B-30 Transport of the users of the building

Aspect B-30 Transport of the users of the building
For building LCA, the environmental impacts of transportation of people during the use stage may influence the decision between alternative construction sites (e.g. is the building located near public transport services?), or between alternative projects for the same site. Generally speaking, if the transport of building occupants is included within the system boundaries,  it can have a significant impact on the results of the use stage. However, it is not always relevant for inclusion in LCA studies.When and how should the transport of people be included for building LCA?

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 The transport of people may be taken into account if it is relevant for the goal and scope of the building LCA study (e.g. during the early design of a building, when a construction site needs to be chosen). If included, all relevant results should be documented separately, and the results should be subject to sensitivity analyses.
Rules from:

EN 15978

No provisions
Generally speaking, when LCA is used during the design process of a building, this aspect is not relevant when the construction site has already been defined. Conversely, in the early design stages of the building project, assessment of the transport of people may be relevant if the goal and scope is to assess different options for the construction site (e.g. choosing between a site in the suburbs, in the countryside or in the city centre). In this case, the share of this aspect in building LCA results may be significant.In specific cases during the stages of the building project, this aspect may also be included if LCA practitioner needs to focus on it (e.g. for assessment in urban structures, or in large retail buildings).If the transport of people is included, the practitioner should identify the key parameters to calculate this contributor outside the scope of the EN 15978 standard, or otherwise use existing calculation rules within the building LCA software used. Such parameters may include:

  • the type of building (e.g. detached houses or office buildings);
  • the location of the building (e.g. in the countryside, in the suburbs, or in the city centre);
  • the number of people who commute to the workplace every working day, and for other activities if relevant (e.g. shopping, leisure etc.);
  • the mode of transport (e.g. bicycle, public transport including tramway, trains, autobus, individual car etc.);
  • the transportation distances between the building site and the workplace, and the distances from the public transport network.

Assessment of the transport of people then needs both default values and scenarios to be defined, particularly for:

  • the different modes of transport (e.g. bicycle, public transport including tramway, trains, autobus or individual car);
  • the transportation distances (e.g. below 10 km, between 10 and 100 km etc.) and the respective fuel consumption (if relevant);
  • the number of people in the building.

The LCA data on transportation processes should be taken from existing generic LCA databases (e.g. Ecoinvent, ELCD, ESUCO). The reference flow of the functional unit of the generic data of transportation processes is generally expressed as tons*km or persons*km. The data usually include a default scenario for fuel consumption and the average load (e.g. an average load of 2.5 persons in a car with a maximum capacity of 5 persons can be assumed in some generic LCA data). As the load factor may influence the results, a sensitivity analysis is needed on this parameter if the corresponding mode of transport significantly influences the results.

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