Mould reliability analysis combined with mould health risks for decision support

Common solutions for building energy-efficient buildings constitute e.g., double-glazed windows, airtight building envelopes and highly insulated walls. These solutions may improve the indoor environment/comfort but can also lead to adverse effect, e.g., mould at the surface of the construction components and consequently human health problems. With this study, a mould risk assessment including health consequences, a decision analysis and their adaptation to different types of building envelopes are developed. Within the frame of a mould risk and decision analysis, a physics and biology-based mould reliability analysis is combined with a medical science-based health occurrence and consequence model on an interdisciplinary basis. For the minimization of the expected consequences, an Inutility Decision Analysis (IDA) including an objective function is introduced and applied to a case study. An external wooden frame wall in a residential building is analysed and optimized with IDA quantitatively modelling the expected life cycle costs and the mould induced health risk of design alternatives. The calculation of the probability of mould occurrence is based on hygrothermal and mould reliability analysis. The health consequences are calculated with the conditional probability of asthma as inferred from the odds ratio in medical literature. The costs of choosing a type of external wall, are modelled based on the costs of the materials and works related to assembling them. The design alternative with the minimum aggregated risks and expected cost, i.e., expected inutility is selected. Within the assumptions of the example, it is demonstrated that mould health consequences constitute an important part of the expected inutilities.