An extinguisher empties in about ten seconds. It puts out the start of a fire, not a fire: it all comes down to the first minutes, and to getting it right the first time.
ACT
- Decide in two seconds. Only fight it if the fire is smaller than you, the smoke stays above your head and the way out is behind you. Otherwise, get out and close the door: see House fire. Either way, have someone call for help.
- Read the letter. On the label: A solids (wood, paper, fabric), B liquids (petrol, solvents), C gases, F cooking oil. The ABC powder extinguisher, the most common one, covers almost everything except the deep fryer.
- Pull the pin, twisting it if a seal holds it. If there's a round knob on top (cartridge model), strike it hard with the flat of your hand and wait two seconds for it to pressurise. Without that, the lever does nothing.
- Test it for half a second at the ground before you move in. You'll know it works and how far it reaches.
- Aim at the base of the flames, not at the flames. Two or three metres away for powder and water, one metre for CO₂.
- Sweep side to side, in short bursts, moving forward as the fire backs off. Outdoors, keep the wind at your back.
- Back away without turning around once it's out, and keep watching: it can flare up again. If it's empty and the fire is still burning, get out and close the door.
CO₂: hold the handle, never the horn. The gas comes out at −78 °C and freezes skin on contact.
ADAPT
It's a deep fryer or a pan. Never water, never a water extinguisher without the letter F. Turn off the heat, cover with a lid or a fire blanket, and leave it covered for half an hour: the oil reignites if you look too soon.
It's electrical. Cut the power first (Shutting off water, gas and power). Then CO₂ or powder. CO₂ leaves nothing behind; powder saves the building but eats the circuits.
It's gas. You close the valve (Shutting off water, gas and power), you don't put out the flame. A gas flame put out with the leak still open fills the room, and the smallest spark blows it all up. If you can't reach the valve: get out.
It's a car. Don't open the bonnet wide: fresh air feeds the fire. Aim through the gap, the grille or the wheel arches, then get away. Electric car or lithium battery: an extinguisher won't stop it, keep well back.
A person is on fire. Get them down and rolling, smother the flames with a blanket or a coat. Never CO₂ on someone. Then cool the burns, see Burns.
Small room, powder. The cloud blinds and irritates within seconds. Keep the exit in sight, and air the room before going back in.
You have no extinguisher. A lid, a blanket, a wool coat soaked and wrung out to smother it. Baking soda or salt on a small grease fire. Never flour: in a cloud, it burns. Sand or soil on a spilled liquid outdoors. A bucket of water, only on wood, paper or fabric.
You find an extinguisher in a wreck or an abandoned building. The gauge needle must be in the green. No gauge: compare its weight with the one marked on the label. Pin and seal in place, hose supple and not cracked, no rust at the bottom: a rusted body under pressure can give way. Turn it upside down and shake it: the powder must move; packed hard, it won't come out. An extinguisher that has already been used, even for a second, slowly loses pressure: treat it as empty.
It's an old brass pump model, or a glass ball. Don't use it indoors. Many contain carbon tetrachloride, which is toxic and forms phosgene on hot surfaces.
UNDERSTAND
A fire stands on four things: fuel, heat, oxygen, and a chain reaction that keeps itself going in the flames. Each extinguisher takes one of them away, and that's what decides where to use it.
Water cools. It soaks into wood and fabric and brings the fuel below its ignition temperature. On hot oil, it turns to steam at once, takes up about 1,700 times more space, and throws burning oil across the room.
CO₂ pushes the oxygen away around the flames. It leaves no trace, which makes it the friend of electronics, but it disperses fast: what was glowing can reignite as soon as it's gone. It reaches a metre, no more.
Powder breaks the chain reaction. That's why it puts out almost anything, and fast. ABC powder also melts onto embers and forms a crust that keeps the air out. The price: a blinding cloud, and a residue that turns acidic with moisture. Clean electronics quickly.
The F agent, for oils, reacts with hot oil and forms a soapy layer that seals it from the air.
Why the base. What burns are the gases escaping from the heated fuel. The flames are only the visible part; aiming at them is spraying air. At the base, you hit the surface that makes those gases.
Why so short. A 6 kg powder extinguisher empties in about ten seconds, a 2 kg CO₂ one even faster. It's made for the bin that catches fire, the fryer, the engine that starts smoking: the start of a fire. After a few minutes, a room fire is beyond what an extinguisher can absorb, and the only answer is House fire.
Letters change by country. In Europe, C means gas. In the United States, C means electrical, and cooking oils are K instead of F.