You may be aware that the American Lumber Standards Committee approved new design values for Southern Yellow Pine in all applications except #2 2×4. Their rationale is that the rapid-growth rate for modern southern yellow pine has reduced its load-carrying capacity.
The new standards reduce the distance spanned by the various lumber dimensions by as much as 15 percent and were set to take effect June 1. Click here to view the update conversion chart for Southern Yellow Pine.
However, your Home Builders Association learned today that the International Code Council has elected not to implement the new design values in the current code and will instead consider them for the 2015 building code. In addition, NAHB has continued its efforts to have the new design values reversed and is currently challenging the validity of the American Lumber Standards Committee’s findings.
Note however that the 2012 International Residential Code is scheduled to take effect in South Carolina on July 1. You may be aware that a provision of the new code includes an increase in the dimension of floor trusses, when a gas appliance is placed in the basement or crawl space, in order to avoid fire-proofing the floor above the gas appliance. Your Home Builders Association is working with the South Carolina Building Officials Association to develop a solution to this expensive new requirement. Stay tuned.
NAHB’s Construction, Codes and Standards experts recently completed a helpful “FAQ” document to address the most often-asked questions they are receiving from our members on recent changes in design values for visually graded Southern Pine lumber.
This useful resource can be downloaded free of charge by NAHB members who are logged into our website with their username and password, and provides updated, clear information regarding the impetus for the design changes, an explanation of what the changes encompass, an idea of what to expect in the future, and a summation of how the new design values will be incorporated into today’s building codes – among other topics.
We encourage you to check out the FAQ document
as well as the other resources that are available to you on Southern Pine Design Values at www.nahb.org/spdv
New design values for #2 and lower grade Southern Pine and Mixed Southern Pine 2×4’s will become effective on June 1, 2012. These reduced values, developed by the Southern Pine Inspection Bureau (SPIB), were approved by the American Lumber Standard Committee’s Board of Review in January. At the urging of NAHB and other industry stakeholders, an effective date of June 1 was provided to allow the industry some time to transition to the new design values while avoiding project delays and market disruptions.
As part of these efforts, the American Wood Council has developed addenda to the National Design Specification for Wood Construction, the Wood Frame Construction Manual, and the Span Tables for Joists and Rafters reflecting the new design values, and has also developed recommended amendments to prescriptive tables in the International Residential Code and International Building Code.
The new values were reduced by 25-30% and will primarily affect the design of roof trusses. Though the maximum allowable spans for 2×4 headers, joists and rafters will be shorter, they are not commonly used in those applications, and so will have minimal effects on most builders. In addition, 2×4 studs used in conventional construction are not affected by this change.
It is NAHB’s understanding that any such adoption would apply only to new construction. Projects already under construction or submitted to the building department prior to an adoption date should not be affected. However, builders are advised to consult with their local jurisdiction regarding any plans to adopt and enforce the new design values.
Going forward, SPIB is testing additional sizes and grades of Southern Pine. A submission to ALSC is expected in late summer or early fall, which may propose reductions to design values for larger sizes (e.g. 2×8 and 2×10) and higher grades (#1 and Select Structural). ALSC has also directed that the other major species (Douglas Fir, Hem-Fir and Spruce-Pine-Fir) should undergo sampling and testing to assure there are no changes to their current design values.
NAHB has created a special web page titled Information and Resources on Propposed Changes to Southern Pine Lumber Design Values that is dedicated to keeping our members updated on this issue. A “Frequently Asked Questions” document is in the process of being developed and will also be posted on that web page.
For additional information, email Gary Ehrlich at NAHB or call him at 800-368-5242 x8545.
According to NAHB, the American Lumber Standard Committee Board of Review did not take action on a proposal to reduce the design value of Southern Yellow Pine by as much as 30 percent. NAHB Chairman-Elect Barry Rutenberg testified on behalf of home builders and opposed the change in design values. However, reduction in the design values is still possible in the future and NAHB will continue to work on the issue.
In minutes released on Jan. 11, the American Lumber Standard Committee (ALSC) announced its Board of Review’s decision NOT to approve reductions in the design values for all grades and sizes of visually-inspected Southern Pine lumber as proposed by the Southern Pine Inspection Bureau (SPIB) and based solely on the testing of 2×4, No. 2 lumber. As previously reported, NAHB Chairman-Elect Barry Rutenberg requested that the ALSC Board not approve any change to the existing design values until SPIB has completed testing of additional grades and sizes of Southern Pine lumber as required by ASTM D1990, the industry standard for establishing design values for visually graded lumber.
The ALSC Board agreed that the proposed changes to the full spectrum of Southern Pine grades and sizes were not technically justified based on the limited testing that had been performed to date. Instead, the Board approved the proposed new values for only 2×4, No. 2 lumber and, in a supplemental ruling on Jan. 12, expanded that ruling to include all lower grades of that size. The Board also urged SPIB “to proceed with all deliberate haste” to complete the testing and analysis of additional grades and sizes of Southern Pine as required by ASTM D1990. Additionally, the Board recommended an effective date of June 1, 2012, for the new design values to “allow for their orderly implementation.” This recommendation was a direct response to concerns voiced by NAHB that immediate approval and implementation of the proposed changes would cause chaos in the marketplace and result in an unjustified spike in lumber prices.
In all, the ALSC’s decision is good news for NAHB members, who might otherwise be facing immediate implementation of a full range of new design values 25%-30% lower than the existing ones. Instead, the full matrix of In-Grade tests can be expected to take place this summer, after which changes to the other grades and sizes of Southern Pine lumber may once again be proposed by SPIB.
NAHB has created a special page that’s dedicated to providing our members with needed information and resources regarding this issue at www.nahb.org/spdv.
The load-carry capacity of Southern Yellow Pine has come into question in recent weeks, and a regulatory body is currently reviewing a proposal to reduce the spanning capacity of Southern Yellow Pine by up to 39 percent.
Late last week the Chairman of the South Carolina Building Codes Council, Greg Parsons, PE, sent out an email that prematurely states that the spanning capacity of Southern Yellow Pine has already been reduced.
The Southern Pine Inspection Bureau is currently reviewing is 1991-published design values for Southern Yellow Pine and is expected to issue a ruling on January 5, 2012, as to the load carrying capacity of Southern Yellow Pine. However, no change in the rule will be valid in South Carolina until the South Carolina Building Code Council takes action.
Currently in South Carolina, the span tables that are approved and in force include those in the 2006 International Residential Code and as an alternative, an “Altnernative to IRC Table R503.5 (1).” Scroll to Page 14 for the table.