Embodied carbon emissions of office building: A case study of China's 78 office buildings

• On average, CO2 emissions at the materialization stage are 326.75 kg-CO2/m2.
• CO2 emissions of unit area of super high-rise building are 1.5 times that of multi-story building.
• CO2 emissions of civil engineering account for 75% of the materialization stage.
• CO2 emissions of steel, concrete, plaster and brick account for more than 80% of civil engineering.

A CO2 emission in construction materialization stage is the key research point of architectural life cycle assessment, which is concentrated in emission time and in absolute emission volume. To build a calculation model for CO2 emissions in the materialization stage of office buildings, it should take into consideration the CO2 emissions generated from production and transportation of construction materials and equipment as well as the CO2 emissions generated from the construction process. By this calculation model, the CO2 emissions are analyzed and calculated of 78 office buildings in construction materialization stage. On average, the CO2 emissions in construction materialization stage are 326.75 kg – CO2/m2; with the increase of building height, CO2 emissions per unit area increase significantly and the CO2 emissions per unit area of super-high-rise buildings are 1.5 times that of the multi-storey buildings; the CO2 emissions of Civil Engineering account for 75% of the whole construction materialization stage; And the carbon emissions of steel, concrete, mortar and wall materials reach over 80% of the Civil Engineering. The storeys of the building and the consumption of construction materials are taken as two independent variables to set up a prediction model for CO2 emissions of office buildings in materialization stage. By statistical analysis and comparison, it can be found that the prediction formula using steel reinforcement, concrete and wall materials as independent variables can better predicate CO2 emissions in the construction materialization stage.