Fyre Shield (FB-520) PYRO-TUMID COATING can be used on all wood based building materials, roof decking and trusses, floor joists, sub-flooring, dry wall, steel structures, I-Beams, columns, etc. Anywhere fire proofing and Thermal protection is needed. The product has passed ASTM & 119 fire tests, performed by 3M Certified Labs. FB-520 is considered a �Pyro-Tumid product.The right way to protect your property against fire. When the surface is impinged by fire or high heat conditions, the surface (product) is converted into semi-hard blisters to repel the flame and reduce the temperature at the surface being protected. FB-520 is considered a sacrificial coating and must be replaced if a fire impinges the coating. Light-weight, white in color, fast drying, easy to apply with brush, roller or airless spray.