CLASS A fires occur in ordinary combustible materials such as wood, cloth and paper. The most commonly used extinguishing agent is water which cools and quenches. Fires in these materials are also extinguished by special dry chemicals for use on Class A,B & C.
CLASS B fires occur in the vapor-air mixture over the surface of flammable liquids such as grease, gasoline and lubricating oils. A smothering or combustion inhibiting effect is necessary to extinguish Class B fires. Dry chemical,foam,vaporizing liquids,CO2 and H2O fog all can be used as extinguishing agents depending on the circumstances of the fire.
CLASS C fires occur in the electrical equipment where non conducting extinguishing agents must be used. Dry chemical, CO2, vaporizing liquids are suitable. Because foam,H2O(except as spray), and H2O type extinguishing agents conduct electricity,their use can kill or injure the person operating the extinguisher, and severe damage to electrical equipment can result.
CLASS k OCCUR IN KITCHEN
CLASS D occur in combustible metals such as MG,TI,ZR(zirconium),NA.