3M CP 25WB+ Fire Barrier Sealant - 10 oz. Typical applications include metal pipe, plastic pipe, cable, cable tray, busway, insulated pipe, HVAC duct penetrations. Firestop tested for through penetration applications up to 4 hours in accordance with ASTM E814 (UL 1479) and CAN/ULC-S115. Sag-resistant properties offer clean application as well as strong adhesion in both wall and floor applications. Water-based and paintable sealant provides easy application and clean-up. Fire resistance tested for static construction joint systems in accordance with ASTM E 1966 (UL 2079). 3M formulated this firestop sealant to dry and form a monolithic seal that also acts as a barrier to airborne sound transmission. 3M™ Fire Barrier Sealant CP 25WB+ is a red, one-component, gun-grade, latex-based, intumescent firestop sealant. This fire barrier sealant helps control the spread of fire, smoke and noxious gases before, during and after exposure to a fire.