Kinds of fire extinguishers
As you know, the fire extinguisher is the most importantand the most effective means of fighting fire. With it, you can stop the fire within a few minutes. Therefore, in each organization, in a prominent and accessible place, this primary means of fire safety must be located. 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 the fire extinguisher is put into operation, a substance is released from its nozzle, which also extinguishes the fire. The release of the contents takes place under very high pressure.
Types of fire extinguishers used in fires,depend on the nature of the ignition. There are four common fire classes that have been 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 do not dissolve 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 - combustion of metals and their alloys (metal hydrides, organometallic compounds). To class E is the ignition of electrical equipment.
When igniting liquid, solid and gaseous substances, such types of fire extinguishers as powder ones are used. The jet of powder must be moved in different directions in order to bring down the flame.
After this is done, you need to finallycover with a layer of powder individual foci of ignition. During these actions, it must be given in intermittent portions. When burning liquids (fire class B), the jet should be sent primarily to the near edge. The powder must be fed continuously. The valve must be fully open at the same time. Moving should be such that the rear and sides do not have unexploited areas, and in the combustion zone, a powder cloud must be constantly maintained.
Upon ignition of gaseous substances, the jetthe powder should be directed almost parallel to the gas stream, directly into the gas stream. When extinguishing the 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.
For extinguishing 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 agent. They are manual, mobile, stationary. Manual extinguishers extinguish the ignition of electrical installations with voltages up to 1000V. Mobile are used to extinguish flammable liquids located on an area of up to five square meters, as well as a small size of electrical installations that are under tension. They are also used in the case when it is undesirable, for example, the use of water (in art galleries, museums or archives). The life of carbon dioxide fire extinguishers is up to ten years.
Almost everywhere foam extinguishers are used. They use chemical foam, obtained from solutions of alkalis and acids, as well as air-mechanical, which is formed from aqueous solutions of foaming agents by air, carbon dioxide or nitrogen.
There are also types of fire extinguishers, such asaerosol. They are used to extinguish flammable liquids, flammable, as well as electrical installations under voltage, of 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 - it is a self-converting powder OSB-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 for everyone and everyone to recall that if an ignition is detected, it is necessary, as soon as possible, to call the fire engine immediately.