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Carbon Expert of the Month November 2019
Duncan Cox
Senior Associate at Thornton Tomasetti. The firm is well-known for creating efficient, high-performance, climate-responsive buildings and communities.
Q: What led you to become a construction carbon expert?
Working for a global structural engineering practice I became frustrated about the limited impact structural engineers could have on the green agenda through lack of regulation and limited scope in green rating systems. Recognising that the largest area my company could have in reducing the environmental impact of our designs was in reducing embodied carbon. Around 8 years ago I then started to collect the embodied carbon data on all the projects that we had worked on through material quantity extraction from our BIM environment and the application of carbon coefficients to different material types. This led to the growth of a large database, collaboration with academia and our industry peers, tool development, the SE2050 Commitment, the development of benchmarks and helping to write guidance on LCA and embodied carbon.
Q: What project and achievements are you the proudest of?
I am particularly proud of the data we have collected on over 600 of our projects. This data has been shared to wider industry so that we could begin to understand how much embodied carbon we find associated to the materials in our projects. It is a database of information that has been the backbone to a number of academic studies and has led to the growing awareness and importance of embodied carbon and has fuelled debate on how we can achieve reductions in our designs.
Q: What are the key value drivers you use to make the business case for materials carbon?
A whole life cycle assessment allows us to look at a project over the full service life of the building. We are not delivering a building to site and then walking away but looking at where there will be additional material carbon throughout the life cycle of that development and through to end-of-life scenarios. This is extremely important in quantifying where the carbon flows are and what those implications are for the design team, future users and owners.
Q: How does your engagement on materials sustainability vary over project phases?
At the early stages of a project we are dealing with a system approach and a design approach. What can I re-use? Where can I remove unnecessary material? Is it through a design change i.e. reducing a basement or is it through material choice? A PT slab rather than a RC slab. Will we need to demolish in 30 years time or can we design to re-purpose? Do we load the project with embodied carbon now knowing that in the future we will make savings as it has been designed to be resilient against future climate change or designed so demolition is unnecessary?
As we progress the design we start to focus on the specifics of the design. Can we repeat details? Can we specify a façade type that has a 20 year rather than 15 year maintenance period. Then we will start to look at the intricacies of those materials. Where can I source this material from? Can I get an option elsewhere that contains more recycled material?
“Do we load the project with embodied carbon now knowing that in the future we will make savings as it has been designed to be resilient against future climate change or designed so demolition is unnecessary?”
Q: How does One Click LCA help you achieve your goals?
One Click LCA is really valuable in being able to quickly compare concept level environmental impact performance such as a framing system or a façade arrangement through to overall building designs and full LCA through all stages. From my experience it has far more flexibility than other tools that I have tried on the market and the team are open to listening to feedback on what may make the software run even better.
What I find most useful in One Click LCA are the vast library of data such as EPDs and industry average coefficients; and the option to quickly compare designs. The ability to play around with the service life and resource location is also invaluable.
“From my experience it has far more flexibility than other tools that I have tried on the market and the team are open to listening to feedback on what may make the software run even better.”
What’s your advice for other sustainability experts?
“There is no one-size fits all solution, what may work on one project may not be the same elsewhere. It is important to get buy-in from everyone on the team that you are seeking to achieve a low-carbon structure, and taking advantage of periods of value engineering is really important. Traditionally an area where sustainable measures are dropped, this is now key to helping to reduce the embodied carbon load. And finally, remember to consider the full balance of embodied AND operational. An efficient façade may load a project with unnecessary embodied carbon which takes years to pay-back through operational energy efficiency.”
Interested in being featured?
Contact annie.nguyen@oneclicklca.com for more information.
About ‘Carbon Expert of the Month’
Carbon Expert of the Month is One Click LCA Ltd’s way to bring forward expertise, inspiration, best practises and great cases among One Click LCA users. Each month, we intend to publish one Carbon Expert of the Month interview, rotating between different countries.
We interview and feature experts who are passionate about reducing carbon in general and from materials in particular, who preferably seek to push projects beyond the boundaries of common practise, and who wish to share from their personal experience.