Michele Florencia Victoria

Carbon and cost critical elements: a comparative analysis of two office buildings

Purpose The purpose of this paper is to identify and compare cost and carbon critical elements of two office buildings, and to help achieve an optimum balance between the capital cost (CC) and embodied carbon (EC) of buildings. Design/methodology/approach Case study approach was employed to study cost and carbon critical elements of two office buildings as it allows an in-depth and holistic investigation. Elemental estimates of CC and EC were prepared from BoQs of the two buildings by obtaining rates from the UK Building Blackbook. Pareto principle (80:20 rule) was used to identify carbon and cost critical elements of the two buildings, and the significance hierarchies of building elements were compared. Findings Substructure, frame and services were identified as both carbon and cost critical elements responsible for more than 70 per cent of the total CC and EC of both buildings. Stairs and ramps, internal doors and fittings, furnishings and equipment were identified to be the least carbon- and cost-significant elements contributing less than 2 per cent of total CC and EC in both buildings. The hierarchy of cost and carbon significance varies between buildings due to the difference in the specification and design. Originality/value The increasing significance of dual currency (cost and carbon) demands cost and carbon management during the early stages of projects. Hence, this paper suggests that focusing on carbon and cost-intensive building elements is a way forward to keep both cost and carbon under control during the early stages of projects.

Carbon and Cost Hotspots: An Embodied Carbon Management Approach During Early Stages of Design

The need for embodied carbon management is well recognised, and possible mitigation approaches are highly sought due to the increasing need arising of carbon reduction targets. This requires the unregulated embodied carbon to be tackled instantly. This chapter presents an approach to manage embodied carbon through the identification of carbon and cost hotspots. Carbon hotspots are the elements of buildings that encompass high levels of carbon (embodied carbon). Evidence from the literature suggest that careful design of such hotspot elements will result in the highest potential carbon savings. However, the state of knowledge regarding carbon hotspots has not been extended beyond a few case studies. Hence, this chapter explored the concept of hotspots by collecting data from a sample of 41 office buildings in the UK. The carbon and cost hotspots were identified based on 80:20 Pareto rule which suggest 80% of emissions are resulting from 20% of building elements. However, findings did not fully comply with Pareto’s 80:20 ratio, instead proposed a new ratio of 80:43 for embodied carbon. Substructure, frame, external walls and services were identified as both carbon and cost hotspots of the sample office buildings. In addition, elements were categorised into three types based on the probability of an element being identified as a carbon hotspot in the building. It was interesting to note that the identified carbon hotspots were also found to be contributing up to 72% of the capital cost and the identified cost hotspots contribute up to 81% of embodied carbon. This implies that there is a possibility of reducing both embodied carbon and capital cost, which are considered as the dual currencies of construction projects, by focusing on the design of the hotspots identified.