SBCA has drafted an engineering policy regarding the transition to lowered Southern Pine lumber design values effective June 1, 2012, entitled, SBCA’s Policy on Building Code Applied Loads and Lumber Related Resistance Implementation: Transitioning to June 1 Southern Pine Design Values (you can view this document by clicking on the first pdf link below).
This SBCA policy provides guidance to structural component manufacturers on how building engineering is affected by design value changes. Specifically, it answers the following several prevalent questions currently in the marketplace, including:
- Does a legal relationship exist between the building code, the National Design Specification (NDS) for Wood Construction and the responsibilities of building design and construction professionals?
- How should builders, building officials, and building design and structural building component industries react on June 1, 2012 with respect to the lumber design values used to provide structural resistance to loads?
- What about projects that have been designed using pre June 1, 2012 lumber design values that are on-going projects after June 1?
- What about the cost of re-designing the building to accommodate the change in design values for projects that are ongoing after June 1?
As follow up to this policy, SBCA has sent a letter to the International Code Code Council (ICC) (you can view this letter by clicking on the second pdf link below), which requests the ICC's plan for addressing lumber design value changes. It states, "Give [pending and potential future] reductions, we are presuming that ICC will be taking swift action to ensure that all jurisdictions will be implementing these new design values per the defined effective date given concepts as found in IBC Chapter 23."
In the unlikely event ICC does not plan swift action, the letter states, "Should ICC instead decide that the design values will be adopted all at once later in 2012 when the SPIB testing is completed, we clearly would like to know that this is the position of the ICC and the engineering justification for this position as our industry will then have this as another implementation pathway that we can follow."
Finally, the letter states that if the ICC does not plan to take a swift adoption approach, "we will recommend that all architects, engineers, builders and component manufacturers place on their building and on the construction design documents and component design drawings the following statements or language to similar effect:
The ICC has determined that the lumber design value reductions DO NOT need to be implemented as defined by SPIB in Supplement No. 9 to the Southern Pine Inspection Bureau 2002 Grading Rules Effective June 1, 2012.
Until otherwise notified by the ICC and/or the local jurisdiction, the adoption and implementation of the SPIB published Southern Pine lumber design value reductions will take place upon adoption and use of the new design values per a publicly stated and written policy by the ICC and the ICC’s recommendations with respect to adoption by the local jurisdiction. In this interim period the ICC determination allows for the pre June 1, 2012 Southern Pine design values to be used by all code defined lumber end uses, so that uniform and equivalent lumber design value provided resistance to all applied loads is maintained."
The ICC has indicated it will respond to SBCA pending their assessment and technical review. All the latest information regarding this issue will be posted on SBCA's lumber web page here: www.sbcindustry.com/lumber.php.