Mat 01 Environmental impacts from construction products - Building life cycle assessment (LCA)

Building LCA – Scope when a BREEAM Assessment covers only part of the new building design - KBCN1172

To give reliable results, building LCA must capture the interactions that occur across an entire design (the system). A design decision in one part of the design will, in many cases, cause knock-on effects to other parts of the design. If only part of a building being designed is included in the building LCA the designer may choose a design option that optimises environmental impacts for the limited part analysed, but will be unaware of potential detrimental effects to the overall environmental impact of the building. In addition, if a building LCA only includes the construction products that form the BREEAM assessment area, inconsistencies arise with regards to construction products that serve all areas of the building in common. For example, an assessment on a central floor that excludes the roof, compared with an assessment on the (otherwise identical) top floor that does include the roof. This approach would be unfair. Therefore, the building LCA scope should normally include the whole building design (as defined in Mat 01, ‘Scope of assessment’) even if the area covered by the BREEAM assessment scope is only part of the building. However, where in the opinion of the BREEAM Assessor this is not reasonable, it is acceptable for the building LCA scope to match the BREEAM assessment scope. Examples where this may be the case include newly-constructed, mixed-use buildings (where the different use zones are assessed under different schemes or some are not being assessed at all) and part new-build part refurbishment projects. Where this is the case:-

• Comparison with the BREEAM benchmark cannot be done, only options appraisal.
• Only include construction elements/components that are both:

Within or forming the boundary of the BREEAM assessment scope. Predominantly the responsibility of the project team undertaking the building LCA work.

Note: Based on the above conditions, if no construction elements/components are included, or what is included is too limited to have significantly different options to appraise, then credits cannot be awarded.

• In the BREEAM Mat 01/02 Results Submission Tool: 

Select ‘Other’ for the ‘BREEAM assessment building use type’ (note: ‘mixed-use’ should only be entered for mixed-use buildings where the whole building is included in the building LCA scope). For ‘Functional quantity…’, enter the value corresponding to the scope included in the building LCA. Include the following text in cell C10 of the ‘DifferencesID2,3,4’ sheet: “The scope of this building LCA work matches the BREEAM assessment scope, which covers only part of a building being newly constructed/refurbished. Of the areas being newly constructed/refurbished, the building use type(s) of the areas included in the building LCA scope are [insert use type(s)] and the building use type(s) of the areas excluded are [insert use type(s)]. The Functional quantity of the areas excluded are [insert value]”.

06-Mar-2024 - Scheme applicability updated to UK NC V6.
01-Dec-2020 - Clarification to previous update added.
27-Nov-2020 - Exceptions paragraph added.
06-Dec-2019 - Scope of KBCN clarified.

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Building LCA – similar buildings approach - KBCN1459

If multiple buildings share an identical design, as per KBCN1226, the one set of LCA evidence can be submitted for (where pursued) the superstructure and core buildings services criteria for each identical building. Where buildings are similar, but not identical the following applies. Level of variation

• For <10% variation in LCA results between the buildings, submit the Mat 01/02 calculator for only the worst performing design. However, results for all buildings must be included in the LCA report.
• For ≥10% variation in LCA results submit the Mat 01/02 calculator for every building. See below:

Tool submission Separate submissions are carried out in BREEAM Projects:

• Upload one zip file per building. Each zip file will contain all required files as if for individual assessments. Clearly identify each building (e.g. the filename should contain 'Building A', 'Building B' etc).
• Identify the worst performing building. By adding ‘_Worst Performing’ to the end of the filename.

Evidence submission Separate and specific building LCA evidence for each building must be submitted for (where pursued):

• The superstructure and core buildings services criteria.
• The substructure and hard landscaping criteria. These aspects will almost always vary irrespective of identical superstructure and core building services design. Refer to the technical manual and relevant KBCNs on how to assign hard landscaping to each building on a shared site.

For options appraisals, common evidence covering all similar buildings can be used. There is no requirement for different design options for each building, although this can still be done if this brings value to the project.

04-Oct-2023 - Title and layout updated for clarity and consistency. Scheme applicability updated.
16-Nov-2021 - Revised and re-published.

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Building LCA – evidence requirements for multiple assessments with identical designs - KBCN1226

Superstructure + core building services Where an identical superstructure design and / or identical core building services design is used for multiple buildings, the same building LCA evidence may be submitted for all these assessments. The following shall be identical:

• Products specified and quantities installed.
• Transport of the products to the site (10km variation in transport distance to site is acceptable).
• In-use assumptions (e.g. maintenance, service lives of products).
• End-of-life assumptions.

Substructure and hard landscaping It is unlikely that the same substructure and hard landscaping design will apply to more than one building due to variations in ground conditions and site layout. Therefore, it is not acceptable for the same substructure / hard landscaping LCA evidence to be submitted for this criteria for more than one assessment. Similar buildings approach If the LCA(s) are part of a similar buildings assessment, please also see KBCN1459.

04-Oct-2023 - Link to KBCN1459 added. Scheme applicability updated. KBCN layout adjusted for clarity.

 

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Third-party verification – Timing - KBCN1603

The third-party LCA verification requirements for concept and technical design stages do not need to be completed at a specific project stage. It is, for example, acceptable for these to be verified as a single exercise, following technical design stage.

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