FprEN IEC 60079-28:2025
(Main)Explosive atmospheres - Part 28: Protection of equipment and transmission systems using optical radiation
Explosive atmospheres - Part 28: Protection of equipment and transmission systems using optical radiation
IEC 60079-28:2025 specifies additional requirements for Ex Equipment, Ex associated equipment or Ex Components containing optical systems emitting optical radiation, which is exposed to explosive atmospheres. These additional requirements are applicable for all equipment groups and all Equipment Protection Levels (EPL). This document contains requirements for optical radiation in the wavelength range from 380 nm to 10 µm. It covers the following ignition mechanisms: • Optical radiation is absorbed by surfaces or particles, causing them to heat up, and under certain circumstances this might allow them to attain a temperature which will ignite a surrounding explosive atmosphere. • In rare special cases, direct laser induced breakdown of the gas at the focus of a strong beam, producing plasma and a shock wave both eventually acting as ignition source. These processes can be supported by a solid material close to the breakdown point. • Annex A provides guidance when considering ignition mechanisms that influence the hazard of optics in explosive atmospheres. This document applies to a) laser equipment; and b) optical fibre equipment; and c) any optical system that converts light into convergent beams with focal points within the hazardous area only. This document does not apply to: d) laser equipment for EPL Mb, Gb, Gc, Db or Dc applications which complies with Class 1 limits in accordance with IEC 60825-1; or e) Single or multiple optical fibre cables not part of optical fibre equipment if the cables: 1) comply with the relevant industrial standards for optical fibre cables, along with additional protective means, for example robust cabling, conduit or raceway (for EPL Gb, Db, Mb, Gc or Dc); or 2) comply with the relevant industrial standards for optical fibre cables (for EPL Gc or Dc); or f) Optical radiation sources as defined in i) to iii) above where the optical radiation is fully contained in an enclosure complying with one of the following Types of Protection suitable for the EPL, or the minimum ingress protection rating specified: 1) flameproof "d" enclosures (IEC 60079-1); or 2) pressurized "p" enclosures (IEC 60079-2); or 3) restricted breathing "nR" enclosure (IEC 60079-15); or 4) dust protection "t" enclosures" (IEC 60079-31); or 5) an enclosure that provides a minimum ingress protection of IP 6X and where no internal absorbers are to be expected and complying with "Tests of enclosures" in IEC 60079-0. This document does not cover ignition by ultraviolet radiation and by absorption of the radiation in the explosive mixture itself. Explosive absorbers or absorbers that contain their own oxidizer as well as catalytic absorbers are also outside the scope of this document. This document supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this document conflicts with a requirement of IEC 60079-0, the requirement of this document takes precedence. This third edition cancels and replaces the second edition published in 2015. This edition constitutes a technical revision
Explosionsgefährdete Bereiche - Teil 28: Schutz von Geräten und Übertragungssystemen, die mit optischer Strahlung arbeiten
Atmosphères explosives - Partie 28 : Protection du matériel et des systèmes de transmission utilisant le rayonnement optique
IEC 60079-28:2025 spécifie les exigences supplémentaires applicables aux appareils Ex, aux appareils associés Ex ou aux composants Ex contenant des systèmes optiques émettant un rayonnement optique, qui sont exposés à des atmosphères explosives. Ces exigences supplémentaires s'appliquent à tous les groupes d'appareils et à tous les niveaux de protection du matériel (EPL, Equipment Protection Levels). Le présent document contient les exigences relatives aux rayonnements optiques dans la plage de longueurs d'onde comprise entre 380 nm et 10 µm. Il couvre les mécanismes d'allumage suivants: – le rayonnement optique est absorbé par les surfaces ou particules, provoquant leur échauffement et, dans certaines circonstances, celles-ci peuvent atteindre une température qui amorce l'inflammation de l'atmosphère explosive environnante; – dans certains cas rares particuliers, le craquage direct d'un gaz par laser, au point de focalisation d'un faisceau puissant, produisant un plasma et une onde de choc, les deux agissant en définitive comme source d'inflammation. Ces processus peuvent prendre naissance dans un matériau solide proche de son point de craquage; – Annexe A fournit des recommandations lors de l'examen des mécanismes d'inflammation qui influencent le danger optique dans les atmosphères explosives. Le présent document s'applique: a) aux équipements laser; et b) aux équipements à fibres optiques; et c) à tout système optique qui convertit la lumière en faisceaux convergents avec des points focaux situés dans la zone dangereuse uniquement. Le présent document ne s'applique pas: d) aux équipements laser pour les applications EPL Mb, Gb, Gc, Db ou Dc qui satisfont aux limites de Classe 1 conformément à l'IEC 60825-1; e) aux câbles à fibres optiques simples ou multiples ne faisant pas partie des équipements à fibres optiques si les câbles: 1) satisfont aux normes industrielles pertinentes pour les câbles à fibres optiques, ainsi que les moyens de protection supplémentaires, comme les câblages robustes, les conduits ou les chemins (pour EPL Gb, Db, Mb, Gc ou Dc); ou 2) satisfont aux normes industrielles pertinentes pour les câble à fibres optiques (pour EPL Gc ou Dc); ou f) aux sources de rayonnement optique telles que définies aux points a) à c) ci-dessus, lorsque le rayonnement optique est totalement contenu dans une enveloppe satisfaisant à l'un des modes de protection suivants adaptés à l'EPL, ou à la caractéristique assignée minimale de protection contre les pénétrations spécifiée: 1) les enveloppes "d" antidéflagrantes (IEC 60079-1); ou 2) des enveloppes "p" sous pression (IEC 60079-2); ou 3) une enveloppe "nR" à respiration limitée (IEC 60079-15); ou 4) les enveloppes "t" de protection contre la poussière (IEC 60079-31); ou 5) une enveloppe qui fournit une protection minimale contre la pénétration IP 6X et lorsqu'aucun absorbeur interne n'est attendu, et qui satisfait aux "Essais des enveloppes" de l'IEC 60079-0. Le présent document ne couvre pas l'inflammation par rayonnement ultraviolet et par absorption du rayonnement dans le mélange explosif lui-même. Les absorbeurs explosifs ou absorbeurs qui contiennent leur propre oxydant/comburant de même que les absorbeurs catalytiques sont également hors du domaine d'application du présent document. Le présent document complète et modifie les
Eksplozivne atmosfere - 28. del: Zaščita opreme, ki uporablja optično sevanje, in sistemov za prenos optičnega sevanja
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN IEC 60079-28:2024
01-november-2024
Eksplozivne atmosfere - 28. del: Zaščita opreme, ki uporablja optično sevanje, in
sistemov za prenos optičnega sevanja
Explosive atmospheres - Part 28: Protection of equipment and transmission systems
using optical radiation
Explosionsgefährdete Bereiche - Teil 28: Schutz von Geräten und
Übertragungssystemen, die mit optischer Strahlung arbeiten
Atmosphères explosives - Partie 28: Protection du matériel et des systèmes de
transmission utilisant le rayonnement optique
Ta slovenski standard je istoveten z: prEN IEC 60079-28:2024
ICS:
29.260.20 Električni aparati za Electrical apparatus for
eksplozivna ozračja explosive atmospheres
oSIST prEN IEC 60079-28:2024 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN IEC 60079-28:2024
oSIST prEN IEC 60079-28:2024
31/1793/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60079-28 ED3
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2024-09-06 2024-11-29
SUPERSEDES DOCUMENTS:
31/1726/CD, 31/1761A/CC
IEC TC 31 : EQUIPMENT FOR EXPLOSIVE ATMOSPHERES
SECRETARIAT: SECRETARY:
United Kingdom Mr Tom Stack
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):
ASPECTS CONCERNED:
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
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clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).
TITLE:
Explosive atmospheres - Part 28: Protection of equipment and transmission systems using optical
radiation
PROPOSED STABILITY DATE: 2029
NOTE FROM TC/SC OFFICERS:
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
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oSIST prEN IEC 60079-28:2024
31/1793/CDV -2- IEC 60079-28 ED3 © IEC 2024
1 CONTENTS
3 FOREWORD . 4
4 INTRODUCTION . 7
5 1 Scope . 8
6 2 Normative references . 9
7 3 Terms and definitions . 9
8 4 Types of Protection . 12
9 4.1 General . 12
10 4.2 Requirements for inherently safe optical radiation “op is” . 13
11 4.2.1 Continuous wave radiation . 13
12 4.2.2 Pulsed radiation . 14
13 4.2.3 Over-power/energy fault protection . 16
14 4.3 Requirements for protected optical radiation “op pr” . 16
15 4.3.1 General . 16
16 4.3.2 Radiation inside optical fibre or cable . 17
17 4.3.3 Radiation inside enclosures . 17
18 4.4 Optical system with interlock “op sh” . 17
19 5 Type verifications and tests . 18
20 5.1 Optical detector . 18
21 5.2 Optical power . 19
22 5.3 Optical irradiance . 20
23 6 Marking . 20
24 Annex A (informative) Ignition mechanisms . 22
25 Annex B (informative) Typical optical fibre cable design . 27
26 Annex C (informative) Overview for the assessment of pulsed radiation . 28
27 Bibliography . 29
29 Figure 1 – Optical ignition delay times and safe boundary curve with safety factor of 2 . 18
30 Figure A.1 – Minimum radiant igniting power with inert absorber target (
31 =83 %, =93 %) and continuous wave-radiation of 1064 nm . 25
nm 805 nm
32 Figure A.2 – Minimum radiant igniting power with inert absorber target
33 ( nm=83 %, nm=93 %) and continuous wave-radiation (PTB: 1064 nm,
1 064 805
34 HSL: 805 nm, [8]: 803 nm) for some n-alkanes . 26
35 Figure B.1 – Example Multi-Fibre Optical Cable Design For Heavy Duty Applications . 27
36 Figure B.2 – Typical Single Optical Fibre Cable Design . 27
37 Figure C.1 – Flow diagram for the assessment of pulses according to 4.2.2 . 28
39 Table 1 – EPLs achieved by application of Types of Protection for optical systems . 12
40 Table 2 – Safe optical power and irradiance for Group I and II equipment, categorized
41 by Equipment Group and temperature class . 13
42 Table 3 –Safe optical power for Group II equipment for temperature classes T1 to T4 . 14
43 Table 4 – Safe optical power and irradiance for Group III equipment. 14
oSIST prEN IEC 60079-28:2024
IEC 60079-28 ED3 © IEC 2024 -3- 31/1793/CDV
44 Table A.1 – AIT (auto ignition temperature), MESG (maximum experimental safe gap)
45 and measured ignition powers of the chosen combustibles for inert absorbers as the
46 target material ( =83 %, =93) . 24
1 064 nm 805 nm
47 Table A.2 – Comparison of measured minimum igniting optical pulse energy
i,min
48 (Q ) at 90 m beam diameter with auto ignition temperatures (AIT) and
e,p
49 minimum ignition energies (MIE) from literature [9] at concentrations in percent by
50 volume () . 26
oSIST prEN IEC 60079-28:2024
31/1793/CDV -4- IEC 60079-28 ED3 © IEC 2024
54 INTERNATIONAL ELECTROTECHNICAL COMMISSION
55 ____________
57 EXPLOSIVE ATMOSPHERES –
59 Part 28: Protection of equipment and transmission
60 systems using optical radiation
64 FOREWORD
65 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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97 International Standard IEC 60079-28 has been prepared by MT 60079-28, of IEC technical
98 committee 31 Equipment for explosive atmospheres.
99 This third edition cancels and replaces the second edition published in 2015. This edition
100 constitutes a technical revision.
101 Users of this document are advised that interpretation sheets clarifying the interpretation of this
102 document can be published. Interpretation sheets are available from the IEC webstore and can
103 be found in the “history” tab of the page for each document.
104 The significance of the changes between IEC 60079-28, Edition 3 and IEC 60079-28, Edition 2
105 is as listed below:
oSIST prEN IEC 60079-28:2024
IEC 60079-28 ED3 © IEC 2024 -5- 31/1793/CDV
106 Significance of changes with respect to IEC 60079-28:2015
Type
Significant Changes Clause Minor and Extension Major
editorial technical
changes changes
Ignition test is removed 5.4 to 5.7;
Annex A
C1
(of Ed.2)
Clarification of the applicability of IEC 60079-28 for laser
equipment, optical fibre equipment and any optical system
1 X
that converts light into convergent beams with focal points
within the hazardous area only.
The structure of this document was modified; new clause
5 X
“Type verifications and tests” added
New subclause “Optical detector” 5.1 X
The possibility to do calculations for the assessment of
5.2 X
optical power is clarified
Additional examples for the marking are added. 6 X
107 NOTE 1 The technical changes referred to include the significance of technical changes in the revised IEC
108 Standard, but they do not form an exhaustive list of all modifications from the previous version. More guidance may
109 be found by referring to the Redline Version of the standard.
Explanation of the Types of Significant Changes:
A) Definitions
1) Minor and editorial clarification
changes:
decrease of technical requirements
minor technical change
editorial corrections
These are changes which modify requirements in an editorial or a minor technical way. They
include changes of the wording to clarify technical requirements without any technical
change, or a reduction in level of existing requirement.
2) Extension: addition of technical options
These are changes which add new or modify existing technical requirements, in a way that
new options are given, but without increasing requirements for equipment that was fully
compliant with the previous standard. Therefore, these will not have to be considered for
products in conformity with the preceding edition.
3) Major technical changes: addition of technical requirements
increase of technical requirements
These are changes to technical requirements (addition, i
...
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