IEC 61508: Functional safety (generic, cross-industry)
IEC 61508 is the foundational international standard for achieving functional safety of electrical/electronic/programmable electronic (E/E/PE) safety‑related systems. It defines a risk‑based safety lifecycle, Safety Integrity Levels (SIL 1–4), and requirements spanning management, system/hardware, and software to reduce risks to an acceptable level.
It serves as the generic base for many sector standards (e.g., road vehicles, medical devices, process industry) and is often applied when no dedicated domain standard exists.
Scope and core concepts (at a glance)
- Risk‑based approach with target risk reduction expressed via SIL 1–4.
- End‑to‑end safety lifecycle from concept, hazard and risk analysis, allocation, development, integration, operation, maintenance to decommissioning.
- Requirements for management of functional safety, competence, independence, verification & validation, configuration and change management.
- Hardware topics: architectural constraints, diagnostic coverage, Safe Failure Fraction (SFF), Hardware Fault Tolerance (HFT), systematic capability.
- Software topics: software safety lifecycle, techniques/measures by SIL, verification, validation, tool qualification, proven‑in‑use.
Why it matters for qualities
- Primary qualities: safety, reliability.
- Supports operability and maintainability through lifecycle rigor, traceability, and change control.
Parts overview (very brief)
- Part 1: General requirements
- Part 2: Requirements for E/E/PE safety‑related systems (hardware/system)
- Part 3: Software requirements
- Part 4: Definitions and abbreviations
- Part 5: Examples of methods for the determination of safety integrity levels
- Part 6: Guidelines on the application of Parts 2 and 3
- Part 7: Overview of techniques and measures
Related standards
- ISO 26262 - Road vehicles — Functional safety — automotive derivative.
- IEC 62304 - Medical device software — software lifecycle for medical devices; often complemented by ISO 14971.
- IEC 61511 — Process industry sector derivative (SIS for process plants).
- IEC 62061 — Machinery sector derivative (functional safety of machinery control systems).
- IEC 62443 — Industrial automation and control systems security; complementary from a cybersecurity angle.