Abstract
A durability assessment system that links an advanced computer model for structural and hygrothermal analysis with damage functions is currently being developed. The computational system has different modules that calculate the different structural and hygrothermal responses of wall systems. Outputs of these modules are input to the module of damage function models to calculate damage, performance and service-life of building envelopes. Details of biological damage functions implemented in the damage function module of IRC’s durability assessment system are presented. The biological damage functions trace deterioration in wood materials subjected to hygrothermal loads that favor fungal growth. The developments of the models are based on recent biological experimental data from the literature. Equations to calculate various parameters in the model are presented and the application of the developed models is demonstrated using air leakage of warm and humid indoor air in a typical wood-frame construction in Ottawa.