For a fire to exist there are four elements that are usually present. Oxygen that sustains the burning, fuel that supports the combustion, heat that raises the burning material to the ignition temperature and a chemical reaction. A fire is put out by eliminating any one of the above elements. The whole concept of fire extinguishing is built around separating any of the four elements. Different fire extinguishers have been made with different mechanisms to ensure they put out certain classes of fire.
Water and Foam Fire Extinguisher
They are the cheapest and most extensively used extinguishers. They extinguish the fire by removing the heating element. Foam agents separate oxygen from other elements. You should use this extinguisher when putting out Class A fires. Make sure not to use this kind of extinguisher when putting out class B or C fires because the discharge stream is capable of spreading the flammable liquid, causing more damage or creating shock hazards respectively.
Dry Chemical Extinguisher
They put out fire mostly by interfering with chemical reactions. It is usually effective when extinguishing class A, B and C fires. The chemical agent creates a barrier between oxygen and fuel elements for class A fires. To put out fire B and C it's advised to use the appropriate extinguisher for the right kind of fuel; otherwise, an inappropriate agent can re-start the fire.
Wet Chemical Extinguisher
They put out the fire by taking away the heat, preventing re-ignition by creating a barrier between fuel and oxygen elements. They are used to put out class K fires and it explains why they are commonly found in commercial cooking kitchens.
Carbon Dioxide Extinguisher
They put out the fire by removing oxygen. They also discharge a cold substance that minimises heat. You should use this kind of extinguisher to put out class B and C fires. It's important to note that they are ineffective for class A fires.
Water Mist Extinguisher
They have been developed recently and they extinguish the fire by removing the element of heat. You should use them to put out Class A fires, and they are also safe for use with class C fires.
Clean Agent Extinguisher
They are also known as halogenated extinguishers and have halon and halocarbon elements embedded, which have little effect on the ozone layer. They put out the fire by interrupting the chemical reaction. They are most effective when used on class B and C fires.Share