UNDERSTANDING EMBODIED CARBON
The threat of climate change has made decarbonisation of our built environment an essential objective. Here, David Oaten - one of our Project Consultants - looks at the issue of embodied carbon, why it is important and how selecting materials and products carefully can help minimise the environmental impact of a building.
There is no doubt that the drive for net zero has never been a higher priority. However, the focus is often on operational carbon – the emissions associated with the heating, lighting and power for a building – rather than the embodied carbon. This is the emissions associated with the production of materials and the construction process. It includes everything from the extraction of the raw materials to the manufacturing process to transportation and installation in the building.
Estimates from the Royal Institute of British Architects (RIBA) suggest that for a typical office building, the embodied emissions up to practical completion could represent as much as 35% of the total carbon emissions for the building throughout its theoretical 60 year lifespan. For a residential block, this figure could be as high as 51% of the total carbon emissions.
However, there are some challenges to calculating the embodied carbon of a building, not least of which are the number of elements that must be assessed and the availability of data on embodied carbon. This is a developing area, and many manufacturers and suppliers are now working to reduce the embodied carbon of their products and provide accurate information to help streamline assessment.
The contribution of embodied carbon to the overall impact of a building means that reviewing this information carefully for all the materials used on a project is essential. Certain products will have much higher levels of embodied carbon by the nature of their production or because of where the raw materials are sourced. For example, products made from recycled aluminium will provide a carbon saving compared with the same product manufactured using primary aluminium. This is because reprocessing recovered aluminium requires only about 5% of the energy needed to turn bauxite ore into usable aluminium, with no compromise in terms of the quality.
At TECHNAL, an increasing number of our door, window and curtain walling products are manufactured using Hydro CIRCAL® 75R aluminium. This is a high-quality aluminium that contains a minimum of 75% recycled end-of-life aluminium (post-consumer scrap), such as from façades and windows that have been removed from buildings. As a result, it has one of the smallest CO2 footprints of any aluminium worldwide with 2.3 kg of CO2 emissions per kilo of aluminium. This is 86% or 7 times less than the global average for primary extraction.