Modelling the outdoor performance of wood products - A review on existing approaches

Service life planning and performance classification are key issues in the building sector. Well-functioning 'performance models' are absolutely essential to predict the service life and functionality of buildings, building assets, and building products overtime. Different types of performance models have been established for various building materials, but cannot necessarily transferred to wood-based materials, primarily due to their organic character. For performance modelling of wood products biological agents need to be considered, such as wood disfiguring and degrading organisms. Different approaches to adequately reflect the influence of biotic and abiotic factors on the performance of wood have been reviewed and evaluated with respect to their usability in the building trade. We found that efforts in developing performance models for both fungal decay and mould growth have been intensified in recent years. A high heterogeneity among the numerous attempts became visible, different strategies have been followed, and were roughly distinguished according to the respective objectives, governing variables (e.g. mass loss, strength loss, remaining strength, decay ratings, service life, aesthetic appearance, etc.), data sources and the resulting level of accuracy. A framework of how exposure, dimension, design details, and the material-intrinsic ability to take up and release water can be linked to model the moisture risk in wood products is in principal available. Methods and models have the potential to get implemented not only in design guidelines, but also in European and international standards. In particular, various dosimeter models could serve as reliable tools to quantify the effects of different construction details. (C) 2014 Elsevier Ltd. All rights reserved.