Multiple buildings’ assessments
Site-wide approaches are not acceptable and each BREEAM assessment needs to have its own Life Cycle Assessment model (using an IMPACT compliant software tool or equivalent).
This applies in all cases, including when the buildings are on the same plot and are built to the same specifications.
Developing assessment-specific LCA models ensures that material quantities are accurate, refer to the actual building (and building type) and account for external works included within the scope of the specific assessment.
Single building with multiple assessments within it
Where multiple assessments are conducted for different parts of a building, it is acceptable to have a single LCA model covering all assessments. In this case, an explanation of the allocation process used should be provided and the following guidance applies:
- Common elements (e.g. roof, foundations, external walls etc): apportion a percentage of the total impact of the element to each assessment based on their percentage share of the total GIFA (e.g. if an assessment accounts for 10% of the total GIFA, 10% of the element’s impact is apportioned to that assessment).
- Elements that are only in a given assessment (e.g. internal partitions, internal finishes etc): 100% of the impact is allocated to the assessment they are in.