IEC 61511
IEC 61511 — Functional Safety for the Process Industry
IEC 61511 — Funktionale Sicherheit der Prozessindustrie
IEC 61511 is the application of the base standard IEC 61508 — Functional Safety of E/E/PE Systems (IEC 61508) to the process industry, governing safety-related systems there — so-called Safety Instrumented Systems (SIS). Such systems automatically bring a plant into a safe state when danger threatens, for instance via emergency shutdown. They are the last technical line of defence in chemical, petrochemical and comparable plants.
History & facts. IEC 61511 addresses planners, integrators and operators of process plants and details the safety lifecycle for Safety Instrumented System (SIS): from hazard analysis through determining the required safety integrity to testing, operation and periodic proof testing. An SIS is deliberately separated from the normal process control system so that it works even when the control fails.
Outlook & recommendation. Notable was the attack by malware that deliberately targeted such safety systems, thereby crossing the line between cyberattack and physical endangerment. The lesson: an Safety Instrumented System (SIS) is only a reliable last line if it is also protected against manipulation and monitored. Safety without security is a deceptive sense of security in connected plants.