Evaluation of BIM-based LCA results for building design

Alexander Hollberg,Guillaume Habert,Gianluca Genova

doi:10.1016/j.autcon.2019.102972

Alexander Hollberg, Guillaume Habert + Show 1 more

Open Access

https://doi.org/10.1016/j.autcon.2019.102972

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Abstract

Abstract Digital tools based on Building Information Modelling (BIM) provide the potential to facilitate environmental performance assessments of buildings. Various tools that use a BIM model for automatic quantity take-off as basis for Life Cycle Assessment (LCA) have been developed recently. This paper describes the first application of such a BIM-LCA tool to evaluate the embodied global warming potential (GWP) throughout the whole design process of a real building. 34 states of the BIM model are analysed weekly. The results show that the embodied GWP during the design phase is twice as high as for the final building. These changes can be mainly attributed to the designers' approach of using placeholder materials that are refined later, besides other reasons. As such, the embodied GWP is highly overestimated and a BIM-based environmental assessment during the design process could be misleading and counterproductive. Finally, three alternatives to the established automatic quantity take-off are discussed for future developments.

Highlights

The built environment has a high impact on the environment and is responsible for more than one third of global greenhouse gas (GHG) emissions [1]
This paper investigates whether Building Information Modelling (BIM)-based Life Cycle Assessment (LCA) throughout the design process allows for environmental performance improvement
Use machine learning and advanced techniques in LCA tools The literature reviews and the results of this paper show that the ideal LCA tool that is easy to use in early design, does not need additional information input, calculates quickly, allows for optimisation throughout the whole design process and allows for an automatic sustainability certification does not exist yet

Summary

Introduction

The built environment has a high impact on the environment and is responsible for more than one third of global greenhouse gas (GHG) emissions [1]. Due to the implementation of energy efficiency regulations in most industrialised in the last years, the operational energy demand and associated GHG emissions of new buildings have been very much reduced [1]. The share of embodied energy and GHG emissions due to the manufacturing, replacement and disposal of building materials gained importance [2]. Energy efficient residential buildings the embodied environmental impact makes up about half of the total GHG emitted in a life time of 50 years [3]. This clearly shows the need for a holistic assessment of the whole life cycle. Life Cycle Assessment (LCA) is increasingly applied for assessing the environmental performance of buildings in research, and in practice – most times in form of a post-design evaluation for sustainability certification purposes, e.g. DGNB [4]

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