OPINION by Troy Coyle
For engineers, carbon reduction is not only a priority but also an opportunity. With the right strategies, significant cuts to embodied carbon in construction projects are within reach, enabling the sector to meet national carbon reduction goals.
The good news is that these solutions are not hypothetical—they’re already being tested in real-world scenarios, as highlighted by a recent study funded by the building research levy (through BRANZ) and heavy engineering research levy (through HERA). Aimed at reducing construction waste and embodied carbon while enhancing the circular economy, a research output has been a design hierarchy which provides practical guidance for cutting emissions in low-rise commercial buildings by more than 50% through smart design and material selection.
How small design changes can lead to massive carbon savings…
Within this HERA led project, a case study from Christchurch was used that featured conventional construction practices: a steel-concrete composite flooring system, concrete shear walls, and steel moment-resisting frames. Using this as a baseline, we explored design variations, including low-carbon steel, hybrid steel-timber flooring, and eccentrically braced frames. Each tweak resulted in significant carbon reductions, showing that even minor design modifications can make a big difference.
Key takeaways for engineers to consider
Overall, the results showed that steel, timber, and concrete all have roles to play in reducing embodied carbon, depending on how they are combined and for what purpose. Hybrid steel-timber designs, for example, offer strong performance while lowering emissions. Additional concepts were also noted that engineers could consider to make significant impact.
- Design for disassembly: Use reversible connections in flooring systems to enable material recovery and reuse at the building’s end of life.
- Seismic resilience: Optimise designs for seismic resilience. For example, steel frame designs can extend a building’s lifespan and reduce carbon-heavy repairs.
- Material substitution: Substituting conventional materials with low-carbon alternatives like low-carbon steel and concrete can reduce embodied carbon by up to 70%.
Applying this to your work
HERA’s Circular Low Carbon Design Hierarchy is a valuable tool for engineers looking to achieve meaningful carbon reductions. It’s important to consider not just material selection, but the entire lifecycle of a building, from cradle to cradle, when making design decisions.
One key finding is the importance of keeping Life Cycle Assessment (LCA) tools up-to-date to include the latest low-carbon materials. Without these updates, assessments may skew in favour of one material over another, missing out on the actual carbon savings newer materials offer. Staying informed about these options is essential for engineers looking to make impactful changes in their projects.
Get started with free resources
Engineers are key players in driving carbon reduction in construction. By applying circular design principles and embracing low-carbon design, the sector can make significant strides toward sustainability goals.
Our work at HERA demonstrates that reducing carbon isn’t just possible—it’s practical and achievable with the tools and knowledge available today. So, the next time you’re specifying materials or designing a building, consider how small changes could make a big difference. After all, cutting carbon is not only about the future; it’s about what we can achieve today with clever, thoughtful design.
For more details, check out HERA’s Low Carbon Circular Design Hierarchy here. If you’d like a poster version for your office, please get in touch with our customer experience manager, Rebecca Symonds.
For more information on the research, listen to our latest podcast.
I also offer free in-house training for practitioners (minimum numbers required). Please get in touch with me at troy.coyle@hera.org.nz to discuss further.
BIO: Dr Troy Coyle brings more than 20 years’ experience in innovation management across a range of industries including materials science, medical radiation physics, biotechnology, sustainable building products, renewable energy and steel. She is a scientist with a PhD (University of NSW) with training in journalism and communications