Using Kinetic Models to Predict Thermal Degradation of Fire-Retardant-Treated Plywood Roof Sheathing

摘要

Between 1985-1995 a substantial number of multifamily housing units in the Eastern and Southern U.S. experienced problems with thermally degraded fire-retardant-treated (FRT) plywood roof sheathing. A series of studies conducted at the USDA Forest Service, Forest Products Laboratory (FPL), examined the materials, chemical mechanisms, and process implications and has developed both practical and theoretical solutions for controlling strength effects during treatment and processing and for minimizing strength loss in-service. In addition to a series of technical publications, FPL research contributed to the development of four new ASTM/ANSI performance-based qualification standards to address performance issues as well as two new American Wood Preservers' Association (AWPA) standards to address treatment processing and strength-effect limits. Currently, field serviceability issues that have been quantified are being combined with formerly developed kinetic degradation models to predict service-life of FRT constructions.