The embodied impact of construction materials

The world of embodied energy has moved on considerably since work started in the 1990s, and embodied carbon, Environmental Product Declaration (EPD) and Building Lifecycle Analysis (LCA) are now increasingly common in construction. Jane Anderson, Principal Consultant at thinkstep (formerly PE International), reviews progress and eyes future potential.

I first heard about embodied energy in 1997, at a lecture presented by Nigel Howard, as part of my MSc course. He was leading BRE’s work on Environmental Profiles  and the Green Guide  and I was fascinated that we knew so little about the impacts of producing and using construction materials, and how important it was for buildings. For my thesis I explored the embodied impact of housing and increasing energy efficiency levels. This led to a career at BRE, putting embodied impacts into the hands of designers and giving manufacturers the opportunity to demonstrate their environmental credentials.

Although embodied impact regulation still seems some way off in the UK, major developers here have recognised the significance of embodied carbon within their corporate activities, and sponsored the UK Green Building Council’s extremely popular Embodied Carbon Week early in 2014. As part of the event, Waste & Resources Action Programme (WRAP) launched their Embodied Carbon benchmarking database , providing a platform to allow users to benchmark the embodied carbon of buildings against others using similar scopes. Both the Greater London Authority (GLA) and the Royal Institution of Chartered Surveyors (RICS) have now published Building Level Embodied Carbon methodologies following the TC350 standards, which aim to enable those new to the subject to start evaluating embodied carbon.

Another driver for the increased focus on embodied carbon has been the inclusion of LCA credits within both BREEAM  and LEED . Using the power of BIM to take material quantities calculated from CAD models to link them to LCA data is the focus of two tools: The IMPACT complaint suite from Integrated Environmental Solutions  (IESVE) and the Tally® Revit plug-in, which both aim to make building LCA a true design tool, used to adapt the design to reduce impact, rather than a compliance assessment completed long after the design has been finalised.

Combined ecodesign and EPD tools using EN 15804 methodology and indicators are now increasingly being used by manufacturers throughout the product design process to reduce product impact, and to allow EPD to be produced ‘on demand’ across large product ranges and for client-specified products. Groups of manufacturers, through bodies such as the Mineral Products Association , Wood for Good , British Precast  and UK CARES , have also started to develop EPD tools to allow their members to produce low-cost EPD quickly, and make use of the tools’ ecodesign facilities to improve and benchmark their products. Clearly, much has changed since the early 1990s.

Research undertaken by PE International for the European Commission suggests that European construction uses over 90% of all cement, aggregates and bitumen, 80% of flat glass, over 55% of PVC, timber and clay, and 25 to 40% of steel, aluminium and copper. The same research also calculated that, as a proportion of impacts from the built environment, materials are responsible for over 90% of elemental resource depletion, over 40% of POCP (summer smog) and ozone depletion, over 20% of water consumption, fossil fuel depletion and acidification, and over 10% of global warming potential. Compared to the impact of Europe as a whole, the UK-consumed construction materials are responsible for 10% of elemental resource depletion, 3% of fossil fuel depletion, nearly 2% of POCP (summer smog), and around 1% of global warming and acidification. So, there is clearly still much to do.

Starting to measure embodied carbon, and making changes to designs and specifications to reduce impact are both essential, and offer a huge opportunity to reduce our environmental impacts in an affordable way.

About this article

This is an abridged version of an article that originally appeared in the NBS Sustainability Report 2014.