Planning for Part Z
It is well known that the largest carbon savings can be made through key decisions at early project stages (e.g. building usage, reuse vs. demolition, building height, basement depth etc). Therefore, a building’s embodied carbon impact should be considered as early as possible within a project to maximise the potential carbon savings, typically at RIBA Stages 1 or 2, a long time prior to planning. If regulation like Part Z were passed, then recognising the carbon impact in these early decisions would reduce the risk of buildings being unable to comply with embodied carbon limits later down the line.
This leads to an obvious question – does whole life (and thus, embodied) carbon need to be assessed and controlled at planning stage, in addition to Building Regulation requirements? The Part Z authors have been in conversation with Richard Blyth, Head of Policy at the Royal Town Planning Institute (RTPI), to better understand what role planners and the planning process could play in relation to Part Z and whole life carbon.
It is important to recognise that Building Regulation compliance is not assessed as part of the planning process. Consequently, in the same way that planning officers do not look at insulation values under Part L or structural integrity under Part A, they would not be expected to review embodied carbon under Part Z.
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. Rather, designers may choose to undertake a high-level carbon appraisal at this stage to maximise chances of compliance with Part Z.
In this respect, it’s useful to note that pre-application engagement with authorities (“pre-app”) is frequently used to obtain feedback on the feasibility of pre-planning designs against aspects such as relevant planning policies, and to discuss potential mitigation. In this way, pre-apps are used to reduce the risk that a project does not receive planning permission. A pre-app meeting could also, if requested, incorporate a review of the potential impact of Building Regulations by involving Building Control.
Following our conversation with Richard Blyth, we concluded that the most appropriate way to help clients get certainty of meeting the requirements of Part Z would be to incorporate a (voluntary) early assessment of embodied carbon into the pre-app process. This would be in response to a request by the client, essentially slotting into an existing process with which most developers are already familiar.
An additional benefit of involving Building Control (or approved WLC assessor consultants) at pre-app in this way is that it could help identify where compliance requirements are likely to affect the building’s appearance, a fundamental assessment criterion for planning.
Planning officers might also be empowered to support this through guidance and training to help them identify “high-carbon” projects (e.g. new-build projects that are particularly tall, have large basements, long spans etc.), although we don’t see this as a fundamental component of the Part Z proposals.
It is interesting to note that some local authorities have implemented their own embodied carbon reporting requirements in the absence of regulation. London’s GLA requires larger schemes (those referrable to the Mayor) to provide WLC assessments to planners at pre-application, planning and post-construction. Although such pre-emptive initiatives are welcome, the mandating of reporting of and limits on embodied carbon at the national level sit most comfortably in Building Regulations.
A WLC assessment prior to planning allows project stakeholders to evaluate the carbon impact of early design decisions. The pre-app process could offer a useful checkpoint by offering the opportunity for clients to engage with Building Control and to receive guidance on carbon impacts.
Although it is crucial for whole life carbon to be on the agenda well before planning stage if the industry is to transition to net zero carbon by 2050, we believe that mandatory reporting of and limits on embodied carbon should reside in Building Regulations.
