The Suitability of the Double Vacuum Process and Its Modifications for Making Class B Impregnated Wood

摘要

The preparation of class B impregnated wood was investigated at the Timber Laboratory of the Technical Research Centre of Finland. Class B covers impregnated wood with a penetration of at least 10 mm in the sapwood and with absorption approved by the Nordic Wood Preservation Council (NWPC). The main idea was to obtain the minimum absorption for a penetration exceeding 10 mm, since class B preservatives are mainly oil based, and their price thus depends on the price of crude oil. The processes studied were the traditional double vacuum process, the Lowry process and the Rueping process.