A Novel, Clear Fire Retardant Waterborne Coating System for Wood Substrates

J. Hughes, M. Wang, L. Zhang
Armstrong World Industries,
United States

Keywords: fire retardant, waterborne coating, wood substrates


A Novel, Clear Fire Retardant Waterborne Coating System for Wood Substrates John Hughes, Principal Scientist; Dr. Michelle Wang, Senior Innovation Manager; Linzhu Zhang, Scientist Abstract Traditionally, opaque intumescent coatings were used to reduce, or prevent, the spread of fire on wood substrates, typically achieving a Class A rating in the ASTM E84 tunnel test, at the cost of covering up the wood visual. Clear intumescent coatings were then developed to allow for presentation of the natural wood visual, but have struggled to achieve an acceptable E84 Class A rating, while also having a plastic-type look to the visual. Many of the current clear, intumescent coatings require application of a solvent topcoat to prevent moisture from contacting the base coating, and/or creating a visual that has some haziness to it. Armstrong World Industries has developed a patent pending novel, clear fire retardant waterborne coating system that has consistently achieve Class A (25 flame spread index/50 smoke developed index) rating in the ASTM E84 Tunnel Test on solid wood substrates, while still presenting a true wood visual. This novel coating system consists of three coatings that can be applied with conventional coating methods, air- or thermally dried, to a water-resistant layer while maintaining fire performance, hardness, adhesion, and coating integrity. The basecoat can be tinted to achieve colored visuals while still obtaining a 25/50 Class A rating, and maintain its other performance properties. Armstrong’s patent pending, new Class A clear coating system is a significant development in the fire-retardant coatings market for wood substrates as it dramatically increases the protection offered by a clear coating against fire and smoke, while presenting a true wood visual.