Global building life cycle assessment: Comparative study of steel and concrete frames across European Union, USA, Canada, and Australia building codes

Abstract

The construction industry has one of the worst carbon footprints among the major industries and accounts for 39% of the world’s total greenhouse gas emissions. One of the main determinants of the carbon footprint of a building is the type of frame used in its structure. The most commonly used types of structural frames are steel and concrete frames, each having its own advantages and drawbacks. This study estimates and compares the carbon footprint of two buildings designed with a steel frame and a concrete frame, respectively, based on the building structural design codes of the European Union (EC), USA (ACI, AISC), Canada (CSA), and Australia (AS). The primary objective of this study is to conduct a comprehensive comparison of carbon emissions from these buildings. The focus extends beyond operational emissions to include an assessment of embodied emissions using the life cycle assessment (LCA) methodology. This comparison aims to gauge the overall emissions of the buildings and also evaluate the impact of major building codes on their carbon footprint. The results show that among the steel frame structures designed based on different building codes, the one designed according to the codes of the European Union has the highest carbon emission (142 kgCO2-eq/m2 floor area), and the one designed based on the Australian code has the lowest carbon emission (119 kgCO2-eq /m2). Among the concrete frame structures, the one designed based on the Canadian codes had the highest carbon emission (221 kgCO2-eq/m2), but again, the structure designed according to the Australian code had the lowest carbon emission (134 kgCO2-eq /m2). Carbon emission estimations for the operational phase showed that, while Canadian Cities exhibit the highest portion of energy consumption, its utilization of a green electricity grid results in the lowest operational carbon emissions. In contrast, Sydney, despite having the lowest energy consumption, exhibits the highest level of operational carbon emissions due to its reliance on coal for electricity generation. The findings of this study can serve as a valuable benchmark for policymakers in various areas. They can identify the shortcomings and advantages of their region's building codes, paving the way for targeted modifications that contribute to achieving a more sustainable built environment in their respective locales.