IEC 61508
IEC 61508 — Functional Safety of E/E/PE Systems
IEC 61508 — Funktionale Sicherheit elektrischer/elektronischer Systeme
IEC 61508 is the overarching base standard for functional safety of electrical, electronic and programmable electronic systems. It defines how safety-related functions are designed such that a dangerous failure becomes sufficiently improbable — quantified via Safety Integrity Levels (SIL 1-4). It is the root from which numerous sector-specific safety standards are derived.
History & facts. IEC 61508 established a lifecycle-oriented approach: from hazard and risk analysis through determining the required SIL to development, operation and decommissioning, functional safety is understood as an end-to-end process. It primarily considers whether a system transitions into a safe state in the event of random or systematic faults — classic safety, not security.
Outlook & recommendation. The historical separation of safety (protection against malfunction) and security (protection against attack) is blurring: a compromised control system can deliberately disable a safety function. This is precisely where IEC 62443 (security) and the safety-oriented standards interlock. For operators of critical processes, integrated thinking across both worlds is indispensable today.