Carbon Expert of the Month, August 2020

Dr John Orr

Dr John Orr is University Lecturer in Concrete Structures in the Department of Engineering at the University of Cambridge. His teaching and research are related to sustainable construction, with emphasis placed on concrete, and structural optimisation. John graduated with a first class MEng(hons) degree in Civil Engineering from the University of Bath in 2009, winning three University Awards.

Optimised flexibly formed beam cast in a fabric mould – reducing concrete use
Bespoke reinforcement for optimised structures

What led you to become a construction carbon expert?

As a student at the University of Bath, I was introduced by my supervisor to a PhD project that would examine how to reduce the environmental impact of concrete structures by using only the right amount of materials, and no more.

That initial hook, and the inspiration of my supervisor at the time, led to completion of a PhD in flexible formwork in 2012 sponsored by Atkins and subsequently a career in academia where my group now looks at how to reduce embodied carbon by learning from real performance.

What kind of projects do you typically work on, and in what role?

As an academic, my role is primarily in leading research projects. Over the last few years I have built a team of 14, working towards my vision for the lightweighting of infrastructure and buildings by learning from real performance and have won funding of more than £9M to help support this.

My projects typically run across multiple universities, and with multiple industrial partners. I believe strongly in co-creation – we need projects with diverse stakeholders to ensure that the end products are valuable to society. Breaking down barriers between industry and academia can be difficult as we work to different timescales and have different pressures, but is essential if we are to solve the carbon challenge.

“Breaking down barriers between industry and academia can be difficult… but is essential if we are to solve the carbon challenge.”
Casting in flexible moulds, using high strength concrete

Which projects and achievements are you the proudest of?

I’m excited by the potential of the ACORN project. Here, we are working on an end-to-end design process that will ensure optimisation of form is guided by what it is physically possible to create using our robotics. This will (hopefully) mean we do not end up with designs that must be simplified or rationalised in order to get built.

In MEICON we used a survey of structural engineers to reveal wide variations and uncertainty in both regulated and cultural behaviours. We showed not only how embodied energy efficiency is not a high priority, but also the wide variability in measures that engineers should agree on. The habitual over-design results in more expensive buildings that consume more of our material resource than is necessary. It is important to shine a light on these issues to catalyse people to help change them.

How do you see carbon performance evolving in the market?

When I completed my PhD in shape optimised concrete beams, the concept of using less concrete was viewed by most people I spoke to as a bit too wacky, a novelty idea. That has changed massively in the last few years alone, and embodied carbon is getting the attention it deserves.

Some clients are getting ahead of the game – they realise that assets built today with wasteful approaches to embodied carbon may be unsellable or unlettable in just a few years’ time. These stranded assets are a risk that I hope will lead to better design.

What are the key value drivers you use to make the business case for materials carbon?

Whole life carbon assessments are essential, and they need to be done with an understanding of the uncertainty behind each stage of the calculations, and the carbon impact of each design choice.

Classic examples include higher floor loading, or longer spans, to enable flexibility. We should design for what we need today, with as little carbon as possible. For example choosing 2.5kPa floor loading is (probably more than) plenty for today.

In the future, it will also probably be enough for most changes in use and if it’s not, we can intervene then in an appropriate way. I am uncomfortable with higher loading or longer spans being chosen based on a very uncertain possibility that someone might want to change something in 10+ years’ time.

How does One Click LCA help you achieve your goals?

One Click has been a valuable tool for my students and post-docs to process building designs and run comparative studies. It is also valuable to be able to compare in-house calculations with those of the tool. The software is very user friendly and intuitive – start up time for a new user is very low and they can rapidly get useful outputs.

What do you think is the potential of achieving embodied carbon reductions in the building industry today?

Reaching zero carbon emissions by the middle of this century will give us a good chance of limiting global temperature rise to 1.5ºC. I don’t believe there are any feasible negative carbon emissions options, and so the simple answer is we must reduce emissions to zero. For buildings this might mean banning demolition, establishing re-use of components as a default design option, stopping the production of new Portland cement, and extending the life of what we already have.

“I don’t believe there are any feasible negative carbon emissions options, and so the simple answer is we must reduce emissions to zero. “

What’s your advice for other sustainability experts?

1. Read Absolute Zero a report led by my colleague Professor Julian Allwood
2. Make carbon as important as safety in your calculations
3. Extend the life of existing assets, re-use structural components, and resist demolition.

Interested in being featured?

Contact for more information.

About ‘Carbon Expert of the Month’

Carbon Expert of the Month is Bionova’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.