Publications / Publicly Available Reports
These reports are in Adobe Acrobat pdf-format.
Investigations commissioned by Wood Focus Oy and the German Federal Ministry of Economics and Labour
A uniform indoor climate with minor variations in temperature and relative humidity contributes to establish a healthy and comfortable environment for the occupants. It is a well-known fact that the thermal mass of the building envelope counteracts strong changes in temperature (e.g. due to solar radiation). The fact that there is also something like a 'hygric mass', antagonising strong variations of moisture, is however less common. Here, 'hygric mass' means the vapour absorption capacity of the enclosing surfaces which is capable of buffering moisture variations inside a space. This would be beneficial in rooms where the generation of moisture (e.g. due to human activities) and the extraction of moisture (by way of ventilation) do not coincide. Concerning this issue, VTT (Finland) conducted numerical investigations which proved timber lining to have a favourable effect on the relative humidity in bedrooms that are ventilated during the daytime only.
To validate the interpretation of these calculations, and to obtain some practice-oriented quantification
of moisture buffering effects of different types of internal linings (based on wooden products or
cellulose fibers) under defined boundary conditions, a series of comparative field tests was conceived
by the Fraunhofer Institute of Building Physics (IBP) at Holzkirchen, Germany.
This report presents the execution and the results of these tests.
