3M fire barrier sealant is a high-performance, ready-to-use, gun-grade, latex-based, intumescent sealant that dries to form a monolithic firestop seal that also acts as a barrier to airborne sound transmission. fire barrier sealant helps control the spread of fire, smoke and noxious gasses before, during and after exposure to a fire when installed in accordance with a listed through penetration or fire-resistive joint assembly system. Firestops blank openings and penetrations passing through fire-rated floor, floor or ceiling or wall assemblies and other fire-rated interior building construction. The unique intumescent property of this material allows fire barrier sealant CP 25WB to expand and help maintain a firestop penetration seal for up to 4 hours as penetrants are exposed to fire. Exhibits excellent adhesion to a full range of construction substrates and penetrants. No mixing is required.