A simple correlation for monitoring the ignition propensity of wet nordic spruce wood

A combination of cone heater experiments and asymptotic analysis was used to determine the moisture content of Nordic spruce with varying degree of drying. The fuel moisture content was measured by weighing the specimens before and after a drying procedure in an oven. A high-flux asymptotic solution from an integral model established that the ignition temperature from the experiments (directly linked to the intercept heat flux) was constant for both the dry and the moist wood. As a result, one simple equation was developed that can be used to determine the time to ignition for a piece of wet spruce from the time to ignition of dry wood. This simple correlation, combined with models giving the fuel moisture content of wood from humidity and temperature of air surrounding, can be used as an engineering equation for monitoring the ignition propensity of timber.