Flammable liquids nfpa classifications

NFPA 497 Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas, 1997 edition. National Fire Protection Association, Quincy, MA. 

NFPA-325 Guide to Fire Hazard Properties of Flammable Liquids, Gases and Volatile Solids, (1994 ed.), NFPA-321 Basic Classification of Flammable and Combustible Liquids (1991 ed.), NFPA-497A, Classification of Class 1 Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas (1992 ed.), and NFPA-497B, Classification of Class II Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas (1991 ed.), National Fire Protection Association, Quincy, MA. 

In a general sense any material than can bum. This implies a lower degree of flammability, although there is no precise distinction between a material that is flammable and one that is combustible (NFPA 30, Combustible and Flammable Liquids Code, defines differences between the classification of combustible liquids and flammable liquids based on flash point and vapor pressure). 

For flammable and combustible liquids, flash point is the primary basis for classifying the degree of fire hazardousness. NFPA Classifications 1, 2, and 3 designate the most to the least fire hazard liquids, respectively. In essence, low flash point liquids are high fire hazard liquids. 

NFPA 497 (2004) Recommended practice for the classification of flammable liquids, gases or vapors and of hazardous (classified) locations for electrical installations in chemical process areas. (National Fire Protection Association). 

It should be recognized that definitions for certain hazardous materials, such as flammable liquids. may not be the same for different classification systems, such as NFPA and DOT. Therefore, it is important to state which classification system a definition is based upon. 

This standard was first tentatively adopted in 1960, officially adopted by the National Fire Protection Association in 1961, and revised in 1964,1966,1975 and 1980. It grew out of development work begun in 1952 by the NFPA sectional committee on Classification, Labeling, and Properties of Flammable Liquids. As originally conceived, this standard is to safeguard the lives of those who are concerned with fires and fire control and prevention, in industrial plants or storage locations. It is particularly useful where the fire hazards of materials may not be readily apparent. 

The NFPA uses a classification system for flammable and combustible liquids in fixed storage facilities (see Figure 5.1). This system is part of the consensus standard NFPA 30, the Flammable and Combustible Liquids Code. The NFPA system further divides the flammable and combustible liquid categories into subdivisions based upon the flash points and boiling points of the liquids. NFPA s classification system does not apply to transportation of hazardous materials, since DOT regulations supersede NFPA 30. Examples of liquids in the various classification categories are listed in Figure 5.2. 

NFPA 45, 2.2.1.5 4.3.2.1 For the purposes of determining laboratory fire hazard classification and the use of tables 2.2.1(a) and (b) quantities of liquefied flammable gases shall be treated as if they were Class I flammable liquids (see definition) that is, 4L (l.lgal) of liquefied flammable gas is to be considered equivalent to 4L (1.1 gal) of Class I flammable liquid. 

NFPA developed a classification system for flammable liquids and combustible liquids (see Table 16-3) that uses flash point, vapor pressure, and expected ambient temperature conditions. A flammable liquid is a liquid with a flash point that does not exceed 100 °F based on testing by closed-cup test methods. A combustible liquid is a liquid with a flash point at 100 °F or higher using the same test methods. The flash point of a liquid is the lowest temperature at which the vapor pressure of the liquid is just sufficient to produce a... 

TABLE 16-3 NFPA Classification for Flammable and Combustible Liquids ... 

NFPA 497 Classification of Flammable Liquids, Gases, or Vapors... 

Flammable and combustible liquids can be designated as Class IA, IB, IC, II, IIIA, or IIIB by the classification system of NFPA 30, Flammable and Combustible Liquids Code. Class IA liquids are considered the most hazardous and Class IIIB the least hazardous. This classification system is based upon the closed-cup flash point temperature and with Class IA and Class IB liquids also the boiling point temperature of the liquid. Liquids are considered flammable if their flash points are below 100°F (37.8°C) and combustible if their flash points are at or above 100°F (37.8°C). 

NFPA 45,2.2.1.1-4 4.3.2 Fire Hazard Classification - Laboratory units shall be classified Class A (High Fire Hazard), Class B (Moderate fire Hazard), Class C (Low fire Hazard), or Class D (Minimal Fire Hazard), according to the quantities of flammable and combustible liquids present in the lab (outside of the storage area) as specified in Table 2.2.1(a) and Table 2.2.1(b) in NFPA 45. 

NFPA 321—Basic classification of flammable and combustible liquids. 

In the US, the electrical area classification for areas that contain flammable/ combustible liquids and gases are usually defined by the requirements of the National Electrical Code (NEC), i.e., NFPA 70, API RP 500, and NFPA 30, which are similar in content. 

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