Proposed Voluntary Product Standard PS 2-02 “Performance Standard for Wood-Based Structural-Use Panels”

AGENCY:

National Institute of Standards and Technology, Commerce.

ACTION:

Notice and request for comments.

SUMMARY:

This notice advises the public that the National Institute of Standards and Technology (NIST) is distributing a proposed revision of Voluntary Product Standard PS 2-92, “Performance Standard for Wood-Based Structural-Use Panels.” This standard, prepared by the Standing Committee for PS 2, establishes criteria for assessing the acceptability of wood-based structural-use panels for construction sheathing and single-floor applications and provides a basis for common understanding among the producers, distributors, and the users of these products. Interested parties are invited to review the proposed standard and submit comments to NIST.

DATES:

Written comments regarding the proposed revision, PS 2-02, should be submitted to the Standards Services Division, NIST, no later than April 28, 2003.

ADDRESSES:

An electronic copy (an Adobe Acrobat File) of the proposed standard, PS 2-02, can be obtained at the following Web site http://ts.nist.gov/ps2revision . This site also includes an electronic copy of PS 2-92 (the existing standard), a summary of significant changes, and a form for submitting comments. Written comments on the proposed revision should be submitted to Ms. JoAnne Overman, Standards Services Division, NIST, 100 Bureau Drive, Stop 2150, Gaithersburg, MD 20899-2150. Electronic comments may be submitted to joanne.overman@nist.gov.

FOR FURTHER INFORMATION CONTACT:

Ms. JoAnne Overman, Standards Services Division, National Institute of Standards and Technology, telephone: (301) 975-4037; fax: (301) 975-5414, e-mail: joanne.overman@nist.gov.

SUPPLEMENTARY INFORMATION:

Proposed Voluntary Product Standard PS 2-02 establishes criteria for assessing the acceptability of wood-based structural-use panels for construction sheathing and single-floor applications. Structural-use panels include: plywood, wafer board, oriented strand board (OSB), structural particle board, and composite panels. The standard provides performance requirements, adhesive bond performance, panel construction and workmanship, dimensions and tolerances, marking, and moisture content of structural-use panels. The standard classifies panels by exposure durability and by grade. It provides test methods, a glossary of trade terms and definitions, and a quality certification program whereby agencies inspect, sample, and test products for qualification under this standard. Information regarding industry practices for reinspection is provided in an appendix.

The proposed revision to the standard “Performance Standard for Wood-Based Structural-Use Panels” has been developed and is being processed in accordance with Department of Commerce provisions in Title 15 Code of Federal Regulations part 10, Procedures for the Development of Voluntary Product Standards, as amended (published June 20, 1986). The current standard, PS 2-92, was published in 1992.

The Standing Committee for PS 2 has the responsibility for maintaining, revising, and interpreting the standard. The Committee is comprised of producers, distributors, users, and others with an interest in the standard. Considerable research and review has gone into completing this revision; much of the work was performed by the document's sponsor, APA—The Engineered Wood Association.

In addition to format, terminology updates, and general clarification, this revision makes several substantial changes to the standard, including: (1) Revision of bond performance criteria and methods for oriented strand board (OSB); (2) revision of linear expansion criteria and methods; (3) revision to structural performance descriptions; and (4) deletion of requirements and methods for Exposure 2 and stability index.

OSB Bond Performance/Exposure 1—APA began evaluation of quality assurance test methods in 1992 at the request of APA members to identify a more appropriate test. The 1″x5″ specimen was viewed as being too small, having an inappropriate orientation (tested on edge), and being poorly related to manufacturing processes and product applications. Several mill trials resulted in the adoption of a flatwise, simple static bending test based on Method D of ASTM D-3043 “Methods of Testing Structural Panels in Flexure.” This test has been added to PS 2 in section 7.6, Small static bending test.

Products sampled on a quarterly basis were evaluated for structural performance, and resulting properties from the same panels were used to develop industry quality assurance property levels (dry properties in Table 7) for the various roof and floor spans covered in PS 2 and PRP-108 “Performance Standards for Structural-Use Panels.” Cycled strength properties for Exposure 1 were established based on a cold-water vacuum soak.

Additional development work was completed in 1998-2000 to update the Exposure 1 criteria. The update was based on industry comments that adding heat to the cycle would be preferable to differentiate among resin modifications. Again, quarterly samples were benchmarked for both structural and Exposure 1 bond performance to establish updated Exposure 1 criteria for small static bending samples after cycling using hot water, vacuum soak, and oven drying (Test 7.16, Moisture cycle test for bond performance). The updated Exposure 1 criteria can be found in Table 6, and the application of the test and criteria are shown in sections 5.3.3.1.b and 6.2.4.1.b of PS 2.

Revisions to the linear expansion method were made based on a need to reflect industry performance and serviceability requirements. Industry samples were benchmarked for linear expansion, and a suitable cycle and criteria were evaluated. The criterion was established at an average level, which is common for serviceability applications. The cycle was based on equilibrium at 50% relative humidity, which is viewed to be more representative of installed conditions than the oven-dry condition. Industry surveys were conducted and reviewed to determine acceptable performance using the revised criteria and test methods. Verification of the methods was conducted on a representative subset of products. The criteria and application are updated in sections 5.3.2.1 and 6.2.3. The test method revisions are reflected in section 7.8.

General comments on the structural performance sections indicated the need for improvement in the instructions. Concerns were expressed about applying structural performance criteria to daily mill quality assurance evaluations. Additionally, there were questions about the linearity of deflection requirements for a given increase in spans. The following changes were made:

(a) Revisions to these sections spell out the test provisions more clearly. Each possible scenario is described independently. The actual percentage resulting in passing results is spelled out for each test and criterion explicitly.

(b) Where appropriate, a clause was added to each performance test stating that the average of the tests should meet the designated requirement.

(c) For cases such as Single Floor 32oc, where the deflection requirement is more stringent than a straightforward linear analysis would predict, it was explained that the linear analysis results in excessive movement under typical floor loading conditions.

The Exposure 2 rating for bond performance has become obsolete. There are no known producers using the Exposure 2 rating. There is also no reason to believe the rating will become necessary for future production. Therefore, performance requirements related to the Exposure 2 rating have been deleted.

The stability index, although applied to product qualifications, was demonstrated to not be a very robust test in that panels evaluated never failed to meet the requirement. It was agreed by the Standing Committee that there is little value in retaining the stability index in the standard.

The dead weight stiffness test was added as a non-mandatory test in Section 7.20. As part of the guidance for using the test, Table 8, Typical pre-loads and test loads, was included.

Concurrent with this Federal Register Notice, the proposed Voluntary Product Standard PS 2-02 is being distributed by the National Institute of Standards and Technology to national experts and other interested parties for review and comment, in order to ensure that the standard constitutes acceptable industry practice. All public comments will be reviewed and considered. The Standing Committee for PS 2 and NIST will revise the standard accordingly.