Improved service life predictions for better life cycle assessments

»1 Deviation in calculated results of the actual service life from RSP = 75 years

»2 The cumulated environmental impact by building elements over the years

»3 Change in contribution by different façade elements over the years

»4 Contribution to the total cumulative impact of the building by two types of building elements used in the façade

»5 The chances of survival of single-family houses according to ownership and number of bedrooms

»6 Average life span of dwellings, according to different stakeholders

»7 Calculation of the environmental impact of six sample projects using different models for service life prediction

»8 Environmental burden illustrated. Current method using average per year (left) or dividing in phases (right)

The importance of assessments of the environmental performance of materials in buildings based on life cycle assessment is growing. The applied life span for the building and service lives of its construction products have a big influence on the outcome of these assessments. This paper shows on basis of conducted research, the influence of the applied life span and service lives on these environmental calculations. Based on the results it is concluded that with the current tools and assumptions the actual environmental impact of less durable building elements will be higher and that of durable elements lower than calculated. Important parameters influencing the service life and solutions for improving service life predictions for buildings and building elements are presented in order to optimize the reliability of the environmental assessments.

1 Introduction

Usually one can only judge afterwards whether a used service or product really has been environmentally sustainable. This applies also to the sustainable performance of buildings. These performances are nowadays frequently assessed based on “calculations” with one of the specialized instruments on the market like e.g. LEED, BREEAM, GPR and Greencalc. It is expected that the applied life span of the building and the applied service life of the building elements have a large impact on the outcome of the assessment of the environmental performance of the building with regard to...