ABSTRACT
The need for firefighting foams arose from the introduction of liquid hydrocarbons into everyday use. Foams will dilute water-soluble fuels, but this is a very inefficient use of them; indeed, foam agents may be formulated to minimize miscibility with such fuels. For general use on solid carbonaceous fuel fires, there have been claims that certain foam agents improve the performance of water. In real-life fires, persistent small flames are likely to burn away progressively a protective foam blanket. The manufacture of protein foam concentrate became more firmly established following the incorporation of iron salts, by Sthamer in 1937, to be followed by other polyvalent metal salts. Foam was produced historically by the chemical interaction of (bi)carbonates with acidic solutions in the presence of a foaming agent. The “foamability” of the agent types varies with surface tension and molecular species; there are differences between the protein-based agents and those formulated from hydrocarbon-derived surfactant.
