Designing for low carbon

HERA is pleased to report that it has received $150K funding from BRANZ, funded by the building research levy, to support the $772K project titled “Circular design for a changing environment: a design framework to reduce construction waste, lifecycle embodied carbon, and to enhance the circular economy for construction materials, with a pilot for low-rise buildings”.

Carbon confusion: the need for guidance and clarity

There is significant confusion in the market about the embodied carbon at the different stages of a building’s life. Carbon calculators are emerging prolifically, but they only tell a one-dimensional story about CO2 equivalent emissions per mass of particular products, with a focus on either the Cradle to Gate or Cradle to Practical Completion, i.e. Module A emissions, or if they do extend to modules C and D, there is very little available data to populate these, and where data is available, the underpinning assumptions can be open to question.

This is in spite of MBIE’s commitments to consider and target opportunities to realise the whole of life (i.e. Modules A-D) carbon reductions and announcements that relate to the Building Act being modified to better report and focus on Modules B and C. Thus, by having a better understanding of the source and contribution of the embodied carbon from each Module and consideration of how design influences choice of material and vice-versa, can it be possible to design a truly carbon efficient sustainable building. This will identify the nexus between material choice and design; that goes beyond a carbon calculator being utilised at a belated stage of its design, when it is too late to implement the necessary carbon reductions. This is a broader set of considerations than what simply comparing building materials using a carbon calculator would provide. It includes, for example, designing for re-use, designing for waste minimisation, evolving how we manage service life, the quality of that service life, and designing for reduced maintenance and longer lifetimes. This will enable increased: 1) awareness of the need to choose materials and designs that reduce the carbon footprint of our buildings; and 2) the framework and tools to actually then choose the materials and designs that will lead to carbon reductions, while producing high-quality buildings.


Initial scope of research

This research project will develop a framework, and a pilot using that framework, to assist design engineers and other practitioners to design low carbon buildings. The deliverables will include:

  • a material and typology agnostic design guidance framework (“the Framework”) that can be used by the sector as a template for preparing design guidance to achieve the lowest embodied carbon;
  • specific guidance for design engineers to reduce carbon in typical low-rise building typologies (Stage 1 pilot) based on steel, steel-concrete, steel-timber and using the Framework; and
  • identification of knowledge gaps that future research can focus on in order to provide guidance for design engineers to reduce carbon in other areas of design using the Framework (informing subsequent stages beyond the scope of this project).

Development of the Framework and the specific guidance pilot will assist the construction sector to proactively respond to the impending changes being introduced by MBIE via the Building for Climate Change programme. This mahi is required because designers do not currently have the tools and guidelines available to comprehensively consider carbon reductions in building design. The project will also identify knowledge gaps that need further research and development to address. This will provide guidance to BRANZ on future research needs and guidance to the sector on future stages of the Framework’s development.


Next steps

HERA will be assisted in this work through subcontracts to Aurecon and WSP, as well as input from a broad range of stakeholders. HERA, Aurecon, WSP and BRANZ have held a kick-off meeting and an initial Industry Advisory Group meeting was held in early May.