This part of IEC 81346 establishes general principles for the structuring of systems including structuring of the information about systems. Based on these principles, rules and guidance are given for the formulation of unambiguous reference designations for objects in any system. The reference designation identifies objects for the purpose of correlating information about an object among different kinds of documents, and for labelling of components corresponding to the objects. The principles are general and are applicable to all technical areas. They can be used for systems based on different technologies or for systems combining several technologies.