Polar liquids including methanol are widely used in various industries. It has unique physical and chemical properties: extreme fire and explosion hazard, corrosive activity, high toxicity. These properties determine the complexity of its extinguishing.
In Russia, there is practically no normative base for the design, construction, and repair of tanks where methanol is stored. In the available recommendations for extinguishing methanol fires by «soft» method the normative intensity of alcohol-resistant foam supply to the fire source is underestimated. Alcohol-resistant foam concentrates such as AFFF/AR, FFF/AR, S/AR allow to ensure reliable extinguishing of polar liquids. To do this, it is required to determine the method of supplying the foaming agent and its standard intensity when extinguishing methanol in the tanks.
Thermophysical properties of the methanol combustion (heat fluxes, burnout rate, heat release rate) determine the possibility of developing methods for its extinguishing on the model fire seats. For these purposes, the pallets with a diameter of more than 3 m can be used with a side thickness of 6 mm.
To extinguish methanol, it is proposed to use a low-expansion self-foaming gas-aerosol filled foam with a standard flow rate of 0.25 l/(m2·s). Specific consumption of the fire extinguishing agent was determined: for methanol, it should be 30 l/m2 with an extinguishing time of 120 s.
Foam generation can take place without the use of traditional foam generators with the help of self-contained solid fuel fire extinguishing installations. When using them, the problem of corrosion resistance of foam generating equipment is solved, and the «soft» fire extinguishing method is also implemented for the tanks with a volume of 5000 m3 or more.
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