When a contractor finishes a public building job in Germany, the client typically requires the Revisionsunterlagen: plans of the building as built, operating and maintenance instructions, test certificates and data sheets. The city of Mülheim an der Ruhr publishes its requirements for tenders. The documents must arrive at least three weeks before acceptance, in two paper copies and a digital copy. Their content muss einem unbeteiligten Dritten den störungsfreien Betrieb eines Gebäudes ermöglichen. It must allow an outside party who was not involved to run the building without disruption. If the documents are missing or incomplete, the city can refuse acceptance and hold back part of the final payment.