Initial situation

The BNB criteria specification 4.1.4 "Deconstruction, separation, recycling" (BNB 4.1.4) aims to optimise buildings as early as the planning process so that they make an optimal contribution to the recycling of building materials at the end of their life cycle and leave behind as little non-recyclable waste as possible. In the currently valid version of the criteria specification (2015 version), the buildings are assessed using a component approach according to the costs for dismantling and separation and the recycling potential of the component layers. Pre-assessed example components are provided in the associated assessment tool, which the auditors use for self-assessment of the structures to be assessed. The self-assessment is then verified by the conformity body using the dual control principle.

Aim

With the help of the research project, the assessment in BNB 4.1.4 is to be converted to a calculable, scientifically based assessment system.
The assessment procedure should
   minimise the loss when dismantling the structure,
   the highest possible utilisation of the circularity potential of the building materials used and
   the use of reusable or recyclable building materials, elements and components.
   promote the use of reusable or recyclable building materials, elements and components.

In addition to the life cycle assessment, the assessment system is intended to provide a technical categorisation of the circular qualities of the materials and structures used in the construction of buildings. The agreed findings were converted into an applicable form of a BNB criteria specification and integrated into the BNB system.

It is planned to extend the web-based LCA component editor (eLCA) with a module for BNB 4.1.4. To this end, a specification for programming services in eLCA was created. The derived assessment method was tested on reference components and example buildings.