Question: Does fire-treating plywood have an effect on allowable design values or application recommendations for plywood?

Answer: APA does not test, promote or trademark Fire Retardant Treated (FRT) plywood. The FRT process is a secondary operation outside the scope of our involvement.

FRT plywood is treated in accordance with treating standards developed by American Wood Preservers Association (AWPA)*. The fire-retardant treating of plywood is accomplished after the plywood is manufactured. It is a process performed by treating companies using proprietary chemical formulations and treating methods, and quality assurance agencies of their own selection. Consequently, the treating process introduces variables outside the control of any plywood producer and APA.

Use and application recommendations, Span Ratings, load capacities and fastening guidelines published by APA are based on untreated panels, and may not apply following fire-retardant treatment. You must obtain structural performance characteristics and application recommendations for FRT panels from the company providing the treatment and redrying service.

A search of the ICC Evaluation Service, Inc. web site (www.icc-es.org) found the following evaluation reports for FRT plywood products:

• Arch Wood Protection, Inc., ICC-ES Report NER-303
• Chemco, Inc., ICC-ES Report ESR-1159
• Chemical Specialties, Inc., ICC-ES Report NER-562
• Hoover Treated Wood Products, Inc., ICC-ES Report ESR-1791
• Osmose, Inc., Wood Preserving Group, ICC-ES Report NER-577

*AWPA Standard U1, Use Category FA (interior) or FB (exterior), Commodity Specification H. No standard currently exists for FRT OSB.