the building complex of the Faculty of Economics and Social Sciences, the University of Cologne is facing the challenges typical of the building stock of the 1950s: energy efficiency, fire protection and [...] stage. The choice of window profiles proved to be a challenge: they had to have particularly narrow face widths in order to preserve the appearance of the façade, but also had to accommodate the considerable [...] profile system forms the basis of the window frames. Thanks to the high rigidity of the material, the face widths of the new 70 mm pivot horizontally pivoted windows are particularly slim. Special light-deflecting