Knowledge of the electromagnetic environment that exists at locations where electrical and electronic equipment and systems are intended to be operated is an essential precondition in the process of achieving electromagnetic compatibility. This knowledge can be obtained by various approaches@ including a site survey of an intended location@ the technical assessment of the equipment and system@ as well as the general literature. This part of IEC 61000 ?C introduces the concept of disturbance degrees and defines these for each electromagnetic phenomena@ ?C classifies into various location classes and describes them by means of attributes@ ?C provides background information on the different electromagnetic phenomena that may exist within the environment and ?C compiles tables of compatibility levels for electromagnetic phenomena that are considered to be relevant for those location classes. This part of IEC 61000 is intended for guidance for those who are in charge of considering and developing immunity requirements. It also gives basic guidance for the selection of immunity levels. The data are applicable to any item of electrical or electronic equipment@ subsystem or system that operates in one of the locations as considered in this document. NOTE 1 This document considers relevant electromagnetic phenomena when describing and classifying electromagnetic environments (except HEMP and HPEM which are covered in other IEC 61000-2 standards). It makes use of the specification of technologies@ of published data and of results from measurements. Not all electromagnetic phenomena considered here are described in detail in this document@ but rather in other documents of the IEC 61000-2 series from which the relevant information and data are taken and used in this document. For more detailed information about those phenomena the user is referred to this series. See also Annex F for an overview of the various parts of the IEC 61000-2 series. NOTE 2 It is noted that immunity requirements and immunity levels determined for items of equipment which are intended to be used at a certain location class are not inevitably bound to the electromagnetic environment present at the location@ but also to requirements of the equipment itself and the application in which it is used (e.g. when taking into account requirements regarding availability@ reliability or safety). These could lead to more stringent requirements with respect to immunity levels or with respect to applicable performance criteria. These levels can also be established for more general purposes such as in generic and product standards@ taking into account statistical and economic aspects as well as common experience in certain application fields. NOTE 3 Electromagnetic phenomena in general show a broad range of parameters and characteristics and hence cannot be related one-to-one to standardized immunity tests which basically reflect the impact of electromagnetic phenomena by a well described test setup. Nonetheless@ this document follows an approach to correlate electromagnetic phenomena and standardized immunity tests up to a certain extent. This might allow users of this document to partly take into account standardized immunity tests such as given for example in IEC 61000-4 (all parts)@ when specifying immunity requirements. The descriptions of electromagnetic environments in this document are predominantly generic ones@ taking into account the characteristics of the location classes under consideration. Hence@ it should be kept in mind that there might be locations for which a more specific description is required in order to conclude on immunity requirements applicable for those specific locations.