IEC 60825-4:1997

Safety of laser products - Part 4: Laser guards

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. Applies to all component parts of a guard including clear (visibly transmitting) screens and viewing windows, panels, laser curtains and walls.

General Information

• Status: Published
• Publication Date: 27-Oct-2003
• ICS: 31.260 - Optoelectronics. Laser equipment
• Technical Committee: TC 76 - Optical radiation safety and laser equipment
• Drafting Committee: WG 7 - TC 76/WG 7
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 16-Aug-2006

Relations

• Amended By: IEC 60825-4:1997/AMD1:2002 - Amendment 1 - Safety of laser products - Part 4: Laser guards
• Effective Date: 05-Sep-2023
• Amended By: IEC 60825-4:1997/AMD2:2003 - Amendment 2 - Safety of laser products - Part 4: Laser guards
• Effective Date: 05-Sep-2023
• Revised: IEC 60825-4:2006 - Safety of laser products - Part 4: Laser guards
• Effective Date: 05-Sep-2023

Standards Content (Sample)

INTERNATIONAL
IEC
STANDARD
60825-4
First edition
1997-11
Safety of laser products –
Part 4:
Laser guards
Sécurité des appareils à laser –
Partie 4: Barrières laser
Reference number
IEC 60825-4: 1997 (E)
Numéros des publications Numbering

Depuis le 1er janvier 1997, les publications de la CEI As from the 1st January 1997 all IEC publications are

sont numérotées à partir de 60000. issued with a designation in the 60000 series.

Publications consolidées Consolidated publications

Les versions consolidées de certaines publications de Consolidated versions of some IEC publications
la CEI incorporant les amendements sont disponibles. including amendments are available. For example,

Par exemple, les numéros d’édition 1.0, 1.1 et 1.2 edition numbers 1.0, 1.1 and 1.2 refer, respectively, to

indiquent respectivement la publication de base, la the base publication, the base publication
publication de base incorporant l’amendement 1, et la incorporating amendment 1 and the base publication

publication de base incorporant les amendements 1 incorporating amendments 1 and 2.

et 2.
Validité de la présente publication Validity of this publication
Le contenu technique des publications de la CEI est The technical content of IEC publications is kept under
constamment revu par la CEI afin qu'il reflète l'état constant review by the IEC, thus ensuring that the
actuel de la technique. content reflects current technology.
Des renseignements relatifs à la date de Information relating to the date of the reconfirmation of
reconfirmation de la publication sont disponibles dans the publication is available in the IEC catalogue.
le Catalogue de la CEI.
Les renseignements relatifs à ces révisions, à l'établis- Information on the revision work, the issue of revised
sement des éditions révisées et aux amendements editions and amendments may be obtained from
peuvent être obtenus auprès des Comités nationaux de IEC National Committees and from the following
la CEI et dans les documents ci-dessous: IEC sources:
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• Catalogue des publications de la CEI • Catalogue of IEC publications
Publié annuellement et mis à jour régulièrement Published yearly with regular updates
(Accès en ligne)* (On-line access)*
Terminologie, symboles graphiques Terminology, graphical and letter
et littéraux symbols
En ce qui concerne la terminologie générale, le lecteur For general terminology, readers are referred to
se reportera à la CEI 60050: Vocabulaire Electro- IEC 60050: International Electrotechnical Vocabulary
technique International (VEI). (IEV).
Pour les symboles graphiques, les symboles littéraux For graphical symbols, and letter symbols and signs
et les signes d'usage général approuvés par la CEI, le approved by the IEC for general use, readers are
lecteur consultera la CEI 60027: Symboles littéraux à referred to publications IEC 60027: Letter symbols to
utiliser en électrotechnique, la CEI 60417: Symboles be used in electrical technology, IEC 60417: Graphical
symbols for use on equipment. Index, survey and
graphiques utilisables sur le matériel. Index, relevé et
compilation des feuilles individuelles, et la CEI 60617: compilation of the single sheets and IEC 60617:
Symboles graphiques pour schémas. Graphical symbols for diagrams.

Publications de la CEI établies par IEC publications prepared by the same
le même comité d'études technical committee
L'attention du lecteur est attirée sur les listes figurant The attention of readers is drawn to the end pages of
à la fin de cette publication, qui énumèrent les this publication which list the IEC publications issued
publications de la CEI préparées par le comité by the technical committee which has prepared the
d'études qui a établi la présente publication. present publication.
* Voir adresse «site web» sur la page de titre. * See web site address on title page.

INTERNATIONAL
IEC
STANDARD
60825-4
First edition
1997-11
Safety of laser products –
Part 4:
Laser guards
Sécurité des appareils à laser –
Partie 4: Barrières laser
 IEC 1997 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun any form or by any means, electronic or mechanical,
procédé, électronique ou mécanique, y compris la photo- including photocopying and microfilm, without permission in
copie et les microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: [phone] e-mail: [e-mail] IEC web site http: //www.iec.ch
Commission Electrotechnique Internationale
PRICE CODE
S
International Electrotechnical Commission
For price, see current catalogue

– 2 – 60825-4  IEC:1997 (E)
CONTENTS
Page
FOREWORD . 3

INTRODUCTION . 4

Clause
1 General. 5
1.1 Scope . 5
1.2 Normative references. 5
1.3 Definitions . 5
2 Laser processing machines . 7
2.1 Design requirements . 7
2.2 Performance requirements . 8
2.3 Validation. 8
2.4 User information . 9
3 Proprietary laser guards . 9
3.1 Design requirements . 9
3.2 Performance requirements . 9
3.3 Specification requirements . 9
3.4 Test requirements. 10
3.5 Labelling requirements. 10
3.6 User information . 11
Annexes
A General guidance on the design and selection of laser guards . 12

B Assessment of foreseeable exposure limits . 14
C Elaboration of defined terms. 21

60825-4  IEC:1997 (E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

___________
SAFETY OF LASER PRODUCTS –
Part 4: Laser guards
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60825-4 has been prepared by IEC technical committee 76: Optical
radiation safety and laser equipment.
The text of this standard is based on the following documents:
FDIS Report on voting
76/159/FDIS 76/168/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
Annexes A, B and C are for information only.
The French version of this standard will be issued separately.

– 4 – 60825-4  IEC:1997 (E)
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.
This part of IEC 60825 deals with protection against laser radiation only. Hazards from
secondary radiation that may arise during material processing are not addressed.
Laser guards may also comply with standards for laser protective eyewear, but such
compliance is not necessarily sufficient to satisfy the requirements of this standard.
Where the term “irradiance” is used, the expression “irradiance or radiant exposure, as
appropriate” is implied.
60825-4  IEC:1997 (E) – 5 –
SAFETY OF LASER PRODUCTS –
Part 4: Laser guards
1 General
1.1 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 standard applies to all component parts of a guard including clear (visibly transmitting)
screens and viewing windows, panels, laser curtains and walls. 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.
In addition this part of IEC 60825 indicates:
a) how to assess and specify the protective properties of a laser guard; and
b) how to select a laser guard.
1.2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 60825. At the time of publication, the editions indicated
were valid. All normative documents are subject to revision, and parties to agreements based
on this part of IEC 60825 are encouraged to investigate the possibility of applying the most
recent editions of the normative documents indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 60825-1: 1993, Safety of laser products – Part 1: Equipment classification, requirements
and user’s guide
ISO/TR12100-1: 1992, Safety of machinery – Basic concepts, general principles for design –
Part 1: Basic terminology, methodology
ISO/TR12100-2: 1992, Safety of machinery – Basic concepts, general principles for design –
Part 2: Technical principles and specifications

ISO 11553: 1996, Safety of machinery – Laser processing machines – Safety requirements
1.3 Definitions
For the purpose of this part of IEC 60825, the following definitions apply in addition to the
definitions given in IEC 60825-1.
1.3.1
active guard protection time
for a given laser exposure of the front surface of an active laser guard, the minimum time,
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.

– 6 – 60825-4  IEC:1997 (E)
1.3.2
active guard termination signal

the 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 – The action of a safety interlock becoming open circuit is considered a "signal" in this context.

1.3.3
active laser guard
a laser guard which is part of a safety-related control system. The control system generates an

active guard termination signal in response to the effect of laser radiation on the front surface

of the laser guard
1.3.4
foreseeable exposure limit (FEL)
the maximum laser exposure on the front surf
...

INTERNATIONAL IEC
STANDARD 60825-4
Edition 1.2
2003-10
Edition 1:1997 consolidated with amendments 1:2002 and 2:2003
Safety of laser products –
Part 4:
Laser guards
Sécurité des appareils à laser –
Partie 4:
Barrières laser
Reference number
Publication numbering
As from 1 January 1997 all IEC publications are issued with a designation in the

60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1.

Consolidated editions
The IEC is now publishing consolidated versions of its publications. For example,

edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the

base publication incorporating amendment 1 and the base publication incorporating

amendments 1 and 2.
Further information on IEC publications
The technical content of IEC publications is kept under constant review by the IEC,
thus ensuring that the content reflects current technology. Information relating to
this publication, including its validity, is available in the IEC Catalogue of
publications (see below) in addition to new editions, amendments and corrigenda.
Information on the subjects under consideration and work in progress undertaken
by the technical committee which has prepared this publication, as well as the list
of publications issued, is also available from the following:
• IEC Web Site (www.iec.ch)
• Catalogue of IEC publications
The on-line catalogue on the IEC web site (www.iec.ch/searchpub) enables you to
search by a variety of criteria including text searches, technical committees
and date of publication. On-line information is also available on recently issued
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INTERNATIONAL IEC
STANDARD
60825-4
Edition 1.2
2003-10
Edition 1:1997 consolidated with amendments 1:2002 and 2:2003
Safety of laser products –
Part 4:
Laser guards
Sécurité des appareils à laser –
Partie 4:
Barrières laser
 IEC 2003  Copyright - all rights reserved
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 the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail]  Web: www.iec.ch
PRICE CODE W
Commission Electrotechnique Internationale
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue

– 2 – 60825-4  IEC:1997+A1:2002+A2:2003(E)

CONTENTS
FOREWORD . 3

INTRODUCTION .5

1 General. 6

1.1 Scope . 6

1.2 Normative references. 6

1.3 Definitions . 6
2 Laser processing machines . 8
2.1 Design requirements . 8
2.2 Performance requirements . 9
2.3 Validation. 9
2.4 User information .10
3 Proprietary laser guards .10
3.1 Design requirements .10
3.2 Performance requirements .10
3.3 Specification requirements .10
3.4 Test requirements.11
3.5 Labelling requirements.11
3.6 User information .12
Annex A (informative) General guidance on the design and selection of laser guards .13
Annex B (informative) Assessment of foreseeable exposure limit .15
Annex C (informative) Elaboration of defined terms.22
Annex D (normative) Proprietary laser guard testing .24
Annex E (informative) Guidelines on the arrangement and installation of laser guards.26
Bibliography .36
Figure B.1 – Calculation of diffuse reflections .16
Figure B.2 – Calculation of specular reflections.16
Figure B.3 – Some examples of a foreseeable fault condition.17

Figure B.4 – Four examples of errant laser beams that might have to be contained
by a temporary guard under service conditions .18
Figure B.5 – Illustration of laser guard exposure during repetitive machine operation .19
Figure B.6 – Two examples of assessed duration of exposure.20
Figure B.7 – Assessed duration of exposure for a machine with no safety monitoring .21
Figure C.1 – Illustration of guarding around a laser processing machine.22
Figure C.2 – Illustration of active laser guard parameters.23
Figure D.1 – Simplified diagram of the test arrangement .24

60825-4  IEC:1997+A1:2002+A2:2003(E) – 3 –

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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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.

International Standard IEC 60825-4 has been prepared by IEC technical committee 76: Optical
radiation safety and laser equipment.
This consolidated version of IEC 60825-4 is based on the first edition (1997) [documents
76/159/FDIS and 76/168/RVD], its amendment 1 (2002) [documents 76/242/FDIS and
76/252/RVD] and its amendment 2 (2003) [documents 76/263/FDIS and 76/273/RVD].
It bears the edition number 1.2.
A vertical line in the margin shows where the base publication has been modified by
amendments 1 and 2.
Annex D forms an integral part of this standard.
Annexes A, B, C and E are for information only.

– 4 – 60825-4  IEC:1997+A1:2002+A2:2003(E)

The French version of this standard will be issued separately.

The committee has decided that the contents of this publication will remain unchanged until
2005. At this date, the publication will be

• reconfirmed;
• withdrawn;
• replaced by a revised edition, or

• amended.
60825-4  IEC:1997+A1:2002+A2:2003(E) – 5 –

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.
This part of IEC 60825 deals with protection against laser radiation only. Hazards from
secondary radiation that may arise during material processing are not addressed.
Laser guards may also comply with standards for laser protective eyewear, but such
compliance is not necessarily sufficient to satisfy the requirements of this standard.
Where the term “irradiance” is used, the expression “irradiance or radiant exposure, as
appropriate” is implied.
– 6 – 60825-4  IEC:1997+A1:2002+A2:2003(E)

SAFETY OF LASER PRODUCTS –
Part 4: Laser guards
1 General
1.1 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 standard applies to all component parts of a guard including clear (visibly transmitting)
screens and viewing windows, panels, laser curtains and walls. 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.
In addition this part of IEC 60825 indicates:
a) how to assess and specify the protective properties of a laser guard; and
b) how to select a laser guard.
1.2 Normative references
The following referenced documents are indispensable for the application 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: 1993, Safety of laser products – Part 1: Equipment classification, requirements
and user’s guide
ISO/TR12100-1: 1992, Safety of machinery – Basic concepts, general principles for design –
Part 1: Basic terminology, methodology
ISO/TR12100-2: 1992, Safety of machinery – Basic concepts, general principles for design –
Part 2: Technical principles and specifications
ISO 11553: 1996, Safety of machinery – Laser processing machines – Safety requirements

1.3 Definitions
For the purpose of this part of IEC 60825, the following definitions apply in addition to the
definitions given in IEC 60825-1.
1.3.1
active guard protection time
for a given laser exposure
...