EN 318 : 2002 

Wood-based panels – Determination of dimensional changes associated with changes in relative humidity

This specifies a method for determining dimensional changes in wood-based panels due to changes in the relative humidity of the air.  This is measured between 65% relative humidity and 85% relative humidity in adsorption and 65% relative humidity and 30% relative humidity in desorption.  This involves the use of a climate chamber.