ISO 14119:2024

Overview

ISO 14119:2024 - Safety of machinery - Interlocking devices associated with guards - Principles for design and selection is the third edition of the international standard that sets out principles for the design, selection and application of interlocking devices associated with machine guards. The standard applies independent of the energy source and covers: parts of guards that actuate interlocks, trapped key interlocking systems, and guidance to minimize the possibility of defeat of interlocks in reasonably foreseeable situations. ISO 14119:2024 complements guard design (ISO 14120) and control-system safety standards (ISO 14118, ISO 13849-1, IEC 62061).

Key topics and technical requirements

• Types and operating principles of interlocking devices associated with guards (including examples for Type 1 through Type 5 devices).
• Design and arrangement requirements for position switches, actuators, cams, fastening and mechanical stops.
• Guard-locking and access-locking considerations: principles for guard locking, locking force, electromechanical and electromagnetic lock behaviour, and whole-body access.
• Supplementary releases and escape/auxiliary/emergency release measures for locked guards.
• Selection criteria: response time, access time, environmental influences (e.g., dust), and trapped key system considerations.
• Defeat minimization: system design, methodology to reduce motivation and likelihood of defeating interlocks, key retention and key reproduction controls for Type 5 devices.
• Control system requirements: fault assessment and exclusions, prevention of common-cause failures, series connection effects, electrical/environmental operating conditions, and immunity from disturbance.
• Information for use: marking and manufacturer instructions required for safe application.
• Normative and informative annexes: test procedures, evaluation methods, practical examples, trapped key system details and bibliography.

Practical applications and who uses it

ISO 14119:2024 is intended for professionals responsible for machine safety and guarding, including:

• Machine designers and OEMs specifying interlocking devices and guard arrangements
• Safety engineers and risk assessors evaluating access controls and guard locking
• Maintenance managers and plant safety officers implementing safe access procedures
• Compliance officers and certification bodies assessing conformity with machine safety requirements

Typical applications include: selecting interlocks for conveyor guards, safety doors, access hatches, isolation procedures using trapped key systems, and integrating guard interlocks into functional safety architectures.

Related standards

• ISO 14120 - Guards - General requirements for design and construction
• ISO 14118 - Prevention of unexpected start-up
• ISO 13849-1 - Safety-related parts of control systems (performance levels)
• IEC 62061 - Functional safety of electrical control systems for machinery

Keywords: ISO 14119, interlocking devices, guard locking, trapped key interlocking, machine safety, design and selection, safety of machinery.