Not every fire can be put out by water – the odds are that sometimes, the use of water to put out a fire can only worsen the problem. Below are the classes of fire, which explain how this can happen:
• Class A fires – this is the first class of fires, and what everyone normally associates with the word fire. They are caused by combustion of ordinary materials such as wood, plastics, clothes, paper, etc. and can be easily put out by the use of water. Fire equipment servicing and supply companies as well as fire protection regulations recommend the use of simple water extinguishers for these fires, but the more expensive foam extinguishers can also be used as well.
• Class B fires – class B fires deal with flammable liquids such as the derivates of petroleum (i.e. petrol, diesel, kerosene, fuel oil, etc.) as well as other inflammable liquids such as various paints and solvents. Class B fires cannot be put out by the use of water, as the use of water can further spread the fire by causing to spread the liquid around. The adequate fire safety equipment for the extinguishment of class B fires includes extinguishers which can either separate the fuel supply for the fire or reduce the level of oxygen below combustion levels: foam extinguishers and dry powder extinguishers do the former, whilst carbon dioxide extinguishers do the latter. Browse this page if you are looking for perfect fire safety equipment.
• Class C fires – class C fires are related to flammable gases. The American protocol for fires lumps flammable gases together with flammable liquids into a single class (class B fires), but the European and Australian classifications separate the two as class C fires and class B fires. Flammable gases include natural gas, butane and propane. Their extinguishment is similar to that of flammable liquids: water is not recommended, and foam, dry powder or carbon dioxide extinguishers should instead be used to put out the fire.
• Class D fires – class D fires denominate all fires caused by combustible metals such as the alkali metals, alkaline earth metals and the group four elements. Class D fires can only be put out by dry powder extinguishers which have special powders or other specific extinguishers for these metal fires.
• Class E fires – known as the class C fires in the American classification (and unclassified in the European classification), the class E fires include any fire that have origins in electric short circuits or overloads. The presence of electricity as a factor in these fires makes the use of water extremely dangerous to put out the fire; foam, dry powder and carbon dioxide extinguishers as well as regular baking soda are effective in putting out electrical fires.
• Class F fires – known as class K fires in the American classification, these are fires caused by fats – either animal or vegetal. The use of water is not recommended in class F fires either, as it can aggravate the fire; instead, special wet chemical extinguishers and wet blankets should be used in this case.