Circular economies and the built environment
Jackie Sharp presents some of the findings from the Buildings As Materials Banks project, which seeks to bring circular economy principles into the construction industry
When you read the figures for waste, resource use and greenhouse gas emissions from the construction sector, it's obvious that buildings are having a massive impact on the environment. Worldwide, the buildings sector was responsible for 39% of energy-related emissions in 2016, with 11% attributable to the construction industry. In the UK, around 200m tonnes of materials are consumed by construction each year, and 61% of all waste is related to construction. Europe creates more than 800m tonnes of construction and demolition waste every year.
There is a great opportunity here to implement circular economy principles, which could lead to huge cost savings – especially as natural resources become more depleted and thus more expensive.
Commercial buildings typically have a design lifespan of 60 years – and this is often far less in reality. Consider what happens when they come to the end of their useful lives: they're demolished. Although, on average, more than 90% of the waste is recovered, much of this is used in a low-level application, such as for inert fill material.
If buildings could be viewed as banks of materials – available to mine for a second or even third life – an entirely new value chain could be created every time a component part was removed from an asset, or when a whole building came to the end of its life. Combine that with design that allows for changes to future use, and it's possible to see where potential disruption in the value proposition might lie.
In order to explore and prove these concepts, the Buildings As Materials Banks (BAMB) project, funded through EU Horizon 2020, brought together a consortium of organisations – from academics to commercial companies. They spent more than three years developing tools to identify and overcome some of the barriers to reuse of buildings and their component materials. Key barriers identified include:
Design culture: Most buildings are currently designed for a single-service life, with little consideration given to future potential changes in function, to the implications of deconstruction at the end of a building's life, or to the future need for building materials.
Value definition: Current short-term perspectives on value mean that circular and reversible building solutions are often viewed as more expensive than conventional solutions. Value is currently usually defined as economic, with social and environmental impacts excluded.
Collaboration: Information from the design and construction stages is often lost once a building changes ownership. Limited information and lack of accurate data makes it difficult to operate the building at its full potential, and reduces the possibility of retaining the value of components during refurbishment and eventual demolition.
Among the solutions developed and tested by the BAMB consortium are:Materials passports – a standardised data format to capture the circular aspects of construction products.
Reversible Building Design Platform – a platform giving access to a suite of tools that identify the reuse potential of a designed building, analyse its capacity for transformation, and support reversible building (without losing the value of the constituent elements).
Circular Building Assessment – a BIM-enabled system for assessing the environmental, social and economic value of a building's design, and allowing for comparison of circular building scenarios against 'business as usual' baselines.
Case study: Circular Building Assessment
Through the BAMB project, the Building Research Establishment (BRE) developed a Circular Building Assessment (CBA) methodology to allow assessment of a building's design against circularity principles. This was further developed into a proof of concept (PoC) software platform, working closely with SundaHus, specialists in material information management for healthy buildings.
Circular Building Assessment
The CBA allows the value of scenarios – such as reusing products, having reusable systems, or designing for life extension – to be tested and captured through a semi-automated process. To develop the CBA, existing approaches such as life-cycle analysis and life-cycle costing were combined with new methodologies, including reversible building design principles and social assessment. Data is drawn from sources including BIM export files, default datasets and material passports, and the output is a set of key performance indicators that can allow for the comparison of various scenarios.