G-10 Definition of system boundaries for new buildings

Aspect G-10 Definition of system boundaries for new buildings
Description
A clear definition of the system boundaries is needed for improved understanding and interpretation of the LCA results, as well as to enable them to be used for comparative assertions (e.g. choice of design alternatives) or stand-alone LCA (e.g. benchmarking purposes).How should this system boundary be defined for new buildings?

related study objective

stand-alone LCA comparative assertion

related study phase

goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for

new buildings existing buildings construction products screening LCA simplified LCA complete LCA
Provisions For a new building, the system boundary should include all stages of the life cycle. This includes all the upstream and downstream processes needed to establish and maintain the function(s) of the building, from the acquisition of raw materials to their disposal, or to the point where materials exit the system boundary, either during or at the end of the building life cycle.For the inclusion of specific contributors (e.g. transport of people, water consumption etc.), the definition of the system boundaries is directly linked to the goal and scope definition (see the corresponding aspects).EN 15978 gives clear rules for setting the system boundary of a building. These rules follow the ‘modularity principle’: that is, where processes influence the building’s environmental performance during its life cycle, they should be assigned to the module in the life cycle where they occur. The system boundary for new buildings should be defined according to EN 15978 and the different study types (screening, simplified or complete).
Rules from:

EN 15978

7.4.2–7.4.6 boundaries“The system boundary determines the unit processes that are taken into account for the object of assessment.For a new building, the system boundary shall include the whole life cycle.”
Guidance
The rules given in EN 15978 should be applied (see above). This covers the entire building life cycle as defined with regard to the study type used. The system boundaries include the entire building and its foundations, the building’s curtilage in the building’s site and connected exterior works. In addition, the study type’s definitions should be applied.

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