Circularity indicators for LCA assessment method
The Dutch foundation for quality in construction (‘Stichting Bouwkwaliteit’) and the consultancy and engineering firms Witteveen+Bos and LBP|SIGHT are currently investigating potential performance-based indicators for expressing the circularity of a building or structure on a project.
In the Netherlands, an assessment method (‘Bepalingsmethode Milieuprestatie Gebouwen en GWW-werken’) sets out the rules and agreements for determining the environmental performance of buildings and civil engineering works using the LCA methodology. Calculation tools such as DuboCalc and GPR perform calculations based on these rules and agreements and are populated with LCA data on materials and products from the National Environmental Database (NMD). The entire system is illustrated in the figure below.
Following the implementation of the results of the raw material efficiency study, since 1 January 2019 the assessment method determines environmental impact in terms of value preservation. In the near future, value measurements for indicators will need to be developed. From 1 July 2019, new calculation rules for the modular Environmental Cost Indicator (ECI) and the MPG will also take effect.
The current study therefore focuses primarily on:
- indicators which quantify and value the technical aspects of a circular building or civil engineering work as an entity, based on the assessment method;
- indicators which express the degree of recycled materials (in or related to the assessment method) in performance-based terms;
- indicators which express demountability/disconnectability (in or related to the assessment method) in performance-based terms.
This project is in line with the government’s formal response to the construction industry transition agenda, aimed at moving towards a circular economy. This response – ‘Kabinetsreactie op de Transitieagenda Bouw’ – indicates that the current LCA methodology is a sound basis for determining environmental performance.
As part of the process, relevant market and chain parties are being consulted and are actively involved in defining the indicators that should be included in the assessment method – for example, the ‘degree of demountability’ or ‘percentage of reusable materials’.
These indicators will then be used to describe the extent to which the system’s structure (see figure) is effective in determining the circularity of a building or civil engineering structure as at 2019.
Finally, an exercise will be conducted using case examples of both buildings and civil engineering structures in which the indicators are measured for the intended circular adaptations. This will take into account the limits desired for each indicator so as to make the best possible contribution to a circular economy.
