ISA/IEC 62443-2-1 clearly recommends that the IACS Security Program (SP) be fully embedded into existing organizational processes, including alignment with the Information Security Management System (ISMS), if present.

“The IACS security program shall be integrated with the organization's overall management systems and processes, including those defined in the ISMS (e.g., ISO/IEC 27001).”

— ISA/IEC 62443-2-1:2010, Clause 4.2.1 – Integration of Security Program

This ensures that security is a sustained operational priority and not a separate or siloed initiative.