This document is applicable to safety-related components and systems of nuclear facilities whose surface condition (inner and outer surfaces) may cause material damage and malfunctions with regard to cleanliness. It is also applicable to components and systems whose failure can be assumed to result in the release of radioactive substances. The scope of application includes all stages of design, fabrication, handling, assembly, repair and testing of the above mentioned equipment, including decontaminated components. In this document, the following three levels of cleanliness are defined for achieving and maintaining surface cleanliness three cleanliness levels for cleanliness areas, symbols for marking these cleanliness levels, and general rules are given for this purpose. This document also contains specifications for packaging, transport, storage, cleaning and preservation of components. Suitable detection methods and detection limits for some impurities harmful to the material as well as some requirements for test aids and cleaning agents are summarized in Annex A, Annex B, Annex C and Annex D. This document is not applicable to fuel assemblies.