Carbon Expert of the Month October 2019
Dr Christopher Drew
Director of Sustainability at Adrian Smith + Gordon Gill Architecture. The firm is well-known for designing high-performance, energy-efficient and sustainable projects, including many of the world’s largest and tallest buildings.
Al Wasl Plaza, Dubai Expo 2020
Q: What led you to become a construction carbon expert?
My first role as a sustainability specialist was on Abu Dhabi International Airport’s expansion programme. In 2007, I was lucky enough to be recruited into the position of sustainability manager for Masdar City. Working with some of the most innovative and imaginative consultants I’ve ever met, we established KPI targets for a range of parameters, including embodied carbon. Working with the team at dCarbon8, later to become part of Deloitte, we set about aggressively reducing the emissions associated with building this new highly sustainable city. Since those days, and with operational emissions saving having become the norm, I’ve had a strong focus on considering whole life carbon emissions.
Currently, as Sustainability Director at Adrian Smith + Gordon Gill Architecture, I lead the sustainability efforts at a corporate and project level. At Corporate level, that includes policies, AIA 2030, CSR and UN Global compact and SDG reporting. At project level, it ranges from establishing the vision, goals and targets to identifying strategies, directing simulations and reporting on progress.
Al Wasl Plaza, Dubai Expo 2020
Q: What project and achievements are you the proudest of?
Nos Al Wasl Plaza project for Dubai Expo 2020 is the most recent project, or more correctly, series of projects, where we have achieved significant savings in life cycle carbon emissions. The project consists of 5 buildings (undergoing LEED certification) and a landscaped plaza beneath a 160m diameter 62m high steel trellis (undergoing CEEQUAL certification). The LEED certification includes Life Cycle Assessment (LCA) and the CEEQUAL certification includes LCA and embodied water calculations.
Before talking about strategies, I should first say that Dubai has already set a high standard for low carbon concrete. At the strengths we were using, building code already required 35% cement replacement and so to achieve our target of 30% LCA reduction against a local baseline for all projects, we had to be very innovative. Some strategies on the buildings included establishing embodied carbon targets for steel, concrete, aluminium and insulation, with the contractor having to provide product specific EPDS (which are now in the One Click LCA database) to demonstrate compliance. Only in the case of aluminium, where we really wanted to support the local aluminium industry did we allow purchase of Gold Standard offsets. Additionally, we used post-tensioned slabs to reduce the amount of material, and optimisation software to determine optimum quantities and placement levels of software and we used waste concrete too make jersey barriers and hoarding ballast weights. On the trellis, we used higher strength steel with narrower walls to reduce materials and weight, the concrete foundations had 70% cement replacement.
As a result, we surpassed our Global Warming Potential (GWP) reduction target of 30% – the building improvements ranged from 38% to 51% lower and the trellis is 34% lower than the baseline.
Close up on one of 16,478 fabric panel mounting brackets. Through design optimization and choosing a steel caster who used high recycled content material and low carbon manufacturing processes, Chris Drew and the team saved over 55 tons of CO2 emissions.
Q: What are the key value drivers you use to make the business case for materials carbon?
This is always a challenge and really depends very much on the client’s vision, whether we engage the consultants or whether it’s through the client and what the likely market for the building is. We always try to identify ways to reduce material quantities – saving cost as well as carbon. We also work with the contractor and structural engineers to develop specifications that push for lower embodied carbon materials while not adding significantly to cost. Many tenants can use the fact that the building has a reduced Life Cycle Cost to support their own CSR initiatives and this obviously helps with the case too. Finally, LEED rewards LCA and provision of EPDs very well – at least 4 points are easily obtained. The cost per point is very low, and this also helps.
Q: How does your engagement on materials sustainability vary over project phases?
It changes as the design progresses. First, establish targets at the outset. Then identify strategies to reduce material quantities and/or use low carbon material alternates. During the design process, undertake more detailed Life Cycle Assessments.
The key stage though is writing specifications – the most important documents in the quest for using low carbon materials. It is crucial to specify an embodied carbon target for the various concrete mixes, structural steel, rebar, masonry and aluminium curtain wall elements. The EPD database within One Click LCA is really helpful in establishing such targets.
“First, establish targets at the outset. Then identify strategies to reduce material quantities and/or use low carbon material alternates. During the design process, undertake more detailed Life Cycle Assessments.”
Q: How does One Click LCA help you achieve your goals?
We use One Click LCA for three main functions:
#1 To track performance throughout the life of the project. We just started using the Le Carbon Designer tool, but it looks like it’ll be very helpful.
#2 To help specify embodied carbon targets in the specifications – primarily using it for benchmark data.
#3 To support, document and earn credits from the LEED and CEEQUAL assessments.
I like the EPD database, and that the support team respond very quickly when we provide EPDs. Regarding the functionalities of the tool, I really like that it is extremely easy to use, but at the same time is comprehensive. For example, when I update a proposed design, the software flashes the change in Global Warming Potential (GWP) as a percentage (%) right away. In the future, we will use Carbon Designer on all of our projects as an early target finder.
“In the future, we will use Carbon Designer on all of our projects as an early target finder.”
What’s your advice for other sustainability experts?
À propos de « l'expert carbone du mois »
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.