ABSTRACT
Hygroscopic materials and structures may have a significant effect on the relative humidity level and also on the comfort of the indoor air. This moisture buffering effect depends on the moisture loads, air change rate, outdoor air conditions and the moisture transfer between structures and the indoor air. A method to experimentally determine the moisture buffering effect of structures is presented and studied. The method is based on diurnal cycles with two relative humidity levels: upper level corresponding to occupation period and lower level corresponding to unoccupied period. The transient moisture transfer between the studied building component and the air is measured by weighing and the representative characteristics for the instantaneous and overall moisture buffering effect can be solved. The results show how much hygroscopic materials can absorb moisture from indoor air during moisture load periods and transfer it back to the indoor air during low humidity periods.
