How to read the map

All four standards share the Annex SL high-level structure: a common clause numbering (4-10) and a common set of management-system requirements. The shared clauses (context, leadership, support, performance evaluation, improvement) are the integration opportunity — one set of policies, one management review cadence, one internal audit programme, one corrective action system can satisfy the requirements of all four standards simultaneously.

The standard-specific clauses (primarily within Clause 6 Planning and Clause 8 Operation) are where each standard's technical content sits. Environmental aspects analysis (14001), hazard identification (45001), and energy review (50001) are not interchangeable; each is the standard-specific substance that no integration approach can compress.

Where integration produces the most economic benefit

The economic case for integrated management system implementation rests on Clauses 4, 5, 7, 9, and 10 — the shared infrastructure. The cost of running four parallel management systems versus one integrated management system is meaningful at scale: four management reviews per year versus one; four internal audit programmes versus one integrated; four sets of competence and training records versus one. For organisations operating two or more of these standards, the integration argument is generally compelling at design time.

Where integration does not work

Integration does not save work in Clauses 6 and 8 where each standard's substantive technical content sits. Environmental aspects identification is not a shorter exercise because the organisation also identifies hazards; energy review is not a shorter exercise because the organisation also assesses quality risks. The substantive technical work has to be done for each standard. The integration savings are in the shared management-system infrastructure surrounding that technical work.

For deeper treatment

The Brookfield Properties case study (read here) shows the integrated ISO 14001 + ISO 45001 implementation pattern in operational detail.