Net Zero Carbon Supplementary Planning Document

7. Policy NZC3 – Embodied Carbon

Embodied carbon overview

Table 19: Summary of Policy NZC3

7.1 Policy NZC3 sets out the following requirements in Table 19.

7.2 Embodied carbon relates to emissions associated with materials, construction processes, maintenance/refurbishment during their lifetime and the eventual end of life of a development, measured in kgCO2e (kilogrammes of carbon dioxide equivalent²⁶). For example, carbon emissions associated with the energy used in the manufacturing process of extracting and producing a product, transporting it to the site, assembling it into a building or using it to maintain or refurbish that building.

7.3 For embodied carbon assessments, embodied carbon is usually reported as kilogrammes of carbon per m² (GIA).

7.4 The majority of a building's embodied carbon is associated with the construction of the building, but a smaller amount of embodied carbon is also associated with the building's lifetime through refurbishment and maintenance, and its eventual demolition and disposal. Table 20 provides a summary of the associated carbon emissions per stage of a buildings lifetime.

Guidance on embodied carbon assessments

7.5 For both major and super-major developments, design principles for embodied carbon reduction should be adopted throughout the planning and construction process. The set of principles noted in the Greater London Authority Whole Life-Cycle Carbon Assessment guidance provides a good example and include:

• Reusing and retrofitting existing built structures
• Utilising repurposed or recycled materials
• Choosing low-carbon materials (e.g. timber, lime or low-carbon production materials)
• Fabric first approach to holistically reduce embodied and operational carbon
• Low-carbon operational water use
• Design for future deconstruction and reuse
• Design an efficient building shape and form
• Incorporate carbon sequestering materials
• Design for durability and flexibility
• Address embodied and operational carbon reductions together
• Determine expected building lifespan
• Source materials locally
• Minimise waste
• Efficient and lightweight construction
• Follow circular economy principles

7.6 Applicants for major developments should demonstrate through their Energy Statement how the proposed development aims to achieve embodied carbon reductions against each of the principles identified above. Reduction measures should be considered in relation to the specific setting and type of development, but the principles and measures in the list above should be used as a starting point to develop a detailed strategy.

7.7 Embodied carbon assessments, of the type relevant to the scale of the proposal, will be required to be submitted at each stage of the planning process:

• For Outline Planning applications: Applicants should identify the expected design principles and materials and how embodied carbon has been considered and reduced.
• For Full Planning applications, Reserved Matters and S73 applications: Applicants should identify how the selection of the specific proposed building design and materials has considered embodied carbon and how this has been reduced.

7.9 When considering the replacement of materials with high embodied carbon, the Materials Pyramid (Figure 5) is a useful high-level tool to identify what alternative sustainable materials are suitable for the development to reduce embodied carbon, and how much improvement these deliver against the more conventional materials.

7.10 To increase understanding of the impacts of typically used materials, the LETI Embodied Carbon PrimerAppendix 8 provides in depth analyses of primary construction materials, such as timber, aluminium, glass, steel and bricks. Applicants are encouraged to review this guidance to determine appropriate material selection for their development, or at the minimum consider low embodied carbon materials as per Materials Pyramid.

Figure 5: Construction materials pyramid. Materials on the top of the pyramid have the highest embodied carbon, therefore should be used most sparingly and where possible substituted with materials further towards the bottom of the pyramid. Interactive version available: www.materialepyramiden.dk

7.11 For major development, which is not required to complete a whole- life embodied carbon assessment, the Council requires that applicants demonstrate consideration to the actions noted below to illustrate how embodied carbon has been reduced where possible.

• Using reused materials
• Using cement replacement, cement products with clinker replacement, or using less cement
• Using recycled aggregate
• Using renewable materials e.g. certified sustainably sourced timber or other plant-based materials
• Using steel sourced from producers that use electric arc furnaces rather than coal-fired furnaces
• Replacing high-carbon materials with lower-carbon materials as per the Materials Pyramid
• Using products with EPD specification or from the BRE Green Guide to Specification.

7.12 To provide evidence of the consideration and reduction of embodied carbon, major development may submit 'life cycle assessment' calculations or other evidence that may have been produced within the following common industry certifications/ approaches:

BREEAM:

• Output from BREEAM LCA tool. These will have been produced where the scheme is targeting credits under BREEAM topic 'Mat 01' ('Environmental impacts from construction products - Building life cycle assessment'). This is not a minimum credit required for any BREEAM rating, but will help a development to achieve the minimum total percentage score for the BREEAM rating that it is targeting.
• Evidence produced in support of BREEAM credit Mat 02 ('Environmental impacts from construction products – Environmental Product Declaration'). Again, this credit is optional within BREEAM but would contribute towards the overarching BREEAM score.

Home Quality Mark (HQM):

• Evidence produced in support of HQM topic '6.2 Environmental Impact of Materials'. These may include the LCA output and/or evidence of specification of products with environmental product declarations (EPDs). As with BREEAM Mat 01/02 (above), this topic within HQM is optional but will earn points towards an overarching HQM score.

BRE Green Guide

• Evidence that the proposed scheme has prioritised materials according to the  BRE Green Guide to Specification .

Whole Life Embodied Carbon Assessment methodologies

7.13 The industry standard method to account for a building's embodied carbon is the RICS Whole Life Carbon Assessment for the Built Environment. This is based on the relevant British and European Standards. The RICS method defines the various parts of the building that should be assessed, and divides the stages of a building's life into several stages or 'modules' as follows:

• A1–A5: All stages up to completion of the building. This is also known as 'upfront embodied carbon'.
• B1–B5: The building's in- use lifespan. Includes use, maintenance, repairs, replacements, refurbishments.
  • (Sometimes also includes B6 and B7, which relate to operational energy use and operational water use respectively).
• • C1–C4: End of life of the building and disposal of its waste materials.

7.14 A 'Whole life embodied carbon' assessment therefore refers to the sum of all carbon in stages A1-A5, B1-B5 and C1-C4.

7.15 The largest contributor to embodied carbon is through stages A1-A5. Carbon emitted through these stages occurs 'today' and can therefore have a greater contribution to reducing carbon emissions to meet local, national and international carbon targets.

7.16 For super-major developments, applicants are required to complete a whole-life embodied carbon assessment, the following construction elements should be examined, as set out under NRM 2 (RICS) and following the RICS Whole Life Carbon Assessment method:

• Substructure
• Superstructure
• Finishes
• Fittings, furnishing and equipment
• MEP services
• Prefabricated buildings and building units
• Work to existing building
• External works

7.17 The RICS methodology is the only extant such methodology that the Council is aware of; however, should applicants propose an alternative methodology in future this must also conform with BS15978 Sustainability of construction works or relevant successor standard of the same or improved quality.

7.18 The following sources of data are preferable for reliable embodied carbon estimations:

• Environmental Product Declarations for specific products you propose to use – these are certificates disclosing the embodied carbon (and other environmental impact factors) that are based on the specific conditions in which an individual product is produced. Not all products on the market have EPDs, but many products claiming 'green' credentials do have these to evidence their claims. You can use embodied carbon data from EPDs in combination with generic embodied carbon data for other products or materials from the databases noted below. EPDs should conform with relevant standards including ISO 14025: 2010 (Environmental labels and declarations. Type III environmental declarations. Principles and procedures).
   
• The University of Bath ICE database – free-to-use; registration required.
• Built Environment Carbon Database – currently in development (as of the time of writing this SPD) led by RICS along with several other industry bodies.

7.19 Where specific carbon factors are not available, carbon factors can be manually generated using the RICS Methodology to Calculate Embodied Carbon of Materials. Associated assumptions and principles should also be addressed, which are set out in the Institution of Structural Engineers' How to Calculate Embodied Carbon for Construction Materials guidance.

7.20 LETI guidance also lists out theactions for embodied carbon at each stage of the project, listing actions for the designer and for the life cycle assessment specialist at each RIBA Stage (see Appendix 0.2 of the LETI Climate Emergency Design Guide).

7.21 Developed by building environment professionals and experts, the RIBA 2030 Climate Challenge sets voluntary targets for embodied carbon, operational energy and water consumption. Version 2 of their targets has been updated so that embodied carbon targets align with LETI, GLA and UKGBC guidance. RIBA states that the Climate Challenge "presents ambitious but achievable forward-facing performance outcomes that are in line with the Future Homes Standard and future regulation, set against business-as-usual complianceapproaches". In their guidance, buildings should adopt the 2025 guidance as a minimum where buildings are being designed today, since the targets are based upon operational performance (as it is likely that buildings designed today will be completed closer to 2025).

7.22 Although applications subject to NZC3 are not required to meet specific embodied carbon emissions targets, it is highly important to understand best practice benchmarks when considering embodied carbon in new developments. Super-major applications in particular, which are required to complete a whole- life embodied carbon assessment, should aim to achieve the 2025 targets set out below in Table 21.

Table 21: RIBA Climate Challenge suggested targets for whole life embodied carbon, differentiated by use.

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