What Do the ABC Ratings on Fire Extinguishers Indicate?

Fire extinguishers may all look broadly similar, but they can and do have different functions. Not all fires are the same — they can vary depending on the material on fire — and it’s essential to know which fire extinguisher is used for which fire type. If you look at a fire extinguisher, you’ll see a letter (and number) clearly labelled, indicating the material the extinguisher is designed for. This blog will look at the ABC ratings of fire extinguishers and other essential information you need to know.

Class A Fire Extinguishers

Type A is the most common fire extinguisher since it deals with materials that commonly catch fire, such as cloth, plastic, trash, wood, and rubber. Most fire extinguishers rely on pressurized water and monoammonium phosphate to put out the fire. They typically weigh about 25 lbs. and indicate how much water the canister holds on the label. If you’ve got a type A fire extinguisher, you can be confident that it’ll put out wood, plastic, cloth, trash, rubber, and other commonly combustible items.

Class B Fire Extinguishers

Class B fire extinguishers are for use against flammable substances. For example, oil, solvents, paint, and kerosene. These fire extinguishers contain a mixture of CO2, sodium bicarbonate, and monoammonium phosphate, which work together to smother and extinguish the fire. As with class A fire extinguishers, you’ll also see several class B extinguishers. However, this number doesn’t refer to the amount of substance contained within the canister but how much space the contents will cover in square feet. They can weigh from 5 to 100 lbs. A fire extinguisher will receive a B rating if it can put out a liquid fire.

Class C Fire Extinguishers

A class C fire extinguisher is for use against electrical fires. For instance, fires caused by tools, electrical appliances, wall outlets, wiring, motors, and fuses. Given the interaction between electrical items and water and other substances, it’s essential that you only use a class C fire extinguisher to put out these types of fires. Class C canisters contain either CO2 or dry chemicals, which are effective at putting out the fire but may damage the electrical appliance. An extinguisher will receive a class C rating if it can put out electrical fires without risk of electrical conductivity.

Close up of fire extinguisher being used

Other Classes of Fire Extinguisher

ABC fire extinguishers can handle many fires that occur in homes, which means that most fire extinguishers that people handle will have one or more of these ratings. There are other classes of fire extinguishers; however, Class D and K are for use against metal fires and cooking grease fires, respectively.


Having a fire extinguisher is essential to keeping your home safe. However, it’s equally important to be aware of the different fire extinguishers and to ensure that you use the correct one for the type of fire you’re fighting.

If you have any other questions about fire extinguishers, please give the experts at Amptec a call.

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