Factor method for aluminium windows and curtain walls

Buildings and building components service life are vital information in a design process because most the choices to be made during this process are influenced by life cycle costs or by environmental impacts over the life cycle, i.e. elements that are strictly related to the service life of building systems and components. The ISO 15686 standard series suggests a way to predict the service life of a building components: the factor method. Estimating the service life a construction products would have in a set of specific in-use conditions (determined from reference service life data after taking into account any differences from the reference in-use conditions) is an error prone process. The error could influence significantly the estimation if the factor method is applied at the multiplication level, therefore significant research on reliability of the factor method to be used for specific construction products is required. Aluminium construction products like windows, CE marked in accordance to EN 14351-1, or curtain walls, CE marked in accordance to EN 13830, are some among the others in a building, of the most influencing life cycle costs and environmental impacts and therefore a highly reliable estimated service life for these products is needed. Applying the factor method, stakeholders and manufacturers have been interviewed to define which are the elements most influencing the service life of aluminium windows and curtain walls. The outcomes of this study have been used to create a specific factor method for each family of components under analysis, which can be classified according to ISO 15686-8 as a combined level factor method where the estimated service life may be computed by combining the multiplication and function level for groups of different factor categories.