61508

IEC 61508 is an international standard published by the International Electrotechnical Commission (IEC) that provides a framework for the functional safety of electrical, electronic, and programmable electronic safety-related systems. First issued in 1998 and subsequently revised, it establishes a lifecycle approach to safety management and system development across industries.

A central concept is the safety lifecycle, which covers stages from concept and hazard analysis through specification, design, implementation, verification, validation, operation, maintenance, and eventual modification or decommissioning. The standard also introduces safety integrity levels (SILs), a graded scale used to specify the required risk reduction for safety functions. SILs range from 1 to 4, with higher levels demanding greater reliability, more rigorous evidence, and more stringent development processes.

IEC 61508 addresses both hardware and software aspects, as well as organizational and management elements needed to achieve functional safety. It requires risk assessment and hazard analysis to determine safety requirements, as well as architecture design, verification, validation, and documentation to prove compliance with the specified SILs. Diagnostics, fault tolerance, and independence of safety-related functions from non-safety operations are often emphasized in implementation.

Industry impact and derivatives: IEC 61508 serves as the foundational framework for sector-specific standards, including IEC 61511 for the process industry, IEC 62061 for machinery safety, and ISO 26262 for automotive functional safety, among others. Many regulatory bodies reference 61508 as a baseline for functional safety practices, certification, and engineering processes.

Overall, IEC 61508 provides a comprehensive, risk-based approach to ensuring functional safety in complex electrical, electronic, and programmable systems.