Sebastian Wernli

As part of urban mining initiatives aimed at reducing waste, CO ₂ emissions and the extraction of raw materials, the demand for sustainable resource recovery and repurposing of construction materials is growing. With many European buildings due to be renovated to meet current energy standards, recovering insulating glass units (IGUs) presents a valuable opportunity to reclaim significant amounts of glass panes while reducing environmental impact of glass facades. However, the outer surfaces of IGUs are especially exposed to environmental influences, such as weathering and mechanical impacts, which may introduce surface defects or changes to the glass surface composition, such as corrosion. These phenomena may affect the processability and remanufacturing processes. This study evaluates the feasibility of producing laminated safety glass (LSG) from reclaimed insulating glass units (IGUs). First the surface roughness is analyzed to evaluate environmental exposure of the glass surfaces. Next, laminated glass, with a new PVB interlayer, is manufactured using two configurations of the glass surfaces, primarily with the reclaimed glass, to determine the effect of natural aging, positioning, and combinations on its adhesion performance tested under temperature and humidity conditions in accordance with EN ISO 12543-4, as well as under mechanical loads in the pummel tests. Comparative tests are also conducted with LSG made entirely from new glass. The results demonstrate the possibility of producing standard-compliant LSG from reclaimed float glass.

Advancing circular economy practices in the construction sector require the development of reuse and remanufacturing pathways for high-quality building materials such as architectural glass. This study investigates the technical feasibility of remanufacturing float glass reclaimed from insulating glass units (IGUs) through the application of functional coatings. Uncoated double IGUs were dismantled, and the reclaimed glass panes were reprocessed and coated with solar control layers using industrial-scale magnetron sputtering at a production site in Germany. The coated samples underwent various testing methods as part of the plant production control, assessing their optical, mechanical, and spectral properties in comparison with reference coatings applied to new float glass. The results demonstrate that reclaimed float glass can be successfully reintroduced into industrial coating lines, achieving comparable performance to conventional substrates. The paper presents experimental results and outlines the critical processing steps and conditions required for successful coating application. Furthermore, it discusses the technical challenges associated with remanufacturing at scale and provides a baseline for future studies aiming to define a set of criteria for successfully coating reclaimed glass substrates. The findings confirm the technical viability of this approach and highlight its potential to significantly reduce raw material demand, energy use, and embodied carbon in future closed-loop glass production systems.