A guide to dry powder fire extinguishers

A dry powder (or powder) fire extinguisher is multi-purpose and can be used on Class A, B and C fires, which is why they’re also known as ABC fire extinguishers. You may sometimes hear of them referred to as dry chemical fire extinguishers. Ideally placed in garage forecourts, commercial boiler rooms and large workshops, a powder fire extinguisher is a versatile piece of fire safety equipment.

In this helpful guide, we outline suitable powder fire extinguisher use, covering both the types of fire a dry powder fire extinguisher is not used for as well as the types of fire it is suitable for. Additionally, we’ll examine how a powder fire extinguisher works and the surroundings that would benefit from having one on site and finally, how a powder fire extinguisher can be identified.

What is a powder fire extinguisher used for??

A versatile option, powder fire extinguisher use is suitable on Class A (flammable solids), B (flammable liquids) and C (flammable gases) fires. They can also be used on electrical fires involving electrical equipment under 1000v, without causing a risk of electric shock. However, where there’s this kind of fire risk (such as in a team kitchen, or around an electrical heater), we’d also recommend having CO2 fire extinguishers on hand.

A dry powder fire extinguisher is not used for electrical equipment over 1000v, and you need to be careful when powder fire extinguisher use is applied to items such as computers, as this can cause corrosion. Finally, it is not a suitable cooking oil fire extinguisher, as the auto-ignition temperature of burning cooking oil is higher than that of other typical combustible liquids, rendering dry powder fire extinguishers ineffective against Class F fires.

How does a powder fire extinguisher work?

The agent in a powder fire extinguisher forms a thick ‘blanket’ over the fire, starving it of oxygen and extinguishing it. However, it’s worth noting that because a dry powder fire extinguisher doesn’t cool the fire, there’s a small risk of re-ignition.

How is a powder fire extinguisher identified?

A blue-coloured label on the powder fire extinguisher stating ‘Powder’ provides clear identification. There should also be an extinguisher ID sign fixed above the fire extinguisher, reading “Powder” to advise what classes of fire it can and cannot be used on

What locations are suitable for powder fire extinguisher use?

Spaces that benefit from having a powder fire extinguisher on site include workshops, garage forecourts and construction sites. Because a powder fire extinguisher is suitable for fires involving flammable liquids and gases, they’re also recommended for all vehicles, including fuel tankers.

However, a powder fire extinguisher isn’t suitable for enclosed spaces as the dry powder can obscure vision and be easily inhaled, and the residue left behind can be difficult to clean up.

How do you use a dry powder fire extinguisher?

Firstly, remove the safety pin to break the anti-tamper seal, and stand well back from the fire. Then, aim at the base of the fire and rapidly move the jet backwards and forwards. For electrical fires, ensure to switch off the power if it’s safe to do so, before aiming at the base of the fire.