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Short guides to carbon factors for key materials

Date published

Arup have assembled a package of quick and easy guides to help practising engineers understand the origins of carbon factors for three key construction materials: steel, concrete and timber.

At Arup, the BIPAS (Buildings and Infrastructure Priority Actions for Sustainability) team is a multi-disciplinary group of engineers, funded via Arup's internal investment programme. They carry out research and create resources relating to sustainability, primarily for use within Arup but shared externally when it is appropriate. Their objective is to address those areas that engineers engage with on a daily basis, to enable them to address sustainability in an informed and effective manner.

These guides are intended to help our practising engineers understand the origins of carbon factors for three key construction materials: steel, timber, and concrete. As engineers, we need to thoroughly understand how the carbon factors we use are determined, as well as the global impact our decisions make.

The documents provide a snapshot of the industry, highlighting carbon hotspots, as well as the major opportunities for each material that will help our industry on the path to Net Zero. It is intended that the guides will be updated periodically to reflect industry changes.

In line with our Construction Declares commitments, Arup have published these guides externally via the Institution of Structural Engineers, to reach a wider audience, and to promote discussion.

Key topics include:


  • The differences between blast oxygen and electric arc furnace production
  • Fabrication processes and considerations
  • Implications of steel reuse and recycling



  • The complexities of sustainable forestry and the importance of biodiversity
  • Embodied carbon associated with adhesives in both CLT and Glulam
  • Approaches to sequestration, and the effect this has on carbon calculations


  • Procurement and sourcing of cement and options for replacements
  • Formwork assumptions and the impact on carbon rates
  • Embodied carbon ranges for cement and cementitious materials


The route to net zero
The route to net zero is different for each material. For example, with concrete, there is a heavy reliance on the possibility of carbon capture becoming mainstream, and severe constraints when it comes to making the right choice for cement replacements. The key for all materials, however, is to simply use less of them.

Arup will be producing further material guides to add to this suite.

Contributors include:
Jo Spencer, Leonora Pilakoutas (Skanska), James Thorneycroft, Yolande Alves de Souza, Chris Carroll, Tim Snelson, Andrew Lawrence, Fragkoulis Kanavaris, Magdalena Janota, Neil Perry, Florence Wu, Ed Hoare, Orlando Gibbons, Liu Chang, Beth Lockhart, Clare Perkins, Lucy Caine, Conor Hayes, George Dalkin, Cameron Creamer, Rogier van Reen, Fiona Cassidy, Rob Vine, Saskia Watts, Grace Kelly, Robbie Firth, Alexia Velev, Matthew Munro, Dominic Munro, Graham Gedge.

Each document has been reviewed with thanks, by several internal and external industry experts to ensure a relevant and holistic suite of guides: Ed Hoare, Stuart Smith, Tim Snelson, Andrew Lawrence, Malcolm Turpin, Conor Hayes, Ulrike Elbers, Heleni Pantelidou, Carsten Hein, Chris Carroll, Dominic Munro, Orlando Gibbons, Eiki Homma, Grace Di Benedetto (Arup), Will Hawkins (Bath University), Jane Anderson (ConstructionLCA), Galina Churkina (Technische Universität Berlin), John Callanan (Kloeckner Metals UK) Ryan Roberts (Holcim), Melanie Jans-Singh (BEIS), Mike de Silva (Clancy Group), Apostolos Tsoumelekas (SCS Railways), Paul Astle (Ramboll), Bahman Ghiassi (Birmingham University), Gareth Wake (MPA Ready-Mixed Concrete), Michal Drewniok (Leeds University).

If there are any questions, please contact Jo Spencer ([email protected])

Additional information



Timber Concrete Guidance Metal - steel Metal - aluminium Climate change Carbon

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