Classification of flammable and combustible

Basic Classification of Flammable and Combustible Liquids Fire Hazard Properties of Flammable Liquids, Gases, and Volatile Solids... 

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. 

NFPA 321 Standard on Basic Classification of Flammable and Combustible Liquids. 

NFPA 321—Basic classification of flammable and combustible liquids. 

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. 

TABLE 5.1.2.1 Properties of Flammable and Combustible Liquids as Defined by the Globally Harmonized System for Classification and Labelling of Chemicals ... 

Fire hazard is viewed from the standpoint of safety, to which in the United States, the Occupational Safety and Health Standard (OSH) is often used as the basis for classification of flammables versus a combustible material. Additionally, the U.S. Department of Transportation also has very specific definitions regarding classification of fire hazards based on safe transport of materials. For initial discussions we will adhere to the OSHA definitions, and later refer to distinctions in U.S. federal definitions which are legal standards. 

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. 

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). 

Further research should be conducted toward establishing a better means to categorize the true fire hazard of all flammable and combustible liquids. The flash point, and in some cases boiling point, are measured values that are used for the current classification system. Additional properties, such as viscosity, dissolved combustible solids, and heat of combustion or heat release rate data should be included in a more comprehensive system. 

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. 

In a general sense, any material capable of burning, generally in air under normal conditions of ambient temperature and pressure, unless otherwise specified. This implies a lower degree of flammability. Although there is no general industry distinction between a material that is flammable and one that is combustible (NFPA 30, Flammable and Combustible Liquids Code, defines the difference between the classification of combustible liquids and flammable liquids based on flash point temperatures... 

Fire testing and classification of building and other materials are based on certain flammability characteristics such as flame spread, ignition temperature, smoke development, non-combustibility, fire resistance, rate of heat release, oxygen index, etc. Some of them are briefly discussed in the following paragraphs [124-126]. 

DMF can be purchased ia steel dmms (DOT 17E, UNlAl, 410 lbs net = 186 kg), tank tmcks, and railcars. On Oct. 1, 1993, new regulations in the United States were estabUshed for DMF under HM-181 the official shipping name is /V, /V- dim ethyl form am i de (shipping designation UN 2265, Packing Group III, Flammable Liquid). Formerly, it was classified as a Combustible Liquid in bulk quantities, but as "Not Regulated" in dmms (49 CFR). International overseas shipments have an IMCO classification of 3.3. 

The subindex of flammability describes the flammability of liquid e.g. in the case of a leakage. Flammability of liquids is measured by their flash points and boiling points. The classification used is based on the EU directive (Pyotsia, 1994). Substances are divided into non-combustible, combustible, flammable, easily flammable and very flammable (Table 11). 

Fires are classified based on the type of fuel involved. Fuels are typically placed into three classes ordinary combustibles (like wood and paper), flammable liquids, and combustible metals. For firefighting, a fourth fire class, electrical fires, is also considered. The four main classifications of fire are shown in Table B-1. 

Some bromine compounds are covered specifically under Hazardous Materials Regulations. Other compounds may usually be shipped under the classification of chemicals, not otherwise indexed by name, without special requirements unless from their nature they would fall under a category such as combustible liquid, compressed gas, corrosive liquid (or solid), disinfectant liquid (or solid), dmg, dye intermediate (liquid), fire extinguisher, flammable gas (liquid or solid), insecticide, medicine, oxidizer or oxidizing material, poisonous liquid (gas or solid), solvent, or tear gas. Specific provisions apply to each of these categories and appropriate packaging and labeling are required. 

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