Fire extinguishing principle of efficient and environmentally friendly foam extinguishing agent

Efficient and environmentally friendly foam fire extinguishing agent is an effective fire extinguishing agent for extinguishing flammable and combustible liquids. It mainly produces a condensed foam floating layer on the surface of the liquid, which suffocates and cools the liquid. Efficient and environmentally friendly foam fire extinguishing agents include chemical foam, air foam, fluorine protein foam, ordinary liquid film-forming foam and insoluble foam. It has wide applicability. Efficient environment-friendly foam fire extinguishing agent is a kind of fire extinguishing agent that can be miscible with ordinary liquid and produce foam fire extinguishing agent through mechanical action or chemical reaction. Efficient and environmentally friendly foam fire extinguishing agent is generally composed of foam generating agent, foam stabilizer, viscosity reducer, antifreeze, cosolvent, preservative and ordinary liquid. It is mainly used to extinguish major disasters caused by flammable liquids and general solids that are insoluble in ordinary liquids. Special and efficient environment-friendly foam fire extinguishing agent can also put out the common liquid soluble flammable liquid major disasters.

Efficient and environmentally friendly foam extinguishing agent is a mixed solution composed of sodium bicarbonate and foam generator (or mechanical foam generator). Foam is a group of small, light-weight bubbles whose surface is surrounded by liquid. It is an effective fire extinguishing agent for extinguishing major disasters in flammable and combustible liquids. Efficient and environmentally friendly foam fire extinguishing agents include chemical foam and air mechanical foam. Chemical foam is produced by a chemical reaction, and carbon dioxide is mainly present in the foam. Aeromechanical foam is produced by the mechanical action of a stream of ordinary liquid, and the foam is mainly air. Their fire extinguishing principle is the same.

After being sprayed on the fire-fighting liquid, the foam can float on the surface of the liquid to cover it. Foam is a poor conductor of heat. It has the function of heat insulation and heat absorption. It can absorb the heat of the liquid and reduce the temperature and evaporation rate of the liquid surface; on the other hand, there is a certain viscosity between the foams to prevent the passage of liquid vapor and isolate the liquid from the combustion zone. When the liquid is completely covered with foam, the flame is forced to extinguish because it cannot be supplemented by combustible vapor.

1. Chemical foam. It is formed by the chemical reaction of a common liquid solution of an acidic substance (aluminum sulfate) and an alkaline substance (sodium bicarbonate). On the one hand, the carbon dioxide produced by the reaction makes the foam solution under pressure, on the other hand, under the action of the foam generator, a foam with carbon dioxide as the core and aluminum hydroxide as the outer layer is formed. It has the characteristics of strong fire resistance, good durability and good viscosity. It is attached to the surface of the ignited object, has a good covering and cooling effect, can isolate combustibles and oxygen, and play a role in extinguishing fire.

Chemical foam can put out a variety of liquid and solid materials of major disasters. It is a good fire extinguishing agent for petroleum and its products and many other oils (such as gasoline, kerosene, etc.), and can also be used for the initial major disasters of general combustible materials (such as bamboo, wood, cotton, grass, etc.). However, alcohol, ether, ketone and other common liquid soluble liquids should not be extinguished together with chemical foam.

2. Ordinary protein foam. A fire extinguishing agent produced by the mechanical action of protein type air foam liquid, ordinary liquid and air. The ratio of air foam liquid to ordinary liquid is 6:94 or 3:97.

Ordinary protein foam has good coverage, cooling and fire extinguishing effect, can effectively put out the flammable liquid major disasters. For example, it can extinguish major disasters in crude oil, gasoline, kerosene and wood, but it is not suitable for extinguishing major disasters in alcohol, ether, ketones and other soluble liquids.

3. Soluble anti-air foam. The fire extinguishing agent used to extinguish the fire is formed by mixing the insoluble air foam liquid and the ordinary liquid in proportion by mechanical action. The fire extinguishing agent added insoluble in ordinary liquid fatty acid zinc soap, can be evenly distributed on the foam wall, effectively prevent ordinary liquid soluble solvent dissolved in the ordinary liquid in the foam, protect the foam, so that the foam can be firmly covered on the solvent layer, play a role in extinguishing fire. Common liquid soluble anti-air efficient environmentally friendly foam fire extinguishing agent can not only put out alcohol (methanol, ethanol, isopropanol), ester (ethyl acetate) and other common liquid soluble organic solvents caused by major disasters, but also put out oil, wood and non-common liquid soluble organic matter caused by major disasters.