Lumber Design Values Altered
Following proposals from the Southern Pine Inspection Bureau (SPIB), the American Lumber Standard Committee (ALSC) recently approved a design value change for No. 2 2×4 visually graded southern pine lumber as well as lower southern pine 2×4 grades such as No. 3, Stud, Construction and Utility. The new design values go into effect on June 1, 2012.
The ALSC declined to approve SPIB-proposed new design values for other southern pine grades and sizes, pending additional testing that the lumber inspection agency is performing on those products. The new southern pine 2×4 design values recently approved by ALSC reflect a 20%-35% reduction in such properties as bending, tension, compression and MOE.
Officials with SFPA say Southern lumber producers and their customers are generally pleased with ALSC’s decision. “Industry and customers need time for an orderly implementation and this announcement provides that,” says Cathy Kaake, SFPA senior director of engineered and framing markets, who adds that the intent of the transition period will give the marketplace time to begin using the new design values or switch to other southern pine grades and sizes that meet strength and stiffness requirements.
The SPIB is in the process of submitting new design value proposals for other southern pine lumber sizes and grades once additional testing is completed, scheduled for later this year.
The new design values result from an ongoing southern pine lumber testing program in place since the early 1990s. In the past few years, testing results and anecdotal evidence from end users prompted a closer look from SPIB officials after reports of some southern pine lumber not meeting published design values in some applications.