United States

Fire extinguishers

Reviewed 2026-07-26

Use at your own risk. Educational and research use only, not medical advice. Verify numbers and rules for the country you are in. They change. Before you rely on these cards in practice, review them with a medical professional or a fire safety specialist. Disclaimer

Do this first

Fight a fire only while it is smaller than you, your exit is clear behind you, and the extinguisher matches what is burning.

A portable extinguisher empties in fifteen to twenty seconds. That is enough for a wastebasket, not for a burning room. The letters on the label are the whole science: they say which fires this unit can touch and which ones it will make worse.

Step by step

Read the class letters before you ever need them. A is solids like wood and fabric, B is liquids, C is gases, D is metals, F is cooking oils and fats.
Match the agent to the fire. Water takes only A. Foam takes A and B. Powder takes A, B and C and most household fires. CO2 takes B and electrical equipment. Wet chemical takes F, the burning pan.
Pull the pin, and test with a short burst before you approach.
Aim at the base of the flames, not at the smoke. The fire lives where fuel meets air, at the bottom.
Squeeze and sweep side to side across the base, moving in slowly. Keep your exit behind your back the whole time.
When the flames are out, watch the spot. Embers reignite, so be ready to repeat, and ventilate powder and CO2 fumes.
If the extinguisher runs empty and anything still burns, close the door on it, get out and call 911. You had your one attempt.

Never do this

Never use water or foam on live electrical equipment, and never water on burning oil or fat. One electrocutes you, the other throws a fireball.
Never hold the metal horn of a CO2 extinguisher. It drops to minus seventy degrees and freezes skin on contact.
Never turn your back on a fire you just put out, and never let the fire get between you and the door.

Call emergency services if

Any fire your first extinguisher did not finish, and any fire in a wall, ceiling or electrical panel.
Any fire in a room filling with smoke, however small the flames look.
After every extinguished fire involving gas equipment, so the installation gets checked.

Common questions

Which single extinguisher should I buy for home?

A six kilogram ABC powder unit covers the widest range, but powder ruins electronics and fills the room with blinding dust. For a kitchen, add a fire blanket and, if you fry often, a small wet chemical unit. Mount them by the exit, not next to the cooker.

How often does it need service?

Look at the gauge monthly, needle in the green. Most manufacturers require professional inspection every one to two years and the pressure test at longer intervals, and the sticker on the unit tells you when the last one was. An extinguisher without service is a decoration.