Fire Extinguishers are uniquely portable firefighting tools which can control or extinguish small fires at the earliest opportunity. The first line of defence in a fire scenario, fire extinguishers are pressurised containers enriched with an agent which smothers flames, removes heat or disrupts the chemical reaction that sustains flames (oxygen).
There are numerous types of fire extinguishers, and each are designed for tackling different fire classifications. For fire safety in all settings and conditions, from residential and commercial spaces to industrial and professional areas, it’s crucial that the right fire extinguisher is utilised, and is correctly positioned should a fire occur.
Made with a range of agents, fire extinguisher types include water, foam, dry powder, carbon dioxide (CO2) and wet chemical.
Which Fire Extinguisher is Needed?
A fire risk assessment can help to identify potential fire hazards in a location or property, which will likely determine which types of fire extinguisher is required. Fire hazards can include any flammable material or liquids stored, faulty wiring, appliances or electrical equipment or presence of chemicals.
Moreover, each fire extinguisher should include a fire classification label to specify its suitability for fire hazards.
| Fire Extinguisher Types | Fire Classifications | Fire Hazard/Material |
| Water | Class A | Wood, Paper & Fabrics |
| Foam | Class A & B | Gasoline & Oil |
| Dry Powder | Class A, B & C | Flammable Gases |
| Carbon Dioxide (CO2) | Class B & C | Electrical Fires |
| Wet Chemical | Class F | Cooking Oils & Fats |
Water Fire Extinguishers
Suitable for Class A fire scenarios, which are the most common fires with combustible materials like wood, paper, fabrics, coal and textiles, water fire extinguishers in the UK should have a bright red label.
Providing a cooling effect on the fuel or heat sources, water fire extinguishers can make Class A fires burn slower, before eventually extinguishing the flames entirely.
Water fire extinguishers should not be used for:
- Fires associated with electrical equipment
- Kitchen fire scenarios
- Flammable gasses and liquids
Foam Fire Extinguishers
Similarly, foam fire extinguishers, which are formulated with water-based agents, can be used on Class A fires, but are most regularly used for extinguishing Class B fires. Foam fire extinguishers in the UK should have a cream-coloured label.
Suitable for combustibles like paper, fabrics, wood and coal, foam fire extinguishers are particularly useful for flammable liquids such as paint, petrol and diesel.
Foam extinguishers, like water extinguishers, providing a cooling effect on the fuel or flame source. For burning liquids, foam extinguishers discharge a foaming agent that creates a barrier between the flame and the fuel, which eventually can extinguish the fire.
Foam fire extinguishers should not be used for:
- Kitchen fires
- Fire associated with electrical equipment
- Flammable metals
Dry Powder Fire Extinguishers
Regular dry powder fire extinguishers, which can also be referred to as “ABC” extinguishers, are very prominent in buildings and properties due to their ability to tackle Class A, B & C fires.
Dry powder fire extinguishers can be used on some electrical fires, and there are specialist designs suitable for flammable metals.
Unlike water and foam fire extinguishers, dry powder fire extinguishers are not suitable for discharge in enclosed spaces as its powder can be inhaled, and the residue is very difficult to remove. Suitable for use on paper, cardboards, fabric, textiles, wood and coal, dry powder extinguishers can effectively tackle flammable liquids, flammable gasses such as petroleum gas or acetylene and electrical equipment up to 1000V.
Dry powder fire extinguishers smother fires by forming a barrier in the middle of the fuel source and oxygen, which can extinguish flames.
Dry powder fire extinguishers should not be used for:
- Fires associated with cooking oil
- Fires associated with electrical equipment over 1000V
- Enclosed spaces
Carbon Dioxide (CO2) Fire Extinguishers
Carbon dioxide fire extinguishers are usually utilised for electrical fires and are the primary fire extinguisher stored around computer server spaces, and can also be used for Class B fire scenarios. CO2 fire extinguishers are identified in the UK with a black label.
CO2 fire extinguishers work by displacing the oxygen fires need to burn, suffocating and extinguishing flames.
Carbon dioxide fire extinguishers should not be used for:
- Kitchen Fires
- Frying Pan & Chip Pan Fires
- Combustibles/Class A Fire Scenarios
- Flammable Metals
Wet Chemical Extinguishers
Suitable for Class F fires with cooking oils and fats, wet chemical fire extinguishers are the solution for commercial kitchen areas and canteens, where there is a very prominent threat of fire scenarios.
Discharging a layer of foam over burning oil or fat, wet chemical fire extinguishers prevent oxygen from fuelling fires, and have a cooling effect. Wet chemical fire extinguishers can also be used for Class A fires.
Wet chemical fire extinguishers should not be used for:
- Fires involved flammable liquid or gas fires
- Electrical fires
- Flammable metals
Using Fire Extinguishers
Fire extinguishers should be used for small fires only.
A fire extinguisher should only be utilised when safe to do so. Any fire which is out of control, large or spreading rapidly should elicit an immediate evacuation and notification of professional fire fighters.
A fire extinguisher is only effective when it’s functioning properly. Businesses and landlords alike are responsible for ensuring fire extinguishers are regularly inspected and serviced to ensure suitability.
Over time, fire extinguishers can sustain damage or pressure loss, and should be assessed by professionals or approved contractors according the manufacturer’s specifications.
PASS – Pull, Aim, Squeeze & Sweep
To safely operate a fire extinguisher, the PASS method is a general rule of thumb. Pull, aim, squeeze and sweep.
- Pull – Pull the safety pin.
- Aim – Aim the nozzle at the base/source of the fire.
- Squeeze – Squeeze the handle to discharge the fire extinguisher.
- Sweep – Sweep the nozzle from side-to-side for maximum coverage.
When utilising a fire extinguisher, it’s crucial to stand between 6-8 feet away. For optimum performance, fire extinguishers should be discharged in short bursts. This conserves the agents, allows the agents to take effect and allows the user to assess whether the fire extinguisher is the best approach during the fire scenario.
