If two or more buildings share an identical design, as per KBCN1226, the same building LCA evidence can be submitted for the superstructure criteria and core buildings services criteria (if pursued) for each building.
For non-identical buildings the following guidance applies:
- If there is less than 10% variation in LCA results between the different buildings, only one submission of the worse performing design is required (However, results for all buildings should be included in the LCA report)
- If there is a greater than 10% variation in LCA results between the different buildings, results must be submitted separately for each building*. Separate submission must be done in BREEAM Projects as follows:
Upload one zip file per building. Each zip file will contain all of the required files as if each building were done as a separate assessment. The filenames of the zip files should refer to the building identifiers used (e.g. the filename should contain BuildingA, BuildingB).
Identify the worst performing building zip file (that the credits are based on) by adding ‘_Worst Performing’ to the end of the filename before the extension ‘.xxx’.
*For non-identical buildings with a greater than 10% variation in LCA results, separate and specific building LCA evidence must be submitted for the superstructure criteria and core buildings services criteria (if pursued) for each one. For all buildings, as per KBCN1226, separate and specific building LCA evidence must be submitted for the substructure and hard landscaping criteria (if pursued) for each one. This is because these aspects will almost always vary irrespective of whether the superstructure is identical.
Regarding the hard-landscaping scope, if pursued, the guidance within the technical manual on how to allocate different parts of the hard landscaping to each building must be followed.
If the designs for each building are closely related (but not identical), it is likely that most of the design work, and therefore the LCA work, is done once and is applicable to each building following some adaptions (e.g. to the quantities installed). As such, the options appraised may be the same for each building – there is no requirement for the designers to come up with different design options for each building (although they are encouraged to if it gains the most value out of the process).
For a ‘similar buildings assessment’, the above steps must be done for all the buildings, likely benefiting from the efficiencies mentioned above. Then, as per the ‘similar buildings assessment’ requirements, the credits finally awarded must be based on the worst performing building, in line with GN10.
16 Nov 2021 - Revised and re-published