Towards a framework for early estimation of lifecycle carbon footprinting of buildings in the UK

The construction industry has become increasingly concerned with understanding the whole life impact of buildings as their customers shift their focus towards declaration of the greenhouse gas (GHG ), carbon footprint or business CO2 emissions. To maximise potential for reduction, this whole life building carbon footprint should be considered at the outset of the design process and requires constant revision with reflection on the impact of design changes in later stages of the building life. A completed building can be viewed as a product at the point of handover and it is possible to calculate the content of materials and process required to provide that product as an Environmental Product Declaration. The procurement team has the challenge of providing an initial impact assessment balanced with a working estimate of the energy use and maintenance requirements across a building design life, and a strategy for deconstruction at end of life. For this process to be effective, data used for converting quantities of materials to CO2 emissions must be appropriate to the specific products to be constructed in the building as they are identified from generic databases. Benchmark data is entered into a framework to calculate impacts from the complex supply chain involved and the direct energy use from processes required to complete the building as the design evolves. This paper outlines a proposed assimilation framework with data, scope and boundary protocols to allow comparison of design scenarios within building type groups. It also supports the formulation of environmental impact reduction strategies throughout the design and construction of buildings and supports life cycle thinking in terms of design life, reuse and recycling necessary for optimising sustainability in the built environment. The protocol uses concepts already well established in estimating and engineering to maximise adaptability from existing documentation of project data. Abbreviated worked examples are also demonstrated. The paper will be of interest to building procurement teams, their clients and supply chains.