This week has seen the launch of the UK Net Zero Carbon Buildings Standard (‘the Standard’). It’s a standard that has been created collaboratively by built environment organisations and leading experts in the profession in response to the market demand for a clear and unified definition for net zero carbon aligned assets in the UK.
The pilot version of the Standard, which was published on Tuesday 24 September (2024), contains the technical details on what limits and targets a building needs to meet, the technical evidence needed, and how it the evidence needs to be demonstrated and reported.
How was the Standard created?
The coalition behind the Standard - led by the Technical Steering group with representatives from BBP, BRE, CIBSE, the Carbon Trust, IStructE, LETI, RIBA, RICS and UKGBC - has been supported by over 350 professionals who volunteered their time and expertise.
Wider stakeholder engagement and feedback through roundtables up and down the country, as well as via a public consultation last summer, have captured the detailed views of over 700 individuals during the Standard’s development. In addition, in a phenomenal show of support for improving knowledge of building and construction performance, data from 4,000 projects was submitted from across the industry- responding to the Standard’s call for evidence last year.
At a business-level, almost 1,000 organisations have been engaged with on a one-to-one consultation basis, introducing them to the Standard and seeking feedback and support. These numbers are staggering, and highlights the breadth and depth of work that has gone on in the past two years.
What does the Standard set out to achieve?
The UKGBC’s market research in 2021 demonstrated that the term net zero carbon was not being applied consistently by those in the UK construction industry. The engagement work undertaken during the Standard’s development has continued to highlight the industry’s desire for harmonisation and uniformity around the topic.
The Standard responds to this market need for consistent rules around net zero carbon. It has been created to both reduce spurious claims around net zero carbon, and to accelerate the design, construction and use of buildings that deliver lower-carbon outcomes in line with the UK’s legally-binding carbon targets.
What does the Standard set out?
The free-to-access technical standard sets out what is needed to decarbonise the UK built environment in line with the nation’s 1.5 degree-aligned carbon and energy budgets, defining mandatory requirements for a ‘Net Zero Carbon Aligned Building’. Threshold limits (a maximum) and targets (a minimum) are provided on key aspects such as upfront carbon, operational energy use, avoidance of fossil fuel use on site, renewables and refrigerants.
The Standard is applicable to all major building types, as well as new build and existing stock.
Offsets may be used to complement, but not replace, the mandatory elements of the Standard, and may be used to achieve net zero carbon at the asset level. This approach is defined by the term ‘Net Zero Carbon Aligned Building (plus offsets)’ within the Standard.
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.
What does the Standard do to streamline carbon accounting?
The Standard builds on previous work in the net zero carbon field by BBP, BRE, CIBSE, IStructE, LETI, RIBA and the UKGBC, and the methodology for carbon accounting adopted in the Standard is in line with the current edition of the RICS Professional Standard – Whole Life Carbon Assessment for the Built Environment, which is referenced throughout.
The RICS Professional Standard is also the reporting methodology behind the other cross-industry initiative - Built Environment Carbon Database (BECD). The database is a free-to-use repository of whole-life carbon assessments of built assets and product LCA. It has been created to become the main source of carbon estimating and benchmarking for the UK construction industry. Through close collaboration between the two initiatives, the BECD will also be the lodging platform for projects with UK NZCBS verified performance data. This alignment across initiatives and guidance reaffirms the process of harmonisation and co-ordination.
What do architects need to know about the Standard?
While the Standard has been written for anyone who wants to fund, procure, design, or specify a net zero carbon building, architects will need to familiarise themselves with the key metrics that underpin the standard. This is not as onerous as it might sound.
Since the stakeholder engagement responses from across the industry repeatedly returned the need for ‘consistency’ as a key ingredient, the development of the key principles focussed on standardisation. The seven key performance metrics which sit at the heart of the Standard are all commonly used measurement units already familiar to industry.
Operational energy use is to be measured in kWh/m2/yr and upfront embodied carbon in kgCO2e/m2. Refrigerant systems are assessed based on their global warming potential (GWP), measured in kgCO2e/kg and on-site renewable electricity generation in kWh/ m2 /yr – based on building footprint area… and so on.
RIBA Practices who have been signatories to the Institute’s RIBA Climate Challenge, will be familiar with the drive for actual in-use building performance data based on 12-months of data. The Standard consolidates this requirement, and takes it a step further, setting out a fundamental pass/fail requirement for sites to be fossil fuel free (with the exceptions of essential emergency and life safety, and essential back-up systems servicing critical functions), and setting out operational energy limits based on in-use building energy consumption at 80% occupation (measured in GIA).
The key for architects using the Standard will be to establish rigorous data collection systems that track and log upfront and embodied carbon data- both for new build and retrofit projects. Without this data, conformity to the Standard cannot be demonstrated. Therefore, for clients wishing to secure a ‘Net Zero Carbon Aligned Building’ maintaining this data has, perhaps for the first time, real value beyond it being a cursory good thing to do. Hopefully we will see this attitude reflected in project appointments, briefs and programmes.
What do the limits of the Standard represent and how were these set?
The Standard sets out mandatory requirements for net zero carbon aligned buildings that could - if the rest of the UK building stock were to collectively implement compatible interventions - enable the UK real estate sector to stay true to the built environment’s share of our national carbon and energy budgets.
The limits have been derived from measured performance data, combined with expert professional experience on future performance trends and buildability, which have been compared against a complex model of the entire existing stock and future UK build-out rates.
The purpose of modelling and the associated development of the limits has been three-fold: 1) to identify a deliverable route to net zero carbon for the UK built environment as a whole, 2) to discern the wider systemic actions required to enable the UK real estate sector to conform to the necessary net zero carbon pathway; 3) to ensure that any building claiming to be ‘Net Zero Carbon Aligned’ is achieving energy and emissions performance aligned to keep the cumulative totals as faithfully as possible within the UK’s remaining carbon and energy budgets.
They represent ambitious but achievable requirements for building performance and construction quality.
Text by Jess Hrivnak. This is a Professional Feature edited by the RIBA Practice team. Send us your feedback and ideas.
RIBA Core curriculum topic: Sustainable architecture.
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