Professional polyurethane fills and fixes foam with a structure of fine cells. High thermal and acoustic insulation. Bostik FP404 Fire Retardant PU Foam was specifically developed for fire resistant sealing and filling of joints and seams in certain areas where fire resistance is required. Fire resistance tested according to EN 1366-4 up to 60 minutes in a 20 mm wide gap. In combination with Bostik FP402 FIRESEAL SILICONE, Bostik FP405 Fire Retardant PU Foam will provide up to 180 minutes fire resistance in a 40 mm wide gap