Water and foam fire extinguishers extinguish fires by taking away the heat element in a fire. Foam extinguishers also separate the oxygen element from the other elements.
Water extinguishers are for class A fires only - they should not be used on class b or c fires. the discharge if steam can spread the flammable liquid or can create an electric shock hazard.
Foam extinguishers can be used on Class A and B fires Only. they are not for use on Class C fires due to the shock hazard.
Carbon dioxide fire extinguishers extinguish the fire by taking away the oxygen element of a fire, and also by removing the heat of the fire with a very cold discharge. Carbon dioxide can be used on Class B and C fires. They are usually ineffective on class A fires.
Dry chemical fire extinguishers extinguish the fire primarily by interrupting the chemical reaction of the fire. The dry chemical that is used today is effective on Class A, B and C fires. This type of extinguisher can act as a barrier between the oxygen element and the fuel element on class A fires.
Ordinary Dry Chemical extinguishers are only suitable for Class B and C fires.
Cartridge operated dry chemical extinguishers extinguish the fire by interrupting the chemical reaction in a fire.
This type of extinguisher is effective on class A,B and C fires.