High Level Structure (Annex SL, Harmonized Structure)

Explanation

The High Level Structure is the common layout of ISO management system standards. It has ten clauses: scope, normative references and terms and definitions (1 to 3), followed by context of the organization, leadership, planning, support, operation, performance evaluation and improvement (4 to 10). Clause numbers, titles, core texts and core terms are the same. Each standard adds its own requirements, for example for environmental aspects or for involving workers.

ISO laid down the structure in 2012 in Annex SL of the ISO/IEC Directives. The name High Level Structure (HLS) is still common, but since the 2021 edition ISO has called it the Harmonized Structure. So anyone searching for HLS, Annex SL or Harmonized Structure means the same thing. ISO 9001, ISO 14001 and ISO 45001 follow the structure, as does ISO 22000 for food safety, for example.

The advantage is that you can build an integrated management system. Elements that recur in every standard, such as policy, objectives, control of documented information, internal audit, management review and corrective actions, you set up once. The structure matches the PDCA cycle: operation (8), performance evaluation (9) and improvement (10) correspond to Do, Check and Act.

A common structure does not mean common content. You still have to show per standard that you meet the requirements, and whether one audit covers several standards is something you agree with your certification body. You also do not have to arrange your own documentation by the clauses, but you must be able to show per clause where the evidence is. Standards are revised, so check which edition applies to your certificate.

Example from practice