Fire extinguishing principle and use method of the four types of fire extinguishers
Jun 27, 2018

I. what is the extinguishing principle and use method of co2 fire extinguisher?

Carbon dioxide extinguishing agent is a kind of extinguishing agent with a history of more than 100 years. Carbon dioxide has a high density, about 1.5 times the density of air. At atmospheric pressure, liquid carbon dioxide vaporizes immediately, and a typical kilogram of liquid carbon dioxide can produce about 0.5 cubic meters of gas. Thus, fire, carbon dioxide gas can eliminate air and surrounded on the distribution of the burning surface of the object or in a confined space, reduce the concentration of oxygen in the fuel or protective space around, smothering action and put out the fire. In addition, when carbon dioxide exhales from a storage vessel, it vaporizes quickly from the liquid into a gas, and attracts some heat from the surrounding area, cooling it down.

Carbon dioxide fire extinguishers are mainly used for extinguishing precious equipment, archives, instruments, electrical equipment and oil under 600 v. When using, the fire extinguisher should be first carried to the fire site, put down the fire extinguisher, and pull out the safety pin. For co2 fire extinguishers without spray hoses, turn the horn up 70-90 degrees. When used, do not directly grasp the outside wall of the horn or metal joint pipe with your hand to prevent frostbite. When using co2 fire extinguisher, if it is used outdoors, it should choose the windward direction to spray. In indoor narrow small space, after extinguishing the fire operators should leave quickly to prevent suffocation.

Ii. What is the extinguishing principle and use method of dry powder fire extinguisher?

The dry powder fire extinguisher is filled with dry powder extinguishing agent. Dry powder fire extinguishing agent is used for fire extinguishing dry and easy to micro powder, by the fire extinguishing performance of inorganic salt and a small amount of additives by a mix of drying, crushing, fine solid powder. It is a widely used extinguishing agent in fire fighting and is mainly used in fire extinguishers. In addition to the special dry powder chemical extinguishing agent for metal fire fighting, dry powder extinguishing agent is generally divided into BC dry powder extinguishing agent and ABC dry powder. Such as sodium bicarbonate dry powder, modified sodium salt dry powder, potassium salt dry powder, ammonium dihydrogen phosphate dry powder, hydrogen diammonium phosphate dry powder, phosphoric acid dry powder and amino dry powder fire extinguishing agents. Dry powder fire extinguishing agent mainly by spewing powder under the action of a pressurized gas fog in contact with the flame, the physics and chemistry of fire occurs when mixing: one is the inorganic salt in the powder of volatile decomposition, generated in the process of fuel combustion with or reactive chemical inhibition of free radicals and vice catalysis, interrupt the chain reaction of burning and fire; The other is that the powder of * dry powder falls outside the surface of combustible material, causing chemical reaction, and forms a glass covering layer under the action of high temperature, so as to isolate oxygen and then suffocate the fire. There is also partial dilution of oxygen and cooling.

Dry powder fire extinguisher opening method of the most commonly used method for pressure, away from the fire will fire extinguisher mentioned after appropriate distance, upside down several times, first to the loose powder inside the cylinder, and then let the nozzle on the burning violently, pull pin insurance, pressed down, the agent will jet fire. You can also use the rotation method. When you start the dry powder extinguishing rods, left hand holding the ministry, aim the nozzle flame root, right hand pull the insurance card, open the knob clockwise, open the cartridge, hysteresis 1-4 seconds, when the powder jet fire.

Iii. What is the fire extinguishing principle and use method of water extinguisher?

The extinguishing agent in a fire extinguisher is water. Water at room temperature has lower viscosity, higher density and higher thermal stability, surface tension, is an ancient and using a wide range of natural fire extinguishing agent, easy access and storage. It mainly according to the cooling and asphyxiation of fire extinguishing. Because each kilogram of water is heated from room temperature to boiling point and evaporates completely, it can absorb 2593.4KJ of heat. Therefore, it USES its own ability to absorb sensible heat and latent heat to play the role of cooling fire extinguishing, which is unmatched by other fire extinguishing agents. In addition, the water vapor formed when it is vaporized is an inert gas and will expand by about 1,700 times its volume. When fire extinguishing, produced by water evaporation of water vapor will occupy the space of burning area, around the dilution combustion oxygen content, block of fresh air into the combustion zone, the oxygen concentration of combustion zone is reduced greatly, thus achieve the goal of smothering. When water is spray mist, the specific surface area of water droplets and fog drops will be greatly increased, enhancing the heat exchange between water and fire, and thus strengthening their cooling and suffocating effects. In addition, some inflammable and flammable liquids which are easy to dissolve in water can be diluted. The water mist produced by strong jet can make combustible and flammable liquid produce emulsifying effect, so that the liquid surface can be cooled quickly and the combustible steam can be produced at a lower speed, so as to achieve the purpose of extinguishing fire.

When using clear water fire extinguisher, can use clapping method, put clear water fire extinguisher upright first steady, take off protective cap, with palm clapping open the convex head of the top of the bar, the water will be ejected from the nozzle.

Iv. What is the applicable scope and use method of the simple fire extinguisher?

Simple fire extinguisher is a portable fire extinguisher developed in recent years. It is characterized by a small fire extinguisher with a charge of less than 500g and a pressure of less than 0.8mpa. According to the type of fire extinguishing agent filled in, the simple fire extinguisher has 1211 extinguishers, also known as aerosol halogenated alkyl extinguishers; Simple dry powder fire extinguisher, also known as portable dry powder fire extinguisher; There are also simple air foam extinguishers, also known as portable air foam extinguishers. Simple fire extinguisher is suitable for family use, simple type 1211 fire extinguisher and simple type dry powder fire extinguishers can save from liquefied petroleum gas stoves and Angle valve on the cylinder, or early fires in the place such as gas burner, can also save hot pot on fire and solid fuel burning fires such as wastepaper basket. Simple air foam is suitable for the initial fire caused by oil pan, kerosene stove, oil lamp and candle, and it can also save the fire caused by solid combustible.

When using a simple fire extinguisher, hold the upper part of the simple body of the fire extinguisher by hand, press the open button with the thumb, and press it hard to spray. In the initial fire of gas burning such as the extinguishing liquefied petroleum gas stove or cylinder Angle valve, as long as the fire is pointed at the point of injection, the fire extinguisher will be closed after the flame is extinguished for reburning; If extinguishing oil pan fire should aim at the flame root spray, and shake left and right until extinguishing fire. Turn off the gas switch immediately after putting out the fire. Or move the oil pan away from the furnace to prevent reburning. When a simple air foam is used to extinguish the oil pot fire, the foam should be sprayed against the wall of the pot, so as not to directly impact the oil surface, preventing the oil from rushing out of the oil pot and expanding the fire.

Related Industry Knowledge