The Nordic Countries are among the most Active Users of BIM in Europe
All Nordic countries and Estonia use BIM authoring tools, such as ArchiCAD and Revit, for architectural modelling and, e.g., Tekla Structures or Revit for modelling structures. These software allow the export of IFC, which is an established way of exchanging information in construction projects. IFC supports the BIM-based building LCA process in a software-independent way.
Many countries have BIM guidelines and requirements to support modelling in general, but the guidelines and requirements are rarely national nor mandatory. In addition, the guidelines rarely support BIM modelling specifically for normative (obligatory) building LCA.
The Challenges and Benefits for Harmonising Building LCA Reporting in the Nordics
The Nordic countries have developed country-specific normative carbon footprint assessment methods based on EN15978 and EU Level(s) methods. Denmark, Norway and Sweden already have normative LCA calculation demands for new buildings, whereas Estonia, Finland and Iceland plan to start requiring it soon.
There are differences between the country-specific methods concerning methodology aspects, such as system boundaries, life cycle scenarios and reporting requirements. To some extent, these differences prevent the harmonisation of building LCA reporting in the Nordics.
Common methodologies would help create a common market for low-carbon buildings and products and thus help boost decarbonisation efforts in the whole area.
Harmonising BIM-Based LCA Calculations
BIM software can help low-carbon building design by supporting the comparison of alternative design choices in the initial design phases through different design disciplines. In this way, BIM software supports finding optimal solutions.
Currently, the naming conventions and classifications for materials and structures are national, and the maturity and usage of those vary by country. Also, the naming conventions in BIM modelling and emission databases are not aligned.
Therefore, BIM modelling and LCA methods must be evaluated and further aligned to harmonise BIM-based building LCA.
BIM can provide information on the materials and geometry depending on the level of detail in the model when the calculation is made. It is important to ensure that elements in the model are classified harmoniously.
Although standards exist, these are not always adopted by the various actors within the construction industry. The models of the various design disciplines – structural, architectural, and HVAC – should also be harmonised, especially as duplicate elements exist between the models.
Current Challenges with BIM-Based Building LCA Process
A BIM-based LCA necessitates the technical integration of product data – product ID and quantity – and emission data in the right format. BIM tools are widely used in the architecture and construction industry, but their seamless integration with LCA tools is still a work in progress. Inaccuracy in quantity take-off is an issue as the information content and identification of objects and materials in BIMs are not standardised.
In the future, BIM can partly support the automation of building LCA calculation and reporting. The calculation of product-related emissions (product quantities from BIM) is only part of the carbon footprint of a building. For example, information on energy consumption during use and energy sources is also needed to include the emissions caused by them. These data are not retrieved from BIM.
Read the report on operating environment of building LCA and BIM in the Nordics and Estonia here