What does Class A Foam do to water during firefighting?

Class A Foam enhances the effectiveness of water during firefighting primarily by reducing the surface tension of the water. Water typically has high surface tension, which can limit its ability to spread and penetrate fuels, especially in wildland and structural firefighting scenarios. By adding Class A Foam, which is specifically formulated to mix with water, the surface tension is lowered. This allows the foam solution to spread more easily and cover surfaces more effectively, leading to improved wetting of materials.

Additionally, the foam's ability to cling to surfaces and fill voids helps to inhibit combustion by creating a barrier that prevents oxygen from reaching the fuel. This characteristic ultimately improves the extinguishing capabilities of water, making it more effective in controlling and suppressing fires.