SIST EN 60079-28:2015
(Main)Explosive atmospheres - Part 28: Protection of equipment and transmission systems using optical radiation (IEC 60079-28:2015)
Explosive atmospheres - Part 28: Protection of equipment and transmission systems using optical radiation (IEC 60079-28:2015)
This part of IEC 60079 specifies the requirements, testing and marking of equipment emitting optical radiation intended for use in explosive atmospheres. It also covers equipment located outside the explosive atmosphere or protected by a Type of Protection listed in IEC 60079-0, but which generates optical radiation that is intended to enter an explosive atmosphere. It covers Groups I, II and III, and EPLs Ga, Gb, Gc, Da, Db, Dc, Ma and Mb. This standard 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 may 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.
NOTE 1 See a) and d) of the introduction.
This standard 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 standard. This standard specifies requirements for equipment intended for use under atmospheric conditions.
This standard supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard takes precedence.
This standard applies to optical fibre equipment and optical equipment, including LED and laser equipment, with the exception of the equipment detailed below:
1) Non-array divergent LEDs used for example to show equipment status or backlight function.
2) All luminaires (fixed, portable or transportable), hand lights and caplights; intended to be supplied by mains (with or without galvanic isolation) or powered by batteries:
– with continuous divergent light sources (for all EPLs),
– with LED light sources (for EPL Gc or Dc only).
NOTE 2 Continuous divergent LED light sources for other than EPL Gc or Dc are not excluded from the standard due to the uncertainty of potential ignition concerns regarding high irradiance.
3) Optical radiation sources for EPL Mb, Gb or Gc and Db or Dc applications which comply with Class 1 limits in accordance with IEC 60825-1.
NOTE 3 The referenced Class 1 limits are those that involve emission limits below 15 mW measured at a distance from the optical radiation source in accordance with IEC 60825-1, with this measured distance reflected in the Ex application.
4) Single or multiple optical fibre cables not part of optical fibre equipment if the cables:
– comply with the relevant industrial standards, along with additional protective means, e.g. robust cabling, conduit or raceway (for EPL Gb, Db, Mb, Gc or Dc),
– comply with the relevant industrial standards (for EPL Gc or Dc).
Explosionsgefährdete Bereiche - Teil 28: Schutz von Geräten und Übertragungssystemen, die mit optischer Strahlung arbeiten (IEC 60079-28:2015)
Atmosphères explosives - Partie 28: Protection du matériel et des systèmes de transmission utilisant le rayonnement optique (IEC 60079-28:2015)
Eksplozivne atmosfere - 28. del: Zaščita opreme, ki uporablja optično sevanje, in sistemov za prenos optičnega sevanja (IEC 60079-28:2015)
Ta del standarda IEC 60079 določa zahteve, preskušanje in označevanje opreme, ki oddaja optično sevanje in je namenjena za uporabo v eksplozivnih atmosferah. Obravnava tudi opremo, ki se uporablja zunaj eksplozivne atmosfere ali je zaščitena z vrsto zaščite, navedeno v standardu IEC 60079-0, vendar oddaja optično sevanje, ki je predvideno za vhod v eksplozivno atmosfero. Obravnava skupine I, II in III ter ravni zaščite opreme Ga, Gb, Gc, Da, Db, Dc, Ma in Mb. Ta standard vključuje zahteve za optično sevanje z valovno dolžino od 380 nm do 10 μm. Obravnava naslednje vžigalne mehanizme:
• Pri absorbiranju optičnega sevanja se površine ali delci v posebnih okoliščinah segrejejo celo do temperature, pri kateri lahko pride do vžiga v določeni eksplozivni atmosferi.
• V nekaterih redkih posebnih primerih je neposredno usmerjen močan laserski žarek razčlenil plin ter pri tem ustvaril plazmo in povzročil tlačni skok, ki sta sčasoma postala vir vžiga.
Te procese lahko spodbudi trden material v bližini točke razčlenitve.
OPOMBA 1: Glejte točki a) in d) v uvodu.
Ta standard ne obravnava vžiga zaradi ultravijoličnega sevanja in absorbiranja sevanja v sami eksplozivni mešanici. Eksplozivni absorberji ali absorberji, ki vsebujejo lastne oksidante, oziroma katalitični absorberji so zunaj področja uporabe tega standarda. Ta standard določa zahteve za opremo, predvideno za uporabo v atmosferskih pogojih.
Ta standard dopolnjuje in spreminja splošne zahteve standarda IEC 60079-0. Kadar je zahteva iz tega standarda v nasprotju z zahtevo iz standarda IEC 60079-0, ima prednost zahteva iz tega standarda.
Ta standard se uporablja za opremo z optičnimi vlakni in optično opremo, vključno z opremo LED in lasersko opremo, ne uporablja pa se za to opremo:
1) Nerazporejeni viri razpršene svetlobe LED, ki se na primer uporabljajo za prikaz stanja opreme ali osvetlitev ozadja.
2) Vse svetilke (nepremične, prenosne ali premične), ročne in naglavne svetilke, ki so predvidene za napajanje prek omrežja (z galvansko ločitvijo ali brez) ali baterij:
– z viri neprekinjene razpršene svetlobe (za vse ravni zaščite opreme);
– s svetlobnimi viri LED (samo za raven zaščite opreme Gc ali Dc).
OPOMBA 2: Viri neprekinjene razpršene svetlobe LED za ravni zaščite opreme, ki niso Gc ali Dc, niso izključeni iz standarda, in sicer zaradi pomislekov glede morebitnega vžiga v povezavi z visoki ravnjo obsevanja.
3) Viri optičnega sevanja za uporabo ravni zaščite opreme Mb, Gb ali Gc in Db ali Dc, ki ustrezajo omejitvam Class 1 v skladu s standardom IEC 60825-1.
OPOMBA 3: Navedene omejitve Class 1 vključujejo omejitve emisij pod 15 mW, izmerjene na razdalji od vira optičnega sevanja v skladu s standardom IEC 60825-1, pri čemer se ta izmerjena razdalja navezuje na uporabo v eksplozivni atmosferi.
4) Kabli iz enorodnih ali večrodnih optičnih vlaken niso del opreme z optičnimi vlakni, če kabli:
– izpolnjujejo zahteve ustreznih industrijskih standardov skupaj z dodatnimi zaščitnimi ukrepi, kot so odporna zaščita okablenja, voda ali tečišča (za ravni zaščite opreme Gb, Db, Mb, Gc ali Dc);
– izpolnjujejo zahteve ustreznih industrijskih standardov (samo za raven zaščite opreme Gc ali Dc).
5) oprema, zaprta z ohišjem, ki povsem zadržuje optično sevanje in je v skladu z ustrezno vrsto zaščite, kot to zahteva povezana raven zaščite opreme, pri čemer ohišje izpolnjuje enega od teh pogojev:
– ohišje, pri uporabi katerega bi bil vžig zaradi optičnega sevanja v kombinaciji z absorberji v njegovi notranjosti sprejemljiv, npr. ognjevarno ohišje »d« (IEC 60079-1); ali
– ohišje z zaščito proti vdoru eksplozivne plinske atmosfere, npr. ohišje v nadtlaku »p« (IEC 60079-2) ali ohišje z omejeno prepustnostjo »nR« (IEC 60079-15); ali
– ohišje z zaščito proti vdoru eksplozivne prašne atmosfere, npr. protiprašno ohišje »t« (IEC 60079-31); ali
– ohišje z zaščito proti vdoru absorberjev (npr. ohišja IP 6X), v katerem notranji absorberji niso pričakovani.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 60079-28:2015
01-december-2015
1DGRPHãþD
SIST EN 60079-28:2007
(NVSOR]LYQHDWPRVIHUHGHO =DãþLWDRSUHPHNLXSRUDEOMDRSWLþQRVHYDQMHLQ
VLVWHPRY]DSUHQRVRSWLþQHJDVHYDQMD ,(&
Explosive atmospheres - Part 28: Protection of equipment and transmission systems
using optical radiation (IEC 60079-28:2015)
Explosionsgefährdete Bereiche - Teil 28: Schutz von Geräten und
Übertragungssystemen, die mit optischer Strahlung arbeiten (IEC 60079-28:2015)
Atmosphères explosives - Partie 28: Protection du matériel et des systèmes de
transmission utilisant le rayonnement optique (IEC 60079-28:2015)
Ta slovenski standard je istoveten z: EN 60079-28:2015
ICS:
29.260.20 (OHNWULþQLDSDUDWL]D Electrical apparatus for
HNVSOR]LYQDR]UDþMD explosive atmospheres
SIST EN 60079-28:2015 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 60079-28:2015
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SIST EN 60079-28:2015
EUROPEAN STANDARD EN 60079-28
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2015
ICS 29.260.20 Supersedes EN 60079-28:2007
English Version
Explosive atmospheres - Part 28: Protection of equipment and
transmission systems using optical radiation
(IEC 60079-28:2015)
Atmosphères explosives - Partie 28: Protection du matériel Explosionsgefährdete Bereiche - Teil 28: Schutz von
et des systèmes de transmission utilisant le rayonnement Geräten und Übertragungssystemen, die mit optischer
optique Strahlung arbeiten
(IEC 60079-28:2015) (IEC 60079-28:2015)
This European Standard was approved by CENELEC on 2015-07-01. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 60079-28:2015 E
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SIST EN 60079-28:2015
EN 60079-28:2015
European foreword
The text of document 31/1178/FDIS, future edition 2 of IEC 60079-28, prepared by IEC/TC 31 "Equipment
for explosive atmospheres" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC
as EN 60079-28:2015.
The following dates are fixed:
(dop) 2016-04-01
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2018-07-01
• latest date by which the national
standards conflicting with the
document have to be withdrawn
This document supersedes EN 60079-28:2007.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a mandate given to CENELEC by the European Commission and
the European Free Trade Association, and supports essential requirements of EU Directive.
For the relationship with EU Directive see informative Annex ZZ, which is an integral part of this document.
Endorsement notice
The text of the International Standard IEC 60079-28:2015 was approved by CENELEC as a European
Standard without any modification.
IEC 60079-2 NOTE Harmonized as EN 60079-2.
IEC 60079-10-1 NOTE Harmonized as EN 60079-10-1.
IEC 60079-10-2 NOTE Harmonized as EN 60079-10-2.
IEC 60079-31 NOTE Harmonized as EN 60079-31.
IEC 61508 (series) NOTE Harmonized as EN 61508 (series).
IEC 60825-1 NOTE Harmonized as EN 60825-1.
IEC 61511 (series) NOTE Harmonized as EN 61511 (series).
2
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SIST EN 60079-28:2015
EN 60079-28:2015
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
NOTE 1 When 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.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60050 - International Electrotechnical Vocabulary - -
(IEV)
IEC 60079-0 - Explosive atmospheres -- Part 0: Equipment - EN 60079-0 -
General requirements
IEC 60079-1 - Explosive atmospheres -- Part 1: Equipment EN 60079-1 -
protection by flameproof enclosures "d"
IEC 60079-11 - Explosive atmospheres -- Part 11: Equipment EN 60079-11 -
protection by intrinsic safety "i"
IEC 60079-15 - Explosive atmospheres -- Part 15: Equipment EN 60079-15 -
protection by type of protection "n"
IEC 60825-2 - Safety of laser products -- Part 2: Safety of EN 60825-2 -
optical fibre communication systems (OFCS)
3
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SIST EN 60079-28:2015
EN 60079-28:2015
Annex ZZ
(informative)
Coverage of Essential Requirements of EC Directives
This European Standard has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association and within its scope the standard covers only
the following essential requirements out of those given in Annex II of the EC Directive 2014/34/EU.
– ER 1.0.1 to ER 1.0.4, ER 1.05 (partly)
– ER 1.2.1, ER 1.2.4, ER 1.2.5 (partly), ER 1.2.6, ER 1.2.8, ER 1.2.9
– ER 1.3.1
– ER 1.5.1
– ER 2.0.1
– ER 2.0.2
– ER 2.1.1
– ER 2.1.2
– ER 2.2.1
– ER 2.2.2
– ER 2.3.1
– ER 2.3.2
Compliance with this standard provides one means of conformity with the specified essential
requirements of the Directive[s] concerned.
WARNING: Other requirements and other EC Directives may be applicable to the products falling
within the scope of this standard.
4
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SIST EN 60079-28:2015
IEC 60079-28
®
Edition 2.0 2015-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Explosive atmospheres –
Part 28: Protection of equipment and transmission systems using optical
radiation
Atmosphères explosives –
Partie 28: Protection du matériel et des systèmes de transmission utilisant le
rayonnement optique
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.260.20 ISBN 978-2-8322-2679-7
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: 7 ----------------------
SIST EN 60079-28:2015
– 2 – IEC 60079-28:2015 © IEC 2015
CONTENTS
FOREWORD . 4
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 10
3 Terms and definitions . 10
4 General requirements . 13
5 Types of protection . 13
5.1 General . 13
5.2 Requirements for inherently safe optical radiation “op is” . 14
5.2.1 General . 14
5.2.2 Continuous wave radiation . 14
5.2.3 Pulsed radiation . 18
5.2.4 Ignition tests . 19
5.2.5 Over-power/energy fault protection . 19
5.3 Requirements for protected optical radiation “op pr” . 20
5.3.1 General . 20
5.3.2 Radiation inside optical fibre or cable . 20
5.3.3 Radiation inside enclosures . 21
5.4 Optical system with interlock “op sh” . 21
6 Type verifications and tests . 22
6.1 Test set-up for ignition tests . 22
6.1.1 General . 22
6.1.2 Test vessel . 22
6.1.3 Criteria to determine ignition . 23
6.2 Verification of suitability of test set-up for type tests . 23
6.2.1 Reference gas . 23
6.2.2 Reference absorber . 23
6.2.3 Reference test for continuous wave radiation and pulses above 1 s
duration . 23
6.2.4 Reference test for pulsed radiation below 1 ms pulse duration . 23
6.3 Type tests . 24
6.3.1 Ignition tests with continuous wave radiation and pulses above 1 s
duration . 24
6.3.2 Ignition tests with single pulses less than 1 ms duration . 24
6.3.3 Tests for pulse trains and pulses from 1 ms to 1 s duration . 24
6.3.4 Absorber targets for type tests . 24
6.3.5 Test acceptance criteria and safety factors . 25
7 Marking . 25
Annex A (informative) Reference test data . 27
Annex B (informative) Ignition mechanisms . 28
Annex C (normative) Ignition hazard assessment . 33
Annex D (informative) Typical optical fibre cable design . 35
Annex E (normative) Flow diagram for the assessment of pulses . 36
Bibliography . 37
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SIST EN 60079-28:2015
IEC 60079-28:2015 © IEC 2015 – 3 –
Figure 1 – Optical ignition delay times and safe boundary curve with safety factor of 2 . 22
Figure B.1 – Minimum radiant igniting power with inert absorber target (α
1064
=83 %, α =93 %) and continuous wave-radiation of 1064 nm . 31
nm 805 nm
Figure B.2 – Minimum radiant igniting power with inert absorber target
(α nm=83 %, α nm=93 %) and continuous wave-radiation (PTB: 1064 nm,
1 064 805
HSL: 805 nm, [8]: 803 nm) for some n-alkanes . 32
Figure C.1 – Ignition hazard assessment . 33
Figure D.1 – Example Multi-Fibre Optical Cable Design For Heavy Duty Applications . 35
Figure D.2 – Typical Single Optical Fibre Cable Design . 35
Figure E.1 – Flow diagram for the assessment of pulses according to 5.2.3 . 36
Table 1 – EPLs achieved by application of types of protection for optical systems . 13
Table 2 – Safe optical power and irradiance for Group I and II equipment, categorized
by Equipment Group and temperature class . 15
Table 3 – Safe optical power and irradiance for Group III equipment . 15
Table 4 – Safe limit values for intermediate area, Group I or II, constant power, T1 –
T4 atmospheres, equipment Groups IIA, IIB or IIC (Data derived from Figure B.1
including a safety factor) . 16
Table A.1 – Reference values for ignition tests with a mixture of propane in air at
40 °C mixture temperature . 27
Table B.1 – AIT (auto ignition temperature), MESG (maximum experimental safe gap)
and measured ignition powers of the chosen combustibles for inert absorbers as the
target material (α =83 %, α =93) . 30
1 064 nm 805 nm
Table B.2 – Comparison of measured minimum igniting optical pulse energy
i,min
(Q ) at 90 µm beam diameter with auto ignition temperatures (AIT) and
e,p
minimum ignition energies (MIE) from literature [9] at concentrations in percent by
volume (ϕ) . 32
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SIST EN 60079-28:2015
– 4 – IEC 60079-28:2015 © IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EXPLOSIVE ATMOSPHERES –
Part 28: Protection of equipment and transmission
systems using optical radiation
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.
International Standard IEC 60079-28 has been prepared by IEC technical committee 31:
Equipment for explosive atmospheres.
This second edition cancels and replaces the first edition, published in 2006, and constitutes
a technical revision.
The significance of the changes between IEC 60079-28, Edition 2.0 (2015) and IEC 60079-28,
Edition 1.0 (2006), is as listed below:
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SIST EN 60079-28:2015
IEC 60079-28:2015 © IEC 2015 – 5 –
Significance of changes with respect to IEC 60079-28:2006
Type
Significant Changes Clause Minor and Extension Major
editorial technical
changes changes
Scope: Expansion to include Group III and EPLs Da, Db and x
1
Dc
Scope: Clarification and list of exclusions for optical 1 x
radiation sources
Normative references: Deletion of IEC 60079-10, and 2 x
addition of IEC 60050-426 and 60050-731
Terms and definitions: Some definitions not used in the 3 x
standard deleted. New definitions added.
General requirements: Introduction of an ignition hazard 4 x
assessment moved to 4, statement for presence of
absorbers added, Explanation of EPLs deleted
Table 1: EPLs versus protection types moved from 5.5 to 5.1 x x
5.1, table modified and extended
Structure of Table 2 changed and extended explanation in 5.2.2.1 x
the notes, but with the same limit values
Table 3 for Group III added 5.2.2.1 x
Table 4 replaces Figure 1 for better application 5.2.2.1 x
Detailed requirements for the measurement of optical power 5.2.2.2 x
added
Detailed requirements for the measurement of optical 5.2.2.3 x
irradiance added
Requirements for the assessment of optical pulses for 5.2.3.1 x
Group II much more detailed 5.2.3.2
5.2.3.3
5.2.3.4
Requirements for the assessment of optical pulses for 5.2.3.5 x
Group I and Group III added
Ignition tests: Notes 1 and 2 added 5.2.4 x
Over-power/energy fault protection: Title changed and 5.2.5 x
wording modified for clarity
Radiation inside optical fibre or cable: requirements added, 5.3.2 C1
e.g. pull test
Radiation inside enclosures: IP 6X enclosures, “p” or “t” 5.3.3 x
enclosures added
Optical system with interlock “op sh” 5.4 x
Table 3 deleted, Figure 1 with interlock cutoff delay times
added
Type verifications and tests: structure changed (editorial, 6 x
without changing the requirements)
Marking: markings required by IEC 60079-0 deleted. 7 x
Examples of marking: example with combination of op is
with other types of protection added
Ignition hazard assessment: Flow chart in Figure C.1 Annex C x
modified for better understanding
Old Annex E (Introduction of EPLs) deleted. New Annex E Annex E x
provides a flow chart for the assessment of pulses
according to 5.2.3
Relevant IEC-Standards moved to Clause 2 Formerly x
Annex F
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SIST EN 60079-28:2015
– 6 – IEC 60079-28:2015 © IEC 2015
Explanation of the Types of Significant Changes:
A) Definitions
1) Minor and editorial changes: – Clarification
– 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, increase of the level or removal) made in a way that a
product in conformity with the preceding edition will not always be able to fulfil the requirements given in the later
edition. These changes have to be considered for products in conformity with the preceding edition. For these
changes additional information is provided in clause B) below.
Note These changes represent current technological knowledge. However, these changes should not normally
have an influence on equipment already placed on the market.
B) Information about the background of ‘Major technical changes’
C1 For the protection concept “protected radiation op pr” some requirements like a pull test for optical fibres or
cables have been added.
The text of this standard is based on the following documents:
FDIS Report on voting
31/1178/FDIS 31/1193/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.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60079 series, published under the general title Explosive
atmospheres, can be found on the IEC website.
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SIST EN 60079-28:2015
IEC 60079-28:2015 © IEC 2015 – 7 –
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication 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.
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SIST EN 60079-28:2015
– 8 – IEC 60079-28:2015 © IEC 2015
INTRODUCTION
Optical equipment in the form of lamps, lasers, LEDs, optical fibers etc. is increasingly used
for communications, surveying, sensing and measurement. In material processing, optical
radiation of high irradiance is used. Where the installation is inside or close to explosive
atmospheres, the radiation from such equipment may pass through these atmospheres.
Depending on the characteristics of the radiation it might then be able to ignite a surrounding
explosive atmosphere. The presence or absence of an additional absorber, such as particles,
significantly influences the ignition.
There are four possible ignition mechanisms:
a) Optical radiation is absorbed by surfaces or particles, causing them to heat up, and under
certain circumstances this may allow them to attain a temperature which will ignite a
surrounding explosive atmosphere.
b) Thermal ignition of a gas volume, where the optical wavelength matches an absorption
band of the gas or vapour.
c) Photochemical ignition due to photo dissociation of oxygen molecules by radiation in the
ultraviolet wavelength range.
d) Direct laser induced breakdown of the gas or vapour 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.
The most likely case of ignition occurring in practice with lowest radiation power of ignition
capability is case a). Under some conditions for pulsed radiation case d) also will become
relevant. These two cases are addressed in this standard. Although one should be aware of
ignition mechanism b) and c) explained above, they are not addressed in this standard due to
the very special situation with ultraviolet radiation and with the absorption properties of most
gases (see Annex A).
This standard describes precautions and requirements to be taken when using optical
radiation transmitting equipment in explosive gas or dust atmospheres. It also outlines a test
method, which can be used in special cases to verify that a beam is not ignition capable under
selected test conditions, if the optical limit values cannot be guaranteed by assessment or
beam strength measurement.
There is equipment outside the scope of this standard because the optical radiation
associated with this equipment is considered not to be a risk of ignition for the following
reasons:
– due to low radiated power or divergent light, and
– as hot surfaces created due to a too small distance from the radiation source to an
absorber which is already considered by general requirements for lighting equipment.
In most cases the optical equipment is associated with electrical equipment and where the
electrical equipment is located in a hazardous area then other parts of the IEC 60079 series
will also apply. This standard provides guidance for:
a) Ignition hazards associated with optical systems in explosive atmospheres as defined in
IEC 60079-10-1 and IEC 60079-10-2, and,
b) Control of ignition hazards from equipment using optical radiation in explosive
atmospheres.
This standard is related to the integrated system used to control the ignition hazard from
equipment using optical radiation in explosive atmospheres.
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SIST EN 60079-28:2015
IEC 60079-28:2015 © IEC 2015 – 9 –
EXPLOSIVE ATMOSPHERES –
Part 28: Protection of equipment and transmission
systems using optical radiation
1 Scope
This part of IEC 60079 specifies the requirements, testing and marking of equipment emitting
optical radiation intended for use in explosive atmospheres. It also covers equipment located
outside the explosive atmosphere or protected by a Type of Protection listed in IEC 60079-0,
but which generates optical radiation that is intended to enter an explosive atmosphere. It
covers Groups I, II and III, and EPLs Ga, Gb, Gc, Da, Db, Dc, Ma and Mb.
This s
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