Washington State University
Voiland College of Engineering and Architecture
Composite Materials and Engineering Center
1615 NE Eastgate BLVD., Section A
PO Box 641806
Pullman, WA 99164-1806
509-335-2262
Lumber yields from small diameter timber (SDT), such as ponderosa and lodgepole pine and grand fir, proposed in this study, are significantly lower (<50%). Variation due to greater percentage of juvenile wood, grain patterns and growth ring orientation lead to lumber drying defects, resulting in lower grade/valueand higher rejection rates during fabrication of cross -laminated timber (CLT ) panels. These variations could lead to residual stresses that result in delamination at the glue line during the service life of composite panels.A strand-based technology leads to greater log conversion efficiencies and, when coupled with appropriate technologies, these strands can be used to produce durable and higher -performing composites such as mass timber panels. Washington State University (WSU) and the University of Minnesota Duluth (UMN-Duluth) received a three-year National Science Foundation (NSF) grant in 2018 to demonstrate that strand-based mass timber panels can outperform traditional CLT. The proposed Thermally Modified-Composite Wood Strand-Veneer Laminated ( TM-CWSVL) panels utilize thin -strand veneers and thermal modification processing (which imparts improved decay resistance and dimensional stability), resulting in new buildings with longer service-lives and improved performance. However, for these durable TM-CWSVL panels to be accepted into commercial building markets, it is critical to evaluate their fire performance. This information is critical for building code officials to determine the fire-rating of the panels, as well as if there would be a need for protective cladding. Based on previous work by others, there are indications that thermally modified wood could have improved flame spread resistance; however, this notion has not been confirmed or corroborated.Therefore, our goal is to conduct small- and large-s cale fire performance tests on the TM-CWSVL panels following the ASTM E119 test standard. These tests will evaluate the structural fire performance and fire resistance of the panels manufactured using thermally modified strands (TM -CWSVL) and unmodified strands(CWSVL). These activities will result in necessary fire performance data for the acceptance of the new mass timber panels into commercial building markets, as well as create a value-added application for SDT from hazardous fuel treatments of our National Forests; with implementation of the Good Neighbor Authority (GNA) program, it would also be possible to access these lower value timber resources for commercial use.
1.Thermally modify wood strands based on optimized conditions as determined in the NSF-funded project and fabricate CWSVL and thermally modified CWSVL (TM-CWSVL) mass timber panels.
2.Conduct small-scale fire testing to evaluate the charring rate of CWSVL and TM-CWSVL for comparison against traditional CLT panels. 3.Evaluate the structural fire resistance (ability to support the applied load for duration of test) and separating fire resistance (preventing passage of flame and hot gases, and temperature rise on unexposed side) of large-scale TM-CWSVL panels f ollowing the ASTM E119 testing standard.
thermally modified wood, small diameter utilization, Washington, pullman, wsu, Ponderosa pine, lodgepole pine, douglas-fir, CLT, mass timber, wood strand veneer
