Firestop Foams are expanding, fire resistant spray foams that fill holes and voids to block the spread of smoke and flames in a potential fire. Boss 812 is a firestop foam insulation that blocks smoke and other toxic fumes from passing through penetrations in walls and floors. Boss 813 is one of the few fire-rated spray foams that meets the firestop code: ASTM E-814. Foam is a fire resistant foam that prevents the spread of fire, smoke and toxic gasses from one compartment to another, while still maintaining the integrity of the Firewall. View our available fire retardant foam sprays below or contact us for more information about our products!