fire extinguishers

There are 4 main types of fire extinguisher in general use, plus dedicated extinguishers for specialist applications such as cooking fats & oils and metal fires. The 'old' British Standard for fire extinguishers (BS 5423) stipulated that the entire body of the extinguisher be colour coded to indicate the contents as follows: Red-Water, Cream-Foam, Blue-Powder and Black-CO2.

BS EN 3 requires that ALL fire extinguishers should be coloured RED, although BS 7863 allows between 3% to 5% of the body (usually the label) to be colour coded in accordance with the 'old' system.


Class A Fires involving solid materials such as wood, paper or textiles.

Class B Fires involving flammable liquids such as petrol, diesel or oils.

Class C Fires involving  gases.

Class D Fires involving metals.

Class *E Fires involving live electrical apparatus

Class F Fires involving cooking oils such as in deep-fat fryers.


*According to British Standard 5306 there is no class 'E', however for simplicity and ease of understanding for the layman, we call it class E for convenience.

Water extinguishers (red label) - For use on Class A fires.

The user can direct water onto a fire from a considerable distance however 9-litre water extinguishers are quite heavy, approx 15kg. Some water extinguishers with additives can achieve the same A rating whilst being much smaller and  lighter. Whilst water 'jet' extinguishers are not suitable for use on live electrical equipment, water spray fire extinguishers often carry a 35kV dielectric test approval. The reason water spray can be used on live electrics is that there is no continuous 'stream', water spray has air gaps between the droplets which breaks the continuity. Water spray extinguishers are rapidly gaining in popularity over the usual '6L foam and 2kg CO2' combination.

The A rating is the test rating of an extinguisher on a 'standard' test fire. The test measures how much of the test crib fire it will extinguish, in the case of a 9L water extinguisher, this is usually 1.3m. For calculation purposes the decimal place is dropped, and the extinguisher is rated at 13A. The A rating of the extinguisher is used to calculate the number of extinguishers needed in a building. This figure is based on an old assumption that a 2 gallon (9L) water extinguisher would provide cover for 200 sq m of area. The number of A rated extinguishers necessary for an average commercial building is calculated as follows:

1. First calculate the floor area in sq m

2. Multiply this by 0.065 (this gives the 'A' rating for the area concerned)

3. Divide the area A rating by the A rating of the extinguishers.

4. Round up to the nearest whole number.

e.g. For a floor area of 2100 sq m, and with 21A extinguishers .......

   2100x.065 = 136.5

   136.5/21 = 6.5

   Round up to 7

   Answer: Seven 21A extinguishers required.

Water extinguishers with additives (red label) - Suitable for Class A fires, and can also be used on Class B fires and where appropriate (this will be indicated on the extinguisher). These are usually more efficient than conventional water extinguishers.

Foam extinguishers (cream label) - Can be used on Class A or B fires and particularly suited to extinguishing liquid fires such as petrol and diesel. They should not be used on free-flowing liquid fires without advanced training as this type of fire has the potential to spread rapidly to adjacent material. This type of extinguisher is not suitable for deep-fat fryers or chip pans.

Powder extinguishers (blue label) - Can be used on most classes of fire and achieve a good ‘knock down’. They can also be used on fires involving electrical equipment but will almost certainly render that equipment useless. Because they do not cool the fire appreciably it can re-ignite. Powder extinguishers can create a loss of visibility and may affect people who have breathing problems, and are not generally suitable for enclosed spaces and are therefore not recommended for use inside buildings unless there is absolutely no alternative.

Carbon dioxide extinguishers (black label) - Particularly suitable for fires involving electrical equipment as they will extinguish a fire without causing damage (except in the case of some electronic equipment e.g. computers). As with all fires involving electrical equipment, the power should be switched off if possible.

Class ‘F’ extinguishers - Particularly suitable for commercial catering establishments with deep-fat fryers.

Fire blankets - should be located in the vicinity of the fire hazard they are to be used on, but in a position that can be safely accessed in the event of a fire. Fire blankets are suitable for dealing with small fires in containers of cooking oils or fats and fires involving clothing.

Previously, the use of wet tea towels was advocated if a fire blanket was not available, however fire & rescue service advice is now NOT to use these as many injuries have been occurring.

Commissioning and installation

BS 5306-6 recommends that fire extinguishers are commissioned and installed by a competent person.

See: Fire Extinguisher Commissioning



BEWARE! Some companies charge extortionate prices for fire extinguishers (£200 - £300).

You can buy fire extinguishers at very reasonable prices on-line from the following web site: 


Fire extinguishers should be serviced by a competent person at least annually.

We can provide fire extinguisher servicing at competitive prices in most areas. Email us for a quote on we need to know where you are and how many extinguishers you have.


The Regulatory Reform (Fire Safety) Order 2005, requires that the responsible person must, where necessary 'take measures for firefighting in the premises'  and 'nominate competent persons to implement those measures and ensure their training and the equipment available to them are adequate......' It is important that anyone expected to tackle a fire should be trained, the implications if anyone is injured. and has not been trained are obvious. Marsden Fire Safety can provide such training.

TRAINING VIDEOS CD's and DVD's are also available - click here for details


Have you seen the new EVACUATION TRAINING AID - The WHAT NOW ??? - Brilliant, simple and providing tremendous benefit during evacuation drills and exercises.


Confined Spaces
Construction Sites
Disabled Evacuation
Fire Engineering
Fire Door Retainers
Fire Safety Equipment
Fire Sprinklers
Fire Legislation
Fire Strategies
Fire Training DVDs
Health & Safety DVDs
Home Safety
Residential Care
Risk Assessment
What Now ???
Contact us
Useful Contacts
Site Map










e-mail    Tel : 0845 644 6515 or 01282 691616

Confined Spaces ] Consultancy ] Construction Sites ] Disabled Evacuation ] Fire Engineering ] Fire Door Retainers ] Fire Safety Equipment ] Fire Sprinklers ] Fire Legislation ] Fire Strategies ] Fire Training DVDs ] Health & Safety DVDs ] Home Safety ] Hospitals ] Hotels ] Residential Care ] Risk Assessment ] Training ] What Now ??? ] Contact us ] Useful Contacts ] References ] Site Map ]