Fire extinguishers are designed to tackle specific types of fire. There are six different classes of fire and several different types of fire extinguishers.
Classes of fire
- 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.
Water extinguishers are one of the most cost-effective ways to fight Class A fires, those fuelled by solid materials such as paper, wood and textiles.
There are four different types of water extinguishers: water jet, water spray, water with additives and water mist or fog.
- Water jet extinguishers work by spraying a jet of water at the burning materials, cooling them and preventing re-ignition. they ought to not be used on live electrical instrumentality.
- Water spray extinguishers use a really precipitation of water droplets, every driblet is encircled by air that is non-conductive. Most water spray hearth extinguishers carry a thirty five kV insulator take a look at approval which implies they need been tested on a thirty five,000 potential unit electrical supply at one meter.
- Water fire extinguishers with additives area unit water extinguishers with foaming chemicals more. The water loses its natural physical phenomenon which means that it will soak into the burning materials a lot of effectively. Adding the chemicals to the water means a smaller fire extinguisher will turn out an equivalent fireplace rating as a bigger, water only, extinguisher.
- Water mist, or fog, extinguishers apply water within the type of mist, or fog, the droplets square measure a lot of smaller than those from the water spray device. The smaller the drop, the larger its area in regard to its size, the faster the drop evaporates that absorbs the warmth energy quicker. The draw back is that the smaller the drop the less it weighs and so the less powerful the cloud of water.
All water extinguishers have a red label.
Powder extinguishers area unit an honest multi-purpose device as a result of they’ll be used on category A, B and C fires. they’ll even be used on fires involving electrical instrumentation but, they are doing not cool the fireplace thus it will re-ignite. Powder extinguishers can even produce a loss of visibility and should produce respiration issues. they’re not usually counseled to be used within buildings unless there’s completely no different.
Powder extinguishers have a blue label.
Foam hearth extinguishers are often used on category A and B fires. area unit|they’re most suited to extinction liquid fires like gas or diesel and are a lot of versatile than water jet extinguishers as a result of they will even be used on solids like wood and paper. the froth extinguishes liquid fires by protection the surface of the liquid, preventing ignitable vapour reaching the air and starving the fireplace of fuel. they’re not appropriate to be used on free flowing liquid fires.
Foam extinguishers have a cream label.
Carbon dioxide extinguishers (CO2)
CO2 extinguishers ar ideal for places with loads of electrical instrumentation like offices or server rooms as a result of they’re safe to use on fires involving electrical equipment. greenhouse gas extinguishers don’t leave any residue, in contrast to a foam device. they’ll even be used on category B fires, those involving ignitable liquids such paraffin or gasoline. carbonic acid gas extinguishers work by dyspnoeal the fireplace and alienating the availability of air.
Carbon Dioxide Extinguishers (CO2) have a black label.
Fire blankets square measure primarily to be used on hot oil fires like sauteing pans or little deep fat fryers. they will even be used on somebody whose wear has caught hearth. They work by dyspnoeic the hearth, stopping access to the element fuelling it and ending it.
Wet chemical extinguishers
Wet chemical extinguishers ar appropriate to be used on category F fires involving cookery oils and fats, like lard, olive oil, sunflower-seed oil, maize oil and butter. they’re extraordinarily effective, once used properly. The wet chemical chop-chop knocks the flames out, cools the burning oil and with chemicals reacts to create a soap-like answer, waterproofing the surface and preventing re-ignition. though they’re primarily designed to be used on category F fires, cookery oils and deep fat fryers. they’ll even be used on category A fires (wood, paper and fabrics) and sophistication B fires (flammable liquids).
Wet chemical extinguishers have a yellow label.