What is BS EN ISO 14119:2025 – Interlocking devices for design and selection about?
To improve the safety of machinery, BS EN ISO 14119:2025 gives guidance on how to design and select interlocking devices for use with machine guards. Interlocking devices – whether mechanical, electrical, or something else – stop the hazardous parts of machines from working under specified conditions – usually when the guard isn’t closed.
Who is BS EN ISO 14119:2025 – Interlocking devices for design and selection for?
- machine manufacturers (small, medium and large enterprises)
- health and safety bodies (regulators, accident prevention organizations, market surveillance)
- machine users/employers (small, medium and large enterprises)
- machine users/employees (e.g. trade unions, organizations for people with special needs)
- service providers, e. g. for maintenance (small, medium and large enterprises)
- consumers (in case of machinery intended for use by consumers).
What does BS EN ISO 14119:2025 – Interlocking devices for design and selection cover?
BS EN ISO 14119:2025 specifies principles for the design and selection — independent of the nature of the energy source — of interlocking devices associated with guards, and provides guidance on measures to minimize the possibility of defeat of interlocking devices in a reasonably foreseeable manner.
- the parts of the guards that actuate interlocking devices
- trapped key interlocking devices and systems for machinery applications.
NOTE: BS EN ISO 14119:2025 is a Type-B2 international standard – meaning that it’s a generic safety standard that deals with one type of safeguard that can be used across a wide range of machinery and that its requirements can be supplemented or modified by a Type-C standard.
Why should you use BS EN ISO 14119:2025 – Interlocking devices for design and selection?
- It’s about safety. BS EN ISO 14119:2025 provides guidelines that help promote a safer working environment, which is essential to employee well-being. It also gives employers a reliable framework with which to ensure safe working conditions.
- It’s about checking. Relevant clauses of BS EN ISO 14119:2025, used alone or in conjunction with provisions from other standards, can be used to verify the suitability of a device for interlocking duties.
- It’s current. This revised version of BS EN ISO 14119:2025 reflects the latest international thinking and technology in this space.
- It can help you improve design efficiency. It strips out doubt about what is the correct interlocking device and can help streamline other decisions in the design phase.
- It strengthens risk management. It helps machine manufacturers to treat the risk that the machinery they produce won’t meet essential health and safety requirements.
What’s new about BS EN ISO 14119:2025?
BS EN ISO 14119:2025 is a revision of the previous (2nd) edition – BS EN ISO 14119:2013. The main changes in comparison are:
- ISO/TS 19837 has been integrated as the new Annex K with specific requirements for Type 5 interlocking devices – trapped key interlocking devices.
- Trapped key interlocking systems and type 5 interlocking devices have been defined.
- Table 5 has been improved and renamed.
- Test procedures are described in the new Annex I Test Procedures, which describes a locking force test and an impact resistance test for guard-locking devices.
- ISO/TR 24119 has been integrated into new Annex J, which provides information on the masking of faults in series connection of interlocking devices with potential free contacts.

