Building lifespan: effect on the environmental impact of building components in a Danish perspective

Construction professionals must now integrate environmental concerns with life cycle assessment (LCA) early in the procurement process. Building lifespan is important to LCA, since results must be normalized on an annualized basis for comparison. However, the scientific literature shows that issues of building lifespan are inadequately addressed. The aim of this research is therefore to explore how environmental impact from building components is affected by building lifespans of 50, 80, 100 and 120 years in a Danish context. LCAs are undertaken for 792 parametric variations of typical construction solutions, covering all primary building components and based on contemporary practice. A full statistical analysis is carried out, which shows a significant statistical correlation between changes in building lifespan and environmental impact for all primary building components, except windows/rooflights. On average, a building lifespan of 80 years reduces environmental impact by 29%, 100 years by 38%, and 120 years by 44%, all in relation to a lifespan of 50 years. The results show that if construction professionals and policy-makers use short building lifespans, then resource allocation to reduce environmental impact during procurement may become disproportionately focused on the construction contra operational phases of the lifecycle.

建筑行业专业人士在采购过程中必须尽早将环境考量与生命周期评估（LCA）相结合。建筑的使用寿命对LCA至关重要，因为评估结果必须按年度化标准进行归一化处理以进行对比。然而，科学文献表明，关于建筑使用寿命的问题尚未得到充分解决。因此，本研究旨在探讨在丹麦语境下，建筑构件的环境影响如何受到50年、80年、100年和120年使用寿命的影响。对典型建筑解决方案的792种参数变化进行了LCA，涵盖了所有主要建筑构件，并基于当前实践。进行了一项全面的统计分析，结果显示，除窗户/天窗外，所有主要建筑构件的建筑使用寿命变化与环境影响之间存在显著的统计相关性。平均而言，80年的建筑使用寿命将环境影响减少29%，100年减少38%，120年减少44%，均相对于50年的使用寿命。研究结果表明，如果建筑行业专业人士和政策制定者采用较短的建筑使用寿命，那么在采购过程中为减少环境影响所分配的资源可能会不成比例地集中于生命周期的建设与运营阶段。