Basic Questions

+ What is embodied carbon?

Embodied Carbon emissions are the greenhouse gas emissions and removals associated with materials and construction processes throughout the whole life cycle of an asset (Life Cycle Modules A1-A5, B1-B5, C1-C4). The Life Cycle Modules are defined in the RICS professional statement: Whole life carbon assessment for the built environment .

+ Is Part Z a real building regulation?

The proposed Part Z is not yet part of the Building Regulations. It has been produced by, and in conjunction with, the construction industry as a proof of concept to demonstrate one way in which embodied carbon could be introduced into UK regulation.

+ Can I provide feedback on the proposals?

Yes, please do! Email any comments on the contents at hello@part-z.uk. A schedule of all comments is being maintained. Recurring themes received in feedback will be discussed in blog posts.

The need for embodied carbon regulation

+ Why are emissions limits on materials not proposed instead?

It is the overall emissions of construction that needs to be regulated, not just that of the original materials used. Suppose only emissions in the production the materials were restricted. Then the potential inefficient use of these materials (whether low-carbon or not) in buildings would then remain unchecked, i.e. a building’s embodied carbon emissions remains unregulated. A useful analogue is that for a building’s energy use: even though energy production is taxed, Part L is used to cap operational energy usage.

+ Why is a carbon tax to disincentivise excessive embodied carbon emissions not proposed instead?

The UK may or may not be ready for a carbon tax, but the consensus is that the UK construction industry is ready for embodied carbon regulation. In order to implement a carbon tax, a reliable and regulated method of calculating and reporting carbon is needed. Part Z sets the groundwork for this in the UK construction sector.

+ Wouldn't this sit better in planning regulations rather than building regulations?

Planning stage is often too early to carry out a detailed whole life carbon assessment, as often the information on the detailed design and quantities is insufficient at this point. Designers may still choose to undertake a high-level carbon appraisal early in design to maximise chances of compliance with Part Z.

Contents of the proposed Part Z

+ What are the contents of the proposed Part Z based on?

The proposal is derived from the principles underlying other existing building regulations, industry best practice, and a series of consultations with carbon experts and industry leader supporters.

+ Why are whole life carbon targets not proposed?

Part Z is about regulating the reporting of whole life carbon, and limiting up-front embodied carbon. This scope balances ambition with industry achievability. The targets are on upfront embodied carbon only, as this is easiest to measure and sign off by Building Control, and has the most consistency in current industry data and assumptions.

+ Could Part Z be expanded to include whole life carbon targets?

Part Z is written in a way that could allow whole life carbon targets in the future if desired.

+ What was the motivation behind the proposed dates of implementation?

The dates shown are the right balance of achievability and ambition. They follow global precedent, allow time for the entire industry to gear up towards reporting whole life carbon on every project, and allow time to use the collected data to set robust and appropriate targets.

+ What is the relationship between Part L and the proposed Part Z?

Part L and Part Z work together. The output from Part L feeds into Module B6 in the whole life carbon assessment in Part Z.

+ Who would "sign off" on Part Z compliance?

As this proposal sits under Building Regulations, the assumption is that compliance would be signed off by Building Control Officers. As it is only upfront embodied carbon (modules A1-A5) that would be limited by the proposal, sign-off could be achieved following reviewing the final material quantities and Environmental Product Declarations used in the construction.

The authors

+ Why did the authors write Part Z?

The authors decided to produce a proof-of-concept document for the regulation of embodied carbon following their various conversations with the construction and real estate industry. As the concept of regulating embodied carbon has recently received more attention among industry and policy makers, the authors took the view that such a document would be useful as proof of concept, in helping the government envisage how embodied carbon could be regulated.

+ What makes the authors the right people to write this?

Whilst the authors are not the only ones who could write such a proof of concept, they have considerable relevant experience to do so. You can read more about them on the authors page.

Industry support for embodied carbon regulation

+ Why are statements being asked for the support of embodied carbon regulation?

The consensus is that the UK construction industry supports – and is ready for – embodied carbon regulation. The statements of support will provide the confirmation of this support and readiness.

+ What are the construction industry statements of support on this website for?

Industry messages shown on this website are provided in support of the principle of embodied carbon regulation, and not necessarily the contents of the proposed draft Proposed Document Z, which is presented on this website as a proof of concept. Firms have not been asked to provide statements of support specific to the documents (Part Z and Proposed Document Z) published on this website. The detail in these documents is expected to evolve over time. However, the principle of the need for embodied carbon regulation will remain unchanged.

What happens next

+ What will happen in the months following the release of Part Z?

The consensus is that the UK construction industry supports embodied carbon regulation. Messages of support are being gathered over the next few months to provide a tangible reflection of this support. If you know someone who would be interested in adding their support, please point them to part-z.uk/support or email hello@part-z.uk.

+ Who decides on the final wording of Part Z and Proposed Document Z?

It is expected that if a government department were given the mandate to bring Part Z into law, then they would take responsibility for developing the text further, likely in public consultation. The authors would make themselves available to help with this process. A schedule of all comments received on the proposals is being maintained.