![]() CO2 extinguishers work by smothering the fire and cutting off the supply of air.Ĭarbon Dioxide Extinguishers (CO2) have a black label. They can also be used on Class B fires, those involving flammable liquids such paraffin or petrol. Carbon dioxide extinguishers do not leave any residue, unlike a foam extinguisher. Carbon dioxide extinguishers (CO2)ĬO2 extinguishers are ideal for places with a lot of electrical equipment such as offices or server rooms because they are safe to use on fires involving electrical apparatus. They are not generally recommended for use inside buildings unless there is absolutely no alternative. Powder extinguishers can also create a loss of visibility and may create breathing problems. They can also be used on fires involving electrical equipment however, they do not cool the fire so it can re-ignite. Powder extinguishers are a good multi-purpose fire extinguisher because they can be used on Class A, B and C fires. They are not suitable for use on free flowing liquid fires.įoam extinguishers have a cream label. The foam extinguishes liquid fires by sealing the surface of the liquid, preventing flammable vapour reaching the air and starving the fire of fuel. They are most suited to extinguishing liquid fires such as petrol or diesel and are more versatile than water jet extinguishers because they can also be used on solids such as wood and paper. The downside is the smaller the droplet the less it weighs and therefore the less powerful the cloud of water.Īll water extinguishers have a red label.įoam fire extinguishers can be used on Class A and B fires. The smaller the droplet, the larger its surface area in relation to its size, the quicker the droplet evaporates which absorbs the heat energy faster. Water mist, or fog, extinguishers apply water in the form of mist, or fog, the droplets are much smaller than those from the water spray extinguisher.Adding the chemicals to the water means that a smaller extinguisher can produce the same fire rating as a larger, water only, extinguisher. The water loses its natural surface tension meaning that it can soak into the burning materials more effectively. Water extinguishers with additives are water extinguishers with foaming chemicals added.Most water spray fire extinguishers carry a 35 kV dielectric test approval which means they have been tested on a 35,000 Volt electrical source at one meter. ![]() Water spray extinguishers use a very fine spray of water droplets, each droplet is surrounded by air which is non-conductive.They should not be used on live electrical equipment. ![]()
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