Assessment of service lives in the design of buildings

Sammanfattning: The built environment usually constitutes a very importantpart of the real capital of a nation and the constructionsector represents more than 10% of the yearly Gross NationalProduct of the industrialised world. The importance of goodplanning of all construction, where the service life of thework is considered, is of great interest and an importantaspect in sustainability considerations. The need for increasedknowledge about degradation of materials, for structuredmethodology, and for working tools for those involved in theplanning process, has resulted in an extensive effort inpre-normative research and standardisation regarding thisfield.This thesis presents a discussion on service life planningand the role of the Factor Method in such a work, andespecially, discussion of modification and development of themethodology. In the design process, the need to evaluate theservice life of products is great, and this is a formidableproblem to solve, as the results will depend on both materialproperties and the environment in which the material is placedor used. A practical solution has to be based on a goodknowledge in the field, but also on a sound working strategy,to ensure that different design scenarios can be compared in astandardised or structured way. The Factor Method is apromising working tool for such an evaluation and comparison,but is as such, still more of a methodology, than a method.Examples of the use of the methodology are still very limitedand the method as such, is much discussed by researchers.However, its future will depend on how practical it will be toapply in use. The method is useful to estimate the service lifeof products, based on a known reference service life and anumber of modifying factors that will depend on the conditiondifferences between the specific project and the referencein-use conditions. The required precision of such a methodologyis discussed, especially in the light of inherent distributionin material properties and the fact that often the consequencesof failure are very limited. In such cases, the standardisedFactor Method is considered to be of great use and should giveparties involved a good means for working in a structured andsystematic way.