Structural plywood standard revised

afaHE venerable plywood panel is a I workhorse for a number of diverse industries, including construction, funriture, materials handling and concrete forming. Its reputation us a high quality and adaptable material is based in part on criteria established more than 40 years ago with the introduction of U.S. Voluntary Product Standard PS l.

Sponsored by APA and originally developed in 1966, PS I provides the structural plywood manufacturer with requirements for producing, market- ing and specifying plywood for a variety of performance-based construction and industrial end uses.

The revised standard. PS l-07 Structural Plywood, reflects the industry's continuous evolution in manufacturing and end-use applications. For instance, the standard provides new overlay grade notations that refine specifications to allow manufacturers to tailor overlays to specific end uses. High Density Overlay grades are now differentiated into HDO-Concrete Form and HDO-

Industrial. and MDO grades are diff'erentiated into MDO-Concrete Form and MDO-General.

"PS l-07 provides increased grade clarity so that producers can better serve market demands for specific attributes such as strength. durability, reuse and finish." said Steve Zylkowski, director of Quality Services Division for APA. "As manufacturers begin phasing in these changes, end-users can expect to see new grades rolling out of mills in the latter half of this year."

A list of the major changes follows. All section references are taken fiom PS 1-07.

. Name Change - Voluntary Product Standard PS l-07 Structural Plywood. This revision to "Structural Plywood" is more consisten( (o marketplace terminology.

. Deletion of Interior and Intermediate Bond ClassificationsThese were removed because the industry transitioned to moistureresistant adhesives in the 1950s, making interior and intermediate bond adhesives extremely rare. Tn addition, the terminology "Interior Bonded with Exterior Glue" was replaced with its common marketolace term "E,xposure 1."

Repairs - The size permitted for synthetic repairs was modified to create compatibility with permissiblc wood repairs.

Exterior Plywood Grades - Table 3 on Exterior Plywood Grades was revised to incorporate new grades of overlaid plywood and concrete form grades.

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