Development of a rapid screening method to determine the susceptibility to mould growth of novel construction and insulation products
B K Stefanowski, S F Curling, E Mansour, G A Ormondroyd
Wood-based materials are commonly used in building construction/insulation as a replacement for solid timber. However, these materials are susceptible to microbiological growth and different environmental conditions influence the vulnerability of wood-based materials. Moulds are a common problem found within homes and cause aesthetic damage, health problems and can increase material vulnerability to degradation fungi. Moulds obtain food from substances contained within wood cell walls and are unable to breakdown the cell wall, hence the structure is largely left intact and the strength properties of the material are not impaired.There are a number of mathematical models available that can be used to evaluate durability and susceptibility of wood and wood-based materials. However, with increasing concern of climate change and new regulations and legislations inforce, novel and experimental materials are being researched and developed. These materials include wood-based materials produced in a different fashion or contain untested ligno-cellulosic components. Current models rely upon the use of known temperature and humidity dynamics of the subject material. These newly developed materials do not have the required historical data to fulfil the models.The purpose of this paper is to develop a quick, reliable screening method that will evaluate different materials for their susceptibility to moulds at optimal and limited conditions. The test methods are a modified version of ASTM 4445-91 and ISO 846. The moulds used are: Trichoderma virens, Aspergillus versicolo, Paecilomyces variotii, Aureobasidium pullulans, Cladiosporum sphaerospermum, Alternaria alternata,Chaetomium globosum and Penicillium rubens. The data obtained is used to determine if there is a correlation between and hygric test methods such as hot/cold immersion tests and Dynamic Vapour Sorption (DVS) tests.
Keywords: mould, construction materials, insulation, water sorption, DVS