ALSC Announces Decision on Strength Value Reduction for Southern Pine Lumber
Effective June 1, 2012, the design values for Southern Pine No.2 graded lumber, 2” to 4” thick and 2” to 4” wide, will be significantly revised based on full-size lumber testing of this material by the Southern Pine Inspection Bureau (SPIB) and Timber Products Inspection (TP) in 2010-2011. The new values are approximately 20-30% lower, dependent upon the specific design value (Extreme Fiber in Bending, Tension Parallel to Grain, Horizontal Shear, Compression Perpendicular to Grain, Compression Parallel to Grain, and Modulus of Elasticity). The reduction also applies to lower grades of these sizes (No.3, Stud, Construction, Standard, and Utility). A request to also reduce the design values of the Southern Pine grades of No.2 Dense and No.2 Non-Dense is awaiting approval from the ALSC Board of Review.
The impetus to review the design values for Southern Pine came about in 2010 when SPIB received anecdotal information from outside parties indicating that their testing of some Southern Pine lumber had resulted in breakage below the published numbers. At that time, SPIB developed a statistically appropriate plan to randomly sample and test No.2 2×4 lumber on a production-weighted basis from all Southern Pine producing areas. This plan was approved by the U.S. Forest Products Laboratory and ALSC’s Board of Review in November 2010 and the sampling/testing plan commenced.
Fast forward to September of 2011. Because of the magnitude of the indicated reductions in the design values based on the No.2 2×4 testing, SPIB submitted an additional sampling plan to ALSC Board of Review to evaluate a range of different sizes and grades of Southern Pine lumber, with results anticipated later in 2012. On October 6, 2011 a press release was distributed from Jim Loy, President of SPIB, announcing their recommendation to reduce design values for all sizes and grades for Southern Pine based upon the results of the first round of testing, and that the ALSC Board of Review would rule on these new values at a meeting on October 20, 2011.
Having received numerous inquiries regarding SPIB’s submission, the ALSC Board of Review scheduled a hearing at their October 20 meeting so all concerned parties could be heard. Approximately 50 people attended the meeting to express their concerns surrounding the requested reduction in strength values. This included primary customer group representatives from the home builders, truss manufacturers, lumber retailers, and lumber manufacturers. Because the documentation for the reduction was available just prior to the meeting, the ALSC Board of Review announced that no action would be taken on the SPIB submission at that time, and a second hearing would take place on January 5, 2012 to give time for all concerned parties to review the information. Approximately 115 individuals participated in the January 5, 2012 Board of Review hearing with further concerns stated from the customer group representatives about the lumber testing process and SPIB’s submission to reduce values across all grades and sizes.
The decision to only apply the reduction to Southern Pine No.2 and lower grades in sizes 2” to 4” thick and 2” to 4” wide was based on the original testing plan for that specific item. Although ALSC’s Board of Review did not approve the reduced values for the other sizes and grades of Southern Pine and the fact that a future effective date was recommended for implementation of the 2×4 reduction, it made the following cautionary statements:
It cautions all interested parties to take note of all available information in making design decisions in the interim. All design professionals are advised in the strongest terms by the Board to evaluate this information on formulating their designs in the interim period.
The results of the approved sampling and testing plan for additional sizes and grades of Southern Pine by SPIB and TP should be available later this year for analysis by the ALSC Board of Review.
During this 2010-2011 period, all other grading agencies that publish design values were charged with developing a sampling plan as part of a regular monitoring program that will either validate their current published design values or require further action. This program includes NELMA and NSLB, being two of the seven rules writing agencies in North America. Sampling plans have been submitted and approved by the ALSC Board of Review regarding the specific species under the two agencies purview. The primary species that involves NELMA and NSLB is the Spruce-Pine-Fir south (SPFs) grouping, also shared with the Western U.S. agencies. NELMA conducted a full-size lumber testing project in 2006, with over 4,000 pieces of Eastern Spruce and Balsam Fir tested. This was a significant cooperative project with lumber agencies in Canada (the Maritime Lumber Bureau and the Quebec Forest Industries Council). The test results for both species indicated the design values are higher than the published values for the overall SPFs grouping. The U.S. Forest Products Laboratory has accepted the data from this testing project as an adequate current monitoring check. Regarding the monitoring of values for species in the Great Lakes region that are part of the SPFs grouping, NELMA is assisting NSLB with a plan to test Red Pine and Jack Pine, along with supplemental testing of Eastern Spruce and Balsam fir samples from this region. This project will begin 1st quarter of this year and results expected later in 2012.