How are indicators in Green Building Rating Systems addressing sustainability dimensions and life cycle frameworks in residential buildings?

Abstract

The use of tools capable of evaluating the sustainability of buildings throughout their life cycle represents a key point enabling the transition towards a sustainable built environment. To this end, different Green Building Rating Systems (GBRS) have been developed over the last few decades. All of them are voluntary schemes and propose a set of indicators to evaluate the associated impacts of buildings throughout their life cycle. However, it is unclear how GBRS are addressing sustainability dimensions and the life cycle frameworks, and particularly in residential buildings, which are responsible for a great part of these impacts. The aim of this study is to explore, in detail, how indicators in GBRS are covering the three dimensions of sustainability (environmental, social and economic) and the information modules proposed by EN 15978, along the life cycle stages of the building construction process. To do so, eight GBRS were selected and the 387 sustainability indicators included in them were analysed and clustered according to three different classification criteria, namely, sustainability dimension, information modules and stage of the construction process life cycle. The analysis and clustering process of indicators was carried out by a panel of experts in the field of study, with multidisciplinary academic and professional background, throughout an iterative process of four rounds and meetings, which led to achieve a consensus in the findings. The results of the analysis revealed that the environmental dimension is the one that is considered most among the tools, and both the social and economic dimensions require more attention to achieve a good balance. GBRS are more focused on the evaluation of the embedded impacts of the building, since most of the indicators are related to the product and construction stages (A1-A5) and therefore need to acquire a more holistic approach throughout the whole life cycle; the indicators should be considered in the very early design stage (not when the building is in operation), when decisions are made and have more potential to improve the sustainability performance of the buildings throughout its lifespan. It was not possible to cluster one set of indicators as they referred to aspects beyond the EN 15978 system boundary (such as site, transport or domestic waste management), thus highlighting the need for more coherence between a building's life cycle and GBRS frameworks, on the one hand, and the inclusion of new information modules covering the above-mentioned additional aspects, on the other.