Water and Foam
These extinguish the fire by taking away the heat. Foam effectively separates oxygen from other elements in the fire. Water extinguishers should only be used for Class A fires.
Carbon Dioxide
These fire extinguishers extinguish fire by taking away the oxygen and removing the heat with a very cold discharge. Carbon dioxide extinguishers are effective for Class B and C fires.
Dry Chemical
This is the most widely used type today. They extinguish the fire primarily by interrupting the chemical reaction of the fire. The multipurpose dry chemical extinguisher can be used for Class A, B, and C fires.
Wet Chemical
This is a new agent that extinguishes the fire by removing the heat and preventing re-ignition by creating a barrier between the oxygen and fuel. This extinguisher was designed especially for Class K fires in commercial kitchens.
Halogenated or Clean Agent
These extinguishers include the halon agents as well as the newer and less ozone depleting halocarbon agents. They extinguish the fire by interrupting the chemical reaction of the fire. Clean agent extinguishers are designed mostly for Class B and C fires.
Dry Powder
These extinguishers are similar to dry chemical except that they extinguish the fire by separating the fuel from the oxygen or by removing the heat of the fire. Dry powder extinguishers are only for Class D fires.
Water Mist
These extinguishers are a recent development that extinguish the fire by taking away the heat element of the fire. They are an alternative to the clean agent extinguishers where contamination is a concern. Water mist extinguishers are intended for Class A fires, and can also be used for Class C fires.
Cartridge Operated Dry Chemical
These fire extinguishers extinguish the fire primarily by interrupting the chemical reaction. A multipurpose dry chemical extinguisher can be used for Class A, B, and C fires; an ordinary dry chemical extinguisher should only be used for Class B and C fires.
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