Construction activities account for much energy consumption and carbon emissions. According to World Wildlife Fund (WWF), the construction sector was the second largest contributor of the Hong Kong carbon emissions in 2007, and 85% of the emissions from the sector was external in nature. The carbon footprint embodied in each building construction material varies considerably under different conditions. This research aims to calculate the embodied carbon footprints of building construction materials.

Cement, concrete and plywood were selected as construction materials for investigation. The methodology framework was developed based on the “cradle-to-site” life cycle boundary, covering the processes of raw materials extraction, manufacturing and transport until the building c...[ Read more ]

Construction activities account for much energy consumption and carbon emissions. According to World Wildlife Fund (WWF), the construction sector was the second largest contributor of the Hong Kong carbon emissions in 2007, and 85% of the emissions from the sector was external in nature. The carbon footprint embodied in each building construction material varies considerably under different conditions. This research aims to calculate the embodied carbon footprints of building construction materials.

Cement, concrete and plywood were selected as construction materials for investigation. The methodology framework was developed based on the “cradle-to-site” life cycle boundary, covering the processes of raw materials extraction, manufacturing and transport until the building construction material reaches the construction site. Data were collected from manufacturers and trading companies in local and nearby regions. Calculation of the greenhouse gas (GHG) emission for the materials was discussed in three categories: upstream materials, manufacture, and transport.

The results indicate that for Portland cement, calcination is the largest contributor to the total GHG emission over the cement life cycle, followed by coal combustion. For ready-mixed concrete, the major contributor is the cement manufacturing. As for plywood, manufacture is the major source if the product is imported from Mainland China manufacturers, whereas transport plays a more important role if the product is bought from the South America.

The accuracy and reliability of the local embodied carbon database under development largely depends on the data comprehensiveness, data quality and availability of the first-hand data. Much more support from the local industry is needed in the future research. The methodology developed in this study can be modified and extended to other building construction materials, thereby helping lower the carbon footprint of construction activities by providing a benchmark for the selection of green materials.