Stock Code: 833236
Fire extinguishing principle and application scope of foam fire extinguishing agent
The fire extinguishing mechanism of foam fire extinguishing agents is mainly cooling and suffocating, that is, a continuous foam layer is formed on the surface of the burning material, and the surface of the burning material is cooled by the foam itself and the precipitated mixed liquid, and covered by the foam layer. It can extinguish fire by isolating combustibles from oxygen.
details as follows:
(1) The foam covering layer formed on the surface of the fire extinguishing foam can isolate the surface of the fire from the air.
(2) The foam layer seals the surface of the combustible material, which can block the thermal radiation of the flame to the combustible material, prevent evaporation or pyrolysis of the combustible material, and make it difficult for the combustible gas to enter the combustion zone.
(3) The liquid precipitated by the foam has a cooling effect on the surface.
(4) The water vapor produced by thermal evaporation of the foam has the effect of diluting the oxygen concentration in the combustion zone.
Foam fire extinguishing agents are mainly suitable for extinguishing water-insoluble flammable and flammable liquid fires and general solid material fires (such as fires flowing from oil tanks into fire dykes or flammable liquids leaking from rotating machinery, etc.), and warehouses Fires in limited spaces such as hangars, basements, underpasses, mines, and ships. In case of leakage of cryogenic liquid storage tanks such as liquefied natural gas, a high expansion foam can also be applied to prevent volatilization of the steam and fire.
Because of its small specific gravity and good fluidity, it can be transported to a certain height or a long distance to extinguish the fire through the appropriate pipeline under the action of the air flow that generates foam.
When the oil tank is on fire, the upward airflow over the oil tank has a large lift, but the proportion of the foam is very small, and it cannot cover the oil surface. Therefore, you cannot use a high multiple foam fire extinguishing agent to extinguish the fire of the oil tank: Fires of water-soluble and flammable liquids can sometimes be extinguished by flooding.
When using a high expansion foam to extinguish fire, care must be taken to prevent the gas entering the high expansion foam generator from containing burned gas, soot and acid gases, so as not to damage the foam.
Protein foam extinguishing agent: It is mainly used to extinguish general non-water-soluble flammable and combustible liquid fires. It can also be used to extinguish general fires of combustible solid materials. Because of its good thermal stability and covering properties, it is also widely used in the fire extinguishing of petroleum storage tanks or spraying foam into unfired oil tanks to prevent igniting heat from nearby fired oil tanks. Use protein foam to rescue crude oil. When a heavy oil storage tank fires, pay attention to possible oil foam boiling or splashing.
Fluoroprotein foam extinguishing agent: It is mainly used to extinguish fires of various insoluble flammable and flammable liquids and some combustible solids. It is widely used to extinguish large-scale storage tanks (submerged jets), bulk warehouses, transfer and transfer devices, production and processing devices, oil terminals and aircraft fires.
Aqueous film-forming foam fire extinguishing agent: It is suitable for extinguishing hydrocarbon type A and B fires, such as fires of petroleum products and fuel oil, gasoline, flammables, etc., as well as extinguishing fires of large oil tanks by means of "under liquid injection". It is currently the most widely used foam fire extinguishing agent in domestic oil fields, oil depots, airports, underground garages, ships, and docks.
Anti-solvent foam fire extinguishing agent: mainly used to extinguish general water-soluble flammable liquid fires such as ethanol, methanol, acetone, ethyl acetate and general solid material fires. It is a kind of foam fire extinguishing agent that chemical units, paint units, pharmaceutical factories and all kinds of hazardous chemicals must use.
High multiple foam extinguishing agent: It has the characteristics of high foaming multiple, strong sealability, high fire extinguishing efficiency, and easy removal after fire extinguishing. With the high expansion foam generating device, it can be used to completely submerge and cover fires of type A and B. It can effectively control the flowing fire of liquefied petroleum gas and liquefied natural gas, and has good permeability for type A fires. High expansion foam extinguishing agent can quickly fill a large area of fire area. It is mainly used in solid materials warehouses, flammable liquid warehouses, industrial buildings (or workshops) at risk of fire, underground construction projects or underground tunnels.
How chemical companies choose fire fighting foam