This document establishes a procedure for the assessment of particle cleanliness levels on solid surfaces in cleanrooms and associated controlled environment applications. Recommendations on testing and measuring methods, as well as information about surface characteristics, are given in Annexes A to D. This document applies to all solid surfaces in cleanrooms and associated controlled environments, such as walls, ceilings, floors, working environments, tools, equipment and products. The procedure for the assessment of surface cleanliness by particle concentration (SCP) is limited to particles of between 0,05 µm and 500 µm. The following issues are not considered in this document: — requirements for the cleanliness and suitability of surfaces for specific processes; — procedures for the cleaning of surfaces; — material characteristics; — references to interactive bonding forces or generation processes that are usually time-dependent and process-dependent; — selection and use of statistical methods for assessment and testing; — other characteristics of particles, such as electrostatic charge, ionic charges and microbiological state.