FireStop Gun Foam is the only USA-manufactured one-component foam approved as a through-penetration firestop sealant for commercial and residential applications, says the maker. It’s used to fill voids around pipes and conduits. It’s also UL-classified for use in common fire penetration joint systems, so it can serve as a fireblock in connecting spaces like the tops and bottoms of studwalls and stair stringers. It bonds to wood, masonry, rigid insulation, metal, plastic, and drywall, and dries red for easy identification as a fire sealant. It costs about $13 per can.
Convenience Products, 800/325-6180, touch-n-seal.com.