First Line of Defense3M™ Fire Barrier Watertight Spray helps control twill act as a barrier to water leakage and airborne sound transmission, while helping to control the transmission of fire, heat and smoke before, during and after exposure to fire. It is'a sprayable, moisture-curing hybrid siliconized polymer that forms a tough, elastomeric coating. This material is used to firestop perimeter joints (curtain wall joints) and other construction joints that need to prevent fire and water from moving floor to floor.The spraymeets UL Water Leakage Test, W Rating - Class 1 requirements for systems tested and listed in accordance with ANSI/UL 1479 and is tested in accordance with ASTM G 21 standard practice for determining resistance of synthetic polymeric materials to fungi. This spray providesremarkable adhesion on most construction surfaces, including: concrete, gypsum, metal, plastic, wood and insulation. The seal is for interior construction voids such as blank openings, metallic pipes, non-metallic pipes, cables, cable trays, insulatedpipes, busways, HVAC vents and ducts, combos and construction joints.Recommended ApplicationsFirestoppingSmoke sealingWater sealingThe Science of Better Fire Protection from 3MSince 1925 when one of our lab assistants invented masking tape, 3M has been applying science to life -developing adhesive products and technologies that help entire industries and individual businesses worldwide. The work that began with a single 3M engineer now spans decades and generations. And all of it goes into each of our adhesives, sealants, protective coatings, devices and the best ways to used them - including Fire Barrier Pass-Through Device Brackets to improve performance, and to help businesses like yours operate faster, better and more efficiently.