The American Lumber Standards Committee (ALSC) held a meeting on Thursday, January 5, to hear feedback from lumber producers, users, and other affected parties regarding a proposal to reduce the key strength values of Southern Pine lumber.
The Southern Pine Inspection Bureau (SPIB), tasked with third-party verification and lumber strength testing in the Southern Pine industry, has proposed a reduction of 25% to 30% in published values for deflection and ultimate strength for all grades and sizes of 2x dimension lumber in the Southern Pine market, after testing of hundreds of No. 2 2x4 specimens showed a significant decline in the strength of the 2x4 stock. If the published values for lumber engineering characteristics are revised downward, that will result in a reduction of allowable spans in official span tables for Southern Pine, which will affect builders, framers, and deck builders. Reduction in the strength values for 2x lumber would also have a major impact in the wood truss industry.
In reaction to SPIB’s proposal, other voices in the industry are urging a slower and more carefully considered response to the new test values — saying that it’s too early to make a broad modification before other sizes and grades of Southern Pine have been comprehensively tested, that a revision of grading practices rather than a change in span tables might be a better way to adjust, and that time should be allowed to phase in any modifications so as not to disrupt projects already in the pipeline.
The current, existing engineering values and span tables for Southern Pine were set back in the 1980s after an industry-wide "In-Grade" testing program, which involved at least six years of lumber testing in all sizes and grades, and another four years of industry discussion and negotiation about grade rules and engineering values. This time around, only one size and grade of Southern Pine has yet to undergo a comprehensive series of tests, and only a few months have passed since those test values were made public. But a full program of sampling and testing of other sizes and grades has now begun — not just for Southern Pine, but for other major wood species (including Western lumber such as Douglas Fir, and Eastern pine, spruce, and fir). The Board of Directors of the ALSC has the authority to adopt an immediate change to Southern Pine engineering values if it so chooses; but given the incomplete information on the table today and the far-reaching consequences of any sudden change, it appears more likely that the ALSC will wait to learn more about the nation’s lumber stock before adopting a comprehensive revision.