EN ISO 13849-1:2023

Overview

EN ISO 13849-1:2023 (identical to ISO 13849-1:2023) - "Safety of machinery - Safety‑related parts of control systems - Part 1: General principles for design" - defines a systematic methodology, requirements, recommendations and guidance for the design and integration of safety‑related parts of control systems (SRP/CS) that implement safety functions. The standard applies to SRP/CS in high‑demand and continuous modes of operation, across technologies and energy types (electrical, hydraulic, pneumatic, mechanical). It does not apply to low‑demand mode (see IEC 61508 series) and does not prescribe specific safety functions or mandated performance levels for particular machines.

Key Topics and Technical Requirements

• Safety requirements specification (SRS): identification, description and documentation of safety functions and their requirements.
• Determination of required performance level (PLr): process for deriving the performance level required for each safety function from risk assessment and risk reduction measures.
• Design and evaluation of SRP/CS architectures: categories and architectures, and how they relate to reliability parameters.
• Reliability metrics and analyses:
  • Mean Time to Dangerous Failure (MTTFD) for components and channels
  • Diagnostic coverage (DC) and its influence on achievable PL
  • Common cause failures (CCF) and measures to mitigate them
  • Systematic failure control and requirements for well‑tried components
• Combination of subsystems: methods to combine subsystem characteristics to achieve an overall PL for a safety function.
• Software safety: principles for software design, verification and restrictions on parameterization, including requirements for tools used for manual software parameterization.
• Documentation, review and validation: SRS review, verification and link to validation guidance (ISO 13849‑2).

Notes: The standard excludes detailed product/component design rules and specific cyber/IT security measures (security can affect safety; see ISO/TR 22100‑4, IEC/TR 63074).

Practical Applications and Who Uses It

• Primary users: machine designers, safety engineers, control system engineers, integrators, machine builders, notified bodies and conformity assessors.
• Typical applications:
  • Designing SRP/CS for industrial machinery (presses, conveyors, robotic cells, material‑handling systems) across electrical and fluid power systems.
  • Preparing SRS, selecting architectures and components to meet required PLs derived from risk assessments.
  • Establishing software safety practices and parameterization controls.
  • Demonstrating conformity with the EU Machinery Directive where applicable (Annex ZA relationship).

Related Standards

• ISO 13849-2 (Validation)
• ISO 12100 (Risk assessment and reduction)
• IEC 61508-3 (Software requirements for functional safety)
• IEC 62061 (Functional safety of safety‑related control systems)
• ISO 20607, IEC/IEEE 82079-1 (instructions and information for use)
• ISO/TR 22100-4, IEC/TR 63074 (security considerations affecting safety)

Keywords: EN ISO 13849-1:2023, ISO 13849-1, safety of machinery, SRP/CS, performance level, PL, safety requirements specification, machine safety.