In modern information society, data centres are the control and storage centres for the electronic data exchange. The ever-growing performance requirements for data centres as well as the unlimited growth of their energy demand call for approved technical specifications that enable the planner and the operator to plan, expand and operate a data centre according to the state of the art in a future-proof manner. This includes requirements for the availability of the services of the data centre, its energy efficiency and economic aspects, amongst others. Of cause there are quite a few standards for the components and subsystems used in data centres (for example, for uninterrupted power supply), a standard suitable for the European market for the design, planning, procurement, integration, installations, operation and maintenance of facilities and infrastructures within data centres has so far been missing. Upon German request CENELEC/TC 215 "Electrotechnical aspects of telecommunication equipment" decided to prepare the series of the European Standards EN 50600. This Part 1 a) describes the individual topics which shall be dealt with during an analysis of the business risk and the running costs in order to allow the application of a suitable classification of the data centre; b) defines the common aspects of data centres including the terminology, the parameters and reference models (functional elements and their accommodation), by considering both the size and the complexity of the intended use; c) describes the general aspects of the facilities and infrastructures necessary for the support of the effective operation of the telecommunication in data centres; d) specifies a classification system for the provision of effective facilities and infrastructures based on the central criteria "availability" "operational reliability" and "energy efficiency" during the planned operating time of the data centre; e) describes the general principles for the design of data centres on which the requirements of the standards of the series EN 50600 are based, including symbols, labels, coding in plans, quality assurance and training. This standard has been prepared under mandate M/462 "Standardisation in the field of ICT to enable efficient energy use in fixed and mobile information and communication networks" given to CENELEC by the European Commission and the European Free Trade Association. The responsible committee is Joint Subcommittee DKE/GUK 715.3 "Informationstechnische Verkabelung von Gebäudekomplexen" ("Customer premises cabling") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.