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Sustainability The use of the terminology “net zero” is being used increasingly in the construction sector. It can mean two main things: net zero building or net zero at organisational level. While the two are linked, this article focuses on net zero building. EMBODIED CARBON IN THE FIT-OUTWORLD T HERE have been discussions about the definition of net zero buildings for over a decade, but there has been renewed interest in the last couple of years. In 2019, the UKGBC published a framework definition for net zero carbon buildings 1 , which sets our definitions and principles around two approaches to net zero: 1. Net zero carbon – construction (referring to the carbon emissions generated during the manufacturing, transport and installation of construction products). 2. Net zero carbon - operational energy. Some organisations choose to be net zero in operation only, but to be truly net zero should require the inclusion of the construction impact. Net zero is different from absolute zero and often requires the need to offset emissions that have not been eliminated. Good practice dictates that emissions should be reduced as much as possible before being offset. UK Net Zero Carbon Standard In 2022, a consortium including RICS, LETI and RIBA partnered to create the UK Net Zero Carbon Standard. They state: “The standard will set out metrics by which net zero carbon performance is evaluated, as well as performance targets and limits that need to be met. The standard will also set out rules for how claims can be verified. The standard will apply to the most common building types (from schools, to homes and offices) and will apply to both existing and new buildings”. There is a lot of focus on buildings and the built environment to reduce their environmental impact. This is because buildings are responsible for roughly 50% of CO 2 eq emissions in the UK, of which 80% is associated with operational carbon. The Building Regulations have been revised over the years to raise the bar for Part L - Conservation of fuel and power to drive up the energy efficiency of building. The other 20% is related to the manufacture, transport, installation, use and end of life disposal of construction products – also referred to as embodied carbon. Embodied carbon has been long overlooked at building level. While schemes, such as BREEAM, have been promoting its importance for over 15 years, its uptake has been slow, particularly in the fit-out sector. Carrying out the measurement of the carbon footprint of a building is done using a life cycle assessment (LCA) approach and should be carried out in accordance with relevant LCA standards and, in particular, with EN15978. When the assessment includes both the embodied and operational impact of the building, it is referred to as whole life carbon. In 2017, RICS published their professional statement called “Whole life carbon assessment for built environment, 1st Edition 2 ”, which is an interpretation of EN15978 and provides guidance on the principles of carrying out a whole life carbon assessment. This professional statement has been adopted by a number of organisations, such as the Greater London Authority, as the method to measure the carbon footprint of buildings. The professional statement is being revised at the start of this year so may have been released by the time this article is published. It is my understanding that it will become the accepted methodology for the measurement of whole life carbon in the UK. Themeasurement of embodied carbon can be a long process. It requires the collection of a lot of data on thematerials used: • their carbon footprint (kgCO 2 eq/kg) • type • quantity • distance they have travelled to site • quantities wasted on site during installation • what happens to them during the life of the building (ie: maintenance, repair, etc) and once the building is demolished. Useful sources of data on embodied carbon products There are quite a few sources of data on the embodied carbon of products (kgCO2eq/ kg) that are free and publicly available, such as the ICE database 3 which was last updated in 2019 and provides datasets for the most widely used materials. These data Flavie Lowres, FIS Sustainability Champion 20 www.thefis.org An embodied carbon saving at Willmott Dixon Interiors’ new offices where carpets were used with a high proportion of recycled content