Development of kiln drying schedule severity indices for degrade control

Summary Severity of kiln schedules used to dry wood has traditionally been determined after the fact. As an alternative, analytical indices using integral calculus have been developed to rate kiln schedule severity. Theoretical justification is presented for the general form of an index as well as for several specific cases. Possible uses of this type of index are also indicated. The indices take into account the dry and wet bulb temperatures used throughout a schedule as well as the duration of application and points of application of each combination of temperature and humidity used.The assistance of the California Cedar Products Company, Stockton, California, and, in particular, Charles Berolzheimer and John Rhemrev, is gratefully acknowledgedThe authors are, respectively, Research Associate and Project Leader, Forest Products Laboratory, University of California, Richmond