In 2001, two vocational schools decided to erect a new campus on the grounds of an abandoned coal mine. In addition to the separate classroom buildings – for 4500 pupils and 200 teachers – the ensemble also boasts a gymnasium with 5 courts and a power plant utilizing coal-mine methane. Both classroom buildings have double-skin glass facades with storey-high panes of toughened glass – this outer layer of the naturally ventilated buffer zone protects the fixed glazing in oak post-and-rail fenestration from vandalism and weathering. The operable sashes serve as smoke vents and allow access for maintenance: controlled ventilation with heat recovery is integrated in the tempered ceiling decks.