How to use a fire extinguisher safely and effectively

In many occurrences of fire, it’s not always safe or practical to try to put it out yourself, so evacuation and calling the fire brigade may be the only option.

This is especially the case if the fire is large or spreading, the room is filling with deadly smoke, or there is no fire escape route.

But for lesser fires contained in a small space, using a fire extinguisher, if it is safe to do so, can be very effective.

Deploying a fire extinguisher correctly depends on which type it is and on what type of material is on fire. Using the wrong extinguisher is at best ineffective, and at worst could intensify the fire, so ascertain the fuel first and then ensure you have the right type of extinguisher to hand before you tackle the fire.

Materials present in the area to be protected from fire in the UK can be divided into six categories of fire involving different substances:

• Class A, combustible carbon-based solids eg paper, wood or textiles
• Class B, flammable liquids eg paraffin, petrol, diesel or oil (but not cooking oil)
• Class C, flammable gases, eg butane, propane or methane
• Class D, burning metals, eg aluminium, lithium or magnesium
• Fires caused by electrical equipment (indicated by an electric spark symbol and not the letter E)
• Class F, fats and cooking oils.

The following types of extinguishers can be used to quench the various types of fire:

• Class A – water, water mist, foam, dry powder, wet chemical
• Class B – water mist, foam, dry powder, CO2, some wet chemical
• Class C – water mist, dry powder
• Class D – specialist dry powder
• Electrical – some water mist, some foam, CO2
• Class F – water mist, wet chemical.

General safety principles

• Familiarise yourself with the extinguisher and how to use it before there is a fire. Most extinguishers include a handle or lever, a hose with a horn or nozzle, a safety pin and seal, a pressure gauge, and the relevant fluid, powder or gas
• Evacuate everyone else from the building
• Ascertain the location of your fire exit or escape route
• Make sure the flames are shorter than you and the fire is contained, eg in a wastepaper basket. Don’t stay near the fire or use the extinguisher unless you feel safe to do so
• Inspect the extinguisher and read the instructions before using it
• Check it is fully charged or it won’t work (the pressure gauge on top should be in the green area. If it’s red, the extinguisher has expired)
• Check the safety pin is not bent or the nozzle clogged or damaged and remove the safety pin to break the tamper seal
• Use the PASS protocol – Pull the pin to unlock the mechanism, Aim the hose at the base of the fire, Squeeze the lever slowly, Sweep the hose from side to side
• Stand so that your back is towards the nearest exit or escape route – never turn your back on a fire
• Stand between 6 and 8 feet away from the fire, moving closer as it is gradually extinguished. Always aim at the base of the fire
• Always ensure all areas of the fire are completely out
• Leave the scene immediately once the extinguisher is discharged and call 999 if the fire isn’t completely out
• Replace or recharge the extinguisher.

Water extinguishers (Class A)

First, it is essential to check that there is no live electrical equipment in the area. Then point the hose at the base of the flames and squeeze the lever slowly to discharge the extinguisher. Keep it moving across the area of the fire or move it slowly upwards if the fire is spreading vertically. Make sure that all areas of the fire are out completely. If not, repeat the process or get help.

Water mist extinguishers (Classes A, B, C, F and some electrical)

The instructions are the same as for water extinguishers, except that some water mist models can be used on electrical equipment up to 1,000 Volts, such as computers and printers.

Foam extinguishers (Classes A, B and some electrical)

For fires involving solids (A), point the jet at the base of the flames and keep it moving across the area of the fire.

For fires involving liquids (B), aim the jet at a vertical surface near the fire, not straight into the liquid, eg in a container, point the jet at the inside edge of the container or a nearby surface above the burning liquid. Allow the foam to build up and flow across the liquid to break the interaction between the flames and the fuel surface.

Dry powder extinguishers (Classes A, B, C, and some D if specialist powder)

Point the jet or discharge horn at the base of the flames, driving the fire towards the far edge with a rapid sweeping motion until extinguished. Make sure the fire does not flare up again, as this type of extinguisher does not cool the fire very effectively. Also, make sure you don’t inhale the toxic powder, so do not use in an enclosed space.

The use of specialist powder extinguishers to tackle burning metals (D) requires a different technique from standard extinguishers. Potential users should be trained in their use.

CO2 extinguishers (Class B and electrical)

Switch off the power if an electrical fire, if safe to do so. Direct the discharge horn at the base of the flames. Keep the jet moving across the area of the fire until it is suffocated. Be careful your fingers do not freeze to the horn. Watch for re-ignition of the fire. CO2 extinguishers have a very short discharge time.

Wet chemical extinguishers (Class A, F, and some B)

These are mainly used to extinguish chip pan fires using animal or vegetable fats. Turn off the heat source if safe to do so. Apply the wet chemical evenly at arm’s length above the fire, at least one metre away from the fire, using the extended long applicator or lance in slow, gentle, circular movements, so that the burning fat or oil does not splash out. Spray until its surface changes into a foamy, soapy substance, which acts as a blanket. Use the entire extinguisher to prevent reignition. Potential users should be trained in how to use these extinguishers properly.

Other extinction methods

Fire blankets. Turn off the heat source if safe to do so. Pull the tapes to release the blanket from its container. Carefully place the blanket over the fire keeping hands out of the way. Leave to cool. If a person is on fire, wrap the blanket around them.

To use hose reels effectively, point the jet at the base of the flames and keep it moving across the area of the fire. Ensure that all areas of the fire are out.

The water or sand in fire buckets should be thrown at the base of the flames, ensuring that all areas of the fire are out.

Finally, if there is no fire extinguisher to hand, and the fire is very small, you could try using a wet cloth or towel or shovelling sand or dirt, if available, onto the fire.

Read more about fire extinguisher types: How to choose the right class.

2023 Fire Safety eBook – Grab your free copy!

Download the Fire Safety in 2023 eBook, keeping you up to date with the biggest news and prosecution stories from around the industry. Chapters include important updates such as the Fire Safety (England) Regulations 2022 and an overview of the new British Standard for the digital management of fire safety information.

Plus, we explore the growing risks of lithium-ion battery fires and hear from experts in disability evacuation and social housing.

Get your copy today!