Overview
ISO 14119:2013 - Safety of machinery - Interlocking devices associated with guards - Principles for design and selection - provides principles for designing and selecting interlocking devices used with machine guards. The standard is independent of energy source and covers the parts of guards that actuate interlocking devices. Its primary aim is to ensure that interlocking solutions reliably prevent access to hazardous machine functions and to minimize the possibility of defeat in a reasonably foreseeable manner.
Key topics and technical requirements
- Scope and definitions: Clarifies terms such as interlocking device, interlocking guard, guard locking device, and safety‑related part of a control system (SRP/CS).
- Types of interlocking devices: The standard defines four types of interlocks and provides informative annexes describing their typical characteristics and technologies.
- Design and installation: Requirements for arrangement and fastening of position switches and actuators, actuation modes, mechanical stops and environmental considerations.
- Guard locking: Principles for interlocking with and without guard locking, and additional requirements where guards must be locked for the duration of a hazard.
- Selection guidance: Criteria for selecting appropriate interlocking devices, including guard locking devices and consideration of environmental conditions.
- Measures against defeat: Guidance to identify and reduce means and motivations to defeat interlocks (e.g., procedural, physical, and design measures).
- Control and safety function integration: Requirements for interfaces to control systems, assessment of faults, prevention of common‑cause failures, release behaviour of guard locks, fault exclusion and logical series connection of interlocks.
- Information for use: Manufacturer and machine builder responsibilities for documentation, marking and instructions.
- Informative annexes: Examples, application cases (including interlocks used within a safety function), trapped key systems considerations and motivation to defeat.
Practical applications and who uses ISO 14119
ISO 14119 is used by:
- Machine designers and manufacturers to select and apply appropriate interlocking solutions on presses, robots, conveyors, packaging lines and other industrial equipment.
- Safety engineers and integrators when implementing SRP/CS and aligning interlocks with functional safety requirements.
- Standards writers and conformity assessors for developing type‑C machine standards or verifying interlock suitability.
- Maintenance and operational staff for safe guarding practices and documentation.
Typical applications include interlocked access doors, removable guards, hinged covers, trapped‑key systems and guard locking solutions where preventing unintended restart or access is critical.
Related standards (normative references)
Keywords: ISO 14119, interlocking devices, safety of machinery, guard locking, trapped key, design and selection, minimize defeat, machine guards.
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