Éco-Conception des ensembles bâtis et des infrastructures
Eco-design of buildings and infrastructure
Sustainability assessment of refurbishment vs. newconstructions by means of LCA and durability-basedestimations of buildings lifespans: A new approach
Thèmes : energy, construction, life cycle assesment
A common practice in Life Cycle Assessment (LCA) of buildings is to consider a default value for their lifespan. Thispaper addresses the importance of estimatingthelifespan of each evaluated building when refurbishment and new constructionare compared, usinga case study.The lifespansof the refurbished and the new buildingsareestimated by applying degradation models of reinforcedconcrete structures.A simplified economic analysis is also performed.Two thermal performance levels are evaluated: standard and passive, in both alternatives, the refurbished and thenew building. Results show that anew building can have a lifespan more than six timeslonger than arefurbished one. Passive refurbishmentappears to be the best choicefrom an environmental point ofview. Evenif a new passive building obtains slightly better results, these can only be ensured if it is in use for a long period, in our case 210 years. This isnot easy to guarantee inrealpractice,according to usual trends. The new passive building results to be the most cost-effective, but the same constraints regarding guaranteeing a long lifespanare applicable. The results reveal a strong dependence of LCA results on the lifespan. Its value can alter the order of preference of the solutions when comparing alternatives. There is a high potential of environmentalimprovement ofbuildingsbehaviorby changing current practices and extending buildings’ lifespanup to their physical limit.