Which is a benefit of Class A foam?

Class A foam is highly effective in reducing the surface tension of water, which enhances the water’s ability to penetrate and saturate combustible materials. By lowering the surface tension, the foam allows water to better wet the surface of materials such as wood, paper, and textiles, ensuring more effective suppression of fires that involve these Class A materials.

This reduction in surface tension is particularly beneficial because it allows the water to spread and absorb into the fuel more effectively, increasing the cooling effect and aiding in extinguishment. The foam can also create a thin film over the surface of the burning material, which assists in reducing the amount of heat available for combustion.

In contrast, while Class A foam does not conduct electricity, does form a vapor barrier, and may be compatible with certain other foam types, these benefits do not directly address the critical function of reducing surface tension, which is key to its effectiveness in fire suppression for solid combustibles.