450=840 Creates an Artificial Competitive Advantage for OSB

Originally published by: SBCRI-SBCA Investigative Report #1October 19, 2015

The following article was produced and published by the source linked to above, who is solely responsible for its content. SBC Magazine is publishing this story to raise awareness of information publicly available online and does not verify the accuracy of the author’s claims. As a consequence, SBC cannot vouch for the validity of any facts, claims or opinions made in the article.

SBCRI's goal is to ask: Is this true or not? SBCA-SBCRI provides the facts and lets the reader decide.

The following discussions and correspondence between APA and SBCA-SBCRI have touched on many of the concepts covered in this research report series:

BJ Yeh articulated, in a very elegant and forthright manner, our industry’s primary concern using the following words to reflect the point of view he expressed, which is a concept we have all heard many times; the prescriptive code is based on historical performance and essentially fundamental engineering does not really “apply” or “work” because structures built using traditional and conventional methods have a good resistance track record.

  1. The technical information required should support or be used to modify existing code-supported provisions such as established systems or risk factors related to product equivalency. This information would most likely be used to support the introduction of new materials and systems, as opposed to challenging existing products. For example, existing OSB design properties are not the target; but currently recognized systems and product equivalency procedures are.
  2. We (APA) believe that a major goal for the SBCA position is to provide a cost-effective engineering solution to their membership and as such this goal serves the SBCA membership well. However, by establishing standard factors in which product equivalency or system performance are applied generically, an unintended consequence may be that non-wood products (e.g. foam sheathing) gain an advantage and supplant traditional OSB market share. This is not in our Association members' best interests.
  3. Our staff is prepared to critically review and support technically justifiable programs brought forth…...

The purpose of this letter is to be precise as to what the SBC industry is going to set as its engineering foundation/performance benchmarks for wood structural panel (WSP) unit shear wall capacity values and section 104.11 equivalency evaluation. This evaluation is based on all of the testing and findings to date that we have access to. We believe that it is important to be completely transparent in our approach so that APA/AWC can provide engineering mechanics test data/analysis and installation procedures to provide justification for different benchmarks than those provided here, if so desired. As you said in your February letter, “The technical information required should support or be used to modify existing code-supported provisions such as established systems or risk factors related to product equivalency.” This work is clearly in the domain of APA/AWC.

This information has been met with the perspective that SBCRI testing is unsubstantiated and that SBCRI-SBCA analysis with respect to OSB shear design values being overstated is based on non-standard test methods such as the real 12x30 foot building test shown below:

Also, it has been asserted, universities and other research organizations, along with the consensus opinion of the code and standard committees, and also the extensive performance history of wall assemblies sheathed with OSB sheathing, show that the current shear design values provided in the APA publications are valid. Finally, the current shear design values are referenced in the International Building Code (IBC) and the IBC referenced Special Design Provisions for Wind and Seismic standard, so they must be correct and do stand as part of adopted law.

For greater details regarding SBCRI-SBCA knowledge, see the following:

Key goals of the SBCRI-SBCA reports include:

  • Focusing on a single issue. We attempt to present the facts surrounding that issue as concisely as possible.
  • Providing a public domain repository and compendium of knowledge.
  • Publicly soliciting test reports and analysis that can provide additional information to enhance or correct our knowledge.

The SBCA-SBCRI Investigative Report Series will continue to provide detailed OSB-related information with the hope that this information, being organized in a public domain environment, will lead to voluntary advocacy for change. The organizations that, ultimately, own these strength and design value properties are APA and AWC.  

SBCA-SBCRI has found that change is hard and changing long-standing tradition is even harder.

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