A new model for prediction and its application in practice

In buildings growing conditions for mould fungi can occur and cause fungus infestation. Therefore, consequent measures have to be taken to avoid health dangers that come from mould fungi in buildings. In order to avoid the mould fungus formation, a strategy has to be set up that focuses on the growth conditions for mould fungi. While in Germany only relative humidity is used as an assessment criterion for mould growth risk, more and more measured isopleths are used abroad. But all these growth curves have been determined for steady state conditions, in spite of the non-steady state conditions in reality. The most important boundary conditions for the growth of fungi are temperature, humidity and substrate conditions which have to be simultaneously available. A new biohygrothermal procedure is developed, which allows the prediction of mould growth under transient boundary conditions. The assessment results from a comparison of the water content in a modeled mould spore determined by transient calculations, with the critical water content, above which the spore germinates and grows. This new model is described and its application is demonstrated on different practical examples.