By the summer of 2001, a new Canadian structural wood adhesive standard is expected to be available for use with the glued wood product standards published by the National Lumber Grades Authority (NLGA) for use with its glued wood product standards. This standard will permit Canadian structural lumber producers to consider and use a wider range of wood adhesives than is currently possible. Prior to the development of this standard, producers of glued structural lumber products were limited to phenol resorcinol formaldehyde or resorcinol formaldehyde adhesives. The same limitations applied to Canadian producers of other glued products such as laminated beams and laminated veneer lumber. This is because a standard for assessing structural wood adhesives other than these adhesives was simply not available in Canada. In other words, newer adhesives offering light-coloured bondlines and potentially more flexibility in processing and/or lower processing equipment costs were not permitted primarily because an acceptable means for evaluating them was not available.
A substantial portion of the new standard was drawn up under this research program. A complete draft structural wood adhesive standard was developed; however, following the completion of an inter-laboratory testing program, the technical information was found to be only sufficient to qualify structural wood adhesives for dry service conditions. The proposed standard was not judged to be suitable for assessing adhesives for wet or exterior service conditions. Consequently, the draft standard was tabled as a “dry use” structural wood adhesive standard.
Following consultation with an Industry Working Group and, shortly afterwards, the NLGA Standards Committee, a strong recommendation was made by industry representatives to continue the program and make another attempt at developing a standard for exterior service conditions. With additional funding from Forest Renewal BC and the Forintek National Research Program, the program was re-started to build on the draft dry use standard.
The extension to the original program was successful in developing a draft standard suitable for exterior service conditions. This draft standard is now the basis of the approved NLGA adhesive document: NLGA SPS Annex A, Standard Specification for Evaluation of Adhesives for Structural Wood Products (Exterior Exposure). The NLGA SPS Annex A is currently under consideration by the Canadian Lumber Standards Accreditation Board and is expected to be approved by the summer of 2001. The NLGA SPS Annex A has also been accepted as the base document for a new CSA wood adhesive standard. Although the CSA process has been shortened considerably by adopting the NLGA SPS Annex A as a starting point, the CSA process is still expected to take several years to complete, as it is a more rigorous consensus process. In the interim, it is expected that many of the needs of the Canadian glued lumber products industry can be met by the NLGA SPS Annex A.