This project provides a draft of the proposed CSA O112.10 standard, "Evaluation of adhesives for structural wood products (limited moisture exposure)", along with a draft of the commentary which will be a permanent companion document to the new standard. This new standard introduces the classification of "limited moisture exposure" service conditions for bonded wood products. The new classification is useful for a product not intended for exterior use which, however, experiences incidental wetting, such as can occur during transportation, further processing, or even in service. The new classification will enable manufacturers to make the best use of advances in adhesives technology, and will provide end-users with a greater choice in cost, aesthetics, and environmental impact.
As well, this report includes a draft of a discussion paper about the new classification, a literature review of typical requirements for "dry service conditions", and the results of a bonding study done in support of the development of the proposed standard relating to block shear test requirements.
Forintek has completed a two-year investigation of the NLGA SPS 6 Standard, Special Products Standard for Structural Face-Glued Lumber. The NLGA SPS 6 Standard prescribes product specifications and qualification and quality control requirements for structural products created by edge-gluing and/or fingerjoining lumber segments. Under the NLGA SPS 6 Standard, the design values assigned are based on the visual grade and the stress level achieved in qualification tests on the glue joints.
The project assessed the effect of the following three factors on strength of the NLGA SPS 6 product:
1. Tension proof-loading;
2. Relative location of fingerjoints in adjacent members when fingerjoined material is edge-glued;
3. Strength of the material used to make the NLGA SPS 6 product.
Results showed a positive effect of proof-loading, a minor effect of staggering of fingerjoints, and a highly significant effect of density of raw material on tensile stress of edge-glued specimens. It was confirmed that SPS6 products of greater commercial value can be obtained from lower grade lumber. However, visual grading of SPS 6 products proved to be more difficult than visual grading of lumber, because grade-determining wood characteristics were sometimes hidden in the bond line, and could not be properly identified.
The findings of this project can be used to fine tune the NLGA SPS 6 standard and the other NLGA fingerjoint and face-glued lumber product standards. The project will help the wood industry maximize the utilization of their raw material resource, resulting in increased profitability.