The fire-fighting foam liquid company stated that the nature of fire is heat. Therefore, the heat resistance of the foam fire extinguishing agent is an important indicator. At this point, protein foam is better than aqueous film-forming foam. Because the percentage of suspended matter in the protein foam is higher, it is more beneficial to resist heat. When the protein foam layer is formed on the hot metal surface, a solid particle isolation layer is formed between it and the hot surface, and is combined with the foam layer. The aqueous film-forming foam layer easily disappears from the hot surface, often leaving exposed combustibles, which will reignite under certain circumstances. The solution is to spray more foam on the surface until the metal cools, or the amount of foam is enough to form a stable foam layer with no damage to the edges.
High-expansion fire-fighting foam liquid is mainly used to extinguish water-insoluble liquid fires in Class A and Class B fires. Especially suitable for fighting fires in limited spaces, such as caverns, warehouses, etc. For these places, high-expansion foam can not only extinguish fire, but also help exhaust smoke and drive out toxic gases. High-expansion foam is also suitable for fighting large-area liquid fires, but when used outdoors, fire dikes should be used to limit the coverage to a certain range.
The ability of fire-fighting foam liquid to "suppress fire" or extinguish fire on the surface of liquid fuel. At this point, the aqueous film-forming foam performs better than the protein foam. In the event of a fire, the aqueous film-forming foam first sprays a small stream of water and then evolves into a foam layer. The film has low viscosity properties, can flow quickly and cover the surface of the object, prevent the spread of fire, and block the surface. Egg white foam is more viscous, flows slower, and controls fire more slowly. As it progresses, a foam layer can also be formed on the surface.