Actually fire extinguishers are differentiated according to the objects /materials which tends to fire. There are different ‘classes’ of fire, for which each extinguisher is designed to tackle. These classes are based on which fuels a fire starts with. It’s the presence of these fuels within your business premises that will help determine which types of fire extinguisher you need and in which locations.
- Class A: freely burning, combustible solid materials such as wood or paper
- Class B: flammable liquid or gas
- Class C: energized electrical fire (energized electrical source serves as the ignitor of a class A or B fire – if electrical source is removed, it is no longer a class C fire)
- Class D: metallic fire (titanium, zirconium, magnesium, sodium)
- Class K: cooking fires – animal or vegetable oils or fats
In all cases….. Regardless of the type of fire, there will always be the same four elements present they are: Fuel, Heat, Oxygen and Chain Reaction
The theory behind portable fire extinguishers is that the fire can be extinguished by removing any one or more of these four elements. For each class of fire, the fuel, heat source and chain reaction varies, which is why there must be different types of fire extinguishers depending on the class of fire. For instance, while a Class A fire can be safely extinguished with water, a class C fire cannot, as water would conduct the electricity and risk harm to the operator.
Multipurpose Dry Chemical Fire Extinguisher:-
The fire extinguisher in your home is most likely a multipurpose fire extinguisher. These contain monoammonium phosphate, a chemical compound that smothers the flames. Since these lack an effective cooling agent, it is important to aim the discharge at the base of the fire as thoroughly as possible to prevent reignition.
Wet Chemical Fire Extinguisher:-
Wet chemical fire extinguishers use a potassium water solution. They have a cooling effect, lowering the temperature of the fire. A variant is commonly used in kitchens, offering better protection against reflash.
Pressurized Water Fire Extinguisher:-
Water extinguishers can use pure water, but often have additives like antifreeze and wetting agents to make them more effective and dependable. These units are ideally suited for all industrial and commercial applications, where easy to use, positive on-off operation is important. Pressurized water extinguishers are highly effective on deep seated Class A fires.
Foam Fire Extinguisher:-
Film-forming foam fire extinguishers are most useful against deep-seated fires. These leave behind a blanket of foam which cools and smothers a fire. Foam agents have the opportunity to get to the seat of the fire and prevents reignition.
Clean Agent Fire Extinguisher:-
Clean agent fire extinguishers are a good option when dealing with sensitive electronic equipment. These extinguishers are non-corrosive, nonconductive, and the agent quickly evaporates, leaving no residue. They can be used at a greater distance than other types of fire extinguishers.
Carbon Dioxide Fire Extinguisher:-
Carbon dioxide fire extinguishers are useful for fires that occur in areas with live electrical equipment. The agent discharges as a gas and leaves no residue while depriving the fire of oxygen. It has a short range and is not suitable for windy areas or small spaces, due to life safety concerns.
