In a recent webinar, a panel of experts discussed four industry initiatives designed to measure, regulate, limit and track whole life carbon in the UK built environment.

Kay Pitman

World Built Environment Forum Manager, RICS

In the UK, four aligned industry initiatives are emerging as a system for managing whole life carbon in the built environment. Put together, this ‘whole life carbon ecosystem’ can help industry to:

WLCA provides the method to measure and report carbon emissions

RICS’ Whole life carbon assessment for the built environment (WLCA), 2nd edition, provides a methodology for measuring and reporting on carbon and greenhouse gas emissions from buildings and infrastructure throughout the life cycle. Having come into force on 1 July 2024, RICS members must follow the standard’s requirements when completing whole life carbon assessments.

WLCA is free to download from the RICS website and builds on existing ISO and EN standards. ‘I don’t think people are going to reduce carbon by ignoring cost’, says Anil Sawhney FRICS, head of sustainability at RICS, so that is why the WLCA is aligned with cost planning through the International Cost Management Standard, 3rd edition (ICMS 3). Through this alignment, RICS members can assess various design or materials options for low carbon buildings and infrastructure alongside the associated life cycle emissions as well as life cycle costs.

RICS provides training, guides, tools and bespoke support for the implementation and adoption of the WLCA, with software validation for compliance with the WLCA underway in early 2025.

Part Z offers the means to embed carbon measurement and reporting

Will Arnold, head of climate action at the Institution of Structural Engineers (IStructE), explains that operational energy use has been regulated in the UK for quite some time. Operational carbon emissions continue to drop year-on-year as the energy grid decarbonises, leaving embodied carbon representing approximately 10% of UK emissions.

Will continues by explaining that unlike other similar countries, there is no mandated reporting methodology that applies to the embodied carbon in buildings in the UK. While different approaches are taken globally, several developed economies are moving towards mandating the reporting of embodied carbon. Examples of regulation in other jurisdictions are California’s CALGreen building code, the EU Energy Performance of Building Directive and the New South Wales Sustainable Buildings State Environmental Planning Policy.

Part Z is an industry-backed proposal for regulating embodied carbon in the UK. It advocates a two-step process to the regulation of embodied carbon:

  1. Developers would only be required to report embodied carbon in building projects using one consistent approach.
  2. Once sufficient comparable data on levels of embodied carbon in different projects has been collected, appropriate limits would be introduced on the amount of embodied carbon permitted in new development projects.
     

Part Z has gained widespread support from industry stakeholders for two primary reasons:

  • Consistency: Different developers, local authorities and other clients ask for different kinds of information on embodied carbon in projects. Implementing Part Z would bring consistency to the submissions these clients receive, saving the industry time and money.
  • Level playing field: Part Z would ensure that all firms operating in the UK consider the 10% of UK emissions generated through embodied carbon, in effect alleviating any perceived cost disadvantage placed on firms that voluntarily choose to consider embodied carbon in their projects currently.
     

Part Z is short, free to download and has been written as a proof of concept to show how the regulation of embodied carbon could be incorporated into the building codes. The task for government is to start setting out the timeline and direction of travel to introduce regulation of this nature in the UK.

NZCBS contains performance criteria to define net zero buildings in the UK

The UK Net Zero Carbon Buildings Standard builds on scientific evidence and existing industry initiatives designed to define a single standard for net zero buildings in the UK. It is underpinned by RICS’ WLCA methodology, says Julie Godefroy, head of net zero policy at CIBSE.

Currently in its pilot stage, Julie explains, the standard is an industry initiative that reflects the work of hundreds of volunteers and participants. The standard addresses the proliferation of targets and limits that the industry is currently experiencing with a single scheme, designed to enable professionals from across different built environment disciplines to give a single piece of advice to a client on what it means to be net zero. The standard sets out the following requirements.

  • Maximum limits to be met for:
    • upfront carbon
    • operational energy
    • use of fossil fuels
    • the performance of district heating and cooling (if the building is connected)
    • the impacts of refrigerants (where relevant) and
    • the heating delivered.
  • Minimum targets for on-site renewable energy generation.
  • Reporting requirements for items not associated with a limit or target:
    • life cycle embodied carbon
    • operational water use
    • electricity demand (with a view to demand management) and
    • heating and cooling of buildings (where there is not yet a limit).
  • Optionally, projects can also choose to offset their residual emissions, but this does not change the other requirements of the standard.
     

As a science-led standard, the NZCBS limits have been developed utilising a bottom-up and top-down analytical approach. By taking a bottom-up perspective, the standard is based on analysis of what is achievable, both now and in the future, for operational energy and embodied carbon performance in buildings. By taking a top-down perspective, the standard aligns this with analysis of UK carbon and energy budgets, and within that, what is necessary for the UK built environment to remain on a 1.5°C trajectory.

The pilot testing stage is expected to conclude at the end of 2025. Alongside the pilot testing, a system is being developed for the administration of verification and communication of adherence to the standard. A tender process for potential verification bodies will be issued in the coming months.

Julie and Will are also putting together a document providing the data that informed the bottom-up element of the analysis for the standard, which will be published on the standard’s website.

BECD is a data repository of carbon assessments

In the early 2020s, RICS and other industry stakeholders were seeing a lot of carbon assessments that were being completed inconsistently, says James Fiske, chief executive officer at BCIS. This was partly due to a variety of methodologies for carbon assessment being employed, but also because assessors were using inconsistent data. In response, he continues, RICS, in collaboration with several other industry bodies, founded a pan-industry initiative to provide carbon data for the built environment in a free to access, consistent way through the Built Environment Carbon Database.

BECD contains two databases:

  • The asset library: a database of carbon assessments for buildings and infrastructure construction projects.
  • The products library: a database of carbon assessments for more than 35,000 different construction materials and products, listed with corresponding A1-3 numbers and links to the original source information.
     

James explains that by sharing project and materials data through BECD, the databases can be used to improve transparency, underpin more accurate benchmarking and track industry progress. By using BECD, industry stakeholders play a vital role in guiding the future development and improvement of the database as an industry repository.

From calculating and reporting to managing and reducing carbon with the PAS 2080

PAS 2080 is a tool that helps users understand, depending on your role in the design and delivery team, where you fit and what questions you should be asking to manage carbon on a project. Anil explains that we can see the ecosystem working with PAS 2080 in the real world with Transport for New South Wales. In their digital engineering framework, they have incorporated ICMS 3 for comparing cost and carbon, RICS’ WLCA as a methodology and PAS 2080 as a carbon management system.

Decarbonising the built environment requires a coordinated set of interventions. In the UK, four key initiatives are driving progress in whole life carbon reduction:

  • RICS Whole Life Carbon Assessment Standard
  • Part Z proposal for Building Regulations
  • UK Net Zero Carbon Buildings Standard
  • Built Environment Carbon Database


This webinar explores how these initiatives work together to overcome barriers to decarbonisation and shape the future of the UK built environment.

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