Understanding vacuum drying technologies for commercial lumber

Abstract

Vacuum drying is an economical alternative to conventional drying for many species under a variety of environmental and economic conditions. Vacuum drying can reduce drying time and be more energy efficient compared with conventional steam drying. But there are many factors to consider when comparing the two technologies. This report describes the principles and practices of vacuum drying and discusses its advantages and disadvantages. Among other concerns, final moisture content variation and residual stress have been significant issues of concern with vacuum drying. Standard vacuum drying schedules by species and thickness are lacking for the various vacuum drying technologies; therefore, proper training and applied research are still needed to develop standard practices for vacuum drying.

Citation

Lyon, S.; Bowe, S.; Wiemann, M. 2021. Understanding Vacuum Drying Technologies for Commercial Lumber. General Technical Report FPL-GTR-287. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 5 p.