Sustainability in the built environment : the embodied carbon of steelwork in non-residential building structures

This thesis describes a doctoral research undertaken on the embodied carbon of steelwork used in non-residential buildings. The broad area of sustainable development in the built environment is reviewed first and a reasoned rationale for the narrowing of the research topic to structural steelwork provided. The research then concentrated on steel, from the energy-intensive steelmaking process to the 100% recyclability of steel components at the end of a building life. Carbon emissions and energy consumption at various stages of steel production, manufacture, construction, maintenance and end-of-life are reviewed in detail. It has been established that a significant amount of research and energy saving initiatives are underway in the steelmaking industry. However, although research is taking place in the downstream processes, the effort is not well co-ordinated, resulting in numerous gaps in existing environmental data. In an attempt to close some of these gaps, a case study has been carried out on the fabrication and erection phases of a real steel building structure. The various activities, from procurement of materials to the erection of the steel frame on site, are described in detail. Furthermore, steel quantities of the fabricated frame were recorded during the case study, from which the carbon emission of the building was calculated using the British Constructional Steelwork Association (BCSA) Carbon Footprint Tool. This carbon footprint was estimated to be 12498 tCO2 from the 4747 tonnes of steel, giving an average emission figure of 2.63 kgCO2/kg for the cradle to end-of-erection boundary case. The building had internal plan dimensions of 94m by 57m, which gave a carbon footprint of 2.3 tCO2/m2 of floor area