BOSS® 814 UL Classified Intumescent Latex Firestop Sealant is a one part, elastomeric, intumescent firestop sealant that expands when exposed to fire or extreme heat, forming an insulated char. BOSS® 814 will prevent the spread of toxic gases, smoke and fire. BOSS® 814 is suitable for adhesion to almost any surface and remains flexible, making it ideal for both horizontal and vertical joints, subject to vibration or dynamic movement. BOSS® 814 can be used for interior or exterior applications, and can be painted (after inspection). BOSS® 814 has been tested to ASTM E-814 (UL 1479) and meets the criteria for fire/smoke/draft stop for BOCA, CABO, UBC, SBCCI, and IRC. Features: >Interior/exterior use on virtually any surface > Remains flexible > VOC compliant > Excellent freeze/thaw properties > Safe to use and handle >Water clean-up > 12 month shelf life > Apply using a standard caulk gun How To Use: > Cut nozzle to desired bead size. Insert cartridge into standard caulking gun. >For a smooth seal, hold at 45° angle and apply by pushing sealant ahead of nozzle. > Apply at 40°F (4°C) or above. > To ensure good adhesion, all surfaces should be clean and free of dust, oil, loose materials or any other substances. > Make sure that BOSS® 814 makes complete contact with the entire surface of the opening and also the surface of the penetrating items. Always follow cartridge directions. Clean the area to be treated so that it is free of all particles and debris. For large openings, mineral wool fibers can be used as a backer to help hold the product in place until cured. Steel screen wire can be stapled in place over the material when a large opening is overhead or configured such that the material will not support its own weight during cure. How to seal Gaps & Cracks.