What does Class A foam primarily combat?

Class A foam is specifically designed for use on ordinary combustibles like wood, paper, and fabric. It works by lowering the surface tension of water, enhancing its ability to penetrate and cool these materials, thus extinguishing the fire more effectively than plain water alone. The foam forms a blanket over the burning material, preventing oxygen from fueling the fire and facilitating heat absorption. This makes it particularly effective for fighting fires involving common materials found in residential and commercial settings.

The other categories do not apply to Class A foam. Flammable liquids typically require Class B foam for effective suppression due to their different combustion characteristics. Electrical fires require careful handling to avoid hazards, and flammable gases require specific tactics and equipment not provided by Class A foam.