Safety of machinery - Interlocking devices associated with guards - Principles for design and selection (ISO 14119:2024)

This document 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.
This document covers principles for the design, selection and application of the following:
—     parts of the guards which actuate interlocking devices;
—     trapped key interlocking devices and systems for machinery applications.
NOTE            ISO 14120 specifies general requirements for the design and construction of guards provided primarily to protect persons from mechanical hazards. The processing of the signal from the interlocking device to stop the machine and prevent unexpected start up is covered in ISO 14118, ISO 13849-1 and IEC 62061.

Sicherheit von Maschinen - Verriegelungseinrichtungen in Verbindung mit trennenden Schutzeinrichtungen - Leitsätze für Gestaltung und Auswahl (ISO 14119:2024)

-Dieses Dokument legt die Grundsätze für die Gestaltung und Auswahl (unabhängig von der Art der Energiequelle) von Verriegelungseinrichtungen in Verbindung mit trennenden Schutzeinrichtungen fest und enthält eine Anleitung für Maßnahmen, mit denen die Möglichkeit Verriegelungseinrichtungen auf vernünftigerweise vorhersehbare Art und Weise zu umgehen, auf ein Minimum verringert wird.
Dieses Dokument behandelt die Grundsätze für die Gestaltung, Auswahl und Anwendung von Folgendem:
   Teilen der trennenden Schutzeinrichtungen, welche die Verriegelungseinrichtungen betätigen;
   Verriegelungseinrichtungen mit Schlüsseltransfer und Schlüsseltransfersystemen für Maschinenanwendungen.
ANMERKUNG   ISO 14120 legt allgemeine Anforderungen an die Gestaltung und die Konstruktion von trennenden Schutzeinrichtungen fest, die hauptsächlich dafür vorgesehen sind, Personen vor mechanischen Gefährdungen zu schützen. Die Verarbeitung des von der Verriegelungseinrichtung ausgehenden Signals zum Anhalten der Maschine und um deren unerwarteten Anlauf zu verhindern wird von ISO 14118, ISO 13849 1 und IEC 62061 abgedeckt.

Sécurité des machines - Dispositifs de verrouillage associés à des protecteurs - Principes de conception et de choix (ISO 14119:2024)

Le présent document spécifie des principes de conception et de choix (indépendamment de la nature de la source d'énergie) des dispositifs de verrouillage associés à des protecteurs et fournit des recommandations concernant les mesures visant à minimiser la possibilité de neutralisation des dispositifs de verrouillage d'une manière raisonnablement prévisible.
Le présent document couvre les principes de conception, de choix et de fonction suivants:
—     des composants constituant les protecteurs responsables de l'activation des dispositifs de verrouillage;
—     des dispositifs et systèmes de verrouillage à clé captive pour l'application aux machines.
NOTE            L'ISO 14120 spécifie les exigences générales relatives à la conception et à la construction des protecteurs principalement destinés à préserver les personnes des phénomènes dangereux mécaniques. Le traitement du signal issu du dispositif de verrouillage entraînant l'arrêt de la machine et empêchant toute mise en marche intempestive est couvert dans l'ISO 14118, l'ISO 13849-1 et l'IEC 62061.

Varnost strojev - Zaporne naprave, povezane z varovali - Načela za načrtovanje in izbiro (ISO 14119:2025)

Ta dokument določa načela za načrtovanje in izbiro (neodvisno od vrste vira energije) zapornih naprav, povezanih z varovali, ter podaja smernice o ukrepih za zmanjšanje možnosti okvare zapornih naprav na razumno predvidljiv način. Ta dokument zajema načela za načrtovanje, izbiro in uporabo: –    delov varoval, ki aktivirajo zaporne naprave; –    zapornih naprav in sistemov z varnostnim mehanizmom za uporabo pri strojih. OPOMBA: Standard ISO 14120 določa splošne zahteve za načrtovanje in izdelavo varoval, namenjenih predvsem zaščiti oseb pred mehanskimi tveganji. Obdelava signala iz zaporne naprave za zaustavitev stroja in preprečitev nepričakovanega zagona je zajeta v standardih ISO 14118, ISO 13849-1 in IEC 62061.

General Information

Status
Published
Publication Date
11-Mar-2025
Withdrawal Date
31-Jan-2023
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Start Date
12-Mar-2025
Completion Date
12-Mar-2025

Relations

Effective Date
06-Jun-2018

Overview

EN ISO 14119:2025 (identical to ISO 14119:2024) - titled Safety of machinery - Interlocking devices associated with guards - Principles for design and selection - provides principles for the design, selection and application of interlocking devices associated with guards. It is published by CEN (adopted March 2025) and supersedes EN ISO 14119:2013. The standard is energy-source independent and gives guidance to minimize the possibility of defeat of interlocking devices in reasonably foreseeable situations.

Key topics and technical requirements

  • Scope and purpose
    • Principles for design and selection of interlocking devices and guidance to reduce deliberate or accidental defeat.
    • Covers parts of guards that actuate interlocking devices and trapped key interlocking systems.
  • Operating principles
    • Interlocking with and without guard locking, actuator modes, cams and mechanical stops.
  • Design and arrangement
    • Requirements for fastening/arrangement of position switches, bolt locks, access locks and actuators.
    • Rules for guard-locking devices (electromechanical, electromagnetic), locking force considerations and whole-body access.
  • Supplementary releases & safety features
    • Escape, auxiliary and emergency releases; requirements for interlock blocking and supplementary release selection.
  • Selection and application
    • System response time vs. access time, environmental considerations (e.g., dust effects), and criteria for trapped key systems.
  • Human factors and defeat prevention
    • Measures and system design approaches to reduce motivation and opportunities to defeat interlocks.
  • Normative references
    • Integrates with risk and control-system standards (see Related Standards).

Practical applications and users

Who uses EN ISO 14119:2025:

  • Machine designers and OEMs selecting interlock hardware and guard actuation methods.
  • Safety engineers and integrators implementing machine safeguarding and control-system interfaces.
  • Compliance officers, notified bodies and assessors demonstrating conformity with the EU Machinery Directive (2006/42/EC) where the standard is cited.
  • Maintenance personnel and safety managers specifying trapped key systems, lock types and emergency/escape release arrangements.

Typical applications:

  • Selecting and positioning interlocks for access panels, hinged guards, removable covers.
  • Designing trapped key interlocking in sequence control or lock-out procedures.
  • Defining guard-locking solutions where personnel access and machine motion must be controlled.
  • Ensuring safeguarding solutions align with functional safety requirements and risk reduction strategies.

Related standards

Key referenced standards for implementation and compliance:

  • ISO 12100 - Risk assessment and reduction
  • ISO 13849-1 / ISO 13849-2 - Safety-related parts of control systems
  • ISO 14118 - Prevention of unexpected start-up
  • IEC 62061 - Functional safety of control systems
  • IEC 60204-1, IEC 60947 series - Electrical/electromechanical components

Using EN ISO 14119:2025 helps organizations choose appropriate interlocking devices and document safe, defendable design choices for machine guarding and compliance.

Standard

EN ISO 14119:2025 - BARVE

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Frequently Asked Questions

EN ISO 14119:2025 is a standard published by the European Committee for Standardization (CEN). Its full title is "Safety of machinery - Interlocking devices associated with guards - Principles for design and selection (ISO 14119:2024)". This standard covers: This document 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. This document covers principles for the design, selection and application of the following: —     parts of the guards which actuate interlocking devices; —     trapped key interlocking devices and systems for machinery applications. NOTE            ISO 14120 specifies general requirements for the design and construction of guards provided primarily to protect persons from mechanical hazards. The processing of the signal from the interlocking device to stop the machine and prevent unexpected start up is covered in ISO 14118, ISO 13849-1 and IEC 62061.

This document 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. This document covers principles for the design, selection and application of the following: —     parts of the guards which actuate interlocking devices; —     trapped key interlocking devices and systems for machinery applications. NOTE            ISO 14120 specifies general requirements for the design and construction of guards provided primarily to protect persons from mechanical hazards. The processing of the signal from the interlocking device to stop the machine and prevent unexpected start up is covered in ISO 14118, ISO 13849-1 and IEC 62061.

EN ISO 14119:2025 is classified under the following ICS (International Classification for Standards) categories: 13.110 - Safety of machinery. The ICS classification helps identify the subject area and facilitates finding related standards.

EN ISO 14119:2025 has the following relationships with other standards: It is inter standard links to EN ISO 14119:2013. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.

EN ISO 14119:2025 is associated with the following European legislation: EU Directives/Regulations: 2006/42/EC; Standardization Mandates: M/396. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.

You can purchase EN ISO 14119:2025 directly from iTeh Standards. The document is available in PDF format and is delivered instantly after payment. Add the standard to your cart and complete the secure checkout process. iTeh Standards is an authorized distributor of CEN standards.

Standards Content (Sample)


SLOVENSKI STANDARD
01-julij-2025
Varnost strojev - Zaporne naprave, povezane z varovali - Načela za načrtovanje in
izbiro (ISO 14119:2025)
Safety of machinery - Interlocking devices associated with guards - Principles for design
and selection (ISO 14119:2025)
Sicherheit von Maschinen - Verriegelungseinrichtungen in Verbindung mit trennenden
Schutzeinrichtungen - Leitsätze für Gestaltung und Auswahl (ISO 14119:2025)
Sécurité des machines - Dispositifs de verrouillage associés à des protecteurs -
Principes de conception et de choix (ISO 14119:2025)
Ta slovenski standard je istoveten z: EN ISO 14119:2025
ICS:
13.110 Varnost strojev Safety of machinery
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 14119
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2025
EUROPÄISCHE NORM
ICS 13.110 Supersedes EN ISO 14119:2013
English Version
Safety of machinery - Interlocking devices associated with
guards - Principles for design and selection (ISO
14119:2024)
Sécurité des machines - Dispositifs de verrouillage Sicherheit von Maschinen -
associés à des protecteurs - Principes de conception et Verriegelungseinrichtungen in Verbindung mit
de choix (ISO 14119:2024) trennenden Schutzeinrichtungen - Leitsätze für
Gestaltung und Auswahl (ISO 14119:2024)
This European Standard was approved by CEN on 21 July 2024.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14119:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of 2006/42/EC aimed to be covered . 4

European foreword
This document (EN ISO 14119:2025) has been prepared by Technical Committee ISO/TC 199 "Safety of
machinery" in collaboration with Technical Committee CEN/TC 114 “Safety of machinery” the
secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by September 2025, and conflicting national standards
shall be withdrawn at the latest by September 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 14119:2013.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
For the relationship with EU Legislation, see informative Annex ZA, which is an integral part of this
document.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 14119:2024 has been approved by CEN as EN ISO 14119:2025 without any modification.

Annex ZA
(informative)
Relationship between this European Standard and the essential
requirements of 2006/42/EC aimed to be covered
This European Standard has been prepared under a Commission’s standardization request “M/396
Mandate to CEN and CENELEC for Standardisation in the field of machinery" to provide one voluntary
means of conforming to essential requirements of Directive 2006/42/EC of the European Parliament
and of the Council of 17 May 2006 on machinery, and amending Directive 95/16/EC (recast).
Once this standard is cited in the Official Journal of the European Union under that Directive,
compliance with the normative clauses of this standard given in Table ZA.1 confers, within the limits of
the scope of this standard, a presumption of conformity with the corresponding essential requirements
of that Directive, and associated EFTA regulations.
Table ZA.1 — Correspondence between this European Standard and Annex I of
Directive 2006/42/EC
The relevant Essential Clause(s)/subclause(s) of this EN Remarks/Notes
Requirements of Directive
2006/42/EC
1.1.2 6, 7, 8, Annex K
1.2.1 6, 9
1.2.2 6, 7, Annex K
1.2.3 9
1.2.4 9
1.4.2.2 5, 6, 7, 8
1.5.4. 6
1.5.14 6, 7, Annex K
1.6.1 6, 8, 10
1.7.3 10
1.7.4.2 10
Table ZA.2 — Applicable Standards to confer presumption of conformity as described in this
Annex ZA
Reference in Clause 2 International Title Corresponding
Standard Edition European Standard
Edition
ISO 12100:2010 ISO 12100:2010 Safety of machinery — EN ISO 12100:2010
General principles for design
— Risk assessment and risk
reduction
ISO 13849-1:2023 ISO 13849-1:2023 Safety of machinery — EN ISO 13849-1:2023
Safety-related parts of
control systems — Part 1:
General principles for design
ISO 13849-2:2012 ISO 13849-2:2012 Safety of machinery — EN ISO 13849-2: 2012
Safety-related parts of
control systems — Part 2:
Validation
ISO 13855:20— ISO 13855:2023 Safety of machinery — EN ISO 13855: 20—
Positioning of safeguards
with respect to the approach
speeds of parts of the human
body
ISO 14118:2017 ISO 14118:2017 Safety of machinery — EN ISO 14118:2017
Prevention of unexpected
start-up
IEC 60204-1:2016 +AM IEC 60204-1:2016 + Safety of machinery — EN 60204-1:2018
D1:2021 AMD1:2021 Electrical equipment of
machines — Part 1: General
requirements
IEC 60947-1:2020 IEC 60947-1:2020 Low-voltage switchgear and EN IEC 60947-1: 2021
controlgear — Part 1:
General rules
IEC 60947-3 IEC 60947-3 Low-voltage switchgear and EN IEC 60947-3: 2021
controlgear — Part 3:
Switches, disconnectors,
switch-disconnectors and
fuse-combination units
IEC 60947-5-1:2016 +C IEC 60947-5-1:2016 Low voltage switchgear and EN 60947-5-1:2017
OR:2016 +COR:2016 controlgear — Part 5-1:
Control circuit devices and
switching elements —
Electromechanical control
circuit devices
IEC 60947-5-3 IEC 60947-5-3 Low-voltage switchgear and EN 60947-5-3:2013
controlgear — Part 5-3:
Control circuit devices and
switching elements —
Requirements for proximity
devices with defined
behaviour under fault
conditions (PDDB)
IEC 62061:2021 IEC 62061:2021 Safety of machinery - EN IEC 62061:2021
Functional safety of safety-
related control systems
The documents listed in the Column 1 of Table ZA.2, in whole or in part, are normatively referenced in
this document, i.e. are indispensable for its application. The achievement of the presumption of
conformity is subject to the application of the edition of Standards as listed in Column 4 or, if no
European Standard Edition exists, the International Standard Edition given in Column 2 of Table ZA.2.
WARNING 1 — Presumption of conformity stays valid only as long as a reference to this European
Standard is maintained in the list published in the Official Journal of the European Union. Users of this
standard should consult frequently the latest list published in the Official Journal of the European
Union.
WARNING 2 — Other Union legislation may be applicable to the product(s) falling within the scope of
this standard.
International
Standard
ISO 14119
Third edition
Safety of machinery — Interlocking
2024-09
devices associated with guards —
Principles for design and selection
Sécurité des machines — Dispositifs de verrouillage associés à des
protecteurs — Principes de conception et de choix
Reference number
ISO 14119:2024(en) © ISO 2024
ISO 14119:2024(en)
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 14119:2024(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols . 9
5 Operating principles and types of interlocking devices associated with guards .10
5.1 General .10
5.2 Principles of guard interlocking without guard locking . 13
5.3 Principles of guard interlocking with guard locking . 13
5.3.1 General . 13
5.3.2 Interlocking device with guard locking .14
6 Requirements for the design and the arrangements of interlocking devices with and
without guard locking .16
6.1 General .16
6.2 Arrangement and fastening of position switches, bolt locks and access locks .16
6.3 Arrangement and fastening of actuators .17
6.3.1 General .17
6.3.2 Cams .17
6.4 Actuation modes of interlocking devices .17
6.5 Mechanical stop .18
6.6 Additional requirements on guard-locking devices .18
6.6.1 General .18
6.6.2 Locking force .19
6.6.3 Electromechanical guard-locking device .19
6.6.4 Electromagnetic guard-locking device . 20
6.7 Additional requirements on access locks .21
6.7.1 General .21
6.7.2 Locking force .21
6.8 Whole body access . 22
6.9 Supplementary releases . 22
6.9.1 Escape release of guard locking. 22
6.9.2 Auxiliary release of guard locking . 22
6.9.3 Emergency release of guard locking . 23
6.10 Interlock blocking . 23
7 Selection of an interlocking device .23
7.1 General . 23
7.2 Selection of a guard-locking device . .24
7.2.1 Overall system response time and access time .24
7.2.2 Specific requirements for selection of guard-locking devices .24
7.2.3 Selection of supplementary guard-locking releases . 25
7.3 Environmental conditions considerations . 26
7.3.1 General . 26
7.3.2 Influence of dust on Type 2 and Type 5 interlocking devices. 26
7.4 Considerations for the application of trapped key interlocking systems . 26
8 Design to minimize the motivation to defeat .26
8.1 System design . 26
8.2 Methodology procedure .27
8.3 Additional measures to minimize possibility of defeat . 28
8.4 Additional measures to minimize possibility of defeat for Type 5 devices .32
8.4.1 General .32
8.4.2 Key retention .32

iii
ISO 14119:2024(en)
8.4.3 Reproduction of keys . 33
9 Requirements for the control system .33
9.1 General . 33
9.2 Assessment of faults and fault exclusions . 33
9.2.1 Assessment of faults . 33
9.2.2 Fault exclusion . 34
9.2.3 Examples for measures to prevent common cause failures through direct and
non-direct mechanical action of the position switches of Type 1 interlocking
devices . 36
9.2.4 Energy source diversity . 38
9.3 Release of guard-locking device . . 38
9.4 Series connection of electro-mechanical interlocking devices . 38
9.5 Electrical and environmental conditions . 38
9.5.1 General . 38
9.5.2 Performance considerations . 39
9.5.3 Immunity from disturbance . 39
9.5.4 Electrical operating conditions . 39
9.5.5 Clearances and creepage distances . 39
10 Information for use .39
10.1 General . 39
10.2 Information for use given by the manufacturer of interlocking devices . 39
10.2.1 Marking . . 39
10.2.2 Instructions . 40
10.3 Information for use given by the manufacturer of the machine .41
Annex A (informative) Type 1 interlocking device — Examples .42
Annex B (informative) Type 2 interlocking device — Examples . 47
Annex C (informative) Type 3 interlocking device — Example .49
Annex D (informative) Type 4 interlocking devices — Examples .51
Annex E (informative) Example of guard-locking devices .54
Annex F (informative) Application examples of interlocking devices used within a safety
function .59
Annex G (informative) Motivation to defeat interlocking devices (defeating of protective
devices) .65
Annex H (informative) Examples for maximum static action forces .69
Annex I (normative) Test procedures .71
Annex J (normative) Evaluation of fault masking in series connections of interlocking devices
with potential free contacts .73
Annex K (normative) Trapped key interlocking systems .89
Bibliography .106

iv
ISO 14119:2024(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 199, Safety of machinery, in collaboration with
the European Committee for Standardization (CEN) Technical Committee CEN/TC 114, Safety of machinery,
in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 14119:2013), which has been technically
revised.
The main changes are as follows:
— ISO/TS 19837 has been integrated as new Annex K with specific requirements for Type 5 interlocking
devices – “trapped key interlocking devices” (see definition 3.18.1);
— trapped key interlocking systems and Type 5 interlocking devices have been defined;
— Table 5 has been improved and renamed;
— test procedures are described in new Annex I;
— ISO/TR 24119 has been integrated into new Annex J.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

v
ISO 14119:2024(en)
Introduction
The structure of safety standards in the field of machinery is as follows:
a) type-A standards (basic safety standards) giving basic concepts, principles for design, and general
aspects that can be applied to all machinery;
b) type-B standards (generic safety standards) dealing with one safety aspect or one type of safeguard
that can be used across a wide range of machinery:
— type-B1 standards on particular safety aspects (e.g. safety distances, surface temperature, noise);
— type-B2 standards on safeguards (e.g. two-hand controls, interlocking devices, pressure-sensitive
devices, guards);
c) type-C standards (machine safety standards) dealing with detailed safety requirements for a particular
machine or group of machines.
This document is a type-B2 standard as stated in ISO 12100.
This document is of relevance, in particular for the following stakeholder groups representing the market
players with regard to machinery safety:
— machine manufacturers (small, medium and large enterprises);
— health and safety bodies (regulators, accident prevention organizations, market surveillance).
Others can be affected by the level of machinery safety achieved with the means of the document by the
above-mentioned stakeholder groups:
— 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).
The above-mentioned stakeholder groups have been given the possibility to participate in the drafting
process of this document.
In addition, this document is intended for standardization bodies elaborating type-C standards.
The requirements of this document can be supplemented or modified by a type-C standard.
For machines which are covered by the scope of a type-C standard and which have been designed and built
according to the requirements of that standard, the requirements of that type-C standard take precedence.
This document has been prepared to give guidance to machinery designers and writers of product safety
standards on how to design and select interlocking devices associated with guards.
Relevant clauses of this document, used alone or in conjunction with provisions from other standards, may
be used as a basis for verification procedures for the suitability of a device for interlocking duties.
Annexes A to E describe the technology and the typical characteristics of the defined interlocking devices
types 1 to 4. Other solutions may be adopted, provided that they are in conformity with the principles of this
document.
Annexes F to H give information on particular aspects such as interlocking devices used within safety
functions, risk assessment considering the motivation to defeat and static action forces.
Annex I describes a locking force test and an impact resistance test for guard-locking devices.

vi
ISO 14119:2024(en)
Annex J provides information on the masking of faults in series connection of interlocking devices with
potential free contacts.
Annex K provides requirements for trapped key interlocking systems and describes their technology.

vii
International Standard ISO 14119:2024(en)
Safety of machinery — Interlocking devices associated with
guards — Principles for design and selection
1 Scope
This document 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.
This document covers principles for the design, selection and application of the following:
— parts of the guards which actuate interlocking devices;
— trapped key interlocking devices and systems for machinery applications.
NOTE ISO 14120 specifies general requirements for the design and construction of guards provided primarily
to protect persons from mechanical hazards. The processing of the signal from the interlocking device to stop the
machine and prevent unexpected start up is covered in ISO 14118, ISO 13849-1 and IEC 62061.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 12100:2010, Safety of machinery — General principles for design — Risk assessment and risk reduction
ISO 13849-1:2023, Safety of machinery — Safety-related parts of control systems — Part 1: General principles
for design
ISO 13849-2:2012, Safety of machinery — Safety-related parts of control systems — Part 2: Validation
1)
ISO 13855:— , Safety of machinery — Positioning of safeguards with respect to the approach speeds of parts of
the human body
ISO 14118:2017, Safety of machinery — Prevention of unexpected start-up
IEC 60204-1:2016+AMD1: 2021, Safety of machinery — Electrical equipment of machines — Part 1: General
requirements
IEC 60947-1:2020, Low-voltage switchgear and controlgear — Part 1: General rules
IEC 60947-3, Low-voltage switchgear and controlgear — Part 3: Switches, disconnectors, switch-disconnectors
and fuse-combination units
IEC 60947-5-1:2016+COR: 2016, Low voltage switchgear and controlgear — Part 5-1: Control circuit devices
and switching elements — Electromechanical control circuit devices
IEC 60947-5-3, Low-voltage switchgear and controlgear — Part 5-3: Control circuit devices and switching
elements — Requirements for proximity devices with defined behaviour under fault conditions (PDDB)
IEC 62061:2021, Safety of machinery — Functional safety of safety-related control systems
1) Under preparation. Stage at the time of publication: ISO/FDIS 13855.

ISO 14119:2024(en)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 12100:2010, ISO 13849-1 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
interlocking device
interlock
mechanical, electrical or other type of device, the purpose of which is to prevent the operation of hazardous
machine functions under specified conditions (generally as long as a guard is not closed)
Note 1 to entry: See Figure 1 and Table 2.
[SOURCE: ISO 12100:2010, 3.28.1, modified — Note 1 to entry and Figure 1 were added.]
Key
1 guard 4 position switch
2 interlocking device 5 actuating system
3 actuator 6 output system
a
Direction of opening.
Figure 1 — Example of an interlocking device
3.2
interlocking guard
guard associated with an interlocking device such that, together with the control system of the machine,
prevents the:
— operation of the hazardous machine functions associated with the guard until the guard is closed;
— if the guard is opened while hazardous machine functions are operating, a command to bring the machine
to a safe state (a stop command) is given
Note 1 to entry: An interlocking guard can contain/be equipped with one or more interlocking devices. These
interlocking devices can also be of different types.
Note 2 to entry: The generation of the (stop) command to bring the machine to a safe state when the guard is open
does not apply to guards locked with a trapped key interlocking system.

ISO 14119:2024(en)
3.3
guard-locking device
device intended to lock a guard in the closed position and to be linked to the control system
Note 1 to entry: A guard-locking device may be a separate device or integrated in an interlocking device.
Note 2 to entry: See Annex E for detailed examples.
3.4
interlocking guard with guard-locking function
guard associated with an interlocking device and a guard-locking device so that, together with the control
system of the machine, the following functions are performed:
— the hazardous machine functions associated with the guard cannot operate until the guard is closed
and locked;
— the guard remains closed and locked until the risk due to the hazardous machine functions associated
with the guard has ceased; and
— when the guard is closed and locked, the hazardous machine functions associated with the guard
can operate (the closure and locking of the guard do not by themselves start the hazardous machine
functions)
[SOURCE: ISO 12100:2010, 3.27.5, modified — Note 1 to entry was deleted and in the first and second list
item, "associated" replaces "covered", in the second list item "ceased" replaces "disappeared".]
3.5
defeat
defeat in a reasonably foreseeable manner
reasonably foreseeable action, either manually or by using readily available objects, that makes interlocking
devices inoperative or bypasses them with the result that a machine is used in a manner not intended by the
designer or without the necessary protective measures
Note 1 to entry: This definition includes the removal of position switches or actuators using tools that are needed for
the intended use of the machine or that are readily available (screwdrivers, wrenches, hexagon keys, pliers).
Note 2 to entry: Readily available objects for substitute actuation include:
— screws, needles and sheet-metal pieces;
— objects in daily use, e.g. keys, coins, adhesive tape, string and wire.
Note 3 to entry: Uncontrolled spare and master keys for Type 5 interlocking devices (see also 8.4.3) and spare actuators
(for all types) are also considered as readily available objects.
3.6
automatic monitoring
diagnostic function, which initiates a fault reaction function if the ability of a component or an element to
perform its function is diminished, or if the process conditions are changed in such a way that hazards are
generated
3.7
direct mechanical action
positive mechanical action
movement of a mechanical component, which arises inevitably from the movement of another mechanical
component either by direct contact or via rigid elements

ISO 14119:2024(en)
3.8
direct opening action
direct opening action of a contact element
achievement of contact separation as a direct result of a specified movement of the switch actuator through
non-resilient members (for example not dependent upon springs)
[SOURCE: IEC 60947-5-1:2016 + COR1: 2016, K 2.2.]
3.9
position switch
part of interlocking device comprising the actuating system and the output system
3.10
actuator
separate part of an interlocking device, which transmits the state of the guard (closed or not closed) to the
actuating system
EXAMPLE Guard-mounted cam, shaped tongue, reflector, magnet, RFID tag.
Note 1 to entry: See also Annexes A to E and Annex K.
Note 2 to entry: For type 1 and Type 3 interlocking devices the actuator can be a part of the guard itself.
Note 3 to entry: Examples of actuators are shown in Figure 2.
Note 4 to entry: A key as used in a trapped key system is not covered by this definition.
3.11
coded actuator
actuator which is specially designed (e.g. by shape) to actuate a certain position switch
3.11.1
low-level coded actuator
coded actuator for which 1 to 9 variations in code are available and the different codes are evaluated by the
interlocking device
3.11.2
medium-level coded actuator
coded actuator for which 10 to 1 000 variations in code are available and the different codes are evaluated
by the interlocking device
3.11.3
high-level coded actuator
coded actuator for which more than 1 000 variations in code are available and the different codes are
evaluated by the interlocking device
3.12
actuating system
part of the interlocking device which transmits the position of the actuator or the key and changes the state
of the output system
EXAMPLE Roller plunger, cam mechanism, and optical, inductive or capacitive sensor.
Note 1 to entry: Examples of actuating systems are shown in Figure 2.
3.13
output system
part of the interlocking device that signals the state of the actuator or the key to the control system
EXAMPLE Contact element (electromechanical), semiconductor output, valve.

ISO 14119:2024(en)
3.14
Type 1 interlocking device
interlocking device with mechanically actuated position switch with uncoded actuator
EXAMPLE Hinged interlocking devices.
Note 1 to entry: See Annex A for detailed examples.
3.15
Type 2 interlocking device
interlocking device with mechanically actuated position switch with coded actuator
EXAMPLE Tongue-actuated position switches.
Note 1 to entry: See Annex B for detailed examples.
3.16
Type 3 interlocking device
interlocking device with non-contact
...

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Le document SIST EN ISO 14119:2025 présente des principes essentiels pour la conception et le choix des dispositifs de verrouillage associés aux protections, garantissant ainsi la sécurité des machines. Ce standard vise à encadrer le processus de conception sans dépendre de la nature de la source d'énergie, ce qui en fait un outil polyvalent et largement applicable à diverses industries. Parmi ses points forts, le document met en avant l'importance de minimiser la possibilité de contournement des dispositifs de verrouillage de manière prévisible. Cela démontre une préoccupation proactive pour le bien-être des travailleurs, car il traite non seulement des aspects techniques, mais également des implications en matière de sécurité. En abordant les parties des protections qui actionnent les dispositifs de verrouillage et en offrant des directives sur les systèmes de verrouillage à clé prisonnière, ce standard assure une couverture exhaustive des dispositifs de sécurité. De plus, le SIST EN ISO 14119:2025 se positionne comme un complément essentiel aux autres standards tels que l'ISO 14120, qui spécifie les exigences générales pour la conception et la construction des protections. Cette interconnexion souligne la pertinence de la norme dans le cadre plus large de la sécurité des machines, intégrant ainsi des exigences spécifiques qui renforcent la protection contre les dangers mécaniques. En résumé, cette norme ne se limite pas à des instructions techniques, mais elle constitue un cadre décisif pour améliorer la sécurité des machines grâce à des dispositifs de verrouillage bien conçus et bien sélectionnés. Sa pertinence est indéniable dans le contexte industriel moderne, où la sécurité et l'efficacité opérationnelle sont primordiales.

SIST EN ISO 14119:2025は、機械の安全性に関連する重要な標準であり、ガードに関連するインターロッキングデバイスの設計および選定の原則を提供しています。この文書は、エネルギー源の性質に関係なく、インターロッキングデバイスとガードの相互作用の設計および選定に関する原則を明確に示しており、機械の安全設計において極めて重要な参考資料です。 この標準の強みは、インターロッキングデバイスを効果的に設計・選定するための具体的な指針を提供している点です。特に、インターロッキングデバイスが機械の運転を停止し、予期しない始動を防ぐための信号処理の重要性を理解する上で、ISO 14118、ISO 13849-1、およびIEC 62061との関連を考慮していることが挙げられます。これにより、適切に設計されたインターロッキングデバイスは、機械におけるメカニカルハザードから人を保護するための効果的な手段となります。 加えて、この文書は、ガードの一部がインターロッキングデバイスを作動させる際の設計原則や、トラップキーインターロッキングデバイスおよびシステムに関する考慮事項も取り扱っており、実際の機械アプリケーションにおいて非常に有用です。このような包括的なアプローチは、ユーザーがインターロッキングデバイスを選定する際の信頼性を向上させ、予測可能な方法でインターロッキングデバイスの無効化の可能性を最小限に抑えるための対策が確立されることに寄与します。 総じて、SIST EN ISO 14119:2025は、機械の安全性に関連するインターロッキングデバイスの設計と選定に関する原則を整理した信頼性の高い文書であり、機械の設計者や安全専門家にとって必携のリソースとなります。

The standard EN ISO 14119:2025 outlines essential principles for the design and selection of interlocking devices associated with guards, significantly contributing to the safety of machinery. Its relevance is underscored by its comprehensive scope, which addresses the design and application of interlocking devices independent of energy source, thus broadening its applicability across various machinery sectors. One of the key strengths of this document is its emphasis on minimizing the possibility of defeat of interlocking devices in a reasonably foreseeable manner. By providing clear guidance on the design principles and selection criteria, EN ISO 14119:2025 serves as an invaluable resource for manufacturers and safety engineers aiming to enhance operational safety and compliance with regulations. The standard extensively covers the components of guards that actuate interlocking devices, ensuring these mechanisms are effectively integrated into machinery design. It also discusses trapped key interlocking devices, which are critical in ensuring that safety measures are not bypassed during machinery operation. Moreover, this document complements existing standards such as ISO 14120 and ISO 14118, establishing a holistic framework for machinery safety that incorporates the essential aspects of mechanical hazards and the safe processing of signals from interlocking devices. In summary, EN ISO 14119:2025 is a vital standard that provides thorough guidelines pertinent to the safety of machinery, particularly in relation to interlocking devices and their associated guards. Its robust framework enhances machinery safety and serves as a crucial reference for industries prioritizing compliance and safety measures.

SIST EN ISO 14119:2025 표준은 기계 안전성에 대한 다양한 원칙을 제공하며, 특히 가드와 관련된 인터록 장치의 설계 및 선택에 중요한 지침을 제시합니다. 이 문서는 에너지원의 성격에 관계없이 인터록 장치의 설계 및 선택의 원칙을 명확하게 규정하고 있으며, 이러한 장치의 고장을 최소화하기 위한 합리적인 조치를 안내합니다. 이 표준의 주요 강점 중 하나는 인터록 장치와 관련된 가드의 구성 요소에 대한 깊이 있는 통찰을 제공한다는 점입니다. 이는 설계자가 장치의 작동 방식과 안전성을 높이기 위해 필요한 정보를 갖출 수 있도록 지원합니다. 신뢰할 수 있는 설계를 통해 기계의 안전성을 향상시키고, 사용자 보호를 위한 기준을 강화하는 데 기여합니다. 또한, SIST EN ISO 14119:2025는 트랩 키 인터록 장치 및 시스템의 적용을 다루고 있어, 다양한 기계 응용 분야에서의 안전성 향상에 기여할 수 있는 중요한 자원입니다. 이러한 시스템은 기계 작동 시 의도치 않은 시작을 방지하며, 이를 통해 사용자와 주변 환경의 안전을 보장하는 데 필수적입니다. 이 표준은 ISO 14120, ISO 14118, ISO 13849-1 및 IEC 62061과 같은 관련 문서들과의 연관성 또한 강조합니다. 이러한 관련성을 통해 기계 안전성에 대한 포괄적인 접근을 가능하게 하여, 설계자와 제조업체가 안전 기준을 충족하도록 돕습니다. 종합적으로, SIST EN ISO 14119:2025 표준은 기계 안전 장치 설계 및 선택의 기준을 명확히 하며, 안전하고 신뢰할 수 있는 기계 운용을 위한 필수 요소들을 포함하고 있습니다. 이러한 이유로 이 표준은 기계 안전성을 향상시키기 위한 중요한 도구로 자리 잡고 있습니다.

Die Norm EN ISO 14119:2025 behandelt die Sicherheit von Maschinen, insbesondere die Prinzipien des Designs und der Auswahl von verriegelnden Geräten, die mit Schutzeinrichtungen assoziiert sind. Der Umfang der Norm ist klar definiert und bietet Richtlinien zur Minimierung der Möglichkeit, dass verriegelnde Geräte in vorhersehbarer Weise umgangen werden. Ein herausragendes Merkmal dieser Norm ist die Unabhängigkeit des Design- und Auswahlprozesses von der Art der Energiequelle. Dadurch wird sichergestellt, dass die Norm in einer Vielzahl von Anwendungen, unabhängig von den spezifischen Energiesystemen, anwendbar ist. Dies erhöht die Relevanz der Norm für unterschiedliche Industriebranchen, in denen mechanische Gefahren präsent sind. Die Norm umfasst wichtige Aspekte, einschließlich der Konstruktion von Teilen der Schutzeinrichtungen, die verriegelnde Geräte betätigen, sowie von Systemen, die gefangene Schlüssel verwenden, um die Sicherheit in Maschinenanwendungen zu gewährleisten. Diese detaillierten Vorgaben tragen dazu bei, dass die Implementierung von Sicherheitsmaßnahmen nicht nur effektiv, sondern auch wirtschaftlich sinnvoll ist. Die Stärke der EN ISO 14119:2025 liegt in der umfassenden Betrachtung von Sicherheitsanforderungen und der praktischen Anwendbarkeit der Prinzipien. Sie ergänzt andere relevante Normen, wie ISO 14120, die allgemeine Anforderungen für die Gestaltung und Konstruktion von Schutzeinrichtungen behandelt, sowie ISO 14118 und ISO 13849-1, die sich mit der Signalverarbeitung zur Notabschaltung von Maschinen befassen. Insgesamt stellt die EN ISO 14119:2025 eine unerlässliche Ressource für Fachleute dar, die sich mit der Sicherheit von Maschinen auseinandersetzen, und bietet fundierte Leitlinien zur Gestaltung und Auswahl von verriegelnden Geräten, die die Sicherheit von Personen in potenziell gefährlichen Umgebungen erheblich erhöhen.