Class A foam lowers the surface tension of water, allowing the foam/water to _____ the fuels.

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Multiple Choice

Class A foam lowers the surface tension of water, allowing the foam/water to _____ the fuels.

Lowering the surface tension of water with Class A foam improves wetting, so the foam/water solution can soak into fuels rather than just sit on the surface. In ordinary combustibles—like wood, paper, and other porous materials—the reduced surface tension allows the liquid to spread into tiny pores and capillaries, reaching hidden flaming areas and cooling the fuel from within. That penetrating wetting is more effective for controlling the fire than simply spreading a layer or attempting to separate or dilute the fuel, or smothering by blanket alone.

Lowering the surface tension of water with Class A foam improves wetting, so the foam/water solution can soak into fuels rather than just sit on the surface. In ordinary combustibles—like wood, paper, and other porous materials—the reduced surface tension allows the liquid to spread into tiny pores and capillaries, reaching hidden flaming areas and cooling the fuel from within. That penetrating wetting is more effective for controlling the fire than simply spreading a layer or attempting to separate or dilute the fuel, or smothering by blanket alone.

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