There are two parts to this publication. Part I is the user's manual for LUSI, which is a computer program developed to simplify the lumber size control process. Part II introduces some basic concpets of statistical lumber size control. It is recommended that LUSI users familiarize themselves with the concept introduced in Part II to enable them to use LUSI effectively.
Western red cedar, with its high natural durability, is ideally suited for use in products that are subject to a high decay hazard in service. The service performance records for such products has been developed over a period of many years and is largely based on old growth wood. Since the raw material supply in today's market increasingly comes from fast grown second growth stands which may be genetically altered from older trees, this study was undertaken to determine if this second growth western red cedar has decay resistance properties similar to old growth wood.
According to the CSA 080.15 Wood Preservation Standard dealing with treatment of material for preserved wood foundations(PWF), treated wood that is cut or machined in the field must be protected with an application of a commercial field cut preservative, usually 2% copper naphthenate solution. In order to determine if present practice in using copper naphthenate is an effective means of protecting cut edges of PWF grade plywood, a number of CCA-C and ACA treated hem fir plywood stakes were prepared and coated with 2% copper naphthenate solution on their cut edges according to the standard. These stakes were then installed in the Ottawa test plot for durability performance evaluation. An equal number of stakes were also installed into the PWF test boxes currently undergoing evaluation at the Ottawa Laboratory in order to expose the stakes to an accelerated decay environment and to establish a correlation between the decay hazard in the test boxes and that in a normal test plot. An initial inspection of the test stakes has indicated that untreated control stakes installed in some test boxes had failed after only four months of service, indicating a significant increase in the decay hazard in the test box environment. Stakes will continue to be rated for performance on a period of years. The durability performance data generated will provide the information necessary to determine if commercial 2% copper naphthenate solution is providing an adequate level of protection to treated PWF grade plywood. Results will be reported to appropriate CSA committees.
A series of CCA and ACA treated hem fir plywood test boxes and untreated controls were examined after the boxes had been subjected to accelerated exposure testing for approximately ten months. The performance of untreated control stakes installed in the test boxes indicated a significant increase in the level of fungal activity in the test boxes over that known to exist in the Petawawa field test plot. Untreated hem fir plywood test panels showed evidence of advanced fungal decay, especially in the test box which had additional wood destroying fungi added to the soil. There was no sign of degradation on either the CCA or ACA treated test panels, even at the lowest retention level of 4.8 kg/m3 (0.3 pcf).