The LWF Blog

Choosing the right fire extinguisher for a fire | Fire safety law and colour coding

April 7, 2014 11:00 am

The majority of facilities provide fire extinguishers in all relevant areas, with a few exceptions. Your fire risk assessment will have shown a need for fire extinguishers to be placed at fire points within the facility and for the fire extinguishers themselves to be colour-coded, to make it easier to choose the correct extinguisher for the type of fire. Additionally, the fire risk assessment will have shown the need for extinguisher training to be a part of the fire safety training to members of staff.

Fire extinguishers provide an inexpensive first line of defence against small fires and when used correctly.

The law relating to fire extinguishers

Two main pieces of legislature relate to the provision and use of fire extinguishers in facilities. The first is the Regulatory Reform (Fire Safety) Order 2005 which lays out the rules regarding the provision of fire extinguishers in all premises and also makes it mandatory for fire extinguisher training to be included in staff fire safety training. It should be noted that ‘staff’ in this instance relates to all permanent and temporary members of staff, including agency and casual workers.

The second piece of legislation is a British Standard – BS EN 3 “Portable fire extinguishers” 1996 and it sets the standards for production method, quality and testing of extinguishers produced after publication. In addition, BS 7863 “Recommendations for colour coding to indicate the extinguishing media contained in portable fire extinguishers” was published, which enforced changes to the colour-coding of fire extinguishers, in order that people were more easily able to recognise which to use in a particular circumstance.

From the date of publication, all fire extinguishers produced had to adhere to the following colour-coding template:

Red – contains water

Cream – contains foam

Green – contains vaporising liquid

Blue – contains powder

Black – contains carbon dioxide

The colour-coding itself is shown on a coloured band around the standard red canister, or a coloured label affixed to the front of the extinguisher. Prior to this, all fire extinguishers had a body colour that indicated use. These extinguishers remain legal to use up until they are no longer serviceable.

How to classify a fire and choose an extinguisher

Class A type fire

Would usually involve easily combustible materials such as wood, paper, textiles, straw, coal etc. The best extinguishers for these fires are usually water (red), foam (cream) or powder (blue).

Class B type fire

Often caused by combustion of liquids or materials that liquefy for example fats, oils, petrol, paints alcohol and paraffin. The best extinguishers to use in the case of these fires would be foam (cream), powder (blue) or carbon dioxide (black).

Class C type fire

Usually caused by the combustion of gases, for example: hydrogen, natural gas, methane, propane and acetylene. The only way to stop this fire would be to shut off the source of fuel, e.g. a gas tap, although the likelihood of an explosion in case of a fire like this is high, so immediate evacuation is suggested. An extinguisher would not stop the fire.


Class D type fire

Class D fires involve combustible metals such as sodium, magnesium, aluminium, lithium and potassium. This type of fire should be fought by experienced fire service professionals only and a normal type of fire extinguisher would not have an effect.

Class F type fire

Usually involves combustible oils and grease commonly found in commercial kitchens. These kind of fires require a special wet chemical extinguishing agent that is specially suited for extinguishing these hot fires, which have the ability to re-flash. Other types of extinguisher, such as water, would make the fire worse and so should not be used.

This short series on fire extinguishers will continue next week, looking in more detail about how fire extinguishers should be located within your facility. In the meantime, if you would like more information on fire extinguishers or any other aspect of fire safety, please contact Peter Gyere on 0208  668 8663.

Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 25 years experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.

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