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Temperature corrections for mechanically graded lumberAuthor(s): David W. Green; James W. Evans; James D. Logan; Jim Allen
Source: Proceedings of the Eleventh International Symposium on Nondestructive Testing of Wood, September 9-11, 1998, Madison, Wisconsin. Madison, WI : Forest Products Society, 1999: page 213-214.
Publication Series: Miscellaneous Publication
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DescriptionThe continuous lumber tester (CLT) is the most widely used grading machine in the world. With the CLT, the flatwise bending stiffness of lumber is measured as it passes through the machine. The modulus of elasticity (MOE) is calculated from the force required to bend the lumber to a fixed deflection of 7.94 mm (5/16 in.), and this MOE is used in assigning a machine grade. Quality control testing is also required to assure proper grade assignment. Usually, quality control is based on tests of bending stiffness and strength. In commercial practice, the lumber passing through the CLT may still be hot from drying. In cold climates, the lumber could also be frozen when passing through the machine or when quality control tests are conducted. Unless allowances are made for the temperature of the lumber, problems may occur in grade assignment or during quality control testing.
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CitationGreen, David W.; Evans, James W.; Logan, James D.; Allen, Jim. 1999. Temperature corrections for mechanically graded lumber. Proceedings of the Eleventh International Symposium on Nondestructive Testing of Wood, September 9-11, 1998, Madison, Wisconsin. Madison, WI : Forest Products Society, 1999: page 213-214.
KeywordsLumber, grading, temperature
- Mechanical grading of oak timbers
- Mechanical grading of round timber beams
- Evolution of tensile design stresses for lumber
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