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WST 02 - Recycled aggregates

Information correct as of 2ndDecember 2021. Please see kb.breeam.com for the latest compliance information.

Apportioning foundations where not all floors are assessed - KBCN0643

Where a development does not include all the storeys of a building, not all of the aggregates used in the building foundations need to be included in the assessment.  Any apportioning must be justified and calculated by a structural engineer, and it is the responsibility of the assessor to ensure that the process used is appropriate, robust and meets the aim of the credit issue.

Considering Sand and Cement Replacements - KBCN0181

Neither sand or cement replacements should be taken into account when assessing the percentage of recycled or secondary aggregate used in a project. The recycled aggregates issue only assesses the use of coarse aggregates.  
29/03/2017 Title amended and additional reference to cement substitutes added
 

Excluding applications from assessment - KBCN0875

Where a structural engineer has determined that recycled or secondary aggregate cannot be used in line with the criteria for a particular application, or where they will not allow the minimum BREEAM level to be used, that application can be excluded from the assessment. Where the engineer allows some content to be used, this percentage must still be specified in the excluded application. The engineer's decision must be suitably justified (for example following the BS8500 series and associated standards) and must be provided as evidence for the BREEAM assessment.

Existing materials recycled on site - KBCN0813

When existing elements are recycled (ie crushed and used as aggregate) on site, they can contribute to awarding credits as recycled aggregates. This issue aims to recognise and encourage the use of recycled and secondary aggregates and addresses waste rather than materials. It refers to recycled aggregate obtained on-site or off-site, based on materials identified as waste and removed during construction works. 
Previous incorrect KBCN text amended. CN 'Aggregates in existing applications' to be amended accordingly in next reissue of the RFO Technical manuals.

Granular fill and capping - KBCN1378

Granular fill and capping only refers to roadworks and not building foundations.

Proposing national best practice guidance on defining granular fill and capping as a high grade use - KBCN1138

Recycled aggregates used for granular fill and capping can only be considered ‘high grade’ if they:
  1. conform to specifications in national best practice guidance (refer to the ASWL).
  2. OR, where there is no national best practice guidance approved, new guidance can be proposed to BRE for approval:
    • Specifications in national best practice guidance must include as a minimum, limits and requirements on the properties listed in Checklist A6.
    • Specifications must be specifically for recycled aggregate for use as granular fill or capping.
    • National best practice guidance is not required to cover test methodologies.
  3. OR, alternatively, the UK standard ‘Specification for Highway Works (SHW) Series 600 Earthworks’ and classifications as listed in the relevant definition section of the UK NC 2014 manual can be used.
If none of these apply, the recycled aggregates should be considered ‘low grade’ and excluded from the assessment of the Issue.

Recycled aggregate evidence prior to contractor’s appointment - KBCN0231

If the contractor has not been appointed at the time of submitting the Design Stage assessment, whilst it is imperative for the design team to demonstrate a firm commitment to meet the criteria and award the credit at this stage, a letter from the design team or developer to confirm that no contractor has been appointed should be submitted in lieu of the stated letter of confirmation. This should also be clarified in the Assessment Report. BREEAM recognises that it may not be desirable to confirm the specification, source and availability of a particular recycled aggregate for a project where the contractor has not been appointed yet. This would restrict the contractor's ability to source the most economically viable recycled aggregate to meet the BREEAM criteria.

Recycled aggregates in concrete - KBCN0823

The relevant CN in the technical manual, which confirms that no concessions are given to the criteria, reads: ‘Where national building regulations limit the use of recycled aggregates in concrete (typically applicable to bound aggregate uses as listed), the onus for achieving this credit is on the unbound uses (please note that the total aggregate figure must still include the bound uses).’ To clarify, in the calculation, the percentage of recycled aggregates in both bound and unbound uses can be considered against the total high grade use for the project.  
Technical manual to be updated accordingly in next reissue.
 
Information correct as of 2ndDecember 2021. Please see kb.breeam.com for the latest compliance information.