Coventry is just about to embark on a mass demolition and rebuild programme across the south of the city centre. The new buildings will have to meet modern energy standards and will be much more energy efficient than their predecessors.
However the demolition of the old buildings will require an input of energy for the deconstruction, disposal and end of life aspects of the materials and systems that make up those buildings.
The construction of the new buildings will require an even larger input of energy associated with the emissions caused by extraction, manufacture, transportation and assembly of a building and later its maintenance. This is known as “embedded carbon”.
In the UK, 49% of total carbon emissions are attributed to buildings. This is a significant amount of greenhouse gas. It is estimated that 75% of a building’s life time emissions are embedded carbon.
Whilst the energy efficiency of new buildings is regulated, there are currently no regulations covering embedded carbon. Major schemes, such as City Centre South, will be approved and given the go ahead with no assessment of the overall carbon impact of the scheme.
A group called Architects Climate Action Network (ACAN) is campaigning to introduce embodied carbon regulation in the UK to reduce the emissions generated over a building’s entire lifespan.
ACAN is calling on UK policymakers to introduce tougher building standards that go beyond regulating the energy efficiency of buildings in use. In its campaign, ACAN demands restrictions to reduce the emissions that result from the manufacturing, construction, maintenance and demolition of buildings.
ACAN believes, that if the construction industry is to truly play its part in tackling the climate and ecological crises, limits on these emissions must be put in place.
More than half of the countries in the world have a smaller national carbon footprint than the footprint of the UK’s construction sector alone. The lack of legislation around embodied carbon is partly due to a belief that reducing it is too complicated.
But ACAN points out that the construction industry already has the tools that it needs to analyse the carbon impact of their designs.
FCBS CARBON is a whole life carbon review tool, designed to estimate the whole life carbon of a building to inform design decisions prior to detailed design. This makes potential carbon impacts clear to the client, architect and the whole design team from the outset of the design process. Using benchmarked data from the ICE Database and EPDs, the tool is designed to give the design team insight into the whole life carbon impact of a building from the very outset of a project.
H\B:ERT is an easy-to-use open source Revit-based tool that enables design teams to quickly analyse and clearly visualise the embodied carbon emissions of different building components and construction material options at any time during the design process.
It is clear that if lifetime carbon assessments were put in place, there would often be a stronger case for improving, remodelling and restoring older buildings rather than demolishing them and rebuilding. If the UK is to achieve its carbon reduction targets, it will be necessary to take embedded carbon in buildings much more seriously.
This article was based on a story in a recent CAN newsletter with grateful thanks to the author.