ISO 13849-1-2023 PDF

Full title and description

ISO 13849-1:2023 — Safety of machinery — Safety-related parts of control systems — Part 1: General principles for design. Edition 4 (April 2023). This international standard specifies a methodology, requirements, recommendations and guidance for the design and integration of safety‑related parts of control systems (SRP/CS) that perform safety functions, including aspects of software design for SRP/CS.

Abstract

ISO 13849-1:2023 provides a structured approach to determine and achieve the required risk‑reduction performance of SRP/CS for high‑demand and continuous modes of operation. The standard describes how to identify safety functions, allocate risk‑reduction performance, select appropriate architectures and technologies, evaluate reliability (MTTFd, PFH), diagnostic coverage and common‑cause failure measures, and validate the SRP/CS design. It explicitly excludes low‑demand mode of operation (for which IEC 61508 and related guidance apply) and does not itself prescribe the safety functions or PLr values for specific machines.

General information

• Status: Published (International Standard).
• Publication date: April 2023 (Edition 4).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 13.110 (Safety of machinery).
• Edition / version: Edition 4 (2023).
• Number of pages: 152 pages.

(General information above is taken from the ISO bibliographic entry for ISO 13849-1:2023.)

Scope

Applies to safety‑related parts of control systems (SRP/CS) and their subsystems that perform safety functions in high‑demand and continuous modes of operation, irrespective of technology or energy type (electrical, hydraulic, pneumatic, mechanical, etc.). The standard does not apply to low‑demand mode of operation, does not itself specify the safety functions or required Performance Levels (PLr) for particular applications, and does not give product‑specific design requirements for components (these are covered by separate ISO/IEC product standards). The standard also does not provide specific security measures, although it notes the potential interaction between security and safety.

Key topics and requirements

• Definition and scope of SRP/CS: where safety‑related inputs start and safety outputs end; boundaries for SRP/CS design and assessment.
• Risk‑based determination of required Performance Level (PLr) for each safety function and allocation of risk‑reduction across system elements.
• Architectural categories, redundancy, diagnostics and measures to limit common‑cause failures (concepts such as Categories, MTTFd, DCavg and PFHd).
• Guidance for design of programmable and non‑programmable elements, including software design considerations for SRP/CS.
• Requirements for verification and validation of safety functions and the SRP/CS (see also Part 2 / validation guidance).
• Documentation, practical calculation methods and examples for assessing reliability and diagnostic effectiveness.

Typical use and users

Primary users are machine builders, control system designers, safety engineers, system integrators, notified bodies and conformity assessment organizations, and occupational safety regulators. The standard is used when designing, assessing or validating safety functions implemented by control systems on industrial machinery, production lines, mobile machinery and similar equipment where SRP/CS must achieve specified risk‑reduction performance.

Related standards

Key related documents and standards referenced by ISO 13849-1:2023 include IEC 61508 (functional safety of E/E/PE safety‑related systems, referenced for low‑demand operation and programmable safety aspects), ISO/TR 22100‑4 and IEC/TR 63074 (security aspects that can affect safety), ISO 12100 (risk assessment principles), and ISO 13849‑2 / DIS updates for validation and application guidance. National/adopted versions (EN ISO 13849‑1) and product/component standards (for sensors, actuators, safety relays, PLCs) are also commonly used alongside ISO 13849‑1.

Keywords

Safety of machinery; SRP/CS; safety‑related parts of control systems; Performance Level (PL); PLr; MTTFd; PFHd; DCavg (diagnostic coverage); categories/architecture; validation; functional safety; risk reduction; ISO 13849; machine safety.

FAQ

Q: What is this standard?

A: ISO 13849-1:2023 is an international standard that defines principles and a methodology for designing and integrating safety‑related parts of control systems (SRP/CS) to achieve required risk‑reduction performance for safety functions.

Q: What does it cover?

A: It covers identification of safety functions, allocation of required Performance Levels (PLr), selection of architectures and components, assessment of reliability (MTTFd, PFHd), diagnostic coverage and measures for common‑cause failures, software considerations for SRP/CS, and guidance for verification/validation. It applies to high‑demand and continuous modes of operation and excludes low‑demand operation (IEC 61508 guidance applies there).

Q: Who typically uses it?

A: Machine manufacturers, control‑system designers, safety and reliability engineers, system integrators, testing/inspection bodies, and regulators use this standard when designing, assessing or validating safety functions implemented by machine control systems.

Q: Is it current or superseded?

A: Current — ISO 13849-1:2023 (Edition 4) was published in April 2023 and supersedes the previous ISO 13849-1:2015 edition.

Q: Is it part of a series?

A: Yes. ISO 13849-1 is part of the ISO 13849 series addressing safety‑related parts of control systems; Part 2 covers validation and application guidance (ISO 13849‑2 and subsequent DIS/updates). It is also commonly used together with IEC 61508 and other ISO/IEC guidance documents.

Q: What are the key keywords?

A: SRP/CS, Performance Level (PL), PLr, MTTFd, PFHd, diagnostic coverage (DCavg), categories, redundancy, validation, functional safety, machine safety.