Standard Revised

(Continued Jrom page 42)

Underlayment - Section 5.6.3 on Underlayment was revised to clarify the grade and intended end-use.

Minimum grade for Exposure 1Table 2 on Exposure I grades was revised to permit D-D grade only for plywood qualified through performance testing specified in PS I or PS 2. The revision creates compatibility with the minimum grade permitted in PS 2.

The U.S. voluntary standardization system is highly regarded and recognized as one of the most effective and efficient standards systems in the world. This success is a direct result of the work performed by certification agencies that audit and verify the quality of U.S. products manufactured and used worldwide. Engineered wood products that bear APA's trademark all have one thing in common: they passed the most rigorous quality verification program the industry has to offer.

Product Standard vs. Performance Standard

APA's ubiquitous mark of quality, the APA stamp, is found on 737o of the plywood, OSB and glulam manufactured in North America. Other products certified through APA include I-ioists. rim board, and LVL.

In the early 1980s. APA pioneered the concept of perJormancebased standards. A performance based standard assures that the product bearing the trademark will satisfy the specific end-use requirements.

For example, all structural panels. regardless of manufacturing method. must meet the end-use performance criteria to receive span ratings-the number in the panel trademark indicating maximum center-to-center support spacing over which panels are installed.

To achieve such results products undergo a multitude of different tests related to adhesive bond performance, product construction, workmanship, dimensions, tolerances and moisture content.