Defines the requirements for the use of ISO/IEC 27001 in any specific sector (field, application area or market sector). It explains how to include requirements additional to those in ISO/IEC 27001, how to refine any of the ISO/IEC 27001 requirements, and how to include controls or control sets in addition to ISO/IEC 27001:2013, Annex A. It ensures that additional or refined requirements are not in conflict with the requirements in ISO/IEC 27001. It is applicable to those involved in producing sector-specific standards that relate to ISO/IEC 27001.