ALSC Changes Southern Pine Design Values
The current editions of the International Building Code (IBC) and the International Residential Code (IRC) include span tables to be used in the design of wood joists. The design criteria is established by Department of Commerce standard DOC PS 20-5, American Softwood Lumber Standard, which is also referenced in both the IBC and IRC. This standard identifies the American Lumber Standard Committee (ALSC) who administers an accreditation program for the grademarking of lumber produced under the system.
On Jan. 30, 2013 the ALSC Board of Review approved changes to design values for all grades and all sizes of visually graded Southern Pine and Mixed Southern Pine lumber, with a recommended effective date of June 1, 2013 to allow for their orderly implementation. The ALSC Board of Review unanimously approved the SPIB submissions of Dec. 11, 2012 and Jan. 11, 2013 as amended by deleting the sentence: “Designers of wood structures….and grade grouping” in Appendix A. The ALSC Board of Review recommended an effective date of June 1, 2013 to allow for an orderly transition to the new values.
Please see the American Wood Council website where the effect of those changed design values on the span tables is contained in the IBC and IRC may be found.
The investigation of the adequacy of design values for other Southern Pine lumber sizes and grades is on-going.