Medium- and high-expansion foam generators produce foam with what kind of air content?

Medium- and high-expansion foam generators are designed to produce foam with a high air content, which is essential for their effectiveness in firefighting operations. When these generators mix foam concentrate with water and air, they create a foam that has a significant volume of air trapped within it. This high air content contributes to the foam's ability to blanket flammable liquids, suppress flammable vapors, and insulate hot surfaces.

The trapping of air makes the foam less dense, allowing it to expand significantly when deployed, which increases coverage and effectiveness. The structure of high-expansion foam allows it to fill spaces and displace oxygen, thereby inhibiting combustion and reducing the potential for fire spread. Therefore, identifying high air content as the characteristic of the foam produced by these generators is crucial for understanding their application in fire suppression techniques.