As you know, a fire extinguisher is the most important and most effective means of fighting a fire. Using it, you can stop a fire within minutes. Therefore, in each organization, this primary means of fire safety should be located in a visible and accessible place. The types of fire extinguishers depend on the substances contained in them. They can be in the form of water, foam, powder, carbon dioxide, nitrogen and other chemical inert gases. When a fire extinguisher is put into action, a substance is released from its nozzle, which extinguishes the fire. Content is released under very high pressure.
The types of fire extinguishers used in fires depend on the nature of the fire. There are four generally accepted fire classes that are assigned the appropriate symbols. The first class (A) is the combustion of solid substances, which is accompanied by decay. These include wood, paper, textiles. Class B includes the combustion of liquid substances that are not soluble in water (gasoline, petroleum products, ether), as well as soluble elements (alcohol, glycerin). Class C includes the ignition of gaseous substances (household gas, propane). Class D fire - burning of metals and their alloys (metal hydrides, organometallic compounds). Class E includes ignition of electrical equipment.
When igniting liquid, solid and gaseous substances, fire extinguishers such as powder are used. The powder jet must be moved in different directions in order to bring down the flame.
After this is done, you need to finally cover with a layer of powder the individual foci of ignition. During these actions, it must be served in intermittent portions. When burning liquid substances (class B fire), the jet should be directed primarily to the near edge. Powder should be supplied continuously. The valve must be fully open. It should be moved so that there are no outstanding areas behind and on the sides, and a powder cloud should be constantly maintained in the combustion zone.
When igniting gaseous substances, the stream of powder should be directed almost parallel to the stream of gas, directly into the gas stream. When extinguishing electrical equipment (of course, de-energized), the stream of powder should be directed directly to the source of the flame. The expiration date of the fire extinguisher (on average) is ten years.
To extinguish fires belonging to class B (ignition of liquid substances), as well as class E (electrical equipment), carbon dioxide types of fire extinguishers are used. Liquefied carbon dioxide is their main active ingredient. They are manual, mobile, stationary. Manual fire extinguishers extinguish the ignition of electrical installations having a voltage of up to 1000V. Mobile ones are used for extinguishing flammable liquids located on an area of up to five square meters, and also small-sized electrical installations that are energized. They are also used when it is undesirable, for example, to use water (in art galleries, museums or archives). The service life of carbon dioxide fire extinguishers is up to ten years.
Foam extinguishers are used almost everywhere . They use chemical foam obtained from solutions of alkalis and acids, as well as air-mechanical foam, which is formed from aqueous solutions of blowing agents by a stream of air, carbon dioxide or nitrogen.
There are also types of fire extinguishers such as aerosol. They are used to extinguish flammable liquids, flammable, as well as electrical installations under voltage, various materials, excluding alkali metals and oxygen-containing substances. They are limited to a shelf life of five years.
There is another type of fire extinguisher - this is a self-working powder OSP-1. It is used for class A, B, C, E. fires. Its main feature is automatic operation without human intervention.
It will not be superfluous to everyone and everyone to recall that in the event of ignition, it is necessary, if possible, to immediately call a fire engine.