Blast and Fragmentation Suppression with Aqueous Foam and a Kevlar Tent

Aqueous foam has long been considered a good material to suppress the blast from an explosive event. The airblast produced is reduced significantly if the explosive is covered with an aqueous foam. However, for fragmenting munitions, the foam does not reduce the velocity of the fragments significantly. In order to reduce the hazard more effectively, the fragments must be stopped or reduced, along with the blast suppression. The U.S. Army Research Laboratory ARL, under sponsorship of U.S. Army Garrison Directorate of Safety, Health, and the Environment DSHE and with the cooperation of the Chemical-Biological Defense Command CBDCOM, Aberdeen Proving Ground APG are currently investigating a field system to suppress the blast overpressure and stop the fragments from chemical munitions that cannot be moved or relocated for disposal and must be blown in place. The system consists of a commercial device developed jointly by CBDCOM and Zumro Inc. It consists of an inner and an outer kevlar tent. The explosive device of interest is prepared for detonation, and the outer tent is placed over it. The outer tent is approximately 13 ft x 10 ft x 8 ft tall and it does not have a floor. The inner tent is approximately 7 ft in diameter at the base tapering, to 4 ft at the top, and is 3 ft tall. It is placed inside the outer tent directly over the explosive device. The inner tent is then filled with Silvex foam formulation The role of the outer tent is to stop any fragments that may have penetrated the inner tent and to contain any chemical or biological agent that may have been released by the explosive device. In the fielded situation under investigation by DSHE, the outer tent system is connected to a portable air scrubbercarbon filter. All escaping gas going out of the primary tent into the secondary tent is captured and run through the scrubbercarbon filter system. The scrubbercarbon system is being independently investigated by DSHE and CBDCOM.