International Standard IEC/ISO 81346 series "Industrial systems, installations and equipment and industrial products – structuring principles and reference designations" [1] defines the rules for reference designation systems (RDS). It is published as a double logo standard prepared by IEC technical committee 3: Information structures and elements, identification and marking principles, documentation and graphical symbols,[2] in cooperation with ISO technical committee 10: Technical product documentation. The 81346 series replaces the deprecated IEC 61346:1996.


  • Part 1: Basic rules (IEC 81346-1:2009) [3]
  • Part 2: Classification of objects and codes for classes (IEC 81346-2:2019) [4][5]
  • Part 10: Power Plants (ISO/TS 81346-10:2015, IDT) [6][7]
  • Part 12: Construction Works (ISO 81346-12:2018) [8]

Double Logo Standards

Future developments of the standards on reference designations will be made in cooperation between the IEC and the ISO and published as IEC 81346. (Standards developed in cooperation between IEC and ISO are assigned numbers in the 80000 series)

Preceding Standard

Preceding standard IEC 61346:1996 has been withdrawn and is replaced by IEC/ISO 81346.


81346-12 is also known as RDS-CW (Reference Designation System for Construction Works).[9] It is maintained by ISO Working Group ISO/TC10/SC10/WG10 [10] responsible for Reference Designation within ISO Process Plant Documentation sub committee SC10. RDS-CW has been designed as an international classification system that can be used by BIM[11][12] allowing for the prospect of integrating classification systems for construction works with classification systems for the Power sector (currently in revision in 81346-10[13]).

See also


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