Everbuild Handheld B1 Firefoam is a quick-setting fire rated, one part polyurethane foam. It expands on application to yield up to 50 times the can content and meets the extremely stringent requirements of the test criteria BS476 Part 20; Class B1. Fire-rated up to 4 hours in certain joint configurations. Once cured, the foam can be cut, sawn or plastered over after approximately one hour.