About fire extinguishers: what do classes A, B, C, D and F mean?

Class A: solid and glowing materials

Class A fires are related to solid and glowing materials.

For example:

• wood;

• paper;

• textiles;

• combustible fibres;

• plastic.

For these materials, a cooling effect is important, because solid materials may continue to smoulder even after the visible flame has been extinguished.

Class B: flammable liquids and melting substances

Class B fires are related to flammable liquids and substances that melt when burning.

For example:

• oil;

• petrol;

• solvents;

• resins;

• adhesives;

• fat;

• most plastics.

Water should not be treated as a universal solution for flammable liquid fires. If the flammable liquid is lighter than water, it may remain on the surface and continue burning.

Class C: flammable gases

Class C refers to flammable gases.

For example:

• natural gas;

• acetylene;

• propane;

• hydrogen.

In the case of a gas fire, it is important to shut off the source of danger, if this can be done safely. If the gas supply cannot be stopped, extinguishing the flame may create an additional explosion hazard.

Class D: metals

Class D fires are related to metals.

For example:

• aluminium;

• magnesium.

Metal fires can burn at very high temperatures and require an extinguishing agent specifically suitable for this type of fire.

Class F: cooking oils and fats

Class F refers to cooking oils and fats.

This is especially important in kitchens, commercial kitchens, restaurants, cafés and other places where hot food is prepared.

A fat fire is not an ordinary fire. Using water to extinguish burning fat is dangerous, because the water may vaporise rapidly in the hot fat and spread the burning fat around.