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February 11, 2013

New Design Values Effective June 1, 2013

SPIB Publishes Supplement No. 13

New design values for all sizes and grades of visually graded Southern Pine dimension lumber were published in the Southern Pine Inspection Bureau’s (SPIB) Supplement No.13 to the 2002 Standard Grading Rules for Southern Pine Lumber on February 11, 2013. The Board of Review of the American Lumber Standard Committee approved the new design values following its hearing on January 30, 2013. New design values apply only to new construction; the integrity of existing structures designed and built using design values meeting applicable building codes at the time of permitting does not change.

The new design values become effective June 1, 2013 to provide time for an orderly transition, but there is no requirement to wait until the effective date to begin using the new design values. The intent of a transition period is to minimize project delays and supply chain disruptions. Throughout this transition period, SFPA will provide both the current design values as well as the new design values. Detailed Questions & Answers, as well as span tables based on both current and the new design values, will be available from SFPA during the transition period.

The American Wood Council (AWC) will work with the International Code Council to incorporate the new design values into span tables in the 2015 International Building Code and 2015 International Residential Code. AWC will also develop addenda and other updates to use with new construction designed in accordance with its standards and design tools, as well as recommended revisions to previous code editions.

The new design values for all sizes and grades result from destructively testing more than 7,400 full-size samples of commercially-produced Southern Pine in a two-step process to complete a full In-Grade testing matrix. No.2 2x4s were tested in the first step of the process, resulting in design value changes for Southern Pine sized 2” to 4” wide and 2” to 4” thick in No.2 Dense and lower grades only for use on an interim basis. Interim design values for those sizes and grades became effective June 1, 2012, as published by SPIB in Supplement No.9 to the 2002 Standard Grading Rules for Southern Pine Lumber.

SPIB’s Supplement No.13 incorporates Supplement No.9’s interim design values with minor changes due to rounding effects. This means that interim design values for the sizes and grades in Supplement No.9 are replaced by the new design values for those sizes and grades in Supplement No.13 effective June 1, 2013.

Southern Pine's strength and stiffness is comparable to other softwood species used in residential and commercial construction. Southern Pine users have many available product options including visually graded dimension lumber and an increasing supply of mechanically graded lumber. From framing a house to building a deck, Southern Pine continues to be a dependable product with superior treatability against decay and termites.

Disclaimer:

Southern Pine design values are published by the Southern Pine Inspection Bureau after approval by the Board of Review of the American Lumber Standard Committee. SFPA does not test lumber or establish design values. Accordingly, neither SFPA, nor its members, warrant that the data or design values herein are correct, and disclaim responsibility for injury or damage resulting from the use of such design values.

Reference design values are based on normal load duration and dry service conditions. Because the strength of wood varies with conditions under which it is used, these design values should only be applied in conjunction with appropriate design and service recommendations from the National Design Specification® (NDS®) for Wood Construction published by the American Wood Council.

The conditions under which lumber is used in construction may vary widely, as does the quality of workmanship. Neither SFPA, nor its members, have knowledge of the quality of the materials, workmanship or construction methods used on any construction project, and, accordingly, do not warrant the technical data, design or performance of the lumber in completed structures.