SIST EN IEC 60825-4:2025

SLOVENSKI STANDARD
SIST EN 60825-4:2025
01-marec-2025
Nadomešča:
SIST EN 60825-4:2008
Varnost laserskih izdelkov - 4. del: Zaščitna oprema za laserje
Safety of laser products - Part 4: Laser guards
Sicherheit von Lasereinrichtungen - Teil 4: Laserschutzwände
Sécurité des appareils à laser - Partie 4: Protecteurs pour lasers
Ta slovenski standard je istoveten z: EN IEC 60825-4:2024
ICS:
31.260 Optoelektronika, laserska Optoelectronics. Laser
oprema equipment
SIST EN 60825-4:2025 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

SIST EN 60825-4:2025
SIST EN 60825-4:2025
EUROPEAN STANDARD EN IEC 60825-4
NORME EUROPÉENNE
EUROPÄISCHE NORM December 2024
ICS 31.260 Supersedes EN 60825-4:2006; EN 60825-
4:2006/A1:2008; EN 60825-4:2006/A2:2011
English Version
Safety of laser products - Part 4: Laser guards
(IEC 60825-4:2022)
Sécurité des appareils à laser - Partie 4: Protecteurs pour Sicherheit von Lasereinrichtungen - Teil 4:
lasers Laserschutzwände
(IEC 60825-4:2022) (IEC 60825-4:2022)
This European Standard was approved by CENELEC on 2022-08-26. CENELEC 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 CENELEC 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 CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60825-4:2024 E

SIST EN 60825-4:2025
European foreword
The text of document 76/704/FDIS, future edition 3 of IEC 60825-4, prepared by TC 76 "Optical
radiation safety and laser equipment" was submitted to the IEC-CENELEC parallel vote and approved
by CENELEC as EN IEC 60825-4:2024.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2025-12-31
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2027-12-31
document have to be withdrawn
This document supersedes EN 60825-4:2006 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a standardization request addressed to CENELEC 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 ZZ, which is an integral part of this
document.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 60825-4:2022 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60204-1 NOTE Approved as EN 60204-1
IEC 61310-3 NOTE Approved as EN 61310-3
IEC 61496-2 NOTE Approved as EN IEC 61496-2
ISO/TR 7250-2 NOTE Approved as CEN ISO/TR 7250-2
ISO 10218-1 NOTE Approved as EN ISO 10218-1
ISO 14120 NOTE Approved as EN ISO 14120
SIST EN 60825-4:2025
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is
available here: www.cencenelec.eu.
EN/HD
Publication Year Title Year
IEC 60825-1 2014 Safety of laser products – Part 1: Equipment EN 60825-1 2014
classification and requirements
IEC 61508 series Functional safety of EN 61508-1:2010 2010
electrical/electronic/programmable electronic
EN 61508-2:2010 2010
safety-related systems
EN 61508-3:2010 2010
EN 61508-4:2010 2010
EN 61508-5:2010 2010
EN 61508-6:2010 2010
EN 61508-7:2010 2010
ISO 11553-1 - Safety of machinery – Laser processing EN ISO 11553-1:2020 2020
machines – Safety requirements

+ A11 2020
ISO 12100 - Safety of machinery - General principles for EN ISO 12100 2010
design - Risk assessment and risk reduction
ISO 13849-1 - Safety of machinery – Safety-related parts of EN ISO 13849-1 2023
control systems – Part 1: General principles
for design
SIST EN 60825-4:2025
Annex ZZ
(informative)
Relationship between this European Standard and the essential
requirements of Directive 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 ZZ.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 ZZ.1 — Correspondence between this European Standard and Annex I of Directive
2006/42/EC
The relevant Essential Clause(s)/sub-clause(s) Remarks/Notes
Requirements of Directive of this EN
2006/42/EC
1.5.12 Clause 4.1 General design requirements
1.5.12 Clause 4.2 General performance requirements
1.5.12 Clause 4.3 Validation
1.5.12 Clause 4.4 User information
1.5.12 Clause 5.1 Special design requirements
1.5.12 Clause 5.2 Special performance requirements
1.5.12 Clause 5.3 Specification requirements
1.5.12 Clause 5.4 Testing and evaluation requirements
1.5.12 Clause 5.5 Labelling requirements
1.5.12 Clause 5.6 Additional user documentation
1.5.12 Appendix D (normative) Test specifications
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.
SIST EN 60825-4:2025
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

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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

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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
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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

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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.
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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.

SIST EN 60825-4:2025
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.
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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.
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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
d
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 (radiant
exposure) falls to 1/e of its central peak value and the second order moments of the power density distribution
(ISO 11146-1:2005 3.2).
3.7
beam path component
optical component which lies on a defined beam path
Note 1 to entry: Examples of a beam path component include a beam steering mirror, a focus lens or a fibre optic
cable connector.
[SOURCE: IEC 60825-1:2014, 3.16, modified — Example has been removed and Note 1 to
entry has been added.]
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3.8
beam shaping component
optical component introduced in the beam path to transform the profile or cross-section of the
laser beam by means of apertures, or reflective, refractive or diffractive optical components
3.9
beam switching component
optical component or an assembly of components introduced in the beam path to direct or divert,
under external control, the beam path along predetermined direction(s) with the external control
allowing the beam path to be switched from one predetermined direction to another
3.10
fibre optic cable
optical beam guiding component that enables the transmission of laser radiation along a
transparent medium
Note 1 to entry: A fibre optic cable may have a glass or other core that carries the laser radiation and be surrounded
by cladding. The outside of the fibre is protected by cladding and may be further protected by additional layers of
other material such as a polymer or a metal to protect the fibre from mechanical deformation, the ingress of water,
etc. This term also includes other forms of transmission devices such as waveguides.
3.11
foreseeable exposure limit
FEL
maximum laser exposure on the front surface of the laser guard, within the maintenance
inspection interval, assessed under normal and reasonably foreseeable fault conditions
Note 1 to entry: The full specification of an FEL comprises different elements, including irradiance and exposure
duration. More details are given in Annex B.
3.12
front surface
face of the laser guard intended for exposure to laser radiation
3.13
laser guard
physical barrier which limits the extent of a danger zone by preventing laser radiation accessible
at its rear surface from exceeding the Class 1 AEL
3.14
laser processing machine
machine which uses a laser to process materials and is within the scope of ISO 11553-1
3.15
laser termination time
maximum time taken, from generation of an active guard termination signal, for the laser
radiation to be terminated
Note 1 to entry: Laser termination time does not refer to the response of an active laser guard but to the response
of the laser processing machine, in particular the laser safety shutter.
3.16
maintenance inspection interval
time between successive safety maintenance inspections of a laser guard
3.17
passive guard protection time
minimum time determined for a laser exposure equal to a specified protective exposure limit
(PEL) at the front (incident) surface of a passive laser guard for which the passive laser guard
can reliably prevent laser radiation accessible at its rear surface from exceeding the class 1
AEL
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3.18
passive laser guard
laser guard which relies for its operation on its physical properties only
3.19
process zone
zone where the laser beam interacts with the material to be processed
3.20
proprietary laser guard
passive or active laser guard, offered by a manufacturer of laser guards as an independent
product placed on the market with a specified protective exposure limit
3.21
protective exposure limit
PEL
maximum laser exposure of the front surface of a laser guard which prevents laser radiation
accessible at its rear surface from exceeding the Class 1 AEL for the determined passive or
active guard detection time
Note 1 to entry: In practice, there may be more than one maximum laser exposure.
Note 2 to entry: Different PELs may be assigned to different regions of a laser guard if these regions are clearly
identifiable (for example, a viewing window forming an integral part of a laser guard).
Note 3 to entry: See 5.3 for the performance requirements and 5.4 for the full specification. The full specification of
a PEL comprises different elements, including irradiance and exposure duration.
3.22
rear surface
surface of a laser guard that is remote from the associated laser radiation and usually
accessible to the user
3.23
reasonably foreseeable
credible and whose likelihood of occurrence or existence cannot be
disregarded
3.24
safety maintenance inspection
documented inspection performed in accordance with manufacturer’s instructions
3.25
temporary laser guard
substitute or supplementary active or passive laser guard intended to limit the extent of the
danger zone during some service operations of the laser processing machine
4 Requirements for laser guards
4.1 Requirement
Clause 4 specifies the requirements for laser guards that enclose the process zone and are
supplied by the laser processing machine manufacturer.

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4.2 Design requirements
4.2.1 Guard requirement
A laser guard shall satisfy ISO 12100 with respect to the general requirements for guards and
also the more specific requirements with regard to its location and method of fixture. In addition,
the following specific laser requirements shall be met for a laser guard.
4.2.2 General requirements
A laser guard, in its intended location, shall not give rise to any associated hazard at or beyond
its rear surface when exposed to primary laser radiation or secondary optical radiation up to
the foreseeable exposure limit. Annex F provides guidance on assessing the suitability of laser
guards.
NOTE 1 Examples of associated hazards include high temperature, plasma, excessive ultra-violet radiation, the
release of toxic materials, fire, explosion, and electricity.
NOTE 2 See Annex B for assessment of foreseeable exposure limit.
4.2.3 Consumable parts of laser guards
Provision shall be made for the replacement of parts of a laser guard prone to damage by laser
radiation.
NOTE An example of such a part would be a sacrificial or interchangeable screen.
4.3 Performance requirements
4.3.1 General
When the front (incident) surface of a laser guard is subjected to exposure to laser radiation at
the foreseeable exposure limit, the laser guard shall prevent laser radiation accessible at its
rear surface from exceeding the Class 1 AEL at any time over the period of the maintenance
inspection interval. For automated laser processing machines intended for unattended and/or
unsupervised operation, the minimum value of the maintenance inspection interval shall be 8 h.
This requirement shall be satisfied over the intended lifetime of the laser guard under expected
conditions of operation.
NOTE 1 This requirement implies both low transmission of laser radiation and resistance to laser-induced damage.
NOTE 2 Some materials can lose their protective properties due to ageing, exposure to ultraviolet radiation, certain
gases, temperature, humidity and other environmental conditions. Additionally, some materials will transmit laser
radiation under high-intensity laser exposure, even if there is no visible damage (i.e. reversible bleaching).
4.3.2 Active laser guards
a) The active guard protection time shall exceed the laser termination time up to the
foreseeable exposure limits.
b) If an active guard detects an excessive exposure, i.e. is triggered, it shall give rise to a
visible or audible warning. A manual reset is required before laser emission can
recommence.
NOTE See Annex C for an elaboration of terms.
4.4 Validation
4.4.1 General guard validation
If the laser processing machine manufacturer chooses to make a laser guard, the manufacturer
shall confirm that the guard complies with the design requirements and can satisfy the
performance requirements set out in 4.3.

SIST EN 60825-4:2025
IEC 60825-4:2022 © IEC 2022 – 13 –
NOTE See Annex A for guidance on the design and selection of laser guards.
4.4.2 Validation of performance
4.4.2.1 The complete laser guard, or an appropriate sample of the material of construction
of the laser guard, shall be tested at each FEL identified.
It is intended that a table of predetermined PELs for common combinations of lasers and
guarding materials, together with suitable testing procedures, will be issued as an informative
annex in a future amendment to this document. This could provide a simple alternative to direct
testing for the majority of cases.
NOTE See Annex B for the assessment of FEL and Annex C for further elaboration of the terms PEL and FEL.
4.4.2.2 For testing purposes, the FEL exposure shall be achieved either:
a) by calculating or measuring the exposure and reproducing the conditions; or
b) without quantifying the FEL, by creating the machine conditions under which the FEL is
produced.
The condition of the laser guard or sample shall be such as to replicate those physical
conditions of the front surface permitted within the scope of the routine inspection instructions
and within the service life of the guard, which minimize the laser radiation protective properties
of the laser guard (for example, wear and tear and surface contamination) (see 4.5.2).
4.5 User information
4.5.1 The manufacturer shall document and provide to the user the maintenance inspection
interval for the laser guard, and details of inspection and test procedures, cleaning, replacement
or repair of damaged parts, together with any restrictions of use.
4.5.2 The manufacturer shall document and provide to the user instructions that after any
actuation of the safety control system of an active guard, the cause shall be investigated, and
checks shall be made for damage. The instructions shall also include the necessary remedial
action to be taken before resetting the control system.
5 Proprietary laser guards
5.1 General
Clause 5 specifies the requirements to be satisfied by suppliers of proprietary laser guards.
5.2 Design requirements
A proprietary laser guard shall not create any associated hazard at or beyond its rear surface
when exposed to laser radiation up to the specified PEL when used as specified in the user
information (see 5.7).
5.3 Performance requirements
The accessible laser radiation at the rear surface of the laser guard shall not exceed the
Class 1 AEL when its front surface is subjected to laser radiation at the specified PEL at least
during the passive guard protection time. For an active laser guard, this requirement shall apply
to laser radiation accessible over the period of the active guard protection time, measured from
the moment an active guard termination signal is issued.
This requirement shall be satisfied over the intended lifetime of the guard under expected
service conditions.
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