3M's ready-to-use Fire Barrier Water Tight Sealant 3000 WT is an intumescent, silicone elastomeric sealant. This gun-grade sealant cures upon exposure to the atmosphere to form a monolithic flexible firestop seal and, when properly installed, this product provides up to 4-hour fire protection in tested and listed systems. This sealant is water-tight to help prevent the intrusion of moisture. It is an ideal choice for CPVC piping. We formulated this sealant to help prevent the spread of fire, smoke and noxious gas and firestop joints and through penetrations through floor slabs, walls and other fire-rated building partitions and assemblies.