If the UK is to reduce its carbon emissions in order to reach its net zero target by 2050, building regulations need to change. The proposed UK building regulations amendment known as ‘Part Z’ has been set out by industry professionals within the built environment to ensure that embodied carbon is assessed on all projects, as part of a comprehensive whole life carbon assessment.

The proposal introduces mandatory assessments ahead of setting carbon limits, giving time to converge on robust yet ambitious targets. It does not form part of the current UK building regulations, but the industry proposes that it becomes part of these in future as early as 2023.

It is supported by organisations, such as the Royal Institute of British Architects and the Chartered Institution of Building Services Engineers.

What is whole life carbon?

Whole life carbon comprises the carbon emitted throughout the full life cycle of a project and includes both embodied carbon and operational carbon:

• Embodied carbon is the carbon associated with materials and construction throughout the whole lifecycle of a building. It includes the carbon emitted during extraction and manufacturing of a building’s materials, transport and installation on site, replacement/ maintenance during the building usage, as well as their disposal at the end of the building’s life.
  
  
• Operational carbon comes from the energy required for heating, cooling, ventilation, lighting, AC plugs, and so on, and from water use.

Why is embodied carbon important?

Embodied carbon will be responsible for almost half of total new construction emissions between now and 2050, according to Architecture 2030. We need to understand and reduce embodied carbon of construction projects if we want to have a chance to meet the 2050 climate targets. 

What is Part Z?

Its aim is to ensure that the whole impact of building is accounted for and that we have clear and measurable ways of achieving the emissions reductions needed to get to net zero.

The suggested requirements are that:

a. Whole life carbon emissions are assessed and reported for projects including both operational and embodied carbon. 

b. The upfront embodied carbon of the overall building and its individual elements should not exceed reasonable standards of carbon intensity.

c. Reasonable provision is made to minimise carbon emissions in projects. No specific targets have been proposed as part of Part Z yet, but RIBA and LETI have suggested possible targets and additional guidance.

It suggests that a. and b. should apply for projects with a gross internal floor area of 1,000m² and above, or that create more than 10 dwellings, but that in the future all buildings should comply with b).  

What is happening now?

A second reading of the bill was carried out on the 25 November 2022. MPs agreed on the need to measure and reduce embodied carbon but asked for further industry consultations. Introduction of Part Z without further delays will be able to ensure that the construction industry measures, understands and tries to reduce the embodied carbon impact of construction in a robust and cohesive way.

Further information

Contact Georgios Askounis

Embodied carbon in buildings: the big debate