. Carroll,'SPI Alternate to C. McCloskey)

D. W. Gates, Natl Cargo Bureau Inc. Alternate to S. F. Sammis)

Kenneth W. Linder, Industrial Risk Insurers Alternate to J. A. Davenport)

Thomas A. Phemister, Assn. of American Railroads Alternate to W. S. Chang)

John J. Rizzo, FMC Corp. Alternate to CMA Rep.)

Richard A. Schwab, Lucidol Div. Alternate to W. A. Keim)

This l i s t represents the membership at the time ~he Committee was balloted on the text of this edition. Since that time, changes in the membership may have occurred.

The Report of the Committee on Chemicals and Explosives is presented in 8 parts.

Part I , prepared by the Technical Committee on Electrical Equipment in Chemical Atmospheres proposes for adoption i ts Report on a complete revision of NFPA 497-1975, Recommended Practice for Classification of Class I Hazardous Locations for Electrical Installations in Chemical Plants, including its redesignation as NFPA 497A, Recommended Practice for the Classification of Class I Hazardous (Classified) Locations for Electrical I'nstallations in Chemical Process Areas. NFPA 497-1975 is published in Volume 7 of the 1984 National Fire Codes and in separate pamphlet form.

Part I has been submitted to letter ballot of the Technical Committee on Electrical Equipment in Chemical Atmospheres which consists of 15 voting members; of whom all 15 voted affirmatively.

Part I has also been submitted to letter ballot of the Correlating Committee on Chemicals and Explosives which consists of 7 voting members; of whom all 7 voted affirmatively.

Part I f , prepared by the Technical Committee on Electrical Equipment in Chemical Atmospheres proposes for adoption its Report on amendments to NFPA 497M-1983, Manual for Clas~ification of Gases, Vapors and Dusts for Electrical Equipment in Hazardous (Classified) Locations. NFPA 497M is published in Volume 7 of the 1984 National Fire Codes and in separate pamphlet form.

Part I I has been submitted to letter ballot of the Technical Committee on Electrical E~uipment in Chemical Atmospheres which consists of 15 voting members; of whom 13 voted affirmatively, and 2 negatively (Mr. Cawley and Mr. Higgins)~

24

Mr. Cawley's negative vote is based on his opinion that the entire document should be revised to reflect new test procedures.

Mr. Higgin's negative vote is based on his opinion that Proposals 1 and 2 should be accepted and o F his opinion that silicon should be listed as a Group G dust.

Part I I has also been submitted to letter ballot of the Correlating Committee on Chemicals and Explosives which consists of 7 voting members; of whom all 7 voted affirmatively.

Part I l l , prepared by the Technical Committee on Hazardous Chemical Reactions proposes for adoption i ts Report on a reconfirmation of NFPA 491M-1975, Manual of Hazardous Chemical Reactions. NFPA 491M-1975 is published in Volume 7 of the 1984 National Fire Codes and in separate pamphlet form.

Part I l l has been submitted to letter ballot of the Technical Committee on Hazardous Chemical Reactions which consists of 5 voting members; of whom all 5 voted affirmatively.

Part I l l has also been submitted to letter ballot of the Correlating Committee on Chemicals and Explosives which consists of 7 voting members; of whom all 7 voted affirmatively.

Part IV, prepared by the Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals proposes for adoption its Report on amendments to NFPA 40E-1980, Code for the Storage of Pyroxylin Plastic. NFPA 40E is published in Volume 2 of the 1984 National Fire Codes and in separate pamphlet form.

Part IV has been submitted to letter ballot of the Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals which consists of 21 voting members; 17 of which are eligible to vote on NFPA 40E. Of these 15 voted affirmatively, 1 abstained (Mr. Sammis) and 1 ballot was not returned (Mr. Lowery).

Part IV has also been submitted to letter ballot of the Correlating Committee on Chemicals and Explosives which consists of 7 voting members; of whom all 7 voted affirmatively.

Part V prepared by the Technical Committee on Storage, Handling and Transportation of Hazardou~ Chemicals proposes for adoption its Report on a new document: NFPA 43B, Code for the Storage of Organic Peroxide Formulations.

Part V has been submitted to letter ballot of the Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals which consists of 21 voting members; 19 of which are eligible to vote on NFPA 43B. Of these, 15 voted affirmatively and 4 abstained (Messrs. Lowery, McAnulty, Sammis and Santos).

Part V has also been submitted to letter ballot of the Correlating Committee on Chemicals and Explosives which consists of 7 voting members; of whom all 7 voted affirmatively.

Part VI, prepared by the Technical Committee on Storage, Handling and Transporation of Hazardous Chemicals proposes for adoption its Report on amendments to NFPA 43C-1980, Code for the Storage of Gaseous Oxidizing Materials. NFPA 43C is published in Volume 2 of the 1984 National Fire Codes and in separate pamphlet form.

Part VI has been submitted to letter ballot of the Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals which consists of 21 voting members; 18 of which are eligible to vote on NFPA 43C. Of these, 16 voted affirmatively, 1 abstained (Mr. Sammis) and 1 ballot was not returned (Mr. Lowery).

Part Vl has also been submitted to letter ballot of the Correlating Committee on Chemicals and Explosives which consists of 7 voting members; of whom all 7 voted affirmatively.

Part VII, prepared by the Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals proposes for adoption its Report on amendments to NFPA 43D-1980, Code for the Storage of Pesticides in Portable Containers. NFPA 43D is published in Volume 2 of the 1984 National Fire Codes and in separate pamphlet form.

Part VII has been submitted to letter ballot of the Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals which consists of 21 voting members; 17 of which are eligible to vote on NFPA 43D. Of these, 15 voted affirmatively, I abstained (Mr. Sammis) and i ballot was not returned (Mr. Lowery).

Part VII has also been submitted to letter ballot of the Correlating Committee on Chemicals and Explosives which consists of 7 voting members; of whom all 7 voted affirmatively.

Part VI I I , prepared by the Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals proposes for adoption its Report on amendments to NFPA 490-1980, Code for the Storage of Ammonium Nitrate. NFPA 490 is published in Volume 2 of the 1984 National Fire Codes and in separate pamphlet form.

Part VIII has been submitted to letter ballot of the Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals which consists of 21 voting members; 18 of which are eligible to vote on NFPA 490. Of these, 16 voted affirmatively, 1 abstained (Mr. Sammis), and I ballot was not returned (Mr. Lowery).

Part VII I has also been submitted to letter ballot of the Correlating Committee on Chemicals and Explosives which consists of 7 voting members; of whom all 7 voted affirmatively.

25

NFPA 49i

PART I

497- 1 - (Chapter 3): Accept in Principle SUBMITTER: Thomas H. Seymour, Port Tobacco, MD ~ A T I O N : Reword the Chapter 3 heading to read as follows:

"Chapter 3 Method of Determining Type, Magnitude and Extent of Hazardous Locations." SUBSTANTIATION: This rewording, i f adopted, would make Chapter 3 consistent with the wording in Section i-1.2 of the standard as well as with the t i t l e of Table 3-1.2. Also i t wil l provide an opportunity for the material that is covered in Chapter 3 to be expanded to include a discussion and recommendations on how one should determine the type of hazardous location -- meaning that information could be provided in determining the proper class and group for the material in question as well as the location where the material is in use. COMMITTEE ACTION: Accept in Principle. COMMITTEE COMMENT: The complete revision of NFPA 497, as preprinted in this TCR, should adequately address the concerns of the submitter.

497- 2 - (2-I) : Accept in Principle SUBMITTER: Dennis Kirson, Sandia National Laboratories RECOMMENDATION: Add a second paragraph to the last sentence of Article 2-1.1. Electrical equipment approved for classified locations is not needed for pyrophoric gases which ignite spontaneously on contact with air. SUBSTANTIATION: While not all flammable gases are pyrophoric, all pyrophoric gases conform to accepted definitions of flammable gases. Article 2-1.1 as now written defines Class I locations as those inwhich "any" flammable gas may be present in the air in quantities sufficient to produce explosive or ignit ible mixtures.

Electrical design engineers may not consider that special electrical equipment would not prevent ignition of pyrophoric gases and interpret NFPA 497, Article 2-1.1 as requiring such locations to be classified. The proposed wording addition would specifically exempt pyrophoric gases from Class I location designation and remove any ambiguity in Article 2-1.1. COMMITTEE ACTION: Accept in Principle.

Add a scope statement to Section 1-1 excluding pyrophoric materials from NFPA 497. COMMITTEE COMMENT: The Committee agrees with the submitter, but feels this is a subject best addressed in the Scope of NFPA 497.

497- 3 - (Entire Document): Accept SUBMITTER: Technical Committee on Electrical Equipment in Chemical Atmospheres RECOMMENDATION: Completely revise NFPA 497-1975 as shown in the following draft. SUBSTANTIATION: Revise existing hazardous area classification diagrams to conform to chemical industry practice.

Add new diagrams for LNG fac i l i t ies. Simplify text for benefit of users.

COMMITTEE ACTION: Accept.

NFPA 497A

Recommended Practice for the Classification of Class I Hazardous (Classified) Locations for Electrical Installations

in Chemical Process Areas

1986 Edition

Chapter 1 General

Information on referenced publications can be found in Chapter 4 and Appendix A.

1-1 Scope.

i-1.1 This recommended practice applies to those locations where flammable gases or vapors, flammable liquids, or combustible liquids are processed or handled and where their release into the atmosphere may result in their ignition by electrical systems or equipment.

1-1.2 This recommended practice applies to chemical process areas. As used in this recommended practice, a chemical process area may be a large integrated chemical process plant or i t may be a part of such a plant. I t may be a part of a manufacturing fac i l i t y where flammable gases or vapors, flammable liquids, or combustible liquids are produced or used in chemical reactions or are handled or used in certain unit operations such as mixing, f i l t ra t ion , coating, spraying, d ist i l lat ion, etc.

26

NFPA 497

i-1.3 This recommended practice does not apply to situations that may involve catastrophic failure of or catastrophic discharge from process vessels, pipelines, tanks, or systems.

i-1.4 This recommended practice does not apply to situations involving enriched oxygen atmospheres. I t also does not apply to situations involving pyrophoric materials.

i-1.5 This recommended practice is not intended to supersede or conflict with applicable requirements of the following:

NFPA 30, Flammable and Combustible Liquids Code; ~

NFPA 33, Standard for Spray Application Using Flammable and Combustible Materials;

NFPA 34, Standard for Dip Tanks Containing Flammable or Combustible Liquids;

NFPA 35, Standard for Organic Coatings Manufacture;

NFPA 36, Standard for Solvent Extraction Plants;

NFPA 45, Standard on Fire Protection for Laboratories Using Chemicals;

NFPA 50A, Standard for Gaseous Hydrogen Systems at Consumer Sites;

NFPA 50B, Standard for Liquefied Hydrogen Systems at Consumer Sites;

NFPA 58, Standard for the Storage and Handling of Liquefied Petroleum Gases; and

NFPA 59A, Standard for the Production, Storage and Handling of Liquefied Natural Gas.

1-2 Purpose.

I-2.1 I t is the intent of this recommended practice to provide the user with a basic understanding of the parameters which determine the degree and the extent of the hazardous (classified) location. This recommended practice also provides the user with examples of the application of these parameters.

i-2.2 This recommended practice is intended as a guide and should be applied with sound engineering judgment. When all factors are properly evaluated, a consistent area classification scheme can be developed.

I-3 National Electrical Code Criteria.

1-3.1 This recommended practice is based on the cr i ter ia established by Article 500 of NFPA 70, NATIONAL ELECTRICAL CODE, but is not intended to supercede or confl ict with the requirements therein. Once an area is properly classified, the NATIONAL ELECTRICAL CODE specifies the type of equipment and the wiring methods that may be used.

Chapter 2 Basic Considerations

2-1 National Electrical Code Criteria.

2-1.1 Article 500 of NFPA 70, NATIONAL ELECTRICAL CODE, designates as hazardous (classified) any location in which a combustible material is or may be present in the atmosphere in sufficient concentration to produce an ignit ible mixture. Article 500 defines three major categories of hazardous location:

Class I, in which the combustible material is a gas or vapor;

Class I I , in which the combustible material is a dust;

Class I l l , in which the combustible material is a fiber or f lying.

This recommended practice is limited to Class I hazardous (classified) locations.

2-1.2 The intent of Article 500 is that electrical equipment and systems in hazardous (classified) locations should not provide a means of ignition for an ignit ible mixture that may be present.

2-1.3 Within each Class, Article 500 recognizes two degrees of hazard: Division 1 and Division 2. In Division 1, an ignit ible mixture is l ikely to be present continuously or intermittently under normal conditions of operation, repair, maintenance, or leakage. In Division 2, an ignit ible mixture is l ikely to be present under abnormal operating conditions, such as failure of process equipment.

2-1.3.1 Electrical installations in Division i locations are designed so that normal operation or failure of any part of the electrical system wil l not release flame, sparks, or hot gases, nor wil l i t result in surface temperatures high enough to ignite the surrounding atmosphere.

NFPA 497

2-1.3.2 Installations for Division 2 locations are designed and arranged so that normal operation of the electrical system does not provide a source of ignition. Protection against ignition during electrical breakdown is not provided. However, electrical breakdowns are suff iciently r a r ~ h a t the chances of one occuring simultaneously with accidental release of an ignit ible mixture is extremely remote. Arcing and sparking devices are permitted only i f suitably enclosed or i f the sparks are of insufficient energy to ignite the mixture.

2-1.4 Electrical installations for areas classified as hazardous may be designed in various manners. No single manner is best in all respects or for all types of equipment used in a chemical process plant. Explosionproof electrical equipment, Types X and Y purged electrical equipment, and intr insical ly safe electrical equipment are applicable to both Division 1 and Division 2 locations. Nonsparking electrical equipment and other less restrictive equipment, as specified in NFPA 70, NATIONAL ELECTRICAL CODE, are permitted in Divison 2 locations.

2-1.5 Factors such as corrosion, weather, maintenance, equipment standardization and interchangeability, and possible process changes or expansion frequently dictate the use of special enclosures or installations for electrical systems. However, such factors are outside the scope of this recommended practice, which is concerned entirely with the proper application of electrical equipment to avoid ignition of flammable mixtures.

2-1.6 Locations which do not need to be classified as Division i or Division 2 are "nonclassified."

2-2 Conditions Necessary for Ignition.

2-2.1 In a Class I location, three conditions must be satisfied for ignition to occur:

a. A combustible gas or vapor must be present.

b. The gas or vapor must be mixed with air in the proportions required to produce an ignit ible mixture. Further, within the context of this recommended practice, a sufficient quantity of this mixture must be present in the atmosphere surrounding the electrical equipment.

c. There must be a release of energy intense enough to cause ignition of the mixture. Within the context of this recommended practice, the energy release is understood to originate within the electrical system.

2-2.2 In classifying a particular location, the f i r s t condition, presence of a combustible gas or vapor, is significant in determining the correct Division. As described in 2-1.3, the presence of an ignit ible mixture during normal conditions of operation, repair, maintenance, or leakage of the process equipment either continuously or intermittently, calls for a Division 1 classification. In other words, combustible gas or vapor is assumed to be present at any time; all that is necessary for elec%rical ignition is failure of "the electrical system. I f combustible gas or vapor is only present as a result of abnormal operation or breakdown of equipment, then the location is designated Division 2; ignition wil l only occur i f there is simultaneous failure of the electrical system and the equipment.

2-2.3 The second condition, presence of an ignit ible mixture, is important in determining the boundaries of the hazardous location, i .e . , how far i t extends. The quantity of material that may be released, i ts physical and chemical properties, and the natural tendency of gases and vapors to disperse all must be recognized.

2-3 Behavior of Gases, Vapors, and Liquids.

2-3.1 Lighter-than-Air Gases. Gases whose densities are less than that of air wil l tend to dissipate rapidly once released to the atmosphere. They wil l not affect as great an area as heavier-than-air gases or vapors. Except in enclosed spaces, such

gases seldom accumulate to form an ignit ible mixture near grade level, where most electrical installations are located.

2-3.2 Heavier-than-Air Gases. Gases whose densities at ambient te~erature are greater than that of air tend to fal l to grade level when released from a container. Under stagnant conditions, diffusion is slow and depends on the particular characteristics of the gas. The gas may remain for a significant period of time, unless disturbed by natural or forced ventilation, which wil l assist the dispersion process. -

2-3.2.1 As the gas diffuses into the surrounding air, the density of the mixture approaches that of air, which also enhances dispersion.

NFPA 497

2-3.2.2 The temperature of the gas, as i t leaves i t s container, must be considered. A gas whose density at ambient temperature is greater than that of air wi l l rise i f i t is heated to a temperature high enough to decrease its density below that of the surrounding atmosphere. The decrease in density causes an increase in the diffusion rate and the gas mixes with the surrounding atmosphere more rapidly. On the other hand, gases which are lighter than air at ambient conditions wil l behave like heavier-than-air gases i f they are very cold. The decreased temperature results in an increased density. I f the density is greater than that of air, the gas sinks to grade level and the rate of diffusion is decreased.

2-3.3 Compressed Liquefied Gases. These gases are stored above their normal boiling point, but kept in the liquid state by pressure. When released from this pressure, the liquid immediately expands and vaporizes, creating large volumes of cold gas. The cold gases behave like heavier-than-air gas, until they warm, mix with air, and dissipate.

2-3.4 Cryogenic Liquids and Other Cold Liquefied Flammable Gases. Cryogenic liquids are generally handled below -IuI°C (-150°F). Those which are combustible, such as hydrogen, carbon monoxide, and natural gas, behave like flammable liqulds when they are spilled. Small spills will immediately vaporize; but larger spills will remain in the liquid state, spreading horizontally and freezing the ground beneath, thus inhibiting heat transfer. As the liquid absorbs heat, i t vaporizes and rises. This results in a vertical cylinder of gas in the ignitable range wnich diffuses as i t rises."

Some liquefied flan~nable gases are stored at low temperatures (above -lOlOC (-150OF)) and pressures close to atmospheric. These materials will behave as described above. Examples of such gases are anhydrous ammonia, propane, ethane, ethylene, and propylene.

2-3.5 Flammable and Combustible Liquids. Flammable and combustible liquids are categorized by NFPA 30, Flammable and Combustible Liquids Code, as follows:

Class I: those having flash points below 100OF (37.8°C);

Class I I : those having flash points at or above 100°F (37.8°C) and below 140°F (60°C):

Class I l l : those having flash points at or above 1400F (6O°C).

2-3.5.1 When released in appreciable quantity, a Class I liquid wil l begin to evaporate at a rate that depends on its vo la t i l i t y : the lower the flash point, the greater the vo la t i l i t y ; hence, the faster the evaporation. The vapors of Class I liquids form ignit ible mixtures with air at ambient temperatures more or less readily. Even when evolved rapidly, the vapors tend to disperse rapidly, becoming diluted to a concentration below the lower flammable l imit. Until this dispersion takes place, however, these vapors wil l behave like heavier-than-air gases. Class I liquids normally will produce ignit ible mixtures that wil l travel some f in i te distance from the point of origin; thus, they wil l normally require area classification for proper electrical system design.

2-3.5.2 With Class I I liquids, the degree of hazard is lower because the vapor release rate is low at the normal handling and storage temperatures. In general, these liquids wil l not form ignitible mixtures with air at ambient temperatures unless heated above their flash points. Also, the vapors wil l not travel as far because they tend to condense as they are cooled by ambient air. Class I I liquids should be considered capable of producing an ignit ible mixture near the point of release when handled, processed, or stored under conditions where the liquid may exceed its flash point.

2-3.5.3 Class I l l liquids are subdivided into two classes: I l IA and I I IB. Class I l IA liquids have flash points at or above 140OF (6OOC), but below 2OOOF (93.4oc). These liquids do not form ignit ible mixtures with air at ambient temperatures unless heated above their flash points. Furthermore, the vapors COOl rapidly in air and condense. Hence, the extent of the area requiring electrical classification wil l be very small or nonexistent.

Class IIIB liquids have flash points at or above 200°F (93.4°C). These liquids seldom evolve enough vapors to form ignit ible mixtures even when heated and are seldom ignited by properly installed and maintained general purpose electrical equipment.

2-3.5.4 The density of air saturated with combustible vapor at ambient temperature is generally less than 1.5 times the density of air. However, when the vapor is diluted with enough air to form an ignit ible mixture, the density of the mixture approaches that of air.

27

NFPA 497

2-4 Division 1 ClassifiedLocations.

2-4.1 The decision to classify a location as hazardous is based upon the possibil i ty that a flammable mixture may be present. Having decided that a location should be classified, the next step is to determine the degree of hazard: Is the location Division 1 or Division 2?

2-4.2 As stated in 2-1.3, a condition for Division 1 is whether the location is l ikely to have an ignit ible mixture present under normal conditions. For instance, the presence of flammable vapors in the v ic in i ty of open-dome loading of flammable liquid tank trucks is normal and requires a Division 1 classification.

2-4.3 Normal does not necessarily mean the situation that prevails when everything is working properly• For instance, there may be cases in ~hich frequent maintenance and repair are necessary. These are viewed as normal and, i f quantities of flammable liquid, gas or vapor are released as a result of the maintenance, the location is Division 1. However, i f repairs are not usually required between turnarounds, the need for repair work is considered abnormal. In any event, the classification of the location, as related to equipment maintenance is influenced by the maintenance procedures and frequencies.

2-5 Division 2 Classified Locations.

2-5.1 The criterion for a Division 2 location is whether the location is l ikely to have ignit ible mixtures present only under abnormal conditions. The term "abnormal" is used here ~n a limited sense and does Dot include a major catastrophe.

2-5-2 As an example, consider a vessel containing liquid hydrocarbons (the source) which releases flammable material only under abnormal conditions. In this case, there is no Division 1 location because the vessel is normally t ight. To release vapor, the vessel would have to leak, and that would not be normal. Thus, the vessel is surrounded by a Division 2 location.

2-5.3 Process equipment does not fai l often• Furthermore, the electrical installation requirements of NFPA 70, NATIONAL ELECTRICAL CODE, for Division 2 locations are such that an ignitlon-capable spark wil l occur only in the event of a breakdown of the electrical system. Otherwise, any spark wil l be contained within a suitable enclosure. On a realist ic basis, the possibil i ty of simultaneous failure of operating equipment and electrical equipment is very remote; this just i f ies the recognition and acceptance of the Division 2 concept.

2-5.4 The Division 2 classification is equally applicable to conditions not involving equipment failure. For example, consider a location classified as Division I because of the normal presence of an ignit ible mixture. Obviously, one side of the Divison i boundary cannot be normally hazardous and the opposite side never hazardous• Therefore, a surrounding Division 2 location separates the Division 1 location from the nonhazardous location. Another example would be a point emission source which releases combustible vapors during normal operation. This source is surrounded by a Division 1 location which, in turn, is surrounded by a larger, concentric Divison 2 location. Division 2 is the transition zone and the area outside the Division 2 location is not classified.

2-5.5 In cases in which an unpierced barrier, such as a blank wall, completely prevents the spread of gas or vapor, area classification does not extend beyond the barrier•

2-6 Nonclassified Locations.

2-6.1 Experience has shown that the release of ignitible mixtures from some operations and apparatus is so infrequent that area classification is not necessary. For example, i t is not usually necessary to classify the following locations where combustible materials are processed, stored, or handled:

Locations that are adequately ventilated, where combustible materials are contained within suitable, well-maintained, closed piping systems.

Locations that are not adequately ventilated but where piping systems are without valves, f i t t ings, flanges, and similar accessories that may be prone to leaks.

Locations where combustible materials are stored in suitable containers.

2-6.2 "Adequate ventilation" is defined by NFPA 30, Flammable and Combustible Liquids Code, as that which is sufficient to prevent accumulation of significant quantities of vapor-air mixtures in concentrations over 25 percent of the lower flammable l imit.

2-6.3 An "adequately ventilated location" is one of the following:

(a) An outside location.

NFPA 497

(b) A building, room, or space which is substantially open and free from obstruction to the natural passage of air, either vert ical ly or horizontally. Such locations may be roofed over with no walls, may be roofed over and closed on one side, or may be provided with suitably designed windbreaks.

(c) An enclosed or pa[t ly enclosed space provided with mechanical ventilation equivalent to natural ventilation. The mechanical ventilation system must have adequate safeguards against failure.

2-6.4 Open flames and hot surfaces associated with the operation of certain equipment, such as boilers and fired heaters, provide inherent thermal ignition sources. Electrical classification is not appropriate in the immediate v ic in i ty of these fac i l i t ies. Consideration should be given, however, to potential leak sources in pumps, valves, etc. or in waste product and other fuel feed lines to flame- or heat-producing equipment to avoid installing electrical devices which could then become primary ignition sources for such leaks.

2-7 Extent of Classified Location.

2-7.1 The extent of a Division 1 or Division 2 location requires careful consideration of the following factors:

- the flammable or combustible material; - the vapor density of the material; - the temperature of the material;

process or storage pressure; size of release; ventilation.

2-7.2 The f i r s t step is to identify the materials being handled and their vapor densities. Hydrocarbon vapors and gases are generally heavier than air, while hydrogen and methane are lighter than air. The following guidelines apply:

In the absence of walls, enclosures, or other barriers, and in the absence of air currents or similar disturbing forces, the gas or vapor wil l disperse. Heavier-than-air vapors wil l travel primarily downward and outward; lighter-than-air vapors wil l travel upward and outward. I f the source of the vapors is a single point, the horizontal area covered by the vapor wil l be a circle.

For heavier-than-air vapors released at or near grade level, ignit ible mixtures are most l ikely to be found below grade level; next most l ikely at grade level; with decreasing likelihood of presence as height above grade increases. In the open, away from the immediate point of release, freely drif t ing gases or vapors from a source near grade have seldom reached ignition sources at elevations more than 6 or 8 f t (1.8 to 2.4 m) above grade. For lighter-than-air gases, the opposite is true: there is l i t t l e or no hazard at and below grade, but greater hazard above grade•

In cases where the source of vapor is above grade or below grade or in cases where the gas or vapor is released under pressure, the limits of the classified location is altered substantially. Also, a very mild breeze may extend these limits. However, a stronger breeze may accelerate dispersion of gases or vapors so that the extent of the classified location is greatly reduced. Thus, dimensional limits recommended for Division 1 or Division 2 zones must be based on experience, rather than relying solely on the theoretical diffusion of vapors.

2-7.3 The degree to which air movement and material vo la t i l i t y combine to effect the extent of the classified location can be il lustrated by two experiences monitored by combustible gas detectors. Gasoline spilled in a sizeable open manifold pi t gave no indication of ignit ible mixtures beyond 3 or 4 f t (0.9 to 1.2 m) from the pi t when the breeze was 8 to 10 (13 to 16 km/hr) mph. A sl ightly smaller pool of a more volati le material, blocked on one side, was monitered during a gentle breeze. At grade, vapors could be detected for approximately 100 f t (30 m) downwind; however, at 18 in.(46 cm) above grade there was no indication of vapor as close as 30 f t (9 m) from the pool.

These examples show the great var iabi l i ty that may be present in situations of this type and points out again that careful consideration must be given to a largenumber of factors when classifying areas.

2-7.4 The size of a building and its design may influence considerably the classification of the enclosed volume. In the case of a small inadequately ventilated sampling or testing room, i t may be appropriate to classify the entire internal volume as Division 1.

28

NFPA 497

2-7.5 When classifying buildings, careful evaluation of prior experience with the same or similar installations should be made. I t is not enough to merely identify a potential source of vapor within the building and proceed immediately to defining the extent of a Division i or Division 2 location. Where experience indicates that a particular design concept is sound, a more hazardous classification for similar installations is not Justified. Furthermore, i t is conceivable that a location might be reclassified from Division 1 to Division 2, or from Division 2 to nonhazardous, based on experience.

2-7.6 Correctly evaluated, an installation wil l be found to be a mult ip l ic i ty of Division I locations of very limited extent. Probably the most numerous of offenders are packing glands. A packing gland leaking a quart per minute (360 gals per day) (0.95 l i te r per minute) would certainly not be commonplace. Yet, i f a quart bottle were emptied each minute outdoors, the zone made hazardous would be d i f f i cu l t to locate with a combustible gas detector.

2-7.7 The volume of liquid or vapor released is of extreme importance in determining the extent of a hazardous location and i t is this consideration which necessitates the greatest application of sound engineering judgment. However, one cannot lose sight of the purpose of this judgment: the location is classified solely for the installation of electrical equipment.

Chapter 3 Determining the Degree and Extent of Hazardous (Classified) LoCations

3- i Diagrams and Recommendations.

3-1.1 This chapter contains a series of diagrams which i l l u s t r a t e the recommended extent of c lass i f ied locations around typ ica l sources of flammable gases or vapors. These locations may be assumed to contain an i g n i t i b l e atmospheric mixture under the condit ions described. Some of the diagrams are for s ingle-point sources, others apply to mul t ip le sources in an enclosed space or in an operating area. The bases for the diagrams are explained in Section 3-2.

3-1.2 The intended use of the diagrams is to aid in developing e lec t r i ca l c lass i f i ca t ion maps of operating un i ts , process plants, or bui ld ings. Elevations or sectional views may be required where d i f f e ren t c lass i f i ca t ions apply at d i f f e ren t levels.

3-1.3 An operating uni t w i l l have many interconnected sources of combustible mater ia l , including pumps, compressors, vessels, tanks, and heat exchangers. These w i l l , in turn, present sources of leaks such as flanged and screwed connections, f i t t i n g s , valves, meters, etc. Thus, considerable judgment w i l l be required to establ ish the boundaries of the Divis ion I and Divis ion 2 locat ions.

3-1.4 In some cases, indiv idual c lass i f i ca t ion of a mult i tude of point sources within an operating uni t is neither feasible nor economical. In such cases, the ent i re un i t may be c lass i f ied as a single source en t i t y . However, th is should be considered only a f ter a thorough evaluation of the extent and in teract ion of the various sources both wi th in the uni t and adjacent to i t .

3-1.5 In developing these diagrams, vapor density is general ly assumed to be greater than that of a i r . L ighter - than-a i r gases, such as hydrogen and methane, w i l l qui te readi ly disperse and the diagrams for l i gh te r - than-a i r gases should be used. However, i f such gases are being evolved from the cryogenic state ( i . e . , l iquef ied hyrdogen or LNG), caution must be exercised because, for some f i n i t e period of time, these gases w i l l be heavier than a i r due to the i r low temperature when f i r s t released.

3-2 Bases fo r Recommendations.

3-2.1 The practices of the petroleum re f in ing industry are published in the American Petroleum I n s t i t u t e ' s RP 500A, Recommended Practice fo r Class i f icat ion of Locations for E lec t r i ca l Ins ta l la t ions in Petroleum Refineries. These practices are based on a survey and an analysis of theprac t i ces of a large segment of the industry, experimental data, and careful weighing of per t inent factors. Refinery operations are characterized by the handling, processing, and storage of large quant i t ies of mater ia ls, often at elevated temperatures. The recommended l imi ts of c lass i f ied locations for re f ine ry ins ta l la t ions may therefore be s t r i c t e r than are warranted fo r more t rad i t i ona l chemical processing f a c i l i t i e s that handle smaller quant i t ies .

3-2.2 Various codes, standards, and recommended practices of the National Fire Protection Association include recommendations for c lass i fy ing hazardous locations. These recommendations are based on many years of experience. NFPA 30, Flammable and Combustible Liquids Code, and NFPA 58, Standard for the Storage and Handling of Liquefied Petroleum Gases, are two of these documents.

29

NFPA 497

3-2.3 Continuous process plants and large batch chemical plants may be almost as large as re f iner ies and should, therefore, fo l low the practices of the re f in ing industry. The volume of leakage from pump and agi ta tor shaft packing glands, piping f langes, and valves increases propor t ionate ly with process equipment size and f low rate, as does the t ravel distance and area of dispersion from the discharge source. S imi la r ly , the volume of the leakage, the t ravel distance, and the area of dispersion a l l increase as operating pressure increases.

3-2.4 In deciding whether to use an overal l p lant c lass i f i ca t i on scheme or indiv idual equipment c l ass i f i ca t i on , process equipment size, f low rate, and pressure should be taken in to considerat ion. Generally speaking, for small or batch chemical plants, point source diagrams can be used; for large, high pressure plants, the API recommendations are more sui table. Table 3-2, gives ranges of process equipment size, pressure, and f low rate for equipment and piping handling flammable or combustible l iqu ids or gases.

3-2.5 The great major i ty of chemical plants f a l l in the moderate range of size, pressure, and f low rate for equipment and piping handling flammable or combustible l iqu ids or gases. However, since a l l cases are not the same, sound engineering judgment is required.

Table 3-2

Relat ive Magnitudes of Process Equipment and Piping Handling Flammable Liquids or Gases

Units Small/Low Moderate Large/High

Process Equipment Size gal <5000 5000 to 25000 >25000

Pressure psi <100 100 to 500 >500 Flow Rate gpm <100 100 to 500 >500

3-3 Procedure for Classifying Locations. The following procedure should be used for each room, section, or area being classified.

3-3.1 Step One -- Need for Classification. The area should be classified i f the answer to either of the following questions is "Yes":

(a) Are flammable liquids or flammable gases l ikely to be present?

(b) Are combustible liquids l ikely to be handled, processed, or stored at temperatures above their flash points?

3-3.2 Step Two -- Assignment of Division Classification. Assuming an affirmative answer to Step One, the following questions should be answered to determine the correct Division classification.

3-3.2.1 Division i locations are distinguished by a "Yes" answer to any one of the following questions:

(a) Is an ignit ible atmospheric mixture l ikely to exist under normal operating conditions?

(b) Is an ignit ible atmospheric mixture l ikely to occur frequently because of leakage due to maintenance and repairs?

(c) Would failure of process equipment, storage vessels, or piping systems be l ikely to cause a failure of the electrical system simultaneous with the release of the combustible material?

(d) Is a piping system containing a combustible material in an inadequately ventilated space and does the system contain valves, f i t t ings, or screwed or flanged f i t t ings that are l ikely to leak?

(e) Is the space or area in question below grade level such that vapors may accumulate there?

3-3.2.2 Division 2 locations are distinguished by a "Yes" answer to any of the following questions:

(a) Is a process equipment system containing a combustible material in an inadequately ventilated space, but the piping system is not l ikely to leak?

(b) Is a piping system containing a combustible material in an inadequately ventilated space and the material can only escape during abnormal situations, such as failure of a gasket or packing?

(c) Is the location adjacent and open to a Division 1 location or can gas or vapor be transmitted'from a Division i location to the location in question by trenches, pipes, or ducts?

(d) I f mechanical ventilation is used, can failure or abnormal operation of the ventilation equipment permit an ignit ible atmospheric mixture?

3-3.3 Step Three -- Extent of Classified Location. The extent of the classified location may be determined by applying, with sound engineering judgment, the distances recommended in the diagrams contained in this chapter.

NFPA 497

3-4 Index of Class i f icat ion Diagrams. This section contains descript ions of the c lass i f i ca t ion diagrams which fo l low. Most of the diagrams include a table of "suggested a p p l i c a b i l i t y , " corresponding to Table 3-2. The check marks show the ranges of process equipment size, pressure, and f lowrate where each diagram most appropr iate ly appl ies. Unless otherwise stated, these diagrams assume that the material being handled is a flammable l i qu id .

Figure 3-4.1 shows a source of leakage located outdoors, at grade. The material being handled is a flammable l i qu id .

Figure 3-4.2 shows a source of leakage located outdoors, above grade. The material being handled is a flammable l iqu id .

Figure 3-4.3 shows a source of leakage located indoors, at f loor level . Adequate ven t i l a t i on is provided. The material being handled is a flammable l iqu id .

Figure 3-4.4 shows a source of leakage located indoors, above f l oo r level . Adequate ven t i l a t ion is provided. The material being handled is a flammable liquid.

Figure 3-4.5 shows a source of leakage located indoors, at floor level, adjacent to an opening in an exterior wall. Adequate ventilation is provided. The material being handled is a flammable liquid.

Figure 3-4.6 shows a source of leakage located indoors, at floor level, adjacent to an opening in an exterior wall. Ventilation is not adequate. The material being handled is a flammable liquid.

Figure 3-4.7 shows a source of leakage located outdoors at grade. The material being handled may liquefied or compressed flammable gas,

Figure 3-4.8 shows a source of leakage grade. The material being handled may liquefied or compressed flammable gas,

be a flammable liquid or a or a cryogenic liquid.

located outdoors above be a flammable liquid or a or a cryogenic liquid.

Figure 3-4.9 shows a source of leakage located outdoors at grade. The material being handled is a flammable liquid. (From API RP5OOA.)

Figure 3-4.10 shows a source of leakage located outdoors above grade. The material being handled is a flammable liquid. (From API RP5OOA.)

Figure 3-4.11 shows a source of leakage located indoors adjacent to an opening in an exterior wall. Ventilation is not adequate. The material being handled is a flammable l iqu id ,

Figure 3-4.12 shows a source of leakage located indoors adjacent to an opening in an ex ter io r wal l . Adequate ven t i l a t ion is provided. The material being handled is a flammable l iqu id .

Figure 3-4.13 shows mul t ip le sources of leakage, located both at grade and above grade, in an outdoor process area. The material being handled is a flammable l iqu id .

Figure 3-4.14 shows mul t ip le sources of leakage, located both at grade and above grade, in an outdoor process area. The material being handled is a flammable l iqu id .

Figure 3-4.15 shows mul t ip le sources of leakage, located both at and above grade, in an outdoor process area. The material being handled is a flammable l iqu id .

Figure 3-4.16 shows mul t ip le sources of leakage, located both at and above f loor level , in an adequately vent i la ted bui ld ing. The material being handled is a flanmlable l iqu id .

Figure 3-4.17 shows a product.dryer located in an adequately vent i la ted bui ld ing. The product dryer system is t o t a l l y enc losed . The material being handled is a sol id wet with a flammable l iqu id .

Figure 3-4.18 shows a plate and frame f i l t e r press. Adequate ven t i l a t i on is provided. The material being handled is a sol id wet. with a flammable l iqu id .

Figure 3-4.19 shows a product storage tank located outdoors, at grade. The material being stored is a flammable l iqu id . (From API RP5OOA.)

Figure 3-4.20 shows tank car (or tank truck) loading and unloading via a closed transfer system. Material is transferred only through the dome. The material being transferred is a flammable l iqu id .

Figure 3-4.21 shows tank car (or tank truck) loading and unloading via a closed transfer system. Material is t ransferred through the bottom f i t t i n g s . The material being t ransferred is a flammable liquid. "

Figure 3-4.22 shows tank car (or tank truck) loading and unloading via an open transfer system. Material is transferred either through the dome or the bottom f i t t ings. The material being transferred is a flamamble liquid.

NFPA 497

Figure 3-4.23 shows tank car (or tank truck) loading and unloading via a closed transfer system. Material is transferred only through the dome. The material being transferred may be a liquefied or compressed flammable gas or a cryogenic liquid.

Figure 3-4.24 shows a drum f i l l i ng station located either outdoors or indoors in an adequately ventilated building. The material being handled is a flammable liquid.

Figure 3-4.25 shows an emergency impounding basin o~ oil/water separator and an emergency or temporary drainage ditch oil/water separator. The material being handled is a flammable liquid.

Figure 3-4.26 shows a liquid hydrogen storage fac i l i t y located outdoors or indoors in an adequately ventilated building. This diagram applies to liquid hydrogen only.

Figure 3-4.27 shows a gaseous hydrogen storage fac i l i t y located outdoors or indoors in an adequately ventilated building. This diagram applies to gaseous hydrogen only.

Figure 3-4.28 shows an adequately ventilated compressor shelter. The material being handled is a lighter-than-air gas. (From AP! RPSOOA.)

Figure 3-4.29 shows an inadequately ventilated compressor shelter. The material being handled is a lighter-than-air gas. (From API RPSOOA.)

Figure 3-4.30 shows storage tanks for the storage of cryogenic and other cold liquefied flammable gases. (From NFPA 59A, Standard for the Production, Storage and Handling of Liquefied Natural Gas.)

Figure 3-4.31 shows a source of leakage from equipment nandling liquefied natural gas or other cold liquefied flammable gas, and located outdoors, at or above grade. (From NFPA 59A, Standard for the Production, Storage and Handling of Liquefied Natural Gas.)

Figure 3-4.32 shows a source of leakage fr~n equipment handling liquefied natural gas or other cold liquefied flammable gas and located indoors in an adequately ventilated building. (From NFPA 59A, Standard for the Production, Storage and Handling of Liquefied Natural Gas.)

Figure 3-4.33 shows the classified zones around liquefied natural gas operating bleeds, drips, vents and drains both outdoors, at or above grade, and indoors in an adequately ventilated buildin 9. This diagram also applies to other cold liquefied flammable gases. (From NFPA 59A, Standard for the Production, Storage and Handling of Liquefied Natural Gas.)

Source 3'

Grade LIE ~l~Beiow grade location such

as a sump or trench.

m Div=slon 1 [ ] Divis=on 2

MATERIAL: Flammable Liquid

SMALL/ MODERATE LARGE/ LOW HIGH

PROCESS EQUIP. SiZE ' / , /

PRESSURE ~

ELOWRATE ~ %~

Figure 3-4.1 Leakage Source Located Outdoors, at Grade.

30

NFPA 497 NFPA 497

/>~\'K<

~ S o u r c e

elow grade location such as a sump or trench.

• Division I ~ Division 2

MATERIAL" Flammable Liquid

SMALL/ MODERATE LOW

PROCESS EOUIP" V / SIZE

LARGE/ HIGH

PR ESSU RE V /

FLOWRATE ~

" ~ . \ \

G r a d e ~

Below grade location such [ ] Division 1 [ ] Division 2 as a sump or trench.


SMALL/ MODERATE I LARGE/ LOW HIGH

PROCESSEOUIP. V / ~v/ SIZE

PRESSURE ~ / %/

F LOWRATE V t V /

Figure 3-4.4 Leakage Source Located Indoors, Above Floor Level. Adequate Ventilation is Provided

Figure 3-4.2 Leakage Source Located Outdoors, Above Grade.

G r a d e ~

/2,"

• Below grade location such as a sump or trench.

• [] Division 1 [ ] Division 2


SMALL/ MODERATE LOW

PROCESS EQUIP. %/ s,zE

PRESSORE , / , /

FLOWRATE , / ~/

LARGE/ HIGH

I P(erced~ + ~ wall I Sou,ce - ~ F--5 ' ~,~,erced

G r . o \ I ,

~ 2 5 ' Max - ~ ~ - B e l o w grade location such %

as a sump or trench, [ ] D=vision 1 [ ] Division 2


PROCESS EQUIP• SIZE

PRESSURE

FLOWRATE

SMALL/ MODERATE LOW

, / , /

, / , /

, / , /

LARGE/ HIGH

Figure 3-4.5 Leakage Source Located Indoors, at Floor Level, Adjacent to Opening in Exterior Wall

Adequate Ventilation is Provided

Figure 3-4.3 Leakage Source Located Indoors, at Floor Level. Adequate Ventilation is Provided.

31

NFPA 497 NFPA 497

Pierced --Unpierced wall arl

Gr ade.,~l 8"

*1,0'Max t. Le,,th;n J L~oo, I . . . . ide~-~ 25' N i ' 4 ~ 2 5 ' / TM I=, 1 'o

building / Below grade location such as a sump either in division 1 or division 2 portion of building.

m Division I ~ ' ~ Division 2



PROCESS EQUIP. ~ SIZE

PRESSURE ~ ~ / /

FLOWRATE ~v / V /

15'

Source

Grade

/ ' / ' ~ " B~elow arad e

• Dwision 1 ~ J Division 2

grade location such as a sump or trench.

Figure 3-4.6 Leakage Source Located Indoors, at Floor Level, Adjacent to Opening in Exterior Wall. Adequate Ventilation

Is Not Provided

NOTE: I f building is small compared to size of equipment and leakage can f i l l the building, the entire building

i n t e r i o r is c lass i f ied Div is ion 1.

Source

15'

Grade~

',.. X- ,< /

I O l v i s i o n 1 ~ Division 2

j \\vv-" -Below grade location such as a sump or trench•

MATER IAL: Flammable Liquid, Liquefied Flammable Gas Compressed Flammable Gas, and Cryogenic Liquid


PROCESS EQUIP. S,ZE

PRESSURE

FLOWRATE ~ /

Figure 3-4.7 Leakage Source Located Outdoors, at Grade

MATERIAL: Flammable Liquid, Liquefied Flammable Gas Compressed Flammable Gas, and Cryogenic Liquid


PROCESS EQUIP. s ,zE ,,/

PRESSURE

FLOWRATE ~ /

Figure 3-4.8 Leakage Source Located Outdoors, Above Grade

Source -I

IF ~2s'~4

Below grade location such as a sump or trench•

• Division 1 [ ] Division 2

25"~ ~ rad~

• Additional division 2 location extra precaution where large release of volatile products may occur.

MATERIAL: Flammable Liqu=d


PROCESS EQUIP• SIZE

PRESSURE

FLOWRATE

Figure 3-4.9 Leakage Source Located Outdoors, at Grade

32

NFPA 497 NFPA 497

~ " 25' -~

Source- 25'

T

~0'

Division 1

--Below grade location such as a sump or trench. .

Division 2

Additional division 2 location extra precaution where large release of volatile products may occur.

MATERIAL: Flammable L=quid


PROCESS EQU IP. SIZE

PRESSURE ~ %//

FLOWRATE /

/ Pierced ~ p wall ierced

Grade

1B"

\\'¢~1 ,o J_ L0ssthao 1 ~ " I Outs,de-i: 2B' ILl I~

building \ ~" Below grade location such

as a BUmp or trench.

• Division ] ~ Division 2

MATE R IAL' Flammable Liquid


PROCESS EQUIP. SIZE

PRESSURE

FLOWRATE

v ~

Figure 3-4.12 Leakage Source Located Indoors, Adjacent to Opening in Exterior Wall. Adequate Venti lation Is Provided.

Figure 3-4.10 Leakage Source Located Outdoors, Above Grade. (From APt Recommended Practice 50OA)

wail ~ Unplerced

F Grade I

~"L'°'--~ I Outside I

building Below grade location such as a Bump or trench.

Division 1 ~ ' ~ Division 2

MATERIAL: Flammable L=quid


PROCESS EQUIP• SIZE V / V /

I-

PRESSURE

FLOWRATE %//

Figure 3-4.11 Leakage Source Located Indoors, Adjacent to Opening in Exterior Wall. Adequate Venti]ation

Is Not Provided. (From API Recommended Practice 500A)

i i 3' Radius I I I r~---------------------]l I I I /-Sohd deck

exchanger level Pipeways' Piplng ] t l d ~;~:~.~ll L / 2 = Rad,u, above w ~ t n o u t ~ ~ v a l v e s , t • o= ; pumps etc

flanges

• F-,0'~l f ~ F.,o "t ,v~,v tGrade 18" J Below grade location such as a sump or trench. L-Pump alley

Division I ~ Dwlslon 2



PROCESS EQUIP. S,ZE , / , / PRESSURE ~, / V /

F LOWRATE . ~ V /

Figure 3-4.13 Multiple Leakage Sources, Both At and Above Grade in Outdoor Process Area

33

NFPA 497

Diwsion 1 ~ Division 2

Additional division 2 area where release may be large


as a sump or trench.


PROCESS EQUIP. S,~E ~/ ~/

PBESSORE ~ ~/

E 3' Radius from vent

~ . ~ / ~ " ~ - - 5' Radius from vent

5' Raoius ~ • ~/////~v~-~ ~ 5' Radius

Emergency dump tank ~ ~/S,'~/~ ~'~//"/~.~ 1 1 - - ~ 5 " Radius

Grade ~"///'~// ~ 1

~e,o~ade,ooo,,on~ L--------- ~5" -----22 such as sump |

• Dwtston 1 ~ DIViSion 2

PROCESS EQUIP. SfZE

PRESSURE

FLOWRATE

MATERIAL:FlammableLiquid

SMALL/ MODERATE LOW

, / , /

, / , /

LARGE/ HIGH

NFPA 497

Figure 3-4.14 Multiple Leakage Sources, Both At and Above Grade, in Outdoor Process Area

Figure 3-4.16 Multiple Leakage Sources, Both At and Above Floor Level, Located Indoors. Adequate Ventilation

Is Provided

® . TLruii:: .... Solid deck ~ ~ ~

///y.//~ ~ _ _ . ~ ~///'~. ~ ~'/..A ~--~Open grid

Emergency " ~ #///h I i L , , . . ~ . ~'~///~ ~ ~ . ~ 3' Radi . . . . . . . . . . I dump tan.... ~' / / / ' / / /~/. I I 77////Ck'//, Y////~ ~ ~ valves d~v~s,on 2

~ ,s,, ~ ~ - ~ s " Below grade locations such as sump /

m Oivision 1 ~7~ Divtsion 2

E

11

G~S BLAHKET EVF~TOR AND BIN

OR

PROCESS EQUIP. SIZE

PRESSURE

FLOWRATE


SMALL/ MODERATE LOW

, / v ~

, / , /

, / , /

LARGE/ HIGH

OIVISION I ~ DIVISIOn4 2

MATERIAL" Solids Wet with Flammable Liquid

Figure 3-4.17 Totally Enclosed Product Dryer Located in Adequately Ventilated Building

Figure 3-4.15 Multiple Leakage Sources, Both At and Above Grade, in Outdoor Process Area.

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NFPA 497 NFPA 497

~ Division I ~ Divl£1on 2

MATERIAL: Solids Wet with Flammable Liquid

ion

3'

Vapor return line ~ + Liquid transfer line

3' Radius 3' Radius "

DCvls~on 2

MATERIAL. Flammable Liquid

Figure 3-4.18 Plate and Frame Fi l ter Press Provided with Adequate Ventilation

Figure 3-4.20 Tank Car/Tank Truck Loading and Unloading vla Closed System. Transfer through Dome Only.

Tank within dike I Tank in open (no dike)

I I [ / 5' Radius around vent

~,oF~ •

~ / ~ Surface of

Dike ~ Below grade trench

~ ' ~ Division I ~ Division 2


Figure 3-4.19 Storage Tanks, Outdoors at Grade. (From API Recommended Practice 500A)

GI , ,

Llquid transfer h n e ~

I - 10' Radius --

Vapor return line

~ ~ 3' Radius

1 11]

~ Z ~ DlVlSlOn 2


Figure 3-4.21 Tank Car/Tank Truck Loading and Unloading via Closed System. Bottom Product Transfer Only.

35

NFPA 497 NFPA 497

A

/ / / / / / '

• Below grade location such as surnp

• Division 1 ~ Division 2

MATERIAL' Flammable Liquid

uid transfer line

Radius

Radius

~ k Grade

Fill p l p e ~

Vent 5' Radius ~ / / ~ ~ / , ~ / / / / .

®

3' Ra , , 18"

~ J ~ ~ .~Grade - -

Figure 3-4.22 Tank Car/Tank Truck Loading and Unloading Via Open System. Top or Bottom Product Transfer.

~ Division I Division 2


Vapor return h n e - ~ / . Z . ~ ' 1 ~ / " Liquid transfer pJpe

' 15' Radius

5' Radtus 5' Radius

"/,'/Z///.'///W//'///,'//~.'/,'HZZ/,~NZr.'i¢/,/////Z ,~X~'~ Below grade location such as sump

Division 1 ~ Division 2

MATERIAL: Liquehed Gas Compressed Gas Cryogenic Liquid

Figure 3-4.23 Tank Car/Tank Truck Loading and Unloading Via Closed System. Transfer Through Dome Only.

Figure 3-4.24 Drum Fil] ing Station, Outdoors or Indoors with Adequate Ventilation

11 4//AI ' ' / ~ - 18" Grade

Gradq

- - - 1 ~ Below grade location

ZL,qu,d such as sump

W Division I ~ Dwision 2


Figure 3-4.25 Emergency Impounding basin or Oil Water Separator (Top) and Emergency or Temporary Drainage

Ditch Oil/Water Separator (bottom).

NOTE: This diagram does not apply to open pits or open vessels, such as dip tanks or open mixing tanks, that normally contain flammable liquids.

36

NFPA 497 NFPA 497

,. R a 0 , u 0 ~ ~ , ~ .....

25' Radius ~ ~ , C Q ~ ~

Point where connections Liquid hydrogen are regularly made storage container

• Division 1 FT~-Divis ion 2

Figure 3-4.26 Liquid Hydrogen Storage System Located Outdoors or in an Adequately Ventilated Building

AREA OF . INADEQUATE ' " VENTILATION .~ ~u

.o~o~oE / II ~// / / / / / / / / / / / / /~ ~ o ENCLOSED AREA ~ 0

SOURCE ~

GRADE

MATERIAL: Lighter-than-A~r Gas

Figure 3-4.29 Inadequately Ventilated Compressor Shelter (API Recommended Practice 500A)

15' Radtus ~ 15 Radt

15' R a d i u s ~ ~ S o u r c e

-o ,0e

Outdoor Indoor adequate ventilation

Division 2

Figure 3-4.27 Gaseous Hydrogen Storage System, Located Outdoors or Indoors in an Adequately Ventilated Building.

B O13"O M OF ENCLOSED AREA ~ . ~

SOURCE II F / ~

~ DIVISION 2

D <

. ts. . . r

MATERIAL: Lighter-than-Air Gas

Area withm 5 ft (1.5 m) of relief valve ~<,~,, ~ _

~ - - - ~ c ~ ,

i j ~ ~ D,v~sioo 1 Below grade pit or trench ~ Diwsion 2

Dike Hmght Less than Distance from Container to Dike (H Less than X).

Area within 5 ft (1.5 m) of relief valve \ K%\?~ .~-~-, 15 FI (4.5 m)

';,:," ;;-... ~ Division 2 co . . . .

--~ x ~ -

D=ke Height Greater than Distance from Container to Dike (H Greater than X).

Area within 5 ft (1.5 m) of relief valve Cx "

/ ~ e l I ~D,v,s,on, ,/ I I ~ Div,sion 2

Figure 3-4.30 Storage Tanks for Cryogenic Liquids. (From NFPA 59A, Standard for the Production.

Storage and. Handling of Liquefied Natural Gas)

Figure 3-4.28 Adequately Ventilated Compressor Shelter (APt Recommended Practice 500A)

37

NFPA 497 NFPA 497

Indoors wl th adequate ventilation

.~,~Q~. ~,~:" ~--,,~ {- Below grade location such as

Division I ~ Division 2 a surnp or trench

Figure 3-4.31 Leakage Source from Equipment Handlin~ Liquefied Natural Gas. Source Is Located At or

Above Grade.

D,v,s,on 2

Figure 3-4.32 Leakage Source from Equipment Handling Liquefied Natural Gas in an Adequately

Ventilated Building.

~ 1 5 Ft radius

, ~ 5 Ft radius

®

Outdoors at or above glade

• Oivlslon I ~ Divlsion 2

Figure 3-4.33 Operating Bleeds, grips, Vents from Liquefied Natural Gas Equipment

Chapter 4 Referenced Publications

4-i The following documents or portions thereof are referenced within this recommended practice and should be considered part of the recommendations of this document. The edition indicated for each reference is current as of the date of the NFPa issuance of this document. These references are listed separately to faci l i ta te updating to the latest edition by the user.

4-1.1 NFPA Publications, National Fire Protection Association, Batterymarch Park, Quincy, MA 02269.

NFPA 30-1984, Flammable and Combustible Liquids Code NFPA 58-1983, Standard for the Storage ano Handling of Liquefied

Petroleum Gas NFPA 59A-1985, Standard for the Production, Storage and Handling

of Liquefied Natural Gas (LNG) NFPA 70-1984, NATIONAL ELECTRICAL CODE.

4-1.2 APt Publication. The following publication is available from the American Petroleum Insti tute, 2101 L Street, NW, Washington, DC 20037.

APt Recommended Practice 500A, Classification of Locations for Electrical Installations in Petroleum Refineries, Fourth Edition, 1982.

Appendix A Referenced Publications

A-1 The following documents or portions thereof are referenced within this recommended practice for informational purposes only and thus shall not be considered part of the recommendations of this document. The edition indicated for each reference is current as of the date of the NFPA issuance of this document. These references are listed separately to fac i l i ta te updating to the latest edition by the user.

A-I.1 NFPA Publications. National Fire Protection Association, Batterymarch Park, Quincy, MA 02269.

NFPA 33-1985, Standard for Spray Application Using Flammable.and Combustible Materials

NFPA 34-1982, Standard for Dip Tanks Containing Flmnmable or Combustible Liquids

NFPA 35-1982, Standard for Organic Coatings Manufacture NFPA 36-1985, Standard for Solvent Extraction Plants NFPA 45-1982, Standard on Fire Protection for Laboratories Using

Chemicals NFPA 50A-1984, Standard for Gaseous Hydrogen Systems at Consumer

Sites NFPA 50B-1985, Standard for Liquefied Hydrogen Systems at

Consumer Sites.

38

PART I I

497M- 1 - (1-3): Reject SUBMITTER: D. B. Wechsler, Union Carbide Corp. RECOMMENDATION: Add new definition as follow:

Combustible Dust. Any f inely divided solid, 420 microns or less in diameter ( i .e . , material passing through a US No. 40 Standard Sieve) which is capable of oxidation at a rate sufficient enough to produce heat and usually light either as a glow or flames. SUBSTANTIATION: Not only is the term "combustible dust" used throughout the 497M document in general statements, but i t is also used in defining "Conductive Dusts" and "Nonconductive Dusts". Because of the nature of 497M, i t is important that the user properly understand the terminology used for proper application of the documents information. Thus along with the other definitions contained in Section 1-3, the need exists for the definition of a "combustible dust".

The basis for the definition is taken from the work of the NFPA 68 "Explosion Ventinbg" committee wherein the term "dust" ( i .e . , any f inely divided solid, 420 microns or less in diameter . . . . ), "combustible" ( i .e . , capable of undergoing combustion), and "combustion" ( i .e . , the chemical process of oxidation that occurs at a rate fast enough to produce heat and usually l ight, either as glow or flames) are defined. COMMITTEE ACTION: Reject. COMMITTEE COMMENT: The definitions of these two words ("combustible" and "dust") are adequately covered by the normal definition, appearing in most dictionaries.

497M- 5 - (1-3): Accept SUBL~ITTER: Technical Committee on Electrical Equipment in Chemical Atmospheres RECOMMENDATION: Revise definition of Class I I , Division 2 to read:

9A location where combustible dust is not normally in the air in quantities sufficient to produce explosive or ignitable mixtures and dust accumulations are normally insufficient to interfere with the normal operation of electrical equipment or other apparatus, but combustible dust may be in suspension in the air as a result of infrequent malfunctioning of handling or processing equipment and where combustible dust accumulations on, in, or in the v ic in i ty of the electrical equipment may be sufficient to interfere with the safe dissipation of heat from electrical equipment or may be ignitable by abnormal operation or failure of electrical equipment. SUBSTANTIATION: Current definition does not agree with that in the 1984 edition of NFPA 70. COMMITTEE ACTION: Accept.

497M- 2 - (Table 3-5, Note 2): Reject SUBMITTER: D. B. Wechsler, Union Carbide Corp. ~ A T I O N : Eliminate this note. SUBSTANTIATION: The t i t l e of Table 3-5 informs the user that the items listed are "selected, nonconductive dusts, classified as Group G." Thus while i t may be possible for the referenced carbonaceous dust materials to be conductive and hence be different from the listed variety, differences may also exist for other dusts listed in this table depending on the real world applications. Further using the classic Frank-Kamenetski thermal theory, i t can be demonstrated that as the conductivity of a dust increases, so wil l the ignition temperature. The notation thus provides misinformation to the user regarding the conductive type of carbonaceous dusts, because i t does not give ignition temperature values for the different variety of carbonaceous dusts. COMMITTEE ACTION: Reject. COMMITTEE COMMENT: The Committee is reluctant to eliminate the footnote because i t warns the user of a particular problem with those particular dusts.

Editorial Corrections

The Committee has identified the following editorial corrections to NFPA 497M.

i - i Revise f i r s t sentence to read: " . . . classification into the groups established by the National Electrical Code for proper selection of electrical equipment in hazardous (classified) locations."

Definition of Class I , Division 2: Insert comma after the word "processed" in line two. Insert comma after the word "vapors" in line three.

I-2 In last sentence, change "those" to "these." 2-2 In the f i r s t sentence, change "culled" to "selected." 2-3 In f i r s t sentence, delete comma. 2-4 In f i r s t sentence, delete comma. 2-5 In f i r s t sentence, delete comma.

497M- 4 - (Table 2-3): Accept SUBMITTER: Technical Committee on Electrical Equipment RECOMMENDATION: Change the autoignition temperature for hydrogen from "752°F (4OO°C)" to "932°F (500°C) ''.

Change t~e autoignition temperature for isoprene from "743°F (395°C)" to "428°F (220°C) ''. SUBSTANTIATION: The new data are the most widely agreed upon temoeratures. COMMITTEE ACTION: Accept.

PART I I I

491M- 1 - (Entire Document): Accept SUBMITTER: Technical Committee on Hazardous Chemical Reactions RECOMMENDATION: Reconfirm the 1975 Edition of NFPA 491M, Manual on Hazardous Chemical Reactions. SUBSTANTIATION: NFPA 491M is s t i l l suitable for current use. COMMITTEE ACTION: Accept. COMMITTEE COMMENT:

497M- 6 - (Tables 2-3 and 2-4): Accept SUBMITTER: Technical CoR~nittee on Electrical.Equipment in Chemical Atmospheres RECOMMENDATION: Move the entry for Isoamyl Alcohol from Table 2-3 to Table 2-4.

Move the entries for l-nitropropane and 2-nitropropane from "Table 2-4 to Table 2-3. SUBSTANTIATION: The flashpoints for these entries are:

Isoamyl Alcohol F.P. 109OF 1-Nitropropane F.P. 96°F 2-Nitropropane F.P. 75°F


497M- 7 - (Tables 2-3, 2-4, and 2-5): Accept SUBMITTER: Technical Committee on Electrical Equipment in Chemical Atmospheres RECOMMENDATIONS: Move Tripropylamine from Table 2-3 to Table 2-4.

Move Cumene from Table 2-4 to Table 2-3. Move Ethylene Chlorohydrin from Table 2-4 to Table 2-5. Change AIT for Benzene (Table 2-3) from 1040°F (560°C) to

928OF (498oc). SUBSTANTIATION: Flash point for Tripropylamine is 105°F.

Flash point for Cumene is 96°F. Flash point for Ethylene Chlorohydrin is 140°F. AIT listed in NFPA 325M for Benzene is 928OF.


39

PART IV

40E- 1 - (Entire Document): Accept SUBMITTER: Technical Conlnittee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Reconfirm NFPA 40E as suitable for continued use. SUBSTANTIATION: No proposals to amend NFPA 40E were received from the public or the Technical Committee during the period in which proposals were solicited, other than the following Technical Co~ittee proposals for editorial corrections. COMMITTEE ACTION: Accept.

40E- 2 - (I-1.3): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Add the following parenthetical:

"(See NFPA 40, Standard for the Storage and Handling of Cellulose Nitrate Motion Picture Film.)" SUBSTANTIATION: Editorial correction. COMMITTEE ACTION: Accept.

40E- 3 - (Chapter 2, Tit le): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Delete footnote to t i t l e . SUBSTANTIATION: Footnote is unnecessary. COMMITTEE ACTION: Accept.

40E- 4 - (4-4.6): Accept SUBMI1-FER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Move footnote to Appendix A and number i t A-4-4.6.

Add asterisk after 4-4.6. SUBSTANTIATION: This footnote belongs in an explanatory Appendix. COMMITTEE ACTION: Accept.

40E- 5 - (Chapter 5 (New) and Appendix A): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Add new Chapter 5 as follows:

Chapter 5 Referenced Publications 5-1 The following documents or portions thereof are referenced

within this Code and shall be considered part of the requirements of this document. The edition indicated for each reference is current as of the date of the NFPA issuance of this document. These references are listed separately to faci l i tate updating to the latest edition by the user.

5-1.1 NFPA Publications. National Fire Protection Association, Batterymarch Park, Quincy, MA 02269.

NFPA 10-1981, Standard for Portable Fire Extinguishers NFPA 13-1985, Standard for the Installation of Sprinkler Systems NFPA 40-1982, Standard for the Storage of Cellulose Nitrate

Motion Picture Film NFPA 70-1984, National Electrical Code NFPA 80-1983, Standard for Fire Doors and Windows NFPA 101-1985, Life Safety Code NFPA 211-1984, Standard for Chimneys, Fireplaces, and Vents NFPA 220-1985, Standard on Types of Building Construction NFPA 251-1985, Standard Methods of Fire Tests of Building

Construction and Materials. RECOMMENDATION: Add new Chapter 5 as follows and delete existing Appendix A. SUBSTANTIATION: Comply with Standards Council directive to move mandatory references in body of standard. COMMITTEE ACTION: Accept.

NFPA 43B PART V

43B- 1 - (Entire Document (New)): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Adopt the following new NFPA document, NFPA 43B, Code for the Storage of Organic Peroxide Formulations. SUBSTANTIATION: The Committee has recognized the need for a storage code for commercially available formulations of organic peroxides. Considerable effort was required to develop a logical classification scheme for the many organic peroxides available, to correlate the classification scheme with the chemical characteristics of the various formulations and with the containers in which they are shipped, and to develop storage requirements consistent with the classification.

The Committee also wishes to point out that the classification system is based, in part, on a series of fu l l scale f i re tests conducted by the organic peroxide producers. COMMITTEE ACTION: Accept.

NFPA 43B

Code for the Storage of Organic Peroxide Formulations

1986 Edition

Chapter i General

i-1 Scope.

1-1.1 "This code shall apply only to commercially available organic peroxide formulations in approved packages, as defined in Section 1-5.

I-1.2 This code shall not apply to the storage of such formulations in process areas where they are manufactured or used.

1-1.3 This code does not apply to organic peroxide formulations that are capable of detonation in their normal shipping containers under conditions of f i re exposure. Such formulations shall be handled and stored as Class A explosives in accordance witb NFPA 495, Code for the Manufacture, Transportation, Storage and Use of, Explosive Materials.

I-2 Purpose. The purpose of this code is to provide reasonable requirements for the safe storage of commercially available formulations containing organic peroxides.

1-3 Applicability of Other Documents. The requirements of NFPA 30, Flammable and Combustible Liquids Code, and NFPA 231, Standard on General Storage, shall apply where applicable and where they are more restrictive than this code.

1-4 Equivalency. Nothing in this standard is intended to prevent the use of systems, methods, or devices which provide equivalent protection from f i re and explosion, provided that suitable data is available to demonstrate equivalency.

1-5" Definitions. For the purpose of this code, the following terms shall have the meanings given below.

Approved. Acceptable to the "authority having jurisdict ion."

NOTE: The National Fire Protection Association does not approve, inspect or cert i fy any installations, procedures, equipment, or materials nor does i t approve or evaluate testing laboratories. In determining the acceptability of installations or procedures, equipment or materials, the authority having jurisdiction may base acceptance on compliance with NFPA or other appropriate standards. In the absence of such standards, said authority may require evidence of proper installation, procedure or use. The authority having jurisdiction may also refer to the listings or labeling practices of an organization concerned with product evaluations which is in a position to determine compliance with appropriate standards for the current production of listed items.

Authority Having Jurisdiction. The "authority having jurisdiction" is the organization, office or individual responsible for "approving" equipment, an installation or a procedure.

40

NFPA 43B NOTE: The phrase "authority having jurisdiction" is used in NFPA documents in a broad manner slnce jurisdictions and "approval" agencies vary as de their responsibilities. Where public safety is primary, the "authority having jurisdiction" may be a federal~ state, local or other regional department or individual such as a f i re chief, f i re marshal, chief of a f i re prevention bureau, labor department, health department, building of f ic ia l , electrical inspector, or others having statutory authority. For insurance purposes, an insurance inspection department, rating bureau, or other insurance company representative may be the "authority having jurisdiction." In many circumstances the property owner or his designated agent assumes the role of the "authority having jurisdiction"; at government installations, the commanding officer or departmental of f ic ia l may be the "authority having jurisdiction."

Deflagration. Propagation of a combustion zone at a velocity which is less than the speed of sound in the unreacted medium.

Detonation. Propagation of a combustion zone at a velocity which is at or above the speed of sound in the unreacted medium.

Explosive Decomposition. Rapid chemical reaction resulting in a large, almost instantaneous, release of energy. The term includes both deflagration and detonation.

Incompatible Materials. Materials which can in i t iate, catalyze or accelerate the decomposition of organic peroxide formulations or which can cause hazardous reactions when in contact with such formulations.

Labeled. Equipment or materials to which has been attached a label, symbol or other identifying mark of an organization acceptable to the "authority having jurisdiction" and concerned with product evaluation, that maintains periodic Inspection of production of labeled equipment or materials and by whose labeling the manufacturer indicates compliance with appropriate standards or performance in a specified manner.

Listed. Equipment or materials included in a l i s t published by an organization acceptable to the "authority having jurisdiction" and concerned with product evaluation, that maintains periodic inspection of production of listed equipment or materials and whose listing states either that the eqdipment or material meets appropriate standards or has been tested and found suitable for use in a specified manner.

NOTE: The means for identifying listed equipment may vary for each organization concerned with product evaluation, some of which do not recognize equipment as listed unless i t is also labeled. The "authority having jurisdiction" should ut i l ize the system employed by the l ist ing organization to identify a listed product.

Organic Peroxide. Any organic compound having a double oxygen or "peroxy" (-0-0-) group in i ts chemical structure.

Organic Peroxide Formulation.* A pure organic peroxide or a mixture of one or more organic peroxides with one or more other materials in various combinations and concentrations.

Organic Peroxide Storage Area. An area used for the storage of organic peroxide formulations.

Shall. Indicates a mandatory requirement.

Should. Indicates a recommendation or that which is advised but not required.

I-6" Classification of Organic Peroxide Formulations. For the purpose of this code, organic peroxide formulations shall be classified according to the system described in this section. The system is based on the behavior of certain specific formulations in their U.S. Department of Transportation approved shipping containers and under conditions of f i re exposure. (See Appendix B for classification of Typical Organic Peroxide Formulations.)

1-6.1 "Class I" shall describe those formulations which are capable of deflagration, but not detonation.

i-6.2 "Class I I " shall describe those formulations which burn very rapidly and which present a severe reactivity hazard.

1-6.3 "Class I l l " shall describe those formulations which burn rapidly and which present a moderate reactivity hazard.

1-6.4 "Class IV" shall describe those formulations which burn in the same manner as ordinary combustibles and which present a minimal reactivity hazard.

1-6.5 "Class V" shall describe those formulations which do not sustain combustion and which present no reactivity hazard.

NFPA 43B

i-7 Classification of Storage Facil it ies.

i-7.1 ~ storage refers to storage in the same room or inside area, but physically separated by distance from incompatible materials. Si l ls, curbs, intervening storage of nonhazardous compatible materials, and aisles may be used as aids In maintaining spacing. (See Chapter 3.)

i-7.2 Cut-off storage refers to storage in the same building or inside area, but physically separated from incompatible materials by partitions or walls. (See Chapter 4.)

1-7.3 Detached storage refers to storage in a separate building or in an outside area located away from all other structures. (See Chapter 5.)

Chapter 2 Basic Requirements

2-i Identification of Materials in Storage. All storage areas containing organic peroxide formulations shall be conspicuously identified by the words "Organic Peroxides" and by the class, as defined in Section i-6.

2-1.1" When organic peroxide formulations having different classifications as defined by Section i-6 are stored in the same area, the area shall be marked for the most severe class present.

2-1.2 Packages containing organic peroxide formulations shall be individually marked with the chemical name of the organic peroxide or with other information suitable and adequate to allow proper area classification as required by this section.

2-1.3 Packages containing organic peroxide formulations that require temperature control shall be marked with the recommended storage temperature range.

2-2 Employee Instruction. Personnel involved in operations in organic peroxide storage areas shall be instructed in proper and safe handling of such materials, proper use of personal protective equipment, proper and safe disposal of spilled material, and proper emergency procedures, Manufacturers' instructions shall be consulted for each specific formulation.

2-3 Building Construction. Any construction materials that may come in contact with organic peroxide formulations shall be compatible with the materials stored.

2-4 Heating and Cooling.

2-4.1 Storage areas shall be maintained within the recommended storage temperature range for the materials stored.

2-4.2 When the required storage temperature range extends beyond normal ambient temperatures, high or low temperature l imit switches, as applicable, shall be provided in addition to the normal temperature controls. These limit switches shall actuate an alarm arranged to ensure prompt response.

2-4.3 Heating systems shall use hot water, low pressure (less than 15 psig (103.4 kPa-gage)) steam, or indirectly heated warm air. Cooling systems shall not ut i l ize direct expansion of a flammable gas.

2-4.4 Heating coils, radiators, air diffusers, cooling coils, piping and ducts shall be installed so as to prevent direct contact with containers and to. prevent overheating or overcooling of the materials stored.

2-5 Electrical Installations.

2-5.1 Electrical installations shall meet all applicable requirements of NFPA 70, NATIONAL ELECTRICAL CODE o.

2-5.2 The interior of any refrigerator o~ freezer cabinet used for the storage.of Class I, I I , or I l l organic peroxide formulations shall be considered a Class I, Group D, Division 1 location as defined in Article 500 of NFPA 70; NATIONAL ELECTRICAL CODE. Any electrical equipment installed in the interior of such cabinets shall be approved for such use and shall be installed according to the requirements of Article 501 of NFPA 70, ELECTRICAL ELECTRICAL CODE.

2-5.3* Any area used for the storage of any organic peroxide formulation that is considered to be a flammable liquid according to NFPA 321, Basic Classification of Flammable and Combustible Liquids, or which evolves flammable gases when heated to 38oc shall be considered a Class I, Group D, Division 2 location as defined by Article 500 of NFPA 70, NATIONAL ELECTRICAL CODE. Any electrical equipment installed in such areas snall be approved for such use and shall be installed according to the requirements of Article 501 of NFPA 70, NATIONAL ELECTRICAL CODE.

2-6 Ventilatlon. Mechanical exhaust ventilation, with suction pick-ups at floor level, shall be provided for the storage areas described in 2-5.3. Installations shall meet the requirements of 4-4.1.6 of NFPA 30, Flammable and Combustible Liquids Code.

41

NFPA 43B

2-7 Smoking. Smoking shall be prohibi ted in a l l organic peroxide storage areas. "No Smoking" signs shall be placed conspicuously wi thin and at a l l entrances to storage areas.

2-8 Maintenance Operations.

2-8.1 Maintenance operations in organic peroxide storage areas shall be subject to pr io r review by and approval of supervisory personnel.

2-8.2 Cutting and welding operations in organic peroxide storage areas shall not be conducted un t i l a l l organic peroxide formulations have been removed. Cutting and welding operations shall be conducted according to the requirements of NFPA 51B, Standard for Fire Prevention in Use of Cutting and Welding Processes.

2-9 Fire Protect ion.

2-9.1" Manual f i r e f igh t ing equipment shal l be provided and maintained according to the requirements of NFPA 10, Standard for Portable Fire Extinguishers, and NFPA 14, Standard for the Ins ta l la t ion of Standpipe and Hose Systems.

2-9.2 Where required by other provisions of th is code, automatic spr inklers and water spray systems shall be designed and insta l led according to the requirements of NFPA 13, Standard for the Ins ta l l a t i on of Spr inkler Systems, and NFPA 15, Standard for Water Spray Fixed Systems fo r Fire Protect ion, and shall provide the fo l lowing discharge densi t ies:

Class I 0.40 gpm/sq, f t . (16.3 Lpm/m~) Class I I 0.35 gpm/sq, f t . (14.3 Lpm/m~) Class I l l 0.30 gpm/sq, f t . (12.2 Lpm/m~) Class IV 0.25 gpm/sq, f t . (10.2 Lpm/m ()

2-9.2.1 The system shall be designed to provide the required discharge density over a 3000 sq f t (279 m 2) area or over ~he entire area of any building of less than 3000 sq f t (279 mL).

2-9.3 Where required water supplies for automatic sprinklers, f i re hydrants, etc. shall be provided in accordance With NFPA 24, Standard for the Installation of Private Fire Service M~ins and Their Appurtenances, and shall be capable of supplying the anticipated demand for at least 90 min.

2-10 Housekeeping and Waste Disposal.

2-10.1 Any accumulation of combustible waste in organic peroxide storage areas shall be prohibited.

2-10.2" Spilled material and leaking or damaged containers and packages shall immediately be removed to a safe location for disposal.

2-10.3 Specific disposal procedures shall be established for all organic peroxide storage areas. Disposal procedures shall conform to all applicable federal, state and local regulations and with the manufacturers' recommendations.

2-11 Storage Limitat ions.

2-11.1 Storage of organic peroxide formulations shall be l imited to those areas within the scope of th is code. The maximum allowable quant i t ies of organic peroxide formulations that can be stored in a single area or bui ld ing shall depend on the c lass i f i ca t ion of the formulations and the c lass i f i ca t ion of the storage f a c i l i t y , as set fo r th in Table 2-11.

Table 2-11 Maximum Allowable Quantity, Pounds

Class AS

I NS 0 AS 0

I I NS 0 AS 4,000

I I I NS 1,500 AS 50,000

IV NS 100,000 AS UNL

V NS/AS UNL

Segregated Cut- Detached Storage- Off Minimum Separation***

Storage Storage 50 Ft 100 Ft 150 Ft

0 1000 4,000 10,000 2000* 2000 20 ,000 175,000

- 2,000 20,000 80,000 500,000 50,000 i00,000 200,000 UNL

3,000** 70,000 200,000 750,000 100,000 200,000 UNL UNL

200,000 300,000 500,000 1,000,000 UNL UNL UNL UNL

UNL UNL UNL UNL

*Interior walls must have a blast resistance of 3 psig. Exterior walls shall be provided with deflagration vents. (See Chapter 4).

** - May be increased to 20,000 Ibs i f the walls or partitions providing the cut-off have a f i re resistance of at least four hours.

*** - Minimum separation means the distance from the property line which is or can be built upon, including the opposite side of a public way or from the nearest important building on the same property.

UNL - Unlimited NS - Nonsprinklered AS - Automatic sprinkler protection provided. For SI Units:

I lb = 0.454 Kg; i f t = 0.305 m. 42

NFPA 43B

2-11.3" When two or more different classes of organic peroxide formulations are stored in the same area, the maxlmum quantity permitted shall be limited to the sum of the proportional amounts that each class bears to the maximum permitted for that class. The total of the proportional amounts shall not exceed 100 percent.

2- i I .4 The quantities of organic peroxide formulations in storage may deviate from the requirements of this section and other sections of this code only when the storage area is protected by a specially engineered f i re protection system acceptable to the authority having jurisdiction. The adequacy of any such system shall be supported by appropriate technical documentation.

2-11.5 Organic peroxide formulations shall not be stored where they may be exposed to explosive materials.

2-12 Storage Arrangements.

2-12.1 Storage shall be arranged to fac i l i ta te manual access and handling, to maintain pile stabi l i ty , to minimize breakage and spillage, and to promote good housekeeping.

2-12.2 A clear space of at least 2 f t (.6 m) shall be maintained between organic peroxide storage and uninsulated metal walls.

2-12.3 Incompatible materials shall not be stored in the same storage area with organic peroxide formulations.

Exception: As permitted in accordance with 3-4.2.

2-12.4 Only closed containers and packages shall be permitted in storage areas.

2-12.5 Bulk storage in bins or piles shall not be permitted.

2-12.6 Storage of Class V organic peroxide formulations need only meet the requirements of NFPA 231, Standard for General Storage, or NFPA 231C, Standard for Rack Storage of Materials, as applicable.

2-12.7 Storage of Class IV organic peroxide formulations shall meet the following requirements:

(a) Bags, drums, and other containers and packages shall not be stored more than 10 f t (3 m) high. Pile width shall.not exceed 16 f t (5 m).

(b) At least one main aisle, at least 4 f t (1.2 m) wide, shall be provided to divide the storage area. All other aisles shall be not less than 3 f t wide (0.9 m).

2-12.8 Storage of Class I l l and Class I I formulations shall meet the following requirements:

(a) Bags and other containers and packages shall not be stored more than 8 f t (2.4 m) high. Pile width shall not exceed 8 f t .

(b) 55 gal. (208 L) drums shall be stored one high only.

(c) At least one main aisle, at least 6 f t (1.8 m) wide, shall be provided to divide the storage area. All other aisles shall be not less than 4 f t (1.2 m) wide.

2-12.9" Storage of Class I formulations shall meet the following requirements:

(a) Bags, drums, and other containers and packages shall not be stored more than 6 f t (1.8 m) high. Pile width shall not exceed 4 f t (1.2 m).

(b) At least one main aisle, at least 8 f t (2.4 m) wide, shall be provided to divide the storage area. All other aisles shall be not less than 4 f t (1.2 m) wide.

Chapter 3 Segregated Storage

3-1 Scope. This chapter shall apply to the storage of organic peroxide formulations when stored under segregated conditions as defined in Section 1-7 of this code and in quantities not exceeding those shown in Table 2-11.

3-2 Basic Requirements. The basic requirements set forth in Chapter 2 shall apply to the segregated storage of organic peroxide formulations.

3-3 Building Construction. I f there are any floors or open spaces located below the organic peroxide storage area, the floor of the storage area shall be made watertight and shall be provided with drainage that leads to a safe location. Every means shall be taken to ensure that spilled material cannot run down into areas below the organic peroxide storage area.

NFPA 43B 3-4 Storage Arrangement.

3-4.1 A minimum 8 f t (2.4 m) clear space shall be maintained between organic peroxide storage and any other storage.

3-4.2 Flammable liquids or incompatible materials shall not be stored within 25 f t (7.6 m) of the organic peroxide storage area unless separated by a wall having a f i re resistance rating of at least one hour, as measured by the procedure described in NFPA 251, Standard Methods of Fire Tests of Building Construction and Materials, and sealed or curbed where necessary.

3-4.3 Segregated storage areas shall meet all applicable requirements of NFPA 231, Standard for General Storage, or NFPA 231C, Standard for Rack Storage of Materials, as applicable.

3-4.4 A clear space of at least 4 f t (1.2 m) shall be maintained between organic peroxide storage and any walls of combustible or limlted-combustible construction. (See NFPA 220, Standard on Types of Building Construction.)

3-5 Fire Protection. Automatic sprinkler protection shall be provided for segregated storage areas, in accordance with subsections 2-9.2 and 2-9.3, under the following conditions:

(a) Wherever storage of Class IV formulations exceeds 100,000 Ib (45,400 Kg).

(b) Wherever storage of Class I l l formulations exceeds 1,500 Ib (681 Kg).

(c) Wherever Class I I formulations are stored, regardless of Floor area or quantity.

Chapter 4 Cut-off Storage

4-i Scope. This chapter shall apply to the storage of organic peroxide formulations when stored under cut-off conditions as defined in Section. l-7 of this code and in quantities not exceeding those shown in Table 2-11.

4-2 Basic Requirements. The basic requirements set forth in Chapter 2 shall apply to cut-off storage of organic peroxide formulations.

4-3 Building Construction.

4-3.1 Cut-off storage areas shall be single story, without basements or crawl spaces.

4-3.2 Where Class I organic peroxide formulations are stored, internal walls shall be capable of withstandin 9 without failure an internal overpressure of 3 psig (20.7 kPa-gage).

4-3.3 Where any Class I, Class I I or any refrigerated organic peroxides are stored, any wall, roof, or ceiling which exposes another occupied building shall be capable of withstanding an internal pressure of 125 psf (6 kPa) without failure.

4-3.3.1 For Class I, Class I I , or any refrigerated Class I l l organic peroxide formulation, the storage area shall be provided with deflagration vents at a ratio of n~t l~ss than one square foot of free vent area to 30 cu f t (1 m~/9m m) of building or room volume. (See NFPA 68, Guide for Deflagration Venting, For information on vent design.)

4-3.4 Any walls common with another building shall have a f i re resistance of at least two hours, as measured by the procedure described in NFPA 251, Standard Methods of Fire Tests of Building Construction and Materials.

4-3.4.1 Any door or window openings in such walls shall be protected by approved f i re doors and f i re windows suitable for the opening and installed according to NFPA 80, Standard for Fire Doors and Windows.

4-3.5 The storage area shall be provided with vents to discharge decomposition gases. Roof vents, eave vents, louvers, etc. are acceptable. The vent ratio for decomposition vents shall be not less than 1 sq f t of free vent area to 100 sq f t (1 m2/100 m 2) of floor area.

Exception: This requirement does not apply to buildings where temperature control is maintained in accordance with Section 2-4.

4-4 Storage Arrangement. A clear space of at least 4 f t shall be maintained between organic peroxide storage and any walls of combustible or limited-combustible construction, (See NFPA 220, Standard on Types of Building Construction.)

NFPA 43B 4-5 Fire Protection.

4-5.1 Automatic sprinkler protection in accordance with 2-9.2 and 2-9.3 shall be provided for all storage areas of combustible construction, regardless of the Class of formulation stored, and for all storage areas of noncombustible Construction where any quantity of Class I organic peroxide formulations are stored. Automatic sprinkler protection shall also be provided for all storage areas of noncombustible construction when quantities exceed:

2000 Ib (908 Kg) for Class I f ; 3000 Ib (1362 Kg) for Class I l l ; 200,000 Ib (90,800 Kg) for Class IV.

Chapter 5 Detached Storage

5-i Scope. This chapter shall apply to the storage of organic peroxide formulations when stored under detached conditions as defined in Section 1-7 in quantities and at separation distances as specified in Table 2-11.

5-2 Basic Requirements. The basic requirements set forth in Chapter 2 shall apply to detached storage of organic peroxide formulations.

5-3 Building Location.

5-3.1 Detached storage buildings shall be separated from normally occupied buildings and from property lines by the distances specified in Table 2-11.

5-3.2 For Classes I I , I l l , and IV organic peroxide formulations, detached storage buildings shall be separated from each other by at least 50 f t (15.3 m) i f the total quantity stored exceeds the maximum quantity allowed in Table 2-11.

5-3.3 For Class I organic peroxide formulations, detaciled storage buildings shall be separated from each other in accordance with Table 5-3.3

Table 5-3.3 Separation of Individual Storage ~uildings

NS Quantity, Ibs 1,000 4,000 I0,000 Distance, f t 20 75 100

AS Quantity, Ibs 2,000 20,000 175,000 Distance, f t 20 75 100

For SI units: I I b = 0.454 k9; I f t : 0.3U5 m.

5-4 Building Construction and Ut i l i t ies.

5-4.1 Detached storage buildings shall be single story, without basement or crawl space.

5-4,2 Nonsprinklered buildings for storing more than 5000 Ib (2270 Kg) Of organic peroxide formulations shall meet the following requirements:

(a) Construction materials shall be noncombustible.

(b~ Roofs shall be of light-weight construction, suitably insulated.

5-4.3 The storage building shall be provided with vents to discharge decomposition gases. Roof vents, eave vents, louvers, etc. are acceptable. The vent ratio for decomposition vents shall be not less than i sq f t of free vent area to 100 sq f t ( i m2/100 m 2) of floor area.

Exception: This requirement does not apply to buildings where temperature Control is maintained in accordance with Section 2-4.

5-4.4 For storage of Class I and I I organic peroxide formulations, the storage building shall be provided with deflagration vents at a ratio of not less than I sq f t of free vent area to 30 c u f t of building volume (I m2/9 m~). (See NFPA 68, Guide for Deflagration Venting, for information on vent design.)

5-4.5* Sun shields such as those il lustrated in Figure A-5-4.5 may be used For detached storage buildings in those areas where the temperature inside the storage building may approach or exceed the maximum recommended storage temperature.

5-5 Storage Arrangement.

5-5.1 No incompatible materials shall be stored in the same detached storage building with organic peroxide formulations.

5-5.1.1 When flammable or combustible liquids are stored with organic peroxide formulations, the requirements of NFPA 30, Flammable and Combustible Liquids Code, shall apply when they are more restrictive than this code.

43

NFPA 43B 5-6 Fire Protection. Where required, automatic sprinkler systems and their water supplies shall meet the requirements of 2-9.2 and 2-9.3.

5-6.1 When required for Class I formulations in quantities exceeding 2000 lbs (908 Kg), automatic sprinkler protection shall be open head deluge type, designed and installed in accordance with NFPA 13, Standard for the Installation of Sprinkler Systems.

Chapter 6 Referenced Publications

6-1 The following documents or portions thereof are referenced within this code and shall be considered part of the requirements of this code. The edition indicated for each reference is current as of the date of the NFPA issuance of this document. These references are listed separately to faci l i ta te updating to the latest edition by the user.


NFPA 10-1984, Standard for Portable Fire Extinguishers

NFPA 13-1985, Standard for the Installation of Sprinkler Systems

NFPA 14-1983, Standard for the Installation of Standpipe and Hose Systems

NFPA 15-1985, Standard for Water Spray Fixed Systems for Fire Protection

NFPA 24-1984, Standard for the Installation of Private Fire Service Mains and Their Appurtenances

NFPA 30-1984, Flammable and Combustible Liquids Code

NFPA 51B-1984, Standard for Fire Prevention in Use of Cutting and Welding Processes.

NFPA 70-1984, National Electrical Code

NFPA 80-1983, Standard for Fire Doors and Windows

NFPA 231-1985, Standard on General Storage

NFPA 231C-1980, Standard for Rack Storage of Materials

NFPA 251-1985, Standard Methods of Fire Tests of Building Construction and Materials

NFPA 495-1985, Code for the Manufacture, Transportation, Storage and Use of Explosive Materials

Appendix A Supplementary Information

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

A-I-5 Organic Peroxide Formulation. Terms such as "accelerator," "catalyst," " in i t ia tor , " etc. are sometimes used to describe organic peroxide formulations. These terms are misleading because they can also refer to materials that are not or do not contain organic peroxides, some of which may present increased hazard when mixed with organic peroxides.

A-1-6 Test procedures described in Bulletin 19-A, "Suggested Relative Hazard Classifications of Organic Peroxides," published by the Society of the Plastics Industry are useful in determining the classification of organic peroxide formulations.

A-2-1.1 The classification system described in Section 1-6 is used only to determine the storage requirements established by this code. I t is not meant to be a substitute for the hazard identification system established by NFPA 704, Standard System for the Identification of the Fire Hazards of Materials. Since the hazard characteristics of organic peroxide formulations vary widely depending on the type of organic peroxide, the diluent, and their relative concentrations, each specific formulation wil l have to be rated individually according to the cri teria established in NFPA 704.

A-2-5.3 The Setaflash Closed Tester (ASTM D3278 -- 1978, Standard Test Methods for Flash Point of Liquids by Setaflash Closed Tester) is customarily used for determination of flash point to minimize possible hazard to the operator.

A-2-9.1 Manual f i re fighting equipment may consist of small hose equipped with adjustable spray nozzles or portable f i re extinguishers suitable for Class A and for Class B/C fires or both. Manual f i re fighting in storage areas should be undertaken only by those having a clear understanding of the storage conditions and the characteristics of fires involving organic peroxides.

A-2-10.2 The method of disposal may vary depending on the specific formulation and with materials with which they may'have been contaminated. Refer to the manufacturer or the supplier of the specific formulation for advice.

NFPA 43B A-2-11.3 For example, a sprinklered building, detached by 50 f t may contain up to 500 Ib of Class I formulatons, 50,000 Ib of

"Class I I , and 50,000 Ib of Class I l l , according to the following ratios:

500 Ib x 100 : 25%; ~O-O'~-Tb (max)

~ b x 100 : 50%; 100,000 Tb (max)

and 50.000 Ib x 100 = 25% 2 ~ (max)

In no case does the quantity in storage exceed the maximum for i ts class, nor does the sum of the percentages exceed 100 percent.

A-2-12.9 Since no commercially available Class I organic peroxide formulations are supplied in 55-gal drums, there is no requirement for such storage.

A-5-4.5 The following diagram is an example of a suitable building for detailed storage of up to 5000 Ibs of organic peroxide formulations.

~ir . ou t

ield o & West Surfaces " °A~rt

~,,

44

Figure A-5-4.5

Appendix B Typical Organic Peroxide Formulations

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

B-I Class I Formulations.

B-1.1 Fire Hazard Characteristics. Class I formulations present a deflagration hazard through easily ini t iated, rapid explosive decomposition. Class I includes some formulations that are relatively safe only under closely controlled temperatures. Either excessively high or low temperatures may increase the potential for severe explosive decomposition.

B-I.2 Fire Fighting Information. The immediate area should be evacuated and the f i re should be fought from a remote location. Some damage to structures from overpressure can be expected, should a deflagration occur.

B-1.3 Typical Class I Formulations.

Concentration, Peroxide Weight Percent

Acetyl Cyclohexane 60-65 Sulfonyl Peroxide

Benzoyl Peroxide 98+

t-Butyl Hydroperoxide 90

t-Butyl Peroxyacetate 75

t-Butyl Peroxyisopropyl- 92 carbonate

Diisopropyl Peroxy- ~i00 dicarbonate

Di-n-propyl Peroxy 98 dicarbonate 85

R - Refrigeration Required OMS - Odorless Mineral Spirits t-BuOH : tert iary Butanol

Maximum Individual Container

Diluent Size

Water I lb R

i Ib

Water & 5 gal t-BuOH

OMS 5 gal

OMS 5 gal

10 I b R

O--MS 1 gal R 1 gal R

NFPA 43B B-2 Class I I Formulations.

B-2.1 Fire Hazard Characteristics. Class I I formulations present a severe f i re hazard similar to Class I flammable l iquids. The decomposition is not as rapid, violent, or complete as that produced by Class I formulations. As with Class I formulations, this class includes some formulations that are re la t ive ly safe when under controlled temperatures or when diluted.

B-2.2 Fire Fighting Information. Fires should be fought from a safe distance, since a hazard exists from rupturing containers.

B-2.3 Typical Class I I Formulations.

Maximum Individual Concentration, Container

Peroxide Weight Percent Diluent Size

Acetyl Peroxide 25 DMP 5 gal

t-Butyl Hydroperoxide 70 DTBP & 55 gal t-BUOH

t-Butyl Peroxybenzoate 98 5 gal

t-Butyl Peroxy-2- e~hylhexanoate 97 55 gal R

t-Butyl Peroxyisobutyrate 75 OMS 5 gal R

t-Butyl Peroxyisopropyl- 75 OMS 5 gal carbonate

t-Butyl Peroxypivalate 75 OMS 5 gal R

Dibenzoyl Peroxydicarbonate 85 Water 14 Ib R

Di-sec-butyl Peroxy- 98 5 gal R dicarbonate

Di-sec-butyl Peroxy- 75 OMS I gal dicarbonate

1,1-Di-( t-butyl peroxy)- 95 5 gal 3,5,5-trimethylcyclohexane

Di-(2-ethylhexyl) Peroxy- 97 1 gal R dicarbonate

2,5-Dimethyl-2,5 di- 92 50 x 1 Ib (benzoylperoxy)hexane 4 x 5 Ib

Peroxyacetic Acid 43 Water, 30 gal HOAc, & H202

R - Refrigeration Required DTBP - Di ter t iary Butyl Phthalate OMS - Odorless Mineral Spir i ts DMP - Dimethyl Phthalate HOAc - Acetic Acid H202 - Hydrogen Peroxide t-BUOH - te r t ia ry Butanol

B-3 Class I l l Formulations.

B-3.1 Fire Hazard Characteristics. Class I l l formulations present a f i re hazard similar to Class I I combustible liquids. They are characterized by rapid burning and high heat l iberation, due to decomposition.

B-3.2 Fire Fighting Information. Caution should be observed due to possible unexpected increases i n . f i r e intensity.

B-3.3 Typical Class I l l Formulations.

Peroxide

Acetyl Cyclohexane Sulfonyl Peroxide

Benzoyl Peroxide

Benzoyl Peroxide paste

Benzoyl Peroxide paste

Cumene Hydroperoxide

Di-(4-butylcyclohexyl) peroxydicarbonate

t-Butyl Peroxy-2-ethyl- hexanoate

t-Butyl Peroxyneodecanoate

Decanoyl Peroxide

Di-t-Butyl Peroxide

1,1-Di(t-butylperoxy)- 3,5,5-trimethylcyclohexane


2,4-Dichlorobenzoyl Peroxide 50

Diisopropyl Peroxy- 30 dicarbonate

2,5-Dimethyl-2,5-di- 90 (2-ethylhexanoylperoxy)- hexane

2,5-Dimethyl-2,5-di- 90 (t-butylperoxy)hexane

Methyl Ethyl Ketone Peroxide 9% AO

Concentration, Weight Percent

29

78

55

50

86

98

97

75

98.5

99

75

NFPA 43B


Diluent Size

DMP I gal R

Water 25 Ib

BBP 380 Ib

BBP 380 Ib

Cumene 55 gal

88 Ib

5 gal R

OMS 5 gal R

i00 Ib R

- 55 gal

DBP & 5 gal OMS


Diluent Size

DBP & 5 gal Si l icone

Toluene 5 gal R

- 5 gal

- 30 gal

DMP 5 gal

R - Refrigeration Required AO - Active Oxygen DMP - Dimethyl Phthalate DBP - Dibutyl Phthalate OMS - Odorless Mineral Spir i ts DTBP - Di ter t iary Butyl Phthalate BBP - Butyl Benzyl Phthalate

B-4 Class IV Formulations.

B-4.1 Fire Hazard Characteristics. Class IV formulations present f i re hazards that are easily controlled. Reactivity has l i t t l e effect on f i re intensity.

B-4.2 Fire Fighting Information. Normal f i re f ight ing procedures may be used.

45

NFPA 43B

B-4.3 Typical Class IV Formulations.


Benzoyl Peroxide 70

Benzoyl Peroxide paste 50

Benzoyl Peroxide slurry 40

Benzoyl Peroxide powder 35

t-Butyl Hydroperoxide 70

t-Butyl Peroxy-2-ethyl- 50 hexanoate

Dicumyl Peroxide 98

Di-(2-ethylhexyl)peroxy- 40 dicarbonate

Lauroyl Peroxide 98

p-Methane Hydroperoxide 52.5

Methyl Ethyl Ketone Peroxide 5.5% AO

Methyl Ethyl Ketone Peroxide 9.0% AO

R - Refrigeration Required AO - Active Oxygen BBP - Butyl Benzyl Phthalate DOP - Dioctyl Phthalate OMS - Odorless Mineral Spirits DMP - Dimethyl Phthalate

B-5 Class V Formulations.

B-5.1 Fire Hazard Characteristics.


Diluent Size

Water 25 Ib

BBP & 380 Ib Water

Water & 380 Ib Plasticizer

Starch 100 Ib

Water 55 gal

DOP 55 gal

55 gal

OMS 5 gal R

110 Ib

Alcohols & 55 gal Ketones DMP 5 gal

Water & 5 gal Glycols

Class V formulations do not themselves burn and do not present a decomposition hazard.

B-5.2 Fire Fighting Information. Fire fighting procedures need only consider the combustibility of containers.

B-5.3 Typical Class V Formulations.


Benzoyl peroxide 35

1,1-Di-t-butyl peroxy- 40 3,5,5-trimethylcyclohexane

2,5-Dimethyl-2,5-di- 47 (t-butylperoxy)hexane

2,4-Pentanedione Peroxide 4% AO


Diluent Size

Dicalcium 100 Ib Phosphate Dihydrate or Calcium Sulfate

Calcium i00 Ib Carbonate

Inert Solid i00 Ib

Water & 5 gal solvent

AO = Active Oxygen

Appendix C Referenced Publications

C-1 The following documents or portions thereof are referenced within this code for informational purposes only and thus should not be considered part of the requirements of this document. The edition indicated for each reference is current as of the date of the NFPA issuance of this document. These references are listed separately to faci l i ta te updating to the latest edition by the user.

C-I.1 NFPA Publications. National Fire Protection Association, Batterymarch Park, Quincy, MA 02269.

NFPA 68-1978, Guide for Deflagration Venting

NFPA 220-1979, Standard on Types of Building Construction

C-I.2 ASTM Publication. American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.

ASTM D3278-1978, Standard Test Methods for Flash Point of Liquids by Setaflash Closed Tester.

C-I.3 SPI Publication. The Society of the Plastics Industry, 355 Lexington Avenue, New York, NY 10017.

Bulletin 19A-1975, Suggested Relative Hazard Classification of Organic Peroxides.

PART VI

43C- i - (Entire Document): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECO~ENDATION: Reconfirm NFPA 43C as suitable for continued use. SUBSTANTIATION: No proposals to amend NFPA 43C have been received from the public or from the Technical Committee as a result of the call for proposals on 43C, other than the following Technical Committee proposals for editorial changes. COMMITTEE ACTION: Accept.

43C- 2 - ( i-2.1): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOr~MENDATION: Add to end of subsection "(See Tables i-2.1(a) and i-2.1(b) for examples of gaseous oxidizing materials)."

Delete footnote at bottom of page. SUBSTANTIATION: Editorial correction. COMMITTEE ACTION: Accept.

43C- 3 - (1-2.5): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Delete reference to NFPA 56B.

Add the following: "Chapter 5, Respiratory Therapy, of NFPA 99, Standard for Health

Care Facil i t ies." SUBSTANTIATION: NFPA 56B has been incorporated into NFPA ~ . COmmITTEE ACTION: Accept.

43C- 4 - (2-1.1): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Revise to read:

"Storage areas shall be identified with a sign stating: "DANGER - GASEOUS OXIDIZERS" and with the hazard identification

symbols of the specific gaseous oxidizers stored in the area. The hazard identification symbols shall be in accordance with NFPA 704, Standard System for the Identification of the Fire Hazards of Materials and as given in either NFPA 49, Hazardous Chemicals Data, or NFPA 325M, Fire Hazard Properties of Flammable Liquids, Gaseous and Volatile Solids.

Delete footnote at bottom of page. SUBSTANTIATION: Editorial rewording. COmmITTEE ACTION: Accept.

43C- 5 - (Chapter 4 (New) and Appendix ~): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Add new Chapter 4 as follows and delete existing Appendix B.

Chapter 4 Referenced Publications 4-I The following documents or portions thereof are referenced

within this code and shall be considered part of the requirements of this document. The edition indicated for each reference is current as of the date of the NFPA issuance of this document. These references are listed separately to fac i l i ta te updating to the latest edition by the user.

4-1.1 NFPA Publications. National Fire Protection Association, Batterymarch Park, Quincy, FtA 02269.

NFPA 10-1981, Standard for Portable Fire Extinguishers NFPA 13-1985, Standard for the Installation of Sprinkler Systems NFPA 14-1983, Standard for the Installation of Standpipe and

Hose Systems NFPA 24-1984, Standard for Outside Protection NFPA 49-1986, Standard for Hazardous Chemicals Data NFPA 50-1985, Standard for Bulk Oxygen Systems at Consumer Sites NFPA 51-1983, Standard for the Design and Installation of

Oxygen-Fuel Gas Systems for Welding and Cutting NFPA 51A-1984, Standard for Acetylene Cylinder Charging Plants NFPA 51B-1984, Standard for Fire Prevention in Use of Cutting

and Welding Processes NFPA 56F-1983, Standard for Nonflammable Medical Gas Systems NFPA 99-1984, Standard for Health Care Facilit ies NFPA 101-1985, Life Safety Code • NFPA 325M-1984, Fire Hazard Properties of Flammable Liquids,

Gases, and Volatile Solids NFPA 704-1985, Standard System for the Identification of the

Fire Hazards of Materials SUBSTANTIATION: Comply with Standards Council Directive to have mandatory references in body of standard. COMMITTEE ACTION: Accept.

46

PART VII

43D- i - (Entire Document): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Reconfirm NFPA 43D as suitable for continued use. SUBSTANTIATION: No proposals to amend NFPA 43D were received from the public or frdm the Technical Committee as a result of the call for proposals, other than the following Technical Committee proposals for editorial changes. COMMITTEE ACTION: Accept.

43D- 2 - (1-1.3): Accept SUBMITTER: Technical Committee on Storage, Handling and Transporation of Hazardous Chemicals RECOMMENDATION: Revise to read:

"This standard shall not apply to noncommercial storage in households and garages of pesticides registered for use in the home by the U.S. Environmental Protection Agency under the Federal Insecticide, Fungicide and Rodenticide Act of 1945 (FIFRA) as amended by the Federal Economic Poison Control Act of 1972 (FEPCA)."

Delete footnote. SUBSTANTIATION: Editorial Change. COMMITTEE ACTION: Accept.

43D- 3 - (Chapter 2, Tit le): Accept SUBMITTER: Technical Committee on Storage, Handling and ~ a t i o n of Hazardous Chemicals RECOMMENDATION: Relocate footnote to Appendix B. Add to f i r s t paragraph of Appendix B. SUBSTANTIATION: Editorial Change. COMMITTEE ACTION: Accept.

43D- 4 - (2-3, 2-6.1 and 2-10): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Relocate the footnotes to these subsections from the bottom of the page to parentheticals at the end of each subsection. SUBSTANTIATION: Editorial change. COMMITTEE ACTION: Accept.

43D- 5 - (2-6.2): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Delete footnote.

Add the following: "Local regulations requiring locked storage shall be complied

with." SUBSTANTIATION: Editorial Change. COMMITTEE ACTION: Accept.

430-6 - (3-1.2.1): Accept SUBMITTER: Technical Committee on Storage, Handling and T-raEsportation of Hazardous Chemicals RECOMMENDATION: Revise to read:

"General f ire, protection shall comply with applicable NFPA standards, including the following:

NFPA 10, Standard for Portable Fire Extinguishers; NFPA 13, Standard for the Installation of Sprinkler Systems; NFPA 14, Standard for the Installation of Standpipe and Hose

Systems; NFPA 20, Standard for the Installation of Centrifugal Fire

Pumps." Delete footnote.

SUBSTANTIATION: Editorial change. COMMITTEE ACTION: Accept.

43D- 9 - (Chapter 4 (New) and Appendix D): Accept SUBMITTER: Technical Committee on Storage, Handling and T~-a-~sportation of Hazardous Chemicals RECOMMENDATION: Add new Chapter 4 as fol lows and delete exist ing Appendix D.

Chapter 4 Referenced Publications 4- i The fol lowing documents or portions thereof are referenced

within th is code and shall be considered part of the requirements, of this document. The edit ion indicated for each reference is current as of the date of the NFPA issuance of this document. These references are l is ted separately to f a c i l i t a t e updating to the la test edit ion by the user.



Hose Systems NFPA 20-1983, Standard for the Installation of Centrifugal Fire

Pumps NFPA 30-1984, Flammable and Combustible Liquids Code NFPA 43A-1980, Code for the Storage of Liquid and Solid

Oxidizing Materials NFPA 231-1985, Standard for Indoor General Storage NFPA 395-1980, Standard for the Storage of Flammable and

Combustible Liquids on Farms and Isolated Construction Projects NFPA 490-1986, Code for the Storage of Ammonium Nitrate 4-2 U.S. Government Publications. Federal Insecticide, Fungicide, and Rodenticide Act of 1945,

U.S. Environmental Protection Agency, Washington, DC Federal Economic Poison Control Act of 1972, U.S. Environmental

Protection Agency, Washington, DC SUBSTANTIATION: Comply with Standards Council directive to move mandatory references in body of standard. COMMITTEE ACTION: Accept.

43D- I0 - (2-2): Accept SUBMITTER: Technical Committee on Storage, Handlin~ and Transportation of Hazardous Chemicals

I RECOMMENDATION: Delete last sentence. SUBSTANTIATION: NFPA 231A has been withdrawn. COMMITTEE ACTION: Accept.

43D- 11 - (Appendix D): Accept SUBMITTER: Technical Committee on Storage, Handling and rTra-n~portation of Hazardous Chemicals RECOMMENDATION: Revise as fol lows:

Appendix D Referenced Publications D-1 The fol lowing documents or portions thereof are referenced

within this code for informational purposes only and thus should not be considered part of the requirements of this document. The edit ion indicated for each reference is current as of the date of the NFPA issuance of th is document. These references are l i s ted separately to f a c i l i t a t e updating to the latest edi t ion by the user.

Environmental Protection Agency, Recognition and Management of Pesticide Poisonings, Washington, DC, Government Printing Office, 1977, 2nd Ed.

Hayes, W. J., Jr., Clinical Handbook of Economic Poisons, Atlanta, GA Communicable Diseases Center, 1963.

Wiswesser, W.J., Editor, Pesticide Index, College Park, MD, Entormological Society of America, 1976, 5th Ed. SUBSTANTIATION: Comply with Standards Council directive to separate mandatory references from advisory references. COMMITTEE ACTION: Accept.

43D- 7 - (3-1~2.2, 3-1.3.1 and 3-3.1.1): Accept SUBMITTER: Technical Committee on Storage, Handling and ~ a t i o n ~ o f Hazardous Chemicals RECOMMENDATION: Relocate footnotes to parentheticals at end of respective subsections. SUBSTANTIATION: Editorial change. COMMITTEE ACTION: Accept.

43D- 8 - (Appendix B, Appendix C): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Delete footnote to Appendix B.

Move footnote to Appendix C to text in Subsection C-3.4. SUBSTANTIATION: Editorial change. COMMITTEE ACTION: Accept.

47

PART VII I

490- 1 - (Entire Document): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Reconfirm NFPA 490 as suitable for continued use. SUBSTANTIATION: No proposals to amend NFPA 490 were received from the public or the Technical Committee as a result of the call for proposals, other than the following Technical Committee proposals for editorial changes. COMMITTEE ACTION: Accept.

490- 2 - (1-1.1): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Revise 1-1.1 to read:

"This Code shall apply to the storage of ammonium nitrate in the form of crystals, flakes, grains, or pr i l ls including fer t i l i zer grade (as defined by Definition and Test Procedures for Ammonium Nitrate Fert i l izer), dynamite grade, nitrous oxide grade (as defined by Standards for Ammonium Nitrate-Nitrous Oxide Grade), technical grade, and other mixture containing 60 percent or more byweight of ammonium nitrate."

Delete footnotes. SUBSTANTIATION: Editorial change. COMMITTEE ACTION: Accept.

490- 3 - (1-1.4 (New)): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Add new 1-1.4 to read:

"This Code shall not apply to ammonium nitrate-based blasting agents. (See NFPA 495, Code for the Manufacture, Transporation, Storage and Use of Explosive Materials.)"

Renumber following subsections. SUBSTANTIATION: Editorial relocation for i-1.1. COMMITTEE ACTION: Accept.

490- 4 - (2-2.4, 4-2.2, 4-3.2 and 6-6.1): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Add asterisk to number.

Relocate footnote to Appendix A (new) as A-2-2.4, A-4.3.2, and A-6.6.1.

Redesignate existing Appendices. SUBSTANTIATION: Editorial relocation. COMMITTEE ACTION: Accept.

490- 5 - (5-2.2.1): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Delete footnote and add the following:

"(This table may be found in NFPA 495, Code for the Manufacture, Transporation, Storage and Use of Explosive Materials.)" SUBSTANTIATION: Editorial Change. COMMITTEE ACTION: Accept.

490- 6 - (Chapter 8 (New) and Appendix C): Accept SUBMITTER: Technical Committee on Storage, Handling and raTra-n-s-portation of Hazardous Chemicals RECOMMENDATION: Add new Chapter 8 as follows and delete current Appendix C.

Chapter 8 Referenced Publications 8-1 The following documents or portions thereof are referenced

within this code and shall be considered part of the requirements of this document. The edition indicated for each reference is current as of the date of the NFPA issuance of this document. These references are listed separately to faci l i ta te updating to the latest edition by the user.



Hose Systems NFPA 24-1984, Standard for Outside Protection NFPA 30-1984, Flammable and Combustible Liquids Code NFPA 58-1983, Standard for the Storage and Handling of Liquefied

Petroleum Gases NFPA 70-1984, National Electrical Code NFPA 78-1983, Lightning Protection Code NFPA 203M-1980, Manual on Roof Coverings NFPA 220-1985, Standard on Types of Building Construction NFPA 495-1985, Code for the Manufacture, Transportation, Storage

and Use of Explosive Materials NFPA 505-1982, Fire Safety Standard for Powered Industrial Trucks 8-2 Other Publications. Definitions and Test Procedures for Ammonium Nitrate Fert i l izer,

Washington, DC, Ferti l izer Institute, 1984. Standard for ~T~onium Nitrate (Nitrous Oxide Grade), New York,

NY, Compressed Gas Assn. SUBSTANTIATION: Comply with Standards Council directive to move mandatory references in body of standard. COMMITTEE ACTION: Accept.

490- 7 - (Appendix C): Accept SUBMITTER: Technical Committee on Storage, Handling and Transportation of Hazardous Chemicals RECOMMENDATION: Add new Appendix C as follows:

Appendix C Referenced Publications C-1 The following documents or portions thereof are referenced

within this code for informational purposes only and thus should not be considered part of the requirements of this document. The edition indicated for each reference is current as of the date of the NFPA issuance of this document. These references are listed separately to fac i l i ta te updating to the latest edition by the user.

C-I.1 The following publications may be obtained from the U.S. Bureau of Mines, Pittsburg Mining and Safety Research Center, 4800 Forbes Ave., Pittsburgh, PA 15213

Report of Investigations 6746, Sympathetic Detonation of Ammonium Nitrate and Ammonium Nitrate Fuel Oil.

Report of Investigations 6775, Explosion Hazards of Ammonium Nitrate Under Fire Exposure.

Report of Investigations 6903, Further Studies of Sympathetic Detonation SUBSTANTIATION: Comply with Standards Council directive to separate mandatory references from advisory references. COMMITTEE ACTION: Accept.

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