Basic countermeasures for extinguishing flammable

Basic countermeasures for extinguishing flammable liquid fires

flammable liquids are usually stored in containers or transported by pipelines. Different from gas, researchers are studying the following kinds of mixtures. Some liquid containers are closed and some are open. Generally, they are under normal pressure, and only the liquid pressure in the reaction pot (furnace, kettle) and transmission pipeline is raised. No matter whether the liquid is on fire or not, if it leaks or overflows, it will drift and flow along the ground (or water surface). Moreover, the specific gravity and water solubility of flammable liquids also involve the problems of whether to use water and ordinary foam to fight the fire, as well as the dangerous boiling and splashing problems. Therefore, fighting flammable liquid fires is often a difficult battle. In case of flammable liquid fire, the following basic countermeasures should generally be adopted

① first, cut off the way of fire spread, cool and evacuate the pressure threatened by fire, closed containers and combustibles, control the combustion range, and actively rescue the injured and trapped people. If there is liquid flowing, embankment (or oil boom) should be built to intercept the flowing flammable liquid or trench diversion

② timely understand and master the product name, specific gravity, water fusibility, and whether there are hazards such as toxicity, corrosion, boiling overflow, splashing, etc. of the fire liquid, so as to take corresponding fire extinguishing and protective measures

③ for large storage tank or flowing fire, the fire area should be accurately judged, taking 2016 as an example

liquid fires in small areas (generally within 50m2) can generally be extinguished with foggy water. It is generally more effective to extinguish the fire with foam, dry powder, carbon dioxide and halogenated alkanes (12111301)

for large-area liquid fires, the correct extinguishing agent must be selected according to its relative density (specific gravity), water solubility and burning area

liquids that are lighter than water and insoluble in water (such as gasoline, benzene, etc.) are often ineffective in extinguishing fires with straight water and mist water. Ordinary protein foam or light water foam can be used to extinguish the fire. When extinguishing with dry powder and halogenated alkanes, the fire extinguishing effect depends on the size of the burning area and the burning conditions. It is best to use water to cool the tank wall

when a liquid (such as carbon dioxide) heavier than water and insoluble in water catches fire, it can be put out with water, and water can cover the liquid surface to put out the fire. Using foam is also effective. The extinguishing effect of dry powder and halogenated alkanes depends on the size of the burning area and the burning conditions. It is best to cool the tank wall with water

water soluble liquids (such as alcohols, ketones, etc.) can be diluted with water theoretically, but in order to make the liquid flash point disappear by this method, water must account for a large proportion in the solution. This not only requires a lot of water, but also easily causes the liquid to overflow and flow, and the ordinary foam will be damaged by the water-soluble liquid (if the strength of the ordinary foam increases, the fire can be weakened). Therefore, it is best to use the insoluble foam to fight the fire. When using dry powder or halogenated alkane to fight the fire, the fire extinguishing effect depends on the size of the burning area and the burning conditions, and water is also required to cool the tank wall

④ to put out flammable liquid fires with strong toxicity, corrosivity or combustion products, the firefighters must wear protective masks and take protective measures

⑤ put out liquid fires with boiling and splashing hazards such as crude oil and heavy oil. If possible, measures such as taking and discharging water and mixing can be taken to prevent boiling and splashing. While extinguishing the fire, attention must be paid to calculating the time when boiling and splashing may occur and observing whether there are signs of boiling and splashing. Eliminate errors as soon as possible. When the commander finds dangerous signs, he should make accurate judgments immediately and issue evacuation orders in time to avoid casualties and equipment losses. After seeing or hearing the unified evacuation signal, the firefighters should immediately withdraw to a safe area

⑥ in case of leakage and fire of flammable liquid pipeline or storage tank, while cutting off the spread and limiting the fire to a certain range, try to find and close the inlet and outlet valves of the transmission pipeline. If the pipeline valve has been damaged or the storage tank leaks, quickly prepare leakage stoppage materials, and then use foam first, which is generally unacceptable to small and medium-sized enterprises; The frequency of the mechanical spring fatigue testing machine can be adjusted to extinguish the flowing flames on the ground, such as powder, carbon dioxide or mist water, to clear the obstacles for plugging, and then extinguish the flames at the leakage port, and quickly take plugging measures. Different from gas plugging, if the liquid fails to plug at one time, it can be blocked several times continuously. As long as the ground is covered with foam, the liquid flow is blocked and the surrounding ignition source is controlled, it is not necessary to ignite the liquid at the leakage port