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Types of Fire Extinguisher

Links to Fire Safety Sections

Section 1: Fire Extinguisher Guide
Section 2: Types of Fire Extinguisher
Section 3: How to use a Fire Extinguisher
Section 4: Positioning & Number Needed of Fire Extinguishers

Portable fire extinguishers are the most universally applicable form of fire extinguishing appliance. Trolley mounted extinguishers are used only for special applications where there may be a need for trained operators to tackle a large fire, such as one involving a significant quantity of flammable liquid.

Fires are classed according to the material that is burning. The fire extinguishers provided need to be appropriate for that class of fire.

Portable fire extinguishers are rated according to the maximum size of fire that a trained operator can control with the extinguisher. In most work places, such as offices, shops and factories, water or water based extinguishers are appropriate. Typically, a 13A rated fire extinguisher should be provided for each 200 square meters of floor area and extinguishers should be sited at fire exits and on escape routes, such that no one needs to walk further than 30 meters to reach the nearest fire extinguisher. These class A extinguishers should be supplemented by extinguishers suitable for use on live electrical equipment (normally a CO2 extinguisher) wherever such equipment is situated within the area. Where there is a commercial kitchen with deep fat fryers, one or more class F extinguishers and fire blankets should be used.

Fire Extinguishers Explained

Across Europe the markings on fire extinguishers have been standardised. The information on an extinguisher is presented in several ways.

All fire extinguishers are colour coded for easy reference.

Extinguishers have their fire rating shown in letters (such as A or B) as well as a pictogram. If the extinguisher is suitable for electrical fires it will also show a pictogram to depict this.

Fire ratings are expressed as a number and letter, ie 21A

All extinguishers carry clear operating instructions on their use printed on the fire extinguisher.

All fire extinguishers for use in the UK should be marked with their fire rating, a CE mark, a BS (BSI) kitemark which indicates BAFE approval. In order to comply with fire safety regulations and for insurance purposes you should make sure that all of your fire extinguishers carry these approvals.

All of A2Z Fire's extinguishers are brand new and comply with all British safety standards. You should never compromise when it comes to fire safety in the work place or at home.

Fire ratings correspond to the type and size of fire that the extinguisher can be used on. The numbers before the letter indicate the size of fire that the extinguisher can be used on as used under test conditions. The letter relates to the class of fire that the extinguisher is suitable for use on.

The larger the number, the larger the fire that the extinguisher can be used on.

Never take chances with fires, if the fire is too large or you have any doubt, get away from the fire and call the Fire Brigade on 999 IMMEDIATELY. Fire can spread extremely quickly if not properly contained.

Fire Extinguisher Classes Explained

Water & Water Additive

The majority of Class A fire extinguishers are water based, with some having additives to help make them more effective at tackling fires (these are generally more popular due to their increased fire fighting capability and smaller sizes). These types of extinguisher are effective for tackling and extinguishing burning materials such as paper or wood in office and warehouse locations. The higher the fire rating, the larger the fire it can tackle.


Foam fire extinguishers are normally AFFF (Aqueous Film Forming Foam). They work by extinguishing the flames and sealing in any potentially dangerous vapours. Foam extinguishers are suitable for class A and B fires. As with all extinguishers, the higher the fire rating number, the bigger the fire it can tackle.


Dry powder fire extinguishers are excellent all round extinguishers due to the large number of fire classes they can be used on. They are recommended for use on vehicles as well as the home and are filled with either ABC or BC powder as standard. They can be used on electrical equipment. They are not recommended for office use due to the fact that they produce a cloud when used which can obscure vision and can cause breathing problems in enclosed spaces. ABC powder is suitable for class A, B, C and electrical fires. BC is not suitable for class A fires.

There are also a range of specialised powder extinguishers such as Monnex (used at airports, fuel depots and in motor racing) and M28 and L2 extinguishers which are used for Class D metal fires. These types of extinguisher usually require training for correct operation.

CO2 (carbon dioxide)

CO2 fire extinguishers are the only ones recommended for use on electrical equipment as the gas is non conductive. They are also suitable for use on class B fires. It is recommended to have water, water additive or foam extinguishers along side CO2 in office, shop and factory locations.

Wet Chemical

Wet chemical extinguishers are specifically designed for use on deep fat fryers and have a class F rating. All commercial kitchens where fats are used should carry at least one wet chemical extinguisher as well as a fire blanket. They are also suitable for use on Class A fires. A wet chemical extinguisher works by extinguishing the fire and cooling the fat. They are for use on animal and vegetable fats only, and should not be used on flammable liquids such as petrol or diesel.