When it comes to finding the right fire extinguisher, no single type of extinguisher is completely effective on all types of fires. So, when making your purchase, it is essential to consider the type of fire you may have to encounter. Use of the wrong sort of fire extinguisher for the job can be dangerous, potentially worsening the fire and endangering anyone attempting to combat it.
The 6 types of fires
The fire classification system divides fires into different classes based on the fuel involved. With the exception of ‘electrical fires,’ each fire class is represented by a letter of the alphabet and an easily identifiable symbol. This is intended to aid users in selecting the appropriate fire extinguisher to handle a particular fire event. We have outlined this class rating system below:
| Classification | Fuel type |
| Class A | Solids, e.g. paper, wood, soft furnishings and plastic |
| Class B | Flammable liquids, e.g. paraffin, petrol and oil |
| Class C | Flammable gases, e.g. propane, butane and methane |
| Class D | Metals, e.g. aluminium, magnesium and titanium |
| Class F | Cooking oils & fats |
| Electrical | Fires involving electrical apparatus. Previously known as Class E, this sort of fire can belong to any of the classes because it is not the electricity that is burning, but rather the surrounding elements that have been set ablaze by the electric current. |
Types of fire extinguishers
There are a variety of fire extinguishers available in different types, each designed to handle specific fire classes. According to current British Standards (BS EN3), fire extinguishers should have a red body (RAL 3000) and an agent specific colour band spanning 5-10% of the surface, corresponding to the extinguisher contents.
| Type of fire extinguisher | Colour | Fire classification | |
| Water | Red | Class A | On Class A fires involving solid combustibles, water extinguishers are employed. They are not effective on flames fuelled by flammable liquids or those involving electricity. |
| Foam | Cream | Class A and B | Foam is a multipurpose fire extinguisher that can be used to suppress both Class A and B fires. The foam agent aids in the prevention of re-ignition. |
| CO2 | Black | Class B and E | CO2 fire extinguishers are used to put out fires affecting electrical equipment. CO2 is not a conductor and does not emit any hazardous byproducts. |
| Dry Powder | Blue | Class A, B and C | Class A, B, C, and electrical fires can all be extinguished with dry powder extinguishers. Due to the risk of inhalation, dry powder is not suggested for usage indoors. It can obstruct eyesight and damage goods and machinery. |
| Specialist Powder | Blue | Class D | These specialised powder extinguishers are efficient on metal flames but ineffectual on all other types of fires. L2 powder extinguishers are appropriate for use against lithium metal fires. As lithium-ion batteries do not contain lithium metal, but instead have liquid electrolytes, they are considered to be class B fires. |
| Wet Chemical | Yellow | Class F | Wet chemical extinguishers are used to put out flames caused by cooking fats and oils. They are particularly effective for usage in restaurants and kitchens. They normally have a class A classification as well. |
When deciding which fire extinguisher you need, a fire risk assessment will enable you to identify the fire dangers and exactly which extinguisher you will need should a fire occur within your premises. According to UK fire extinguisher regulations, every floor of a structure should contain a minimum of two ‘Class A’ extinguishers (for wood/paper/’Carbonaceous’ fires) – these can be in the form of water or foam extinguishers. Exceptions to this include if your premises are particularly small and having two extinguishers would be an obstacle to escape, then only one extinguisher may be required. Other types of fire extinguishers, as determined in your risk assessment, may be required depending on the equipment in your premises. CO2 extinguishers are the most commonly used supplementary extinguishers when fighting electrical fires. UK regulations request the following:
- All premises with electrical equipment need at least 2kg CO2 extinguishers
- 415 volt rated equipment requires 5kg CO2 extinguishers
As computers and electronic equipment are commonplace in any building, there are very few situations in which a CO2 extinguisher is not required. As a result, it is standard to see CO2 extinguishers coupled with foam or water extinguishers, meeting UK fire extinguisher legal requirements. Other types of extinguishers you may require (subject to your location) include:
- Dry powder extinguishers: used in gas-risk environments such as boiler rooms (not recommended for other indoor use)
- Wet chemical extinguishers: for use in restaurants and kitchens where cooking oils and fats can be the cause and fuel of fire.
For all your fire extinguisher needs, give us a call on 01376 519 627.
