Forest & Wood Products Australia has shared new research introducing biased position testing as a cost-effective and efficient method for the verification of structural softwood timber properties. Source: Timberbiz
This innovative approach can unlock significant cost savings and improved efficiency whilst maintaining rigorous verification of structural softwood timber strength and stiffness properties.
When it comes to quality control and product performance, random selection is traditionally used for sampling structural timber. However, biased selection can also be used. Random selection is like drawing names from a hat; every item has an equal chance to be tested, giving a statistically clear picture of overall quality. Biased selection, however, is based on picking samples (i.e. with known defects) which give specific insights, but not about the whole group.
Biased ratios are essentially formulas that help translate results from that second biased sample into the results expected, as if the whole sample set was randomly tested. So, biased selection testing allows for a reduction in testing costs by utilising a smaller sample size while achieving the same level of confidence in the verification results. This cost-saving measure is particularly advantageous for sawn timber products such as MGP12, MGP10, and F5.
This project was led by Professor Jon Shanks, Director of TimberED Services and Associate Professor in Timber Engineering at University of Tasmania and was conducted in collaboration with University of South Australia.
“By focusing on the grade-determining features of the timber, biased position testing provides direct feedback on the grading process with fewer boards tested,” Prof Shanks said.
To ensure compatibility with existing design values and standards, this project developed a process to establish appropriate Biased Ratios for quality control testing.
“This research demonstrates what can be achieved by collaboration between industry stakeholders, in this case showing that biased position testing does work and can ensure continued product compliance,” Gavin Matthew, CEO at Engineered Wood Products Association of Australasia, said.
“By embracing this new sampling method, the timber industry can maintain high levels of quality control, whilst reducing costs and improving overall productivity.”
Chris Lafferty, RD&E Manager at FWPA said this innovative approach offered cost savings, improved efficiency, and accurate estimation of properties.
“It is a significant step towards enhancing the competitiveness and sustainability of the industry,” he said.
