The different types of fire extinguishers
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This article will go through the various types of fire extinguisher, how they operate and the types of fire that they are designed to be used on. Having worked as fire safety advisers in Leeds for many years, we can say with confidence that the vast majority of employees in the various businesses visited do not know difference between the different types of fire extinguisher. Using the wrong fire extinguisher on the wrong type of fire can at best mean your actions are ineffective, and at worst it could make matters much worse.
The classes of fire
- Class A fire = solids such as items made of wood including paper, fabrics or plastic.
- Class B fire = volatile liquids like petrol which are flammable.
- Class C fire = volatile gases like cooking gas bottles containing butane or propane.
- Class D fire = metals (eg aluminium, magnesium etc)
- Glass E fire = electrical items and electrical based fires
- Class F fire = organic based materials specifically things like cooking fat and oil
The types of fire extinguisher
There are a number of different types of extinguishers which are designed to be used only on specific classes of fire. This is based on what they use to combat the fire, and how they mitigate additional hazard which may be present.
Water – These are the most common types of fire extinguisher as they are easily purchased, available for use on common types of fire, and relatively low cost. They are suitable for class A fires involving solids like wood, plastic and paper. They should not be used on flammable liquids or cooking fats and oils (class B and class F).
Foam – These fire extinguishers are versatile and for use on a more extensive range of fire sources. They can be used for wood, plastic and paper (class a), and also flammable class b liquids. Like water fire extinguishers they should not be used on electrical items, however there is less risk if the foam fire extinguisher is inadvertently sprayed on to electrical appliances than would be the case with a water extinguisher.
Powder – Dry powder fire extinguishers may be considered as multi use as they are usable and safe for class a, b and c fires. There are special powders which can be used for extinguishing metal based fires and extra care should be taken when using powder on flammable gases. There are additional hazards when tackling a class c fire using a powder extinguisher if the source of the fire has not been identified and shut off.
Carbon dioxide – CO2 fire extinguishers are ideal for electrical based fires which present a hazard if using water, foam or powder. The carbon dioxide will suffocate the fire, however you should remember that unlike powder, water or foam, CO2 gas does little to prevent a fire reigniting once extinguished as it dissipates quickly.
Fire extinguisher colour coding
Fire extinguishers have colour codes to help with quick identification, and they will also often show clear diagrams and labelling to try and ensure you use the correct extinguisher on the correct class of fire.
- Water fire extinguishers are colour coded red.
- Foam fire extinguishers are colour coded in cream.
- Powder fire extinguishers are colour coded with blue.
- Carbon dioxide fire extinguishers are colour coded with black.
Fire extinguishers are mostly coloured red and the colour coding will be represented using a colour band around the top of the apparatus.