Using Measurements of Fungal Activity by Isothermal Microcalorimetry as a Base for Modelling Fungal Growth in Buildings

Mould growth in buildings affects indoor air quality. To prevent mould growth in building components, there is a need for design tools that take into account both microclimate and mould growth patterns. We propose a novel laboratory method to assess mould growth as a function of RH, temperature and substrate by measuring the thermal power produced by the fungal metabolism as a measure of growth rate with an isothermal calorimeter. Isothermal calorimetry gives a continuous recording of the thermal power released by a sample. It is a non-destructive technique so that many measurements can be made on a single fungal sample under different conditions. By combining the calorimeter with a humidity generator in which the RH (water activity) of a sample can be changed, it is possible to measure the activity of a mould sample at many different RH-temperature conditions in a relatively short time. Measurements can be made with the samples growing on realistic substrates like wood or gypsum board paper. In the present paper we describe how data on mould activity generated by isothermal microcalorimetry can be used together with data on the mould microclimate to model the growth of the fungi.