Calculations show that in a microclimate box the Equilibrium Moisture Content (EMC) is more relevant tha Relative Humidity (RH). In a microclimate box the ratio of wood to air will extensively exceed 1 kg of wood per 100 litres of air, a ratio that is critical for controlling the humidity of wood in an enclosed space. It is also often assumed that a sealed microclimate box containing a large quantity of wood becomes dry when the temperature is raised. The contrary is true: hygroscopical materials such as wood stay in equilibrium with a higher RH level at higher temperatures, and vicevers. A more recent approach for constructing a microclimate box is therefore relying on the hygroscopical behaviour of the wooden panel itself as a stabilizing factory within the small air volume of the box. The wood of the panel or stretcher will maintain internal moisture equilibrium at changing temperatures, which is unaffected by any outside change in humidity. A small enclosed environment such as a microclimate box where the ratio of the wood to air is approximately 1:1 has shown to be sufficient for controlling the EMC within the box. On long journeys, thermally insulated transit crates can ensure a relatively stable temperature, and thus RH, inside the microclimate box.
|Status||Udgivet - 2000|