A rapid screening method to determine the susceptibility of bio-based construction and insulation products to mould growth

Mathematical models have been developed to evaluate materials' durability and susceptibility to biodeterioration by moulds, however models are material and mould species specific. Ultimately the best way to determine a materials' susceptibility is to expose the material to microorganisms. This study attempted to develop a quick, reliable screening method to evaluate a number of different materials for their susceptibility to moulds at optimal and limiting conditions. This test method was based on modified versions of ASTM 4445-91 and BSEN 846. The water absorption coefficient and Dynamic Vapour Sorption tests were also conducted to determine any correlation between the materials hygric properties and mould growth. The materials used to validate the novel screening method were: MDF, laminated MDF, Chipboard, Laminated chipboard, Wool, Hemp, Wood fibre insulation and pine. It was found chipboard was the most susceptible to mould growth and wool the least when in direct and indirect contact with agar. Primary colonisers (A. niger) easily colonised the materials, regardless of the environmental conditions, whereas secondary (A. alternate) and tertiary (T, virens) colonisers were absent on materials under limiting conditions.