Home › Fire extinguishers

Fire Extinguisher Classes for the G3 Exam

All five classes, what each is used on, and how the exam asks about them.

Class	For	Examples
Class A	Ordinary combustibles	Paper, wood, cardboard, cloth
Class B	Flammable liquids	Gasoline, kerosene, grease, oil
Class C	Electrical equipment	Appliances, wiring, circuit panels
Class D	Combustible metals	Magnesium, titanium, sodium, potassium
Class K	Cooking oils and fats	Commercial kitchen fryers

How the exam asks

Two directions, and you need both. Sometimes you are given the class and asked what it is used on; sometimes you are given the situation and asked for the class. Learning them one way round only gets you half the marks available.

Class D and Class K are the ones people forget, precisely because they come up least in everyday work. They still come up in the exam.

Also worth knowing

• Aim at the base of the fire, not at the flames.
• An extinguisher rated for several classes carries several letters.
• Using the wrong class can make a fire worse — water on a grease fire, for instance.

Common questions

What is a Class B fire extinguisher used on?

Flammable liquids — gasoline, kerosene, grease and oil.

What is a Class C fire extinguisher used on?

Electrical equipment such as appliances, wiring and circuit panels.

What are the five fire extinguisher classes?

Class A for ordinary combustibles, Class B for flammable liquids, Class C for electrical equipment, Class D for combustible metals, and Class K for cooking oils and fats.

Where do you aim a fire extinguisher?

At the base of the fire, not at the flames.

Practise safety questions free →

More on safety and workplace practices →