Is fire-retardant plywood permitted as part of a fire-rated assembly?
A. Yes. Fire-resistant rated assemblies are determined in accordance with the ASTM E119 test procedure. Fire-retardant treated plywood may be found in such assemblies. Where fire-resistant rated assemblies are required in interior and exterior non-bearing walls and roof construction, the rating and combustibility must be in accordance with BC Table 601. Note that in footnote c, item 3, combustible material is allowed in buildings not over two stories in height. BC section 603.1 discusses the use of combustible material in type I and II construction applicable to non-bearing walls and partitions, and roof construction. Except for roof construction in one and two story type I and II buildings, all structural materials, interior and exterior bearing walls and floor construction must be non-combustible.
