Building Code Clear on Lumber Design Value Implementation
Originally published by: SBCA — January 30, 2012
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There is going to be much said by a wide variety of parties that the new 2x4 No. 2 Southern Pine design values will be implemented at the time of code adoption, and that could be sometime well into the future. This concept may cause confusion in the market over the implementation of the ALSC approved and the SPIB stated effective date of June 1, 2012 for its Supplement #9. The building code seems to be clear on the controlling authorities with respect to design value implementation where the International Residential Code (IRC) says the following in chapter 5:
Load-bearing dimension lumber for joists, beams and girders shall be identified by a grade mark of a lumber grading or inspection agency (Note: SPIB, Timber Products, etc.) that has been approved by an accreditation body (Note: SPIB, as approved by American Lumber Standards Committee (ALSC)) that complies with DOC PS 20 (Note: US Department of Commerce, as implemented through the National Institute of Science and Technology (NIST) and ALSC). In lieu of a grade mark, a certificate of inspection issued by a lumber grading or inspection agency meeting the requirements of this section shall be accepted.
R502.2 Design and construction.
Floors shall be designed and constructed in accordance with the provisions of this chapter, Figure R502.2 and Sections R317 and R318 or in accordance with AF&PA/NDS. (Note: Span tables will be revised by the American Wood Council in concert with the effective date as published by SPIB, which will then become the code compliance documents.)
These are from the section on floor framing. Similar sections appear in the wall and roof framing chapters.
ALSC has recommended and SPIB has implemented June 1, 2012 as the effective date for the new design values. According to ALSC, this was to “allow for their orderly implementation.”