Pilot UK net zero carbon buildings standard launched

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The UK Net Zero Carbon Buildings Standard (UKNZCBS) has been developed to robustly prove that built assets align with the UK’s carbon and energy budgets. Until this point, there has been no single, agreed methodology for defining what ‘net zero carbon’ means for buildings in the UK.

Consequently, the area has been rife with spurious claims around the topic. The free-to-access technical standard provides a set of consistent rules to create a level playing field around such claims.

Developed by a number of the UK’s leading bodies in construction, the standard is for anyone who wants to fund, procure, design, or specify a net zero carbon building, and definitively demonstrate that their building is net zero carbon aligned. As a robust industry-backed initiative, the standard should be useful to policymakers as it outlines what is needed to support the UK’s net zero carbon transition.

It has been developed and agreed through collaboration between built environment organisations and industry leaders spanning architects, engineers, carbon assessors, developers, and more. Over 350 experts from across the industry have supported the technical steering group during the standard’s development phase. Wider stakeholder engagement and feedback through roundtables up and down the country, as well as through public consultation, captured the views of over 700 individuals.

The standard’s mandatory requirements for building performance and construction quality are ambitious but achievable. They cover a range of topics such as upfront carbon, operational energy use, avoidance of fossil fuel use on site, renewables and refrigerants.

The upfront carbon requirement relates to embodied carbon emissions released in the construction of a finished building, including in the manufacture of materials, transport to site, and the construction process itself. The upfront total does not include CO2 stored in biogenic materials. It is the intention that future versions of the standard also include whole life cycle embodied carbon limits - including projected emissions from maintenance, repair, replacement, and end of life disposal of buildings.

The pilot version contains the technical details on how a building should meet the standard, including what limits and targets it needs to meet, the technical evidence needed to demonstrate this, and how it should be reported. Details on the subsequent verification process will be published separately.

The built environment industry is encouraged to use the pilot version to prepare for the process of verifying buildings as net zero carbon-aligned. Katie Clemence-Jackson, chair of the standard’s technical steering group, said: “The standard has been created not just using industry data on what is achievable, but also cross referencing this with ‘top down’ modelling of what is needed to decarbonise our industry in line with 1.5°C aligned carbon and energy budgets. It covers all the major building sectors, as well as both new and existing buildings.

“With access to the standard, the built environment industry is equipped to target, design and operate buildings to be net zero carbon aligned, driving the positive change that we need to meet our climate goals. I would like to thank all our volunteers from across the built environment who have contributed their time, experience and knowledge to allow us to develop a robust standard. This has been an immensely collaborative process, and we couldn’t have achieved it without your support.”

David Partridge, chair of the standard’s governance board, said: “The standard brings together data from thousands of buildings submitted by professionals from across the built environment and will be an important step towards a net zero carbon economy. I encourage everyone within the built environment and real estate sector, from investors, funds and lenders, through developers to building designers, managers and contractors, to start to use the pilot version of the standard. We will shortly be launching a pilot testing programme to glean feedback on applying the process on real projects.”

Performance targets in the standard will align with science-based trajectories needed to achieve net zero by 2050 and a 78 per cent reduction by 2035 in the UK, in order to stand a reasonable chance of mitigating global warming to 1.5°C. It will also align with the energy demand reductions projected to be required to enable a net zero carbon energy supply sector.

The approach will be applicable to both existing and new buildings, including homes, offices, education, industry, retail, hotels and healthcare. To start, the focus will be on the most common building typologies, especially those for which industry stakeholders have already robust performance data available to inform the setting of performance targets. The standard will not apply to infrastructure.

Commenting on the standard’s publication, Passivhaus Trust research and policy director Sarah Lewis said the passive house plus standard “offers a tried and tested route to achieving the operational carbon performance required for the UKNZCBS, with the additional benefits of addressing other important issues such as indoor air quality, overheating, and occupant comfort.

“The Passivhaus Trust welcomes the UKNZBCS as a means for improving the clarity and rigour of net zero carbon definitions and as a step towards achieving higher performance building in the UK."

Organisations involved in developing the standard include the Better Buildings Partnership (BBP), the Building Research Establishment (BRE) the Carbon Trust, the Chartered Institution of Building Services Engineers (CIBSE), the Institution of Structural Engineers (IStructE), LETI, the Royal Institute of British Architects (RIBA), the Royal Institution of Chartered Surveyors (RICS) and the UK Green Building Council (UKGBC).