The energy associated with a building’s construction and operation comprises two components:
Operating – electricity, gas and other fuels used in a building for heating, cooling, ventilation, lighting, hot water, computers, servers and other equipment.
Embodied – energy consumed in manufacturing, delivering and installing the materials used to build, refurbish and fit-out a building, and their disposal at end of life.
The carbon emissions are due to the fuel used to generate energy (coal, gas, biomass, sun, etc.) and emissions, such as CO2, released in the production of materials like cement. In the whole lifecycle of a building the embodied carbon due to construction can typically account for 10 to 20% of the whole carbon footprint; in warehouses this could be over 50%. In a typical new office building the structure represents over 50% of the initial embodied carbon. There are many ways that the structural engineer can seek to reduce this.
Reduce the embodied carbon of materials
- Specify concrete mixes to reduce Portland cement content by considering strength, cement replacement (eg ggbs, fly ash) and admixtures
- Consider low carbon masonry products instead of concrete blocks and clay fired bricks
- Use timber framing where practical
- Consider alternatives to cement stabilisation of groundworks (eg lime and fly ash mix)
- Specify materials with Environmental Product Declarations to encourage manufacturers to measure, report and reduce their carbon footprint
Use resources efficiently over their design life
- Efficient design (eg measure then reduce the governing utilisation ratio (by weight) of steel structures)
- Design to reduce waste (eg off-site fabrication, standard dimensions)
- Design for disassembly and re-use at end of life
- Design for durability and adaptability
The Institution’s How to calculate embodied carbon guide provides further guidance concerning reducing the carbon footprint of structures, focusing mainly on embodied energy and carbon associated directly with the structure.
More information
Institution papers and publications
Embodied CO2 of Structural Frames by Sarah Kaethner (Arup) and Jenny Burridge (The Concrete Centre), The Structural Engineer, May 2012
Mansion block becomes offices, Graham Pocock, WSP Cantor Seinuk, The Structural Engineer, 18 September 2007
Publications
Embodied Carbon: The Inventory of Carbon and Energy (ICE), by M. G. Hammond and C. Jones, BSRIA Guide BG10/2011
What Colour Is Your Building?, David Clark, RIBA Publishing 2013
Sustainable Concrete Architecture, David Bennett, RIBA Publishing 2010
Free resources
Cutting embodied carbon in construction projects, WRAP Information Sheet
Methodology to calculate embodied carbon of materials, RICS Professional Information, IP 32/2012
Target Zero Guides, Tata Steel and BCSA, 2010-12
Embodied CO2, The Concrete Centre
Embodied carbon of steel versus concrete buildings, David Clark and Dan Bradley, Info paper 31 – What Colour is Your Building?, RIBA Publishing
Embodied carbon standards, David Clark, Info paper 13 – What Colour is Your Building?, RIBA Publishing