Abstract
The in- and outflows of expanded polystyrene (EPS) and extruded polystyrene (XPS) in the Norwegian residential and service building stock were estimated for the period from 1980 to 2050. Archetypes were selected to represent typical structures within each building type and age cohort. EPS and XPS material intensities were calculated based on construction details of relevant building components and assumptions about the presence of EPS and XPS in those components. Key findings include a comparison between model estimates and production data for EPS and XPS materials. Based on this comparison, a calibration of material intensities was carried out to improve the model's predictive accuracy, especially for future material flows. Material outflows resulting from demolition activities are significantly lower than inflows from new construction and renovation activities. Although material outflows have likely been somewhat underestimated, due to the exclusion of material outflows from renovation activities, the results indicate that future EPS/XPS demand in new construction and renovation cannot be met solely with recycled material from existing buildings. This also reflects the fact that large amounts of EPS/XPS were not introduced into the Norwegian building stock until after the 1980s. Therefore, it can be expected that material outflows will increase further in the future, which enhances the opportunities for circular use of EPS and XPS.