Fire classes are divided depending on fire objects. 5 classes are distinguished in total, some of which have subclasses. For each type of fire, certain options for fire extinguishing agents should be used. To date, the following types of fire extinguishing are distinguished: water, gas, foam, powder and aerosol.
Fire classes are indicated by the letters of the Latin alphabet: a, b, c, d, e.
First class a. This includes fires associated with the burning of solid components. The class includes two subclasses. A1 — combustion, which is accompanied by the overwhelming of solids, such as cotton, wood, textiles, etc. D.). The A2 subgroup includes the burning of solid structures without smoldering, for example, plastic or rubber. In this case, the use of all options for fire extinguishing agents is applicable. However, the use of cooling reagents, for example, water, aqueous solutions or gas substance NOVEC 1230 include effective,.
Second class b — burning of liquid substances. Includes two subclasses. B1 — burning of liquid hydrophobic substances, for example, gasoline, as well as solid liquefied substances, such as paraffin. B2 — includes ignition of polar liquid soluble substances in water, for example, acetone and alcohol. All types of fire extinguishing agents are also used to combat fires of this class. The most effective in the fight against extinguishing this kind of fires are foam. The use of water is ineffective, as it quickly plunges into a burning liquid.
The third grade C is fires associated with the burning of gaseous substances, for example, ammonia, hydrogen, household gas. All groups of funds are used to combat fire, except for isolating foam.
Class D fires are caused by metals burning. Three subclasses are distinguished. D1 — associated with ignition of light metals and their alloys, except for alkaline, for example, magnesium. D2 — combustion of alkaline metals. D3 — ignition of metal -containing connections. When extinguishing fires of this class, the use of water is unacceptable. Especially for combating this type of fire, fire extinguishing powders were developed, which are used in industries associated with this type of metals.
The last class E is associated with the burning of objects that are under electric voltage, for example, various kinds of electrical installations. In terms of safety, the use of substances with high electrical conductivity, such as water, is prohibited in this case. To extinguish fires of this type, it is effective to use gas fire extinguishing using gases inhibitory or diluting nature. This includes a group of coladons, as well as gases of Argon, carbon dioxide and their mixture.
