5 Circular Economy in Relation to LCA

Circular economy principles are becoming increasingly important in the building sector, especially with the growing pressure to reduce environmental impacts and resource consumption. When a building is assessed through LCA, circular strategies such as reuse, recycle, and rethink present both opportunities and challenges due to the limitations of current regulatory frameworks and available data.

Reuse of materials is an effective way to reduce the climate impact of a building. Danish LCA legislation encourages reuse by allowing directly reused materials to be calculated with a climate impact of 0 through the entire consideration period of the building. However, this presumes proper documentation and traceability, which can potentially be a barrier in practice.

Recycling presents a more complex picture. While recycled materials can also reduce climate impacts compared to virgin production, the benefit is highly dependent on the specific product. Unlike reuse, BR18 provides no benefit for using recycled materials. Unless the specific product using recycled material is documented by an EPD, BR18 mandates that the recycled material be modelled as new. This, combined with the often higher cost, can discourage the use of recycled material and buildings.

Rethink includes broader design strategies such as designing for disassembly, robustness, maintenance and repair. These approaches aim to extend the lifespan of the entire building or the individual materials of the building. Unfortunately, these efforts are often not reflected in the LCA results due to limitations in the BR18 LCA methodology. Since module C1 (deconstruction), is not included in a BR18 LCA, there is no reward in designing for disassembly in the current legislation. Design for disassembly would also make it easier to reuse materials in a new project. This, however, is also not rewarded in current legislation. Similarly, robust design may extend component’s lifespan well beyond 50 years, but since the BR18 LCA is limited to a standard consideration period of 50 years, there is no reward in creating a building that can last more than 50 years. Lastly, maintenance and repair activities are included in the B2 and B3 modules, which are also excluded in the BR18 LCA minimum requirements, despite their relevance in the real-world context. This means that choosing a material with a low impact in the product and end-of-life phases will often be beneficial to the LCA calculation, even if the required maintenance and repair results in the actual climate impact being larger.