What percentage of water is found in most fire fighting foam?

Firefighting foam is primarily composed of water, which serves as the main carrier for the foam concentrate. The correct choice, indicating that firefighting foam contains between 94-99.9% water, reflects the importance of water in generating the foam's effectiveness in suppressing flammable liquid fires. The high water content helps to cool the surface of the burning material, smother the fire, and minimize the release of flammable vapors.

Foams are designed to form a blanket over flammable liquids, preventing ignition and allowing for safe extinguishment of fires. The relatively high percentage of water in the foam formulation is essential as it ensures sufficient thermal inertia and aids in forming a stable foam blanket. This stability is crucial for effective fire suppression, making the understanding of foam composition vital for effective firefighting operations. When considering the options, the other choices do not accurately reflect the true composition of firefighting foam, as they suggest lower or upper bounds that do not align with standard formulations used in fire suppression.