Abstract: A stable aqueous foam concentrate for use in the generation of a stable aqueous foam having an expansion ratio of between 10:1 to as high as 1000:1 or more includes an anionic surfactant material of a chain length of between C12 to C14, a glycol or mixtures thereof, a fatty alcohol of between C12 and C14 chain length and a copolymer of maleic anhydride. The components, other than the polymer are mixed to form a micellar structure and the polyer is then added to react with at least one of the components of at least some of the micelles. Upon foam formation, the polymer which is covalently bound operates to reduce the water drainage rate to increase the foam stability, the foam being biodegradable.

Abstract: An improved method of blast suppression involves forming an expanded foam barrier maintained in position by a barrier element which, in a preferred form, is inflated and maintained inflated by the foam used to form the foam barrier. Various barrier structures and methods are disclosed for suppression of the blast wave.

Abstract: An improved riot and crowd control interdiction method involves forming, in a defined location, a foam barrier which effectively inhibits passage through the barrier. Other anti-personnel devices may be placed and obscured by the foam barrier. Various barriers and methods to form a contained interdiction foam barrier are disclosed.

Abstract: Proportioning apparatus comprising a pair of coaxial tubular members with passages having first and second outwardly extending walls of the same cross-sectional configuration, first and second valve bodies for coaction with said walls for progressively opening and closing said passages, said first valve body slidably mounted on one of said tubular members, said second valve body connected to said first valve body for movement therewith and biasing means urging said valve bodies to their closed positions.