Global warming potential and energy consumption of temporary works in building construction: A case study in Hong Kong

The importance of the building industry on environmental impacts, especially global warming potential (GWP) impact due to greenhouse gases emissions is undisputed. Thus, significant efforts have been devoted to minimize environmental impacts and waste management problems from building construction globally. Numerous studies have particularly focused on assessing the environmental impacts of buildings based on materials, construction processes and whole building systems. However, less attention has been given on some critical features, especially on temporary works (e.g., hoarding system). But the temporary works also consume considerable amounts of materials and generate significant amounts of waste due to its short service life time. Therefore, this study evaluated the environmental impacts of hoarding systems as a case study in Hong Kong with the aim to identify the areas of impacts reduction and improvements in its waste management system. A case-specific structured questionnaire survey was conducted to the relevant stakeholders to identify the essential materials, and construction, deconstruction and waste management processes of hoarding systems, whereas life cycle assessment was employed to assess the associated environmental impacts. The findings demonstrated that more than 3 tonnes of CO2 eq GWP and 39 GJ of non-renewable energy consumption impacts were associated with 1 m of hoarding construction. This is mainly due to the use of large amounts of steel products and concrete in the construction of the hoarding system. This results and analysis can help the building industry to identify the opportunity for reducing environmental impacts, and facilitate resource-efficient and effective design of hoarding systems.