NSi Fireblock136 fire-blocking caulk is a single component, non-combustible material for residential applications. Colored red for easy inspection, fireblock136 creates an effective barrier against flames, smoke, and toxic gasses and has superior adhesion and gunnability. Fireblock136 is for use in annular spaces around wires, pipes, ducts, vents and other penetrating items at ceiling and floor openings; and room to room in wood and steel frame constructions. It restores the integrity of fireblocks in one and two family construction. Exceeds A5TM-E136 standards for fireblocking residential requirements prescribed by all major-model building codes, and also meets or exceeds requirements of UBC, BOCA, SBC, IRC, NYS and MA codes. Meets UL 1479/ ASTM-E136 standards. 10.3-ounces caulk tube. Non-combustible for residential applications.