Episode 171 - Part Z (Building Regulations proposed amendment)

This week we will be talking about the industry proposed amendment to Building Regulations - Part Z. This episode content meets PC3 - Legal Framework & Processes of the Part 3 Criteria.

Resources from today's episode:

Websites:

• https://www.architecture.com/knowledge-and-resources/knowledge-landing-page/how-can-architects-reinvigorate-support-for-part-z?utm_campaign=Member Update 150525&utm_content=A cityscape with glass high rise buildings and green trees.&utm_term=&utm_medium=email&utm_source=Adestra
• https://part-z.uk/proposal

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Transcript

Episode 171:

Hello and Welcome to the Part3 with me podcast. 

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I am your host Maria Skoutari and this week we will be talking about Part Z. Todays episode meets PC3 of the Part 3 Criteria.

And make sure to stay until the end for todays scenario.

Although not formally published and implement by the government as a Building Regulations Approved Document, Part Z has been a point of discussion within the industry for a number of years now and many disciplines within the industry are campaigning in support of introducing Part Z to Building Regulations.

What would Part Z focus on and why is it important:

Part Z would be intended for the required assessment for whole life carbon emissions and set limits for upfront embodied carbon for all major building projects. 

It’s importance lies with the need for the government to introduce legislation in driving the UK towards meeting its Net Zero Carbon commitments that have become evident from last year’s Climate Change Committee report. Embodied carbon emissions make up one tenth of the UK’s current annual emissions, but because they remain unregulated in the UK they have barely decreased over the last 30 years despite the efforts of manufacturers to decarbonise products and materials. Several European countries have already introduced some form of embodied carbon regulation and the European Commission has updated the Energy Performance of Building Directive to require the reporting of embodied carbon from 2028. 

The Ministry of Housing, Communities and Local Government are actively looking at Part Z proposals and are collaborating with AECOM to release a report on industry readiness. 

So what would the document itself and its requirements consist of: 

As mentioned, Part Z is a proposed amendment to the Building Regulations, which would see the reporting of whole life carbon with limits set on upfront embodied carbon. The regulations would apply to all major buildings over 1000sqm and/or 10 or more dwellings which is aligned with the proposed size limit set in the Future Homes Standard.

Although the UK is no longer in the EU, it is anticipated that Approved Document Z will potentially be introduced sometime in 2028, as per the European Commissions requirements, and will be split into two phases, Part Z1 and Part Z2. 

Part Z1, is intended to normalise the use of whole life assessments within the building design process, enabling design teams to identify ways in which to reduce the whole life carbon of the building and assessment data will be used to determine national targets for carbon in construction. This transparency will ensure that all stakeholders including developers, designers, and clients are aware of the carbon impact of their projects and can make informed decisions to reduce emissions. The first phase Z1 will, therefore, focus on the initial data collected from applying the principles of the Approved Document requiring mandatory assessments.

Then Part Z2, is intended to discourage excessive and unnecessary use of material within the built environment by requiring a reasonable standard of efficiency of upfront embodied carbon. The second phase will essentially use the data from the first phase and set the actual limits relating to embodied carbon targets allowing the industry to collect the data and build robust baselines. 

In order to comply with Parts Z1 and Z2 it is anticipated developments will need to meet Criteria 1 & 2. Under Criterion 1, it will require a Whole Life Carbon Assessment with guidance to be provided within the Approved Document demonstrating how this criterion can be met. Then Criterion 2, will require the upfront embodied carbon of the overall building and its individual elements expected not to exceed reasonable standards of intensity which will again be provided within the Approved Document. It is anticipated that the limits set within Criterion 2, in conjunction with the energy limits enforced by Part L, will enable the built environment to start to reduce the impact of its emissions, however the longer term ambition must be to extend the limits to include all whole life carbon modules that are reported. Data gathered as part of Criterion 1 would help this.

The Whole Life Carbon Assessment is proposed to be undertaken using the RICS Professional Standard ‘Whole life carbon assessment for the built environment’ 2nd Edition as a guide, which is the go to document on this topic in the UK. I will aim to cover it under a separate episode. For non-domestic buildings where Approved Document L requires an energy forecast in addition to the compliance model, the energy forecast would also be suitable for use for the Whole life carbon assessment. A cross-industry team is currently developing a free-to-use Built Environment Carbon Database that was launched in 2023 and can be used to meet the requirements under Criterion 1. The Built Environment Carbon Database also includes a Product Database that will be reviewed regularly, and is therefore proposed to be referenced for the generic carbon factors required for Criterion 1. 

Now, in terms of Embodied Carbon limits required under Criterion 2, it is currently envisioned that the Approved Document will set the limits what would need to be achieved in future carbon assessments. But to start with, it will be proposed that only upfront embodied carbon is limited by regulation enabling Building Control and Building Regulations Principal Designers to sign off compliance with Part Z by reviewing the final material quantities and environmental product declarations used in the building. It is anticipated that this limit requirement in conjunction with the energy limits enforced by Part L, will enable the built environment to start to reduce the impact of its emissions. The longer term ambition, however, must be to extend the limits to include all life-cycle modules that are reported. Prior to Part Z2 being mandated, guiding figures could be taken using the benchmarks provided in the Greater London Authority’s whole life-cycle carbon assessments guidance. This would align with targets set and undertaken by the RIBA, LETI and IStructE. 

The overall aim of both Parts is that the mandatory whole life carbon assessments will reshape material choices in the built environment by prioritising transparency, data-driven decision-making and carbon reduction. Projects will therefore be required to provide detailed Environmental Product Declarations to quantify embodied carbon at every stage. Clients together with design teams will then compare the materials based on lifecycle impacts, favouring options with lower embodied carbon.

Once published, it is expected that the proposed Part Z limits to reflect the need to meet the requirements of Parts F, H, L, O and any other relevant regulatory constraints that will have an impact on both embodied and operational carbon. 

These proposed amendments to the Building Regulations and the Approved Document have already been fully drafted and ready to be published.

So that’s a brief overview of how Approved Document Z is expected to take shape and what requirements will be anticipated from it. 

Now Part Z is expected to work alongside a number of existing standards, apart from other Approved Document, including, as mentioned, the Future Homes Standard and also it is anticipated it will work with the UK Net Zero Carbon Buildings Standard which launched its Pilot Version last year and I covered in Episode 135. The UK Net Zero Carbon Buildings Standard, sets asset-level requirements for different building types across a number of building sectors including operational energy, renewable electricity generation and upfront embodied carbon. The UK Net Zero Carbon Buildings Standard and Part Z will both be aligned in that they will both be setting limits for upfront carbon, requiring the reporting of whole life carbon, and requiring embodied and whole life carbon calculations to follow recognised industry standards and guidance. The key difference is that the standard is of course voluntary guidance whereas Part Z will be mandatory. 

Additionally, Part Z is also expected to work in alliance with the RIBA 2030 Climate Challenge and guidance made by the Institution of Structural Engineers, the Chartered Institution of Building Services Engineers, the UK Green Building Council and the Low Energy Transformation Initiative. 

Approved Document Z represents a significant step toward reducing the carbon footprint of the UK’s built environment, with robust industry backing and clear implementation pathways. If you would like to show support and endorse the initiative, head over to the Part Z website, I have provided a link for it in the episode notes. 

To sum up what I discussed today:

• Part Z is a proposed amendment to the UK Building Regulations, not yet published, aimed at regulating whole life carbon emissions and setting limits on upfront embodied carbon for major building projects. The regulation would apply to all major buildings over 1,000 sqm and/or 10 or more dwellings.
• Part Z is intended to be split into two phases: Part Z1 focuses on normalising whole life carbon assessments and collecting initial data, while Part Z2 will set actual embodied carbon limits based on that data.
• Part Z aims to drive transparency, data-driven decision-making, and carbon reduction across the built environment, ultimately helping the UK meet its Net Zero Carbon commitments and is an initiative supported by robust industry backing, with collaboration among government, consultants, and professional bodies, and is expected to work alongside voluntary standards like the UK Net Zero Carbon Buildings Standard.