Exploration of probabilistic mould growth assessment

A sufficiently long continuous duration of favourable conditions, particularly the availability of water and nutrients, is necessary for the mould growth on the surface of a building component. The availability of water is commonly quantified by the relative humidity on the building component surface. Some parameters, substantially affecting the relative humidity randomly fluctuate in time. Therefore, considering continuous duration of favourable conditions as a basic characteristic for mould growth assessment, its occurrence in time is represented by a stochastic process. Exploration and comparison of current methods for probabilistic assessment of mould growth resulted in emphasising the application of the theory of extreme values. Exceedance probabilities of practically important duration levels are estimated by the classical block maxima model for extremes and the point process model. As a quantification of potential mould risk the mean return period of a considered duration of favourable mould growth conditions is suggested. This quantification may be used for comparison of different designs, assessment of retrofitting effectiveness or as an input for cost–benefit analysis.