The series of guidelines VDI 3810 gives recommendations for the various building services and trades regarding safe, specified, demand-oriented and sustainable operation. The guidelines describe the prerequisites for fulfilling the operataor's obligations, safe operation of installations, economic efficiency and environmental compatiblity. Furthermore, they contain practical recommendations for operating and maintaining building-services installations. Installation owners and operators are obliged to operate installations in accordance with the ackn owledged rules of technology or state of the art, depending on the object in question.