Class B fires

CLASS B FIRE A firc involving liquids or liquefiable solids. 

The penetration and eooling aetion of water is required with Class A fires, e.g. those involving paper, wood, textiles, refuse. Water is applied in the form of a jet or spray foam or multi-purpose powder extinguishers are alternatives. Extinguishment of a Class B fire ean be aehieved by the smothering aetion of dry ehemieal, earbon dioxide or foam. Most flammable liquids will float on water (refer to Table 6.1 under Speeifie gravity ), so that water as a jet is unsuitable a mist may, however, be effeetive. Water is also widely used to proteet equipment exposed to heat. Dry powders are effeetive on flammable liquid or eleetrieal fires. 

Class B fire Flammable liquids, petrol, oils, greases, fats Blanketing/ smothering most effective Dangerous Most suitable Most suitable Most suitable " Small fires only Most suitable Small fires only Small fires only... 

CO2 gas and a foaming agent combine to produce and expand frotli often used on Class B fires. 

Carbon dioxide systems often used on Class B fires. 

Water is not suitable for electrical (Class C) fires, but is effective on all combustible (Class A) and many flammable liquid (Class B) fires. Water can be applied by hose streams, monitors, sprinklers, water spray systems, or as water curtains for such purposes as ... 

Potassium bicarbonate has greater extinguishing capability on Class B fires than sodium bicarbonate and is usually foam compatible. This characteristic permits emergency response personnel to fight fire more effectively. 

Properly designed water mist systems can be effective on both liquid fuel (Class B) and solid fuel (Class A) fires. Research indicates that fine (i.e., smaller than 400 microns) droplets are essential for extinguishing Class B fires, although... 

Multipurpose dry chemical extinguishers (20-A 80B-C) should be provided in warehouses and shop buildings where wood, paper, plastics, and other flammable solids, as well as flammable liquids, may be stored. In grease manufacturing and compounding or similar operations where little or no wood, paper, and similar combustibles are stored, but where flammable liquids may be prevalent, potassium bicarbonate dry chemical extinguishers should be used. Extinguishers should be located not more than 75 ft (23 m) away from any potential Class A fire hazard and not more than 50 ft (15 m) from Class B fire hazards. 

To protect the control room area from incidents occurring in the support areas, the control room area should be separated from the support areas by minimum 1-hour fire-rated partition walls. All penetrations of the walls, floors, ceilings, and roof for cables, etc. should be closed with an approved sealant having a fire resistance rating of at least one-hour. Approved y4-hour rated (Class B) fire doors equipped with self-closing devices should be installed on all openings between the control room and other portions of the building. 

Class C Electrical fires Fires that involve energized electrical equipment where the electrical nonconductivity of the extinguishing media is of importance. (When electrical equipment is deenergized, fire extinguishers for Class A or Class B fires can be used safely.)... 

Class B Fires. These are fires in flammable liquids (oils, gasoline, solvents, etc.), where a blanketing or smothering effect is essential to put the fire out. This effect keeps oxygen away from the fuel, and can be obtained with carbon dioxide, dry chemical (essentially sodium bicarbonate), foam, or a vaporizing-liquid type of extinguishing agent. Water is most effective when used as a fine spray or mist... 

Fires that involve flammable liquids, such as gasoline and paint, are Class B fires. Dry chemical... 

Class B fires occur with liquid hydrocarbons and similar combustible liquids. Foam, dry-chemical, halocarbon, and C02 extinguishers are recommended. 

Class B fires involve flammable or combustible liquids such as gasoline, kerosene, and common organic solvents used in the laboratory. 

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