Comparative Embodied Carbon Analysis of the Prefabrication Elements Compared with In-situ Elements in Residential Building Development of Hong Kong

Abstract

This paper reviews the greenhouse gas emissions of prefabrication elements for residential development in Hong Kong. Prefabrication becomes a common practice in residential development in Hong Kong and is considered as a green approach. In Hong Kong, prefabrication took place at factories in Pearl River Delta. Although prefabrication reduces construction wastage, it might generate more greenhouse gas emission from transportation and manufacturing processes. This study attempts to measure the cradle to greenhouse gas emission from prefabrication elements for a public housing development in Kai Tak area. The findings could help further reduction of greenhouse gas emissions through process improvement. Although prefabrication reduces construction wastage, it might generate more greenhouse gas emission. In Hong Kong, prefabrication took place at factories in Pearl River Delta. Some of the raw-materials might source from Hong Kong. The travel distance will be double-up as raw-materials will travel from Hong Kong to Pearl River Delta and to Pearl River Delta and back to the construction site in Hong Kong. The real benefit from prefabrication on the reduction of cradle to greenhouse gas emission in Hong Kong's context is unclear. This study attempts to measure the cradle to greenhouse gas emission from prefabrication elements (precast facade, precast wall, precast stair, precast tie beam, precast landing, precast refuse chute, semi-precast slab) for a public housing development in Kai Tak area. The prefabrication factory was located at Shenzhen, China. The greenhouse gas emission from the raw-material extraction, prefabrication manufacturing, and transportation from extraction to factory and from factory to site was accounted. Improvement scheme would be proposed in this paper to reduce the greenhouse gas emission of prefabrication elements.