Ouality Assurance O&A

ITOIIOWING industry review, L' APA-The Ensineered Wood Association r"""-ntly instituted changes to its Quality Assurance Policy for performance rated oriented strand board as part of a continuous program of quality improvement. APA explains the changes and what to expect as a result:

Q. Wttut are the testing provisions of APA performance standards?

A. ePe't performance standards for OSB include test methods and cri-

Story at a Glance

APA revises OSB quality program ... effect on available thicknesses, span ratings.

teria that address suitability for use in construction applications. The tests are performance based, evaluating panel performance under actual loads during and after construction. Panels are evaluated under uniform loads (for example, snow) and concentrated loads (for example, construction workers and materials). The APA performance criteria for these tests meet or exceed code requirements.

In order to apply the APA trademark, a mill must first qualify the product according to the performance criteria. Upon passing, production is then subject to APA's rigorous quality assurance program designed to detect changes in panel properties which may affect panel performance. Under this Quality Assurance program, panels are randomly sampled daily at every mill and tested at one of frve APA regional laboratories.

Q. Wtt"t has changed and what hasn't changed?

A. ttr" performance test requirements used to qualify panels are the same as before, and continue to meet or exceed building code requirements. Only the test methods and criteria used for daily quality assurance have changed.

The new QA test methods more directly measure strength and stiffness, with the test requirements intentionally set high in recognition ofproduction variables across the industry. Mills are permitted to establish their own daily performance limits, provided full-panel performance test requirements continue to be met, and several mills are evaluating this option. From the practical standpoint of the customer, the product is the same; only the method used to routinely assure quality has changed.

Q. Wt V were the QA test methods and criteria changed?

A. nPe continually refines and improves its quality program. APA and industry consideration of these latest changes began in 1992 as a means to provide an even higher degree of assurance to users and specifiers that the product meets APA performance test requirements and will perform well in actual service.

Q. Hrr" building codes changed regarding allowable loads for OSB?

A. No. The allowable loads for OSB have not changed in the building codes, nor will changes be proposed, since APA's performance criteria have not changed.

Q. witt all osB thicknesses continue to be available?

A. fn" new daily test methods, by yielding better information on manufacturing process and product performance, provide manufacturers a new opportunity to assess production efficiencies. Some mills, for example, have historically produced a com- mon span rating at two distinct thicknesses (e.g., 32116 in both l5l32" and l/2). They may now find it more efficient to produce 32116 in only one thickness. So, all thicknesses will continue to be available, although some mills may elect to make changes in available thicknesses based on production efficiencies.

Q. Wilt the present OSB span ratings continue to be available?

A. Y"t. And span rating rather than thickness is what is important from a performance standpoint for conventional sheathing applications.

Q. Wttrt about l5l32" panels rabd3A16?

A. tStlZ" rated sheathing panels with a span rating of 32/16 should continue to be available. However, since 32" roof framing supports are rarely if ever used in residential construction, some producers may opt to market 15132" 24116 panels for 24" o.c. roof applications.

Q. Wtt.t about Structural I OSB? How is that different?

A. oss with the Structural I rating is intended for applications where the panel is used with the long dimension parallel to supports (i.e., panelized commercial roof decks) and/or where a higher allowable shear is required (e.g., shear walls and engineered roof diaphragms). APA's new QA program increases the assurance that Structural I panels possess the critical cross panel properties necessary for these applications. Normal residential roof and wall construction does not require Structural I panels.

Q. witt these changes affect the availability of Structural I OSB?

A. ln an effort to supply customers with the most efficient panel for a given application, some manufacturers mav refine their product lines as to span rating/Structural Vthickness combinations. However, historically produced combinations in demand by the marketplace will continue to be available.

- For answers to other OSB Quality Assurance questions, contact APA, Box I 1700, Tacoma, lla. 984 I I ; (206) 565-6600.