An estimation of thawing time for hemlock dimension lumber

Since the heat-treatment of lumber may start at a temperature below freezing, two distinct stages, thawing and heating, are encountered during this treatment. This paper discusses the estimation of both thawing and heating times for hemlock (T. heterophylla) dimension lumber. An approximate analytic solution is used for the thawing process while a numeric simulation is utilized for the heating process. Heat-up experiments were carried out in a laboratory kiln. Core temperature in lumber was accurately determined when heating under various combinations of dry and wet bulb temperature. The results indicate that the calculated heating rates agree well with the experimental outcome.