Following a simplified understanding of a building’s life cycle, the reference study period can be seen as the timespan of use, i.e. the duration of services within Module B. Hence the reference study period has a significant impact on the use stage’s contribution to the life cycle impacts. This means that the reference study period influences the relation of impacts from the different life cycle stages, and thus may cause different conclusions to be drawn regarding the importance of a life cycle stage.
The following table provides definitions for reference study periods from various sources. These definitions are not based on scientifically proved lifetimes, but usually reflect a consensus, e.g. within one country.
|Germany: building certification (DGNB)||50 years||Default reference study period for all building types except for industrial buildings|
|Germany: building certification (DGNB)||20 years||Reference study period for industrial buildings|
|Germany: building assessment (federal government)||30 years, 80 years||Alternative values for scenario analyses|
|France||50 years, 100 years||Commonly used reference study periods; no general definition available|
Other default values