LINEAR EXPANSION AND ITS RELATIONSHIP TO MOISTURE-CONTENT CHANGE FOR COMMERCIAL ORIENTED STRANDBOARDS

Linear expansion (LE) was measured along two principle directions for five types of commercial oriented standboard (OSB). The measurements w ere made over four wetting steps from 35 percent to 95 percent relativ e humidity (RH) at 24 degrees C. LE along both parallel and perpendicu lar directions of all OSBs occurred at a greater rate for moisture con tent (MC) change in the lower MC region. Statistical comparisons of th e LE data between parallel and perpendicular directions for a given OS B and among various OSBs were performed. Regression equations expressi ng LE as a function of MC change were established for various products .