What is the principle of foam fire extinguishers in extinguishing fires?
2 Answers
Foam fire extinguishers primarily work on the principles of cooling and suffocation. They form a continuous foam layer on the surface of the burning material, cooling it through the foam itself and the released mixed liquid, while also isolating the burning material from oxygen via the foam layer's coverage, thereby achieving fire suppression. Foam fire extinguishers are categorized into portable foam fire extinguishers, cart-type foam fire extinguishers, and air foam fire extinguishers. They should be stored in a dry, cool, well-ventilated, and easily accessible location, away from high temperatures or areas prone to direct sunlight to prevent the decomposition of carbonates and loss of effectiveness. In winter, anti-freezing measures should be taken to prevent freezing, and regular dust removal and nozzle cleaning are necessary to ensure smooth operation.
As a veteran mechanic, I've seen quite a few car fires, and foam fire extinguishers really come in handy during emergencies. They're filled with water and foam agents, and when sprayed, they form a thick layer of foam that covers the fire source, cutting off the air supply and depriving the fire of oxygen, effectively putting it out. At the same time, the water in the foam evaporates, absorbing heat and quickly cooling high-temperature surfaces, preventing reignition. This is particularly effective for car engine oil fires, as the foam can penetrate into crevices to eliminate hidden dangers. I often remind fellow car owners to regularly check the pressure gauge and expiration date of their fire extinguishers, so they don't find out it's ineffective when they need it most. Choosing the right type is also crucial—for oil-based fires, foam extinguishers are more reliable than water-based ones, ensuring safety comes first.
