Wet Water: Improving on Mother Nature

One inherent problem preventing water from utilizing its full potential is the tendency of water to form into droplets, or bead. To improve the wetting, penetrating, and durability characteristics of water, man has been adding surface active agents for over fifty years. Class A foam concentrate added to water as a surfactant reduces the surface tension of water allowing more water droplets to contact the ordinary combustible surface. This provides increased heat transfer through conduction.

Class A foam concentrate is a synthetic detergent hydrocarbon surfactant, and when mixed with water at the recommended ratios, is biodegradable. Because it is a hydrocarbon surfactant, it also has an affinity for carbons and causes the water to penetrate into wood fuels. The basic form of Class A foam-treated water for improved extinguishing efficiency is wet water. The surface tension of plain water is reduced by two-thirds in a 0.3 percent Class A foam solution. This permits the water droplet to spread out and contact more of the burning fuel surface which therefore results in more rapid heat absorption. Carbon particles are a major by-product of the combustion process. The high affinity for carbon particles facilitates rapid water absorption and fuel wetting.

In laboratory tests, wet water has been shown to be three to five times more effective in extinguishing fire than water alone.