Changing carbon calculations and the path to Part Z

As the Future Homes Standard approaches, we’re seeing more consideration for embodied carbon in construction projects, says Dean Asher, Head of Technical Services at Polypipe Building Products

The built environment has been dominated by the topic of decarbonisation in recent months and years, driven by a combination of changing building regulations and environmental targets, as well as a growing consumer awareness and education around the need for more sustainable solutions. The industry has already made considerable adjustments to meet the 31% reduction in carbon emissions target set out by Part L of the Building Regulations, and there’s further pressure to step up decarbonisation efforts with the Future Homes Standard setting a 75-80% carbon reduction target in 2025. 

On the more distant horizon sits Net Zero, and while the 2050 target still stands, changes to government green policy, including the weakening of the gas boiler phase out by 2035, has cast serious doubts over the pace of change and how realistic the goal truly is. Yet, many in the industry are advocating for further amends to building regulations, especially around the measurement and limitation of carbon emissions produced as part of construction projects.

A holistic approach to carbon calculations

The Greenhouse Gas Protocol categorises emissions into three ‘scopes’, and this is currently the most widely-accepted method of calculating carbon emissions in the industry. It requires builders and developers to consider emissions they’re indirectly responsible for up and down the value chain. The calculation is made up of scope 1; emissions from the developer in their day-to-day activities, scope 2; the emissions from purchased energy used by the developer, and scope 3; the emissions of all upstream and downstream third parties involved in the construction of the property. This more holistic approach across the entirety of a project encourages stakeholders to be more mindful of upstream purchased goods, related fuel and energy, downstream transport and distribution, the use of products throughout their lifecycle, and end-of-life outcome. Many industry bodies are calling for more to be done to enforce this more holistic view with the introduction of Part Z.

Part Z is a construction industry proposal rather than government-led and is based on guidance and recommendations made by groups including Royal Institute of British Architects (RIBA), the Chartered Institution of Building Services Engineers (CIBSE), and the UK Green Building Council (UKGBC), to name just a few. The proposed amendment to the UK Building Regulations 2010 would ensure that both ‘whole life carbon’ and ‘embodied carbon’ are assessed and capped on all major construction projects. ‘Whole life carbon emissions’ refer to the carbon produced from materials, construction and the use of a building throughout its useful life, and at end-of-life, while ‘embodied carbon’ refers to the emissions generated through the production of materials, transport to site, and through the construction of a building. 

Architecture 2030 estimates that embodied carbon is responsible for 11% of annual greenhouse gas emissions and 28% of building sector emissions globally. While the contribution of embodied carbon to the climate emergency is significant, it’s often also underestimated by builders and developers as it’s not their direct responsibility. In fact, Jonathan Falkingham, co-founder and creative director at Urban Splash and a support of Part Z, told the group, “The elephant in the room is embodied carbon and this needs addressing urgently. A recent study of our own Scope 1, 2 and 3 emissions shows that our Scope 3 embodied carbon emissions are by far the largest, accounting for 94% of whole life cycle emissions.”

Levelling the playing field

It’s thought by many industry groups that regulating and introducing limits on embodied carbon will help the built environment to decarbonise and meet ambitious building regulations and environmental targets by creating a more level playing field whereby all organisations abide by the same rules. However, while a proposal seeking to introduce embodied carbon regulations for buildings was debated as part of discussions around the Levelling Up and Regeneration Bill earlier this year, it was not progressed further. 

As the Future Homes Standard deadline rapidly approaches, questions remain over how the industry will fair. However, there are positive signs and steps towards decarbonisation. We’re seeing greater demand for renewable heating solutions, with recent research showing that a third (33%) of heating installers said their customers are generally very passionate about reducing carbon emissions, and 29% said their customers only ask for renewable energy solutions. In addition, the MCS reported a record-breaking number of heat pumps were installed in the UK in the first half of 2023. 

Part Z is garnering support from across the industry, and while its progress has stalled, it’s positive to see so many industry groups and developers taking embodied carbon into account. As such, it’s likely data and information management will become even more important across the supply chain, through design, construction, post-occupation, and at end-of-life, while greater innovation and transparency from manufacturers will become key.