Architect and CIC Climate Change Expert Panel member Simon Sturgis tracks the progress of the UK’s emerging carbon standards, and how they can help architects reduce emissions, improve resource efficiency, and future-proof building value.
The UK’s trajectory to net zero received a major boost in July with the launch of the UK’s Net Zero Carbon Building Standard’s (NZCBS) ‘Net Zero Carbon Aligned Verification’. This follows the March launch of the NZCBS after a period of intense consultation. Important though the NZCBS is, it should not be seen in isolation. Also launched this May was the UKGBC’s ‘Whole Life Carbon Framework.’ Each of these builds on the RICS’s professional standard ‘Whole Life Carbon Assessment for the Built Environment – 2023’ (RICSPS). Finally, what has happened with Part Z, the carbon answer to Part L? I will try and make sense of how these work together.
The NZCBS is the product of an industry-wide initiative to standardise carbon reporting. It is based on what must be achieved, project by project, for the built environment sector to contribute to the UK achieving net zero by 2050. Meeting the NZCBS’s ‘Limits’ therefore means making a measurable contribution to UK decarbonisation. At this stage, the Limits cover ‘upfront’ embodied carbon, up to practical completion, and ‘operational’ energy use. Both must be measured after practical completion using actual measured data rather than predictions.
The NZCBS also requires a full whole life carbon (WLC) assessment to be reported and will introduce Limits for life-cycle embodied carbon and WLC once sufficiently robust data is available. A further key feature is that the Limits become more demanding each year up to 2050. Broadly, the current Limits are achievable within existing technology and budgets. Over time, however, compliance will become more challenging as the limits reduce. Designs will need to become more efficient in form, material selection, design and construction to reduce upfront emissions, while also becoming more durable, low maintenance and energy efficient to reduce in-use emissions. This is why whole life carbon assessment is so important, as it encourages the fully integrated thinking necessary to get us to net zero, e.g., how to balance out embodied vs operational emissions as well as upfront vs life cycle impacts to achieve the lowest overall emissions.
Although formal reporting is based on post-completion measurement, clients will want early confidence that their projects are on track to meet the relevant Limits which means carrying out predictive assessments throughout the RIBA design stages to make any necessary design changes as early as possible.
Why is it necessary to get your WLC assessments verified by NZCBS? Ultimately it is about underwriting the value of your building. NZCBS verification will:
- cut greenwashing, i.e. ensure that actions taken to produce a ‘green’ building really do the job;
- build consistency in assessment and reporting, which will in turn:
- provide greater confidence in reported outcomes and:
- enable like for like comparisons with other similar buildings;
- help improve in-use energy performance and, once WLC Limits are provided, better lifetime material efficiency;
- help future proof asset value.
As noted, NZCBS is built on the foundation of the RICSPS (I was lead author). The RICSPS is mostly technical and covers assessment methodology, i.e. how do you reliably calculate both operational and embodied emissions and report them.
Most practitioners will undertake WLC assessments using a software tool and have no direct connection with the RICSPS. There are several tools available, and it is worth checking that they are fully RICS compliant. Even so, I would recommend reading at least the first three chapters of RICSPS which are short, very helpful and well worth having a look at. The RICSPS is a free download from the RICS website. The RICSPS standard is now recognised as the de facto UK assessment methodology, and is also now used internationally.
Other recent guidance is the UKGBC’s ‘Whole Life Carbon Framework’ launched in May and can be seen as the ‘how to do it’ guidance. In essence the framework breaks down the actions required to reduce emissions into key ‘Delivery Principles’ to be addressed over the life cycle, and practical actions required at each life cycle stage. Invariably there will be choices to be made; for example if you want, ideally, to achieve low ‘upfront’ carbon and low ‘in use’ carbon this is sometimes difficult as there can be carbon cost/benefit trade-offs such as quantity/type of insulation vs energy performance, or the upfront carbon cost of a new facade vs in-use carbon costs of maintenance and replacement cycles.
Rationalising these potentially conflicting requirements to achieve the optimum low carbon solutions requires good knowledge as well as practical experience. This is fundamentally about those involved in the design of buildings developing a carbon intuition which is where the architect or engineer has sufficient experience to develop the right combination of actions to produce a low carbon solution before even attempting detailed calculations.
So, what of Part Z? I am part of a group led by Will Arnold (and including Tim den Dekker, Julie Godefroy, Jannik Giesekam, Tom Hesslenberg and Ludovica Pototschnig) that has been working on an industry-wide proposal to develop a Building Regulation covering embodied and whole life carbon (see part-z.uk). This initiative has gained a lot of enthusiasm across all sectors of the built environment industry with over 200 key supporters including consultants, client bodies, housebuilders, banks and many others. There has also been a debate, led by Ellie Chowns MP, in the House of Commons. The problem seems to be that before such legislation can be enacted, significant, supportive data needs to be collected. It is for this reason and the lack of government interest that the private sector needs to continue to take the lead.
Even without Part Z, there is now a mature and robust set of standards as described above defining what to do
and how to do it. Apart from those standards, there is a whole range of additional professional guidance from the RIBA, CIBSE, IStructE and others. If you want training in WLC assessment, CIBSE has a comprehensive course that is available. Two of the RICSPS authors (Jane Anderson and myself) were part of the team that put this together. Importantly the economic benefits of WLCA are becoming apparent. This is starting to manifest itself in improved resource efficiency as well as the items listed above.
Resource efficiency is in effect the flip side of carbon efficiency, and also leads to financial efficiency. Therefore among the many positive outcomes from WLC assessment are the climatic and economic benefits from engaging fully with RICSPS, the NZCBS and other supporting guidance.
Simon Sturgis is an architect and founder of Targeting Zero, member of the Construction Industry Council’s Climate Change Expert Panel, and lead author of the RICSPS Whole Life Carbon Standard