13849IEC

IEC 13849-1, also known in practice as ISO 13849-1, is an international standard for the safety of machinery focusing on safety-related parts of control systems (SRP/CS). Published by the International Electrotechnical Commission, it provides a framework for designing, integrating, and validating the safety functions implemented by electrical, electronic, and programmable electronic systems that protect against machine hazards. The standard covers the full lifecycle of safety-related control systems, from initial risk assessment and concept development to design, installation, verification, and ongoing operation.

A central concept in IEC 13849-1 is the Performance Level (PL), designated from a to e, which expresses the capability of a safety-related control system to perform its protective function under fault conditions. The required PL is determined by a risk assessment and influences architectural choices and the degree of diagnostic coverage, redundancy, and safe-state behavior. The standard promotes general design principles such as fault avoidance, fault detection, safe failures, and simple, verifiable architectures to achieve the desired PL.

IEC 13849-1 is frequently used in conjunction with other safety standards. It is often aligned with IEC 62061, which uses Safety Integrity Levels (SIL) for functional safety, and with IEC 13849-2, which addresses validation and partial proof testing of SRP/CS. The standard is widely cited in regulatory contexts, particularly in European machinery safety compliance under the Machinery Directive, and serves as a common reference for documenting the safety performance of control systems in industrial automation.

Limitations include that PL is a design objective derived from risk assessment rather than a direct reliability claim, requiring careful interpretation and rigorous verification to avoid misapplication. The standard has undergone revisions to reflect evolving technology and risk assessment practices, maintaining its role as a foundational reference in machinery safety.