Containment device comprising a dry curtain

A containment device comprising a dry explosive gas containment curtain designed so as to deploy from a folded position to an extended position in response to a blast in a room or building so as to contain or recontain at least explosive gaseous discharge from a discharge zone made of an opening of said room or building, the containment device further comprising a ballast bar in a lower part of the curtain, wherein said ballast bar, providing a mass at a bottom of the curtain, includes an alternation of first cylinders, said first cylinders being made of a high density foam and of second cylinders, said second cylinders being made of compressible low density foam, and wherein said first and second cylinders effect conforming of the dry curtain to a ground surface and impede gases of the blast from escaping under the dry curtain.