EMBODIED CARBON | VENTILATION PRODUCTS Removing the guesswork Embodied carbon is rising up the agenda as operational efciencies peak, but it is challenging to obtain comparable and reliable data without an industry-agreed denition, says Vent-Axias Louise McHugh T he launch of the consultation on the Future Homes & Buildings Standards has given the industry a route to net zero operational carbon, but there was no standard or legal definition for embodied carbon. The government says it intends to consult on its approach to measuring and reducing embodied carbon in new buildings in due course. Until then, the issue of embodied carbon is a challenge for manufacturers such as Vent-Axia. Yselkla Farmer, CEO at Beama, the UK trade association for suppliers of energy infrastructure technologies, summed up the issue: We are in a position where fragmented and missing standards, practices and processes are causing challenges for manufacturers in providing comparable and reliable embodied carbon data to the market. Having no agreed definition for embodied carbon is one of the challenges. Embodied carbon is the carbon footprint of a product (inclusive of all components/ materials), measured in kg CO2e. It excludes operational use, but can cover upstream activities such as material extraction, transport and manufacturing and downstream activities, such as maintaining it and end of life. Opinion differs on what is included. There are no set boundaries for embodied carbon in a full life-cycle assessment (LCA) and groups in the supply chain are setting their own embodied carbon definitions. This means figures are not comparable. Another difficulty is around collection of data. Supply chains are complex; it is hard to track the origin and use of materials. It is also tricky to ensure the data supplied is reliable or comparable. Although there is no UK regulation mandating embodied carbon measurement or reduction, there are requirements through regional planning or certification for some approvals. There is also an international standard for the sustainability of construction works, BS EN 17472:2022 and other intiatives being worked on such as the UK Net Zero Carbon Buildings Standards, and the Built Environment Carbon Database. These are all driving a commercial demand for manufacturers to supply embodied carbon data. Calculating embodied carbon requires an LCA. This can be done by a manufacturers software or process (a third party will give assurance); via third-party software or methodologies for internal use, including CIBSEs TM65 Embodied carbon in building services: A calculation methodology (2021); or by attaining a Type III environmental declaration (quantified and independently verified environmental information over the life-cycle of goods and services, which has a financial cost), such as an Environmental Product Declaration or Product Environmental Profile. We have opted to use TM65, as it is specifically designed for building services products. TM65 considers embodied carbon to be the greenhouse gas emissions associated with the manufacture of a product, its installation, maintenance, repair, replacement, and end of life. We can provide TM65 data for our latest heatrecovery ventilation products. However, we must not let embodied carbon narrow our focus at the expense of other ways of reducing CO2 emissions and it must not trump the reason we install building services. For instance, heat recovery ventilation may, in some instances, have higher embodied carbon than other ventilation types, which may, therefore, be selected to tick the embodied carbon box. But heat recovery ventilation provides excellent indoor air quality plus, employing heat recovery ventilation solutions in airtight, optimally insulated buildings enables reductions in the operational energy and emissions used for heating or cooling. Another area to consider is the use of recycled material, which can reduce embodied carbon by a third. At Vent-Axia, we have moved from using virgin to recycled material in the production of our fans. Although there is no universally accepted method of reporting avoided emissions, the company asked Arup to model the carbon avoidance for its group. The methodology considers both domestic and non-domestic buildings, following standards and guidance in SAP 2012 and CIBSE Guide B2. Until regulation comes into force, specifiers should consider the complexity of embodied carbon, as well as the wider operational carbon savings to be made in different areas, when selecting products for low carbon buildings. TM65 is available at www.cibse.org/knowledge We must not let embodied carbon narrow our focus at the expense of other ways to reduce carbon emissions LOUISE McHUGH is a product manager at Vent-Axia www.cibsejournal.com February 2024 39 CIBSE Feb 24 pp39 Vent Axia embodied carbon.indd 39 26/01/2024 14:43