There are four classes of fires. Before you extinguish a fire, you need to make sure you identify the type of fire; otherwise, you might make things worse.

Classes of fires:

• class A ordinary combustibles or fibrous material: wood, paper, plastic;

• class B flammable or combustible liquids: paint, kerosene;

• class C energized electrical equipment: switches, panel boxes;

• class D combustible metals: magnesium, potassium.

Most labs are equipped with dry chemical extinguishers (ABC extinguishers) that can be used for the first three classes.

CO₂灭火器s are also very popular. They can be used for class B and C fires. Don't use CO₂灭火器s on people as it can cause serious frostbites.

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Further reading:

• Fire emergency

• Lab safety practices

• Safety equipment