IEC 60825-4:2022

Safety of laser products - Part 4: Laser guards

IEC 60825-4:2022 is available as IEC 60825-4:2022 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 60825-4:2022 deals with basic issues concerning laser guards, including human access, interlocking and labelling, and gives general guidance on the design of protective housings and enclosures for high-power lasers. Laser guards may also comply with standards for laser protective eyewear, but such compliance is not necessarily sufficient to satisfy the requirements of this document. This part of IEC 60825 specifies the requirements for laser guards, permanent and temporary (for example for service), that enclose the process zone of a laser processing machine, and specifications for proprietary laser guards. This document applies to all component parts of a guard including clear (visibly transmitting) screens and viewing windows, panels, laser curtains and walls. In addition, this document indicates
- how to assess and specify the protective properties of a laser guard, and
- how to select a laser guard.

Sécurité des appareils à laser - Part 4: Protecteurs pour lasers

IEC 60825-4:2022 est disponible sous forme de IEC 60825-4:2022 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.
L’IEC 60825-4:2022 traite de questions fondamentales concernant les protecteurs pour laser, y compris l’accès humain, les dispositifs d'interverrouillage et l’étiquetage, et fournit des recommandations générales relatives à la conception de capots et d’enceintes de protection pour les lasers de forte puissance. Les protecteurs pour laser peuvent également être conformes aux normes pour les protecteurs oculaires contre le rayonnement laser, mais une telle conformité n’est pas nécessairement suffisante pour satisfaire aux exigences du présent document. La présente partie de l’IEC 60825 spécifie les exigences relatives aux protecteurs pour laser, permanents et temporaires (par exemple, pour l’entretien), qui protègent la zone de traitement d’une machine à laser, ainsi que les spécifications pour les protecteurs d'origine pour laser. Le présent document s’applique à tous les composants d’un protecteur, y compris les écrans clairs (visiblement transmetteurs) et les fenêtres d’observation, les panneaux, les rideaux pour laser et les parois. De plus, le présent document indique
- comment évaluer et spécifier les propriétés de protection d’un protecteur pour laser, et
- comment sélectionner un protecteur pour laser.

General Information

• Status: Published
• Publication Date: 21-Jul-2022
• ICS: 31.260 - Optoelectronics. Laser equipment
• Technical Committee: TC 76 - Optical radiation safety and laser equipment
• Current Stage: PPUB - Publication issued
• Completion Date: 22-Jul-2022

Standards Content (sample)

IEC 60825-4
Edition 3.0 2022-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Safety of laser products –
Part 4: Laser guards
Sécurité des appareils à laser –
Partie 4: Protecteurs pour laser
IEC 60825-4:2022-07(en-fr)
---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2022 IEC, Geneva, Switzerland

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form

or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from

either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC

copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or

your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni

utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et

les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des

questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez

les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Secretariat Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC

The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes

International Standards for all electrical, electronic and related technologies.
About IEC publications

The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the

latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch

The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the

variety of criteria (reference number, text, technical publications previews. With a subscription you will always have

committee, …). It also gives information on projects, replaced access to up to date content tailored to your needs.

and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 300 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
a month by email.
Also known as the International Electrotechnical Vocabulary
(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc
If you wish to give us your feedback on this publication or need
further assistance, please contact the Customer Service
Centre: [e-mail].
A propos de l'IEC

La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des

Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC

Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la

plus récente, un corrigendum ou amendement peut avoir été publié.

Recherche de publications IEC - Découvrez notre puissant moteur de recherche et consultez

webstore.iec.ch/advsearchform gratuitement tous les aperçus des publications. Avec un

La recherche avancée permet de trouver des publications IEC abonnement, vous aurez toujours accès à un contenu à jour

en utilisant différents critères (numéro de référence, texte, adapté à vos besoins.

comité d’études, …). Elle donne aussi des informations sur les

projets et les publications remplacées ou retirées. Electropedia - www.electropedia.org

Le premier dictionnaire d'électrotechnologie en ligne au monde,
IEC Just Published - webstore.iec.ch/justpublished
avec plus de 22 300 articles terminologiques en anglais et en
Restez informé sur les nouvelles publications IEC. Just
français, ainsi que les termes équivalents dans 19 langues
Published détaille les nouvelles publications parues.
additionnelles. Egalement appelé Vocabulaire
Disponible en ligne et une fois par mois par email.
Electrotechnique International (IEV) en ligne.
Service Clients - webstore.iec.ch/csc
Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
[e-mail].
IEC Products & Services Portal - products.iec.ch
---------------------- Page: 2 ----------------------
IEC 60825-4
Edition 3.0 2022-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Safety of laser products –
Part 4: Laser guards
Sécurité des appareils à laser –
Partie 4: Protecteurs pour laser
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.260 ISBN 978-2-8322-3985-8

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 60825-4:2022 © IEC 2022
CONTENTS

FOREWORD ........................................................................................................................... 5

INTRODUCTION ..................................................................................................................... 7

1 Scope .............................................................................................................................. 8

2 Normative references ...................................................................................................... 8

3 Terms and definitions ...................................................................................................... 8

4 Requirements for laser guards ....................................................................................... 11

4.1 Requirement ......................................................................................................... 11

4.2 Design requirements ............................................................................................. 12

4.3 Performance requirements .................................................................................... 12

4.4 Validation .............................................................................................................. 12

4.5 User information ................................................................................................... 13

5 Proprietary laser guards ................................................................................................ 13

5.1 General ................................................................................................................. 13

5.2 Design requirements ............................................................................................. 13

5.3 Performance requirements .................................................................................... 13

5.4 Specification requirements .................................................................................... 14

5.5 Test requirements ................................................................................................. 14

5.6 Labelling requirements .......................................................................................... 14

5.7 User information ................................................................................................... 15

Annex A (informative) General guidance on the design and selection of laser guards .......... 16

A.1 Design of laser guards .......................................................................................... 16

A.2 Selection of laser guards ...................................................................................... 16

Annex B (informative) Assessment of foreseeable exposure limit (FEL) ............................... 18

B.1 General ................................................................................................................. 18

B.2 Reflection of laser radiation .................................................................................. 19

B.3 Examples of assessment conditions ...................................................................... 19

B.4 Exposure duration ................................................................................................. 22

Annex C (informative) Elaboration of defined terms ............................................................. 25

C.1 Distinction between FEL and PEL ......................................................................... 25

C.2 Active guard parameters ....................................................................................... 25

Annex D (normative) Proprietary laser guard testing ............................................................ 27

D.1 General ................................................................................................................. 27

D.2 Test conditions ..................................................................................................... 27

D.3 Protection time corresponding to the specified protective exposure limit

(PEL) .................................................................................................................... 31

D.4 Information supplied by the manufacturer.............................................................. 31

Annex E (informative) Guidelines on the arrangement and installation of laser guards ......... 33

E.1 Overview............................................................................................................... 33

E.2 General ................................................................................................................. 33

E.3 Risk assessment ................................................................................................... 34

E.4 Examples of risk assessment ................................................................................ 36

E.5 Aids to risk assessment ........................................................................................ 39

Annex F (informative) Guideline for assessing the suitability of laser guards ........................ 42

F.1 Identification of hazards ........................................................................................ 42

F.2 Risk assessment and integrity ............................................................................... 42

---------------------- Page: 4 ----------------------
IEC 60825-4:2022 © IEC 2022 – 3 –

F.3 General design ..................................................................................................... 45

F.4 Selection of safeguards ........................................................................................ 46

F.5 Guard design and construction .............................................................................. 46

F.6 Guard construction and materials .......................................................................... 48

F.7 Other safety devices ............................................................................................. 50

F.8 Interlocking considerations ................................................................................... 51

F.9 Environmental considerations ............................................................................... 55

F.10 Installation consideration – Environmental factors – Services ............................... 56

F.11 Maintenance and service considerations ............................................................... 56

Annex G (normative) Guided beam delivery systems ........................................................... 67

G.1 General ................................................................................................................. 67

G.2 General requirements ........................................................................................... 67

G.3 Verification of safety requirements or protective measures ................................... 69

G.4 Information for users ............................................................................................. 69

G.5 Examples of risk assessments .............................................................................. 70

Bibliography .......................................................................................................................... 75

Figure B.1 – Calculation of diffuse reflections ....................................................................... 19

Figure B.2 – Calculation of specular reflections .................................................................... 19

Figure B.3 – Some examples of a foreseeable fault condition ............................................... 20

Figure B.4 – Four examples of errant laser beams that might have to be contained by a

temporary guard under service conditions ............................................................................. 21

Figure B.5 – Illustration of laser guard exposure during repetitive machine operation ........... 22

Figure B.6 – Two examples of assessed duration of exposure .............................................. 23

Figure B.7 – Assessed duration of exposure for a machine with no safety monitoring ........... 24

Figure C.1 – Illustration of guarding around a laser processing machine ............................... 25

Figure C.2 – Illustration of active laser guard parameters ..................................................... 26

Figure D.1 – Simplified diagram of the test arrangement ....................................................... 29

Figure D.2 – Simplified diagram of the ventilation for the guard under test ............................ 29

Figure F.1 – Damage resistance of 1 mm thick zinc coated steel sheet derived from

10 s exposure to a defocused beam during experiments using a CW CO laser .................... 57

Figure F.2 – Damage resistance of 1 mm thick zinc coated steel sheet derived from

100 s exposure to a defocused beam during experiments using a CW CO laser .................. 58

Figure F.3 – Damage resistance of 2 mm thick zinc coated steel sheet derived from 10

s exposure to a defocused beam during experiments using a CW CO laser ........................ 58

Figure F.4 – Damage resistance of 2 mm thick zinc coated steel sheet derived from

100 s exposure to a defocused beam during experiments using a CW CO laser .................. 58

Figure F.5 – Damage resistance of 3 mm thick zinc coated steel sheet derived from 10

s exposure to a defocused beam during experiments using a CW CO laser ........................ 59

Figure F.6 – Damage resistance of 3 mm thick zinc coated steel sheet derived from

100 s exposure to a defocused beam during experiments using a CW CO laser .................. 59

Figure F.7 – Damage resistance of 2 mm thick aluminium sheet derived from 10 s

exposure to a defocused beam during experiments using a CW CO laser ........................... 59

Figure F.8 – Damage resistance of 2 mm thick aluminium sheet derived from 100 s

exposure to a defocused beam during experiments using a CW CO laser ........................... 60

---------------------- Page: 5 ----------------------
– 4 – IEC 60825-4:2022 © IEC 2022

Figure F.9 – Damage resistance of 1 mm thick stainless steel sheet derived from 10 s

exposure to a defocused beam during experiments using a CW CO laser ........................... 60

Figure F.10 – Damage resistance of 1 mm thick stainless steel sheet derived from 100

s exposure to a defocused beam during experiments using a CW CO laser ........................ 60

Figure F.11 – Damage resistance of 6 mm thick polycarbonate sheet derived from 10 s

exposure to a defocused beam during experiments using a CW CO laser ........................... 61

Figure F.12 – Damage resistance of 6 mm thick polycarbonate sheet derived from 100

s exposure to a defocused beam during experiments using a CW CO laser ........................ 61

Figure F.13 – Damage resistance of 1 mm thick zinc coated steel sheet derived from

10 s exposure to a defocused beam during experiments using a CW Nd:YAG laser .............. 62

Figure F.14 – Damage resistance of 1 mm thick zinc coated steel sheet derived from

100 s exposure to a defocused beam during experiments using a CW Nd:YAG laser ............ 62

Figure F.15 – Damage resistance of 2 mm thick zinc coated steel sheet derived from

10 s exposure to a defocused beam during experiments using a CW Nd:YAG laser .............. 63

Figure F.16 – Damage resistance of 2 mm thick zinc coated steel sheet derived from

100 s exposure to a defocused beam during experiments using a CW Nd:YAG laser ............ 63

Figure F.17 – Damage resistance of 3 mm thick zinc coated steel sheet derived from

10 s exposure to a defocused beam during experiments using a CW Nd:YAG laser .............. 64

Figure F.18 – Damage resistance of 3 mm thick zinc coated steel sheet derived from

100 s exposure to a defocused beam during experiments using a CW Nd:YAG laser ............ 64

Figure F.19 – Damage resistance of 2 mm thick aluminium sheet derived from 10 s

exposure to a defocused beam during experiments using a CW Nd:YAG laser ...................... 65

Figure F.20 – Damage resistance of 2 mm thick aluminium sheet derived from 100 s

exposure to a defocused beam during experiments using a CW Nd:YAG laser ...................... 65

Figure F.21 – Damage resistance of 1 mm thick stainless steel sheet derived from 10 s

exposure to a defocused beam during experiments using a CW Nd:YAG laser ...................... 66

Figure F.22 – Damage resistance of 1 mm thick stainless steel sheet derived from

100 s exposure to a defocused beam during experiments using a CW Nd:YAG laser ............ 66

Table D.1 – Laser guard test classification ............................................................................ 30

Table F.1 – Application of ALARP ......................................................................................... 45

Table G.1 – Beam delivery systems using free space beam delivery systems ....................... 70

Table G.2 – Beam delivery systems using fibre optic cables ................................................. 72

---------------------- Page: 6 ----------------------
IEC 60825-4:2022 © IEC 2022 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SAFETY OF LASER PRODUCTS –
Part 4: Laser guards
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international

co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and

in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,

Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their

preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with

may participate in this preparatory work. International, governmental and non-governmental organizations liaising

with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for

Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence between

any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

rights. IEC shall not be held responsible for identifying any or all such patent rights.

IEC 60825-4 has been prepared by IEC technical committee 76: Optical radiation safety and

laser equipment. It is an International Standard.
This third edition cancels and replaces the second edition published in 2006,

Amendment 1:2008 and Amendment 2:2011. This edition constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:

a) Significant amendments have been included and this edition has been prepared for user

convenience.
---------------------- Page: 7 ----------------------
– 6 – IEC 60825-4:2022 © IEC 2022
The text of this International Standard is based on the following documents:
Draft Report on voting
76/704/FDIS 76/711/RVD

Full information on the voting for its approval can be found in the report on voting indicated in

the above table.
The language used for the development of this International Standard is English.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in

accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available

at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are

described in greater detail at www.iec.ch/standardsdev/publications.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under webstore.iec.ch in the data related to the

specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it

contains colours which are considered to be useful for the correct understanding of its

contents. Users should therefore print this document using a colour printer.
---------------------- Page: 8 ----------------------
IEC 60825-4:2022 © IEC 2022 – 7 –
INTRODUCTION

At low levels of irradiance or radiant exposure, the selection of material and thickness for

shielding against laser radiation is determined primarily by a need to provide sufficient optical

attenuation. However, at higher levels, an additional consideration is the ability of the laser

radiation to remove guard material – typically by melting, oxidation or ablation; processes that

could lead to laser radiation penetrating a normally opaque material.

IEC 60825-1 deals with basic issues concerning laser guards, including human access,

interlocking and labelling, and gives general guidance on the design of protective housings and

enclosures for high-power lasers.

Laser guards may also comply with standards for laser protective eyewear, but such compliance

is not necessarily sufficient to satisfy the requirements of this document.

Where the term "irradiance" is used, the expression "irradiance or radiant exposure, as

appropriate" is implied.
---------------------- Page: 9 ----------------------
– 8 – IEC 60825-4:2022 © IEC 2022
SAFETY OF LASER PRODUCTS –
Part 4: Laser guards
1 Scope

This part of IEC 60825 specifies the requirements for laser guards, permanent and temporary

(for example for service), that enclose the process zone of a laser processing machine, and

specifications for proprietary laser guards.

This document applies to all component parts of a guard including clear (visibly transmitting)

screens and viewing windows, panels, laser curtains and walls.
In addition, this document indicates
a) how to assess and specify the protective properties of a laser guard, and
b) how to select a laser guard.

NOTE Requirements for beam path components, beam stops and those other parts of a protective housing of a

laser product which do not enclose the process zone are contained in IEC 60825-1.

This document deals with protection against laser radiation only. Hazards from secondary

radiation that may arise during material processing are not addressed.
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.

IEC 60825-1:2014, Safety of laser products – Part 1: Equipment classification and requirements

IEC 61508 (all parts), Functional safety of electrical/electronic/programmable electronic safety-

related systems

ISO 11553-1, Safety of machinery – Laser processing machines – Laser safety requirements

ISO 12100, Safety of machinery – General principles for design – Risk assessment and risk

reduction

ISO 13849-1, Safety of machinery – Safety-related parts of control systems – Part 1: General

principles for design
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60825-1 and the

following apply.
---------------------- Page: 10 ----------------------
IEC 60825-4:2022 © IEC 2022 – 9 –

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
access panel
panel which when removed or displaced gives human access to laser radiation

Note 1 to entry: Sheathing around a fibre, tubing used as an enclosure component or any device serving the function

of a removable or displaceable panel, can also be an "access panel" within the terms of this definition.

3.2
active guard protection time

minimum time for a given laser exposure of the front (incident) surface of an active laser guard,

measured from the issue of an active guard termination signal, for which the active laser guard

can safely prevent laser radiation accessible at its rear surface from exceeding the Class 1 AEL

3.3
active guard termination signal

signal issued by an active guard in response to an excess exposure of its front surface to laser

radiation and which is intended to lead to automatic termination of the laser radiation

Note 1 to entry: The action of a safety interlock becoming open circuit is considered a "signal" in this context.

3.4
active laser guard

laser guard which is part of a safety-related control system whereby failure of the front surface

of the laser guard triggers a termination signal
3.5
beam delivery system

system comprised of all those components, including all optical beam components and potential

beam paths and their enclosures, which when combined, transfer laser radiation emitted from

the laser radiation generator (the laser) to the workpiece

Note 1 to entry: These components may include all elements for guiding, shaping and switching the laser beam as

well as the enclosure of and support for the beam path components. See Annex G for detail on guided beam delivery

systems.
3.6
beam diameter

diameter of the smallest circular aperture in a plane perpendicular to the beam axis that contains

86 % of the total laser power (or energy)

Note 1 to entry: In the case of a Gaussian beam (TEM ), d corresponds to the point where the irradiance

...