MR.BUILD PROFESSIONAL FIRE RETARDANT B2 FOAM It’s a ready to use, one-component, self-expanding, fire-retardant sealing foam with fire rating properties up to 120 minutes based on 1k Polyurethane technology. It hardens at ambient temperatures to a low-density mass by reacting with atmospheric moisture & on curing it exhibits excellent adhesion to wood, metals door/window frames, glass, painted surfaces, some plastics, concrete, plasters etc. Microcellular structure of the foam reveals a majority closed cell structure. It has excellent thermal insulation characteristics & can be used for insulating hot/cold water piping, refrigerating systems etc.