Types, Use and Colours of Portable Fire Extinguishers

Before you need to use a fire extinguisher read the label to make sure you fully understand the type of fire extinguisher it is and for which types of fires it is appropriate and safe to use on.

For example, standard water extinguishers should not be used on electricity. However, foam and dry water mist extinguishers, though water based, can be safely used on electrical fires, as long as they had the dielelctrical test up to 35000V (also written 35kV) carried out and as long as you keep a safety distance of 1m from the electrical fire. Nevertheless, it is good practice to try to switch off the electric supply before tackling a fire caused by electricity with any extinguisher.

Before you can operate most portable extinguishers you need to remove the safety pin. With hose reels you may have open a water valve before it can be used. Make sure that before you tackle a fire you are between the fire and exit or escape route.

Water Extinguisher

Signal Red
Best For
Fires involving organic solid materials such as wood, cloth, paper, plastics, Coal etc.
Danger
Do not use on burning fat or oil or on electrical appliances
How to Use
Point the jet at the base of the flames and keep it moving across the area of the fire. Ensure that all areas of the fire are out.
How it Works
Water has a great effect on cooling the fuel surfaces and thereby reducing the pyrolysis rate of the fuel


Water Spray Extinguisher (Water with additive)

Water Extinguisher Signal Red
Best For
Fires involving organic solid materials such as wood, cloth, paper, plastics, Coal etc. These offer significantly improved fire fighting capability than traditional jet type water fire extinguishers. Available in 3 and 6 litres.
Danger
Do not use on burning fat or oil or on electrical appliances
How to Use
Point the jet at the base of the flames and keep it moving across the area of the fire. Ensure that all areas of the fire are out.
How it Works
Water has a great effect on cooling the fuel surfaces and thereby reducing the pyrolysis rate of the fuel. Instead of a jet nozzel a spray nozzel is used, with a higher pressure, which creates a fine spray. This allows for a given quantity of water to have a considerable increase in the surface area presented to the fire. This makes extinguishing more efficient by more rapid extraction of heat, formation of steam etc. They can also contain surfactants which help the water penetrate deep into the burning material which increase the effectiveness of the extinguisher.


Water Mist Extinguisher (‘Dry’ Water Mist)

Water Mist Extinguisher Signal Red on a White Background
Best For
The first broad spectrum extinguisher to tackle A, B, C rated risks as well as fats, deep fat fryers (Class F). Models with dielectric test to 35k Volt can be safely used on electrical fires (up to 1000 Volt) if a safety distance of 1m is adhered to, as their mist (de-ionised water) does not conduct electricity and the extinguisher does not normally form puddles, which could conduct electricity.
Danger
na
How to Use
Point the jet at the base of the flames and keep it moving across the area of the fire. Ensure that all areas of the fire are out.The fire draws the microscopic water particles into the fire
How it Works
Water is turned into microscopic particles in the supersonic nozzle. The water mist is drawn to the fire where it cools and suffocates the fire. The mist also forms a safety barrier between user and fire, which keeps some of the heat back.


Powder Extinguisher (Multi-Purpose)

Dry Powder Extinguisher Blue
Best For
Can be used on fires involving organic solids, liquids such as grease, fats, oil, paint, petrol, etc but not on chip or fat pan fires. Can also be used on gas fires.
Danger
Safe on live electrical equipment, although does not penetrate the spaces in equipment easily and the fire may re-ignite. This type of extinguisher does not cool the fire very well and care should be taken that the fire does not flare up again.
Smouldering material in deep seated fires such as upholstery or bedding can cause the fire to start up again. Do not use on domestic chip or fat pan fires.There is danger of inhalation if powder extinguishers are used within buildings.
How to Use
Point the jet or discharge horn at the base of the flames and, with a rapid sweeping motion, drive the fire towards the far edge until all the flames are out. If the extinguisher has a hand control, wait until the air clears and if you can still see the flames, attack the fire again.
How it Works
Similarly to almost all extinguishing agents the powders acts as a thermal ballast making the flames too cool for the chemical reactions to continue. Some powders also provide a minor chemical inhibition, although this effect is relatively weak. These powders thus provide rapid knockdown of flame fronts, but may not keep the fire suppressed.


Dry Powder Extinguisher (Special Powders)

Specialist Powder Extinguishers Blue
Best For
These specialist powder extinguishers are designed to tackle fires involving combustible metals such as lithium, magnesium, sodium or aluminium when in the form of swarf or powder.

There are three special powders based on graphite, copper and sodium chloride.

Danger
Do not allow water to come in contact with the burning metal and the powder must be gently applied. Sodium Chloride is not recommended for Lithium.
How to Use
The lance enables the user to tackle fire at a safe distance and the low velocity applicator to reduce the energy of the jet allowing the powder to gently smother the surface of the burning material thus avoiding scattering of high temperature particles and stimulating the formation of a crust. The method of application is completely different from a standard extinguisher and user training is required. They are not suitable for use on live electrical fires.
How it Works
This extinguisher works by forming a crust which insulates the metal to prevent access to other combustible material nearby and smothering the fire to prevent oxygen from the atmosphere reacting with the metal


Foam Extinguisher (AFFF)

Fire Extinguishers Cream
Best For
Fires involving solids and burning liquids, such as paint and petrol but not suitable for chip or fat pan fires. Safe on fires caused by electricity if tested to 35kV (dielectric test) and a 1m safety distance is adhered to.
Danger
Do not use on chip or fat pan fires.
How to Use
For fires involving solids, point the jet at the base of the flames and keep it moving across the area of the fire. Ensure that all areas of the fire are out. For fires involving liquids, do not aim the jet straight into the liquid. Where the liquid on fire is in a container, point the jet at the inside edge of the container or on a nearby surface above the burning liquid. Allow the foam to build up and flow across the liquid.
How it Works
They are mainly water based, with a foaming agent so that the foam can float on top of the burning liquid and break the interaction between the flames and the fuel surface.


Carbon Dioxide Extinguisher

CO2 Fire Extinguishers Black
Best For
Live electrical equipment, although it allows re-ignition of hot plastics. Now mainly used on large computer servers, although care has to be taken not to asphyxiate people when using the extinguisher in small server rooms.
Danger
Do not use on chip or fat pan fires, as it carries burning fat out of container. This type of extinguisher does not cool the fire very well and you need to ensure that the fire does not start up again. Fumes from CO2 extinguishers can asphyxiate if used in confined spaces: ventilate the area as soon as the fire has been controlled.Only use CO2 extinguishers with frost-free horns, as the hand holding the horn can otherwise be frozen to the horn, as the gas is getting very cold during the discharge.
How to Use
The discharge horn should be directed at the base of the flames and the jet kept moving across the area of the fire.
How it Works
Carbon dioxide extinguisher works by suffocating the fire. Carbon dioxide displaces oxygen in the air. However, once discharged, the CO2 will dissipate quickly and allow access for oxygen again, which can re-ignite the fire.


Wet Chemical

Canary Yellow
Best For
Wet chemical fire extinguishers are ideal for Class F fires, involving cooking oils and fats, such as lard, olive oil, sunflower oil, maize oil and butter.
Danger
Check manufacturer’s instructions for suitability of use. These extinguishers are usually not recommended for class B fires such as petrol, although Gloria has produced a 3l wet chemical extinguisher with B rating.
How to Use
Apply the wet chemical using the extended applicator in slow circular movements, which give a gentle, yet highly effective application. Apply the fine spray onto the burning fat until the surface of the burning cooking oil changes into a soapy like substance which prevents re-ignition. The gentle application helps to prevent burning oil splashing out of the container. Make sure that you empty the entire content of the wet chemical extinguisher onto the oil/fat, as the fire can re-ignite otherwise.
How it Works
Most class F extinguishers contain a solution of potassium acetate, sometimes with some potassium citrate or potassium bicarbonate. The extinguishers spray the agent out as a fine mist. The mist acts to cool the flame front, while the potassium salts saponify the surface of the burning cooking oil, producing a layer of foam over the surface. This solution thus provides a similar blanketing effect to a foam extinguisher, but with a greater cooling effect. The saponification only works on animal fats and vegetable oils, so most class F extinguishers cannot be used for class B fires. The misting also helps to prevent splashing the blazing oil.

Tests have established that a 6 litre wet chemical fire extinguisher with a 75F rating can deal with a fat fire of maximum 0.11 m2 surface area.


Fire Blanket

Fire Blankets Fire Blanket Fire blankets are made of fire resistant materials. They are particularly useful for smothering flammable liquid fires or for wrapping round a person whose clothing is on fire. Fire blankets conforming to British Standard BS EN 1869 : 1997 are suitable for use in the home BS 7944 : 1999 is suitable for industrial use. These will be marked to show whether they should be thrown away after use or used again after cleaning in accordance with the manufacturers instructions.
Best For
Fires involving both solids and liquids. Particularly good for small clothing fires and for chip and fat pan fires providing the blanket completely covers the fire.
Danger
If the blanket does not completely cover the fire, it will not be able to extinguish the fire.
How to Use
Place carefully over the fire. Keep your hands shielded from the fire. Do not waft the fire towards you.
How it Works
Smothers the fire and prevents oxygen getting to the fire.


Hose Reel

Fire Hose Reels Hose Reel
Best For
Fires involving organic solid materials such as wood, cloth, paper, plastics, coal etc.
Danger
Do not use on burning fat or oil or on electrical appliances before the electric supply has been isolated.
How to Use
Point the jet at the base of the flames and keep it moving across the area of the fire. Ensure that all areas of the fire are out.
How it Works
Water has a great effect on cooling the fuel surfaces and thereby reducing the pyrolysis rate of the fuel


Fire Buckets

Fire Buckets A simple bucket of water can be used on Class A type of fires either to supplement a water extinguisher or as a first attack if an extinguisher is not immediately available. It also can be filled with dry sand and used as an absorbing agent or to dam a flow of flammable liquid. They do have serious disadvantages as they are often misused, left empty or allowed to be used as a refuse container.
Best For
Wood, Cloth, Paper, Plastics, Coal
Danger
Do not use on burning fat or oil or on electrical appliances before the electric supply has been isolated.
How to Use
Throw at the base of the flames. Ensure that all areas of the fire are out.
How it Works
Water has a great effect on cooling the fuel surfaces and thereby reducing the pyrolysis rate of the fuel