prEN ISO/IEC 80079-41

SLOVENSKI STANDARD
01-maj-2025
Eksplozivne atmosfere - 41. del: Batni motorji z notranjim zgorevanjem (ISO/IEC
DIS 80079:41:2025)
Explosive atmospheres - Part 41: Reciprocating internal combustion engines (ISO/IEC
DIS 80079-41:2025)
Explosionsfähige Atmosphären - Teil 41: Hubkolben-Verbrennungsmotoren (ISO/IEC
DIS 80079:41:2025)
Atmosphères explosives - Partie 41: Moteurs alternatifs à combustion interne (ISO/IEC
DIS 80079-41:2025)
Ta slovenski standard je istoveten z: prEN ISO/IEC 80079-41
ICS:
27.020 Motorji z notranjim Internal combustion engines
zgorevanjem
29.260.20 Električni aparati za Electrical apparatus for
eksplozivna ozračja explosive atmospheres
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/IEC
DIS
80079-41
ISO/TMBG
Explosive atmospheres —
Secretariat: ISO
Part 41:
Voting begins on:
Reciprocating internal combustion 2025-04-04
engines
Voting terminates on:
2025-06-27
Atmosphères explosives —
Partie 41: Moteurs alternatifs à combustion interne
ICS: 29.260.20; 27.020
THIS DOCUMENT IS A DRAFT CIRCULATED
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© ISO/IEC 2025
ISO/IEC DIS 80079-41:2025(en)
DRAFT
ISO/IEC DIS 80079-41:2025(en)
International
Standard
ISO/IEC
DIS
80079-41
ISO/TMBG
Explosive atmospheres —
Secretariat: ISO
Part 41:
Voting begins on:
Reciprocating internal combustion
2025-04-04
engines
Voting terminates on:
2025-06-27
Atmosphères explosives —
Partie 41: Moteurs alternatifs à combustion interne
ICS: ISO ics
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
This document is circulated as received from the committee secretariat.
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This draft is submitted to a parallel vote in ISO and in IEC.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO/IEC 2025
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Published in Switzerland Reference number
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ISO/IEC DIS 80079-41:2025(en)
© ISO/IEC 2025 – All rights reserved
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ISO/IEC DIS 80079-41:2025(en)
31M/252/CDV 2 ISO/IEC 80079-41 ED1 © ISO/IEC 2025
2 INTERNATIONAL ELECTROTECHNICAL COMMISSION
3 ____________
5 EXPLOSIVE ATMOSPHERES –
7 Part 41: Reciprocating internal combustion engines
9 FOREWORD
10 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
11 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
12 co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
13 in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
14 Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC Publication(s)"). Their
15 preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
16 may participate in this preparatory work. International, governmental and non-governmental organizations liaising
17 with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
18 Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
19 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
20 consensus of opinion on the relevant subjects since each technical committee has representation from all
21 interested IEC National Committees.
22 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
23 Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
24 Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
25 misinterpretation by any end user.
26 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
27 transparently to the maximum extent possible in their national and regional publications. Any divergence between
28 any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
29 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
30 assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
31 services carried out by independent certification bodies.
32 6) All users should ensure that they have the latest edition of this publication.
33 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
34 members of its technical committees and IEC National Committees for any personal injury, property damage or
35 other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
36 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
37 Publications.
38 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
39 indispensable for the correct application of this publication.
40 9) IEC and ISO draw attention to the possibility that the implementation of this document may involve the use of (a)
41 patent(s). IEC and ISO take no position concerning the evidence, validity or applicability of any claimed patent
42 rights in respect thereof. As of the date of publication of this document, IEC and ISO had not received notice of
43 (a) patent(s), which may be required to implement this document. However, implementers are cautioned that this
44 may not represent the latest information, which may be obtained from the patent database available at
45 https://patents.iec.ch and www.iso.org/patents. IEC and ISO shall not be held responsible for identifying any or
46 all such patent rights.
47 ISO/IEC 80079-41 has been prepared by ISO/IEC subcommittee 31M: Non-electrical equipment
48 and protective systems for explosive atmospheres, of IEC technical committee XX: Equipment
49 for explosive atmospheres. It is an International Standard.
50 It is published as a double logo International Standard.
51 The text of this International Standard is based on the following documents of IEC:
FDIS Report on voting
31M/XX/FDIS 31M/XX/RVD
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53 Full information on the voting for its approval can be found in the report on voting indicated in
54 the above table. In ISO, the document was approved by XXX P members out of YYY having
55 cast a vote.
56 The language used for the development of this International Standard is English.
57 A list of all parts in the ISO/IEC 80079 series, published under the general title Explosive
58 atmospheres, can be found on the IEC website.
59 This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
60 accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
61 at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
62 described in greater detail at www.iec.ch/publications.
63 The committee has decided that the contents of this document will remain unchanged until the
64 stability date indicated on the IEC website under webstore.iec.ch in the data related to the
65 specific document. At this date, the document will be
66 • reconfirmed,
67 • withdrawn,
68 • replaced by a revised edition, or
69 • amended.
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72 EXPLOSIVE ATMOSPHERES –
74 Part 41: Reciprocating internal combustion engines
78 1 Scope
79 This part of ISO/IEC 80079 specifies the technical requirements for design, construction,
80 conversion, testing, marking, and the information required for use to avoid or minimise the
81 possibility of ignition which could result from a from reciprocating internal combustion engine
82 intended for use in explosive atmospheres including:
83 – Group I EPL Mb for use in underground workings susceptible to firedamp or combustible
84 dust,
85 – Group II EPL Gb and EPL Gc for use in explosive atmospheres of flammable gas and
86 vapour, and
87 – Group III EPL Db and EPL Dc for use in explosive atmospheres of combustible dust.
88 – For EPL Gc and Dc engines, only normal operating conditions need to be considered.
89 Malfunctions need not be considered (see B.2.1).
90 This document includes those tests of the engine and its ancillary devices that are required to
91 verify compliance with this document.
92 This document applies to reciprocating internal combustion engines with compression ignition
93 for EPL Mb, Gb, Gc, Db, Dc and gaseous fuelled spark ignition engines for EPL Gc. See
94 Annex G.
95 This document does not define requirements relating to the driven machinery and equipment.
96 This document does not apply to
97 • explosive mixtures of vapours and gases, which tend to self-decompose (for example
98 carbon disulphide (CS2), ethylene oxide (C2H4O), acetylene (C2H2)) or which are
99 chemically unstable;
100 • hydrogen fuelled engines, including blends;
101 • engines used in areas for the processing, manufacture or storage of explosives;
102 • gasoline and other spark ignited engines where the fuel is injected into the combustion
103 chamber as a liquid; or
104 • electrical ignition spark systems.
105 Note 1 Spark ignition systems used with equipment covered by ISO/IEC 80079-41 is covered by IEC 60079-45
106 This document solely deals with explosion protection requirements. Requirements on gaseous
107 or particulate exhaust emissions are not covered by this standard.
108 General safety requirements are not included in this International Standard.
109 NOTE 1 General safety requirements are covered for the EU in EN 1679-1:1998+A1:2011.
110 This document does not specify requirements for safety, other than those directly related to the
111 possibility of ignition of flammable mixtures in the surrounding atmosphere which can lead to
112 an explosion.
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113 This document supplements and modifies the general requirements of IEC 60079-0 and
114 ISO 80079-36. Where a requirement of this document conflicts with a requirement of
115 IEC 60079-0 and ISO 80079-36 as is applicable for Ex engines, the requirement of this standard
116 takes precedence.
117 The standard atmospheric conditions (relating to the explosion characteristics of the
118 atmosphere) under which it may be assumed that the engine can be operated are:
119 • temperature –20 °C to +60 °C
120 • pressure 80 kPa (0,8 bar) to 110 kPa (1,1 bar); and
121 • air with normal oxygen content, typically 21% v/v.
122 Additional consideration and additional testing may be required for Ex engines operating outside the standard
123 atmospheric conditions.The ignition hazard assessment, ignition, protection provided, additional testing, (if
124 necessary) manufacturer’s technical documentation and instructions to the user are intended to clearly demonstrate
125 the engine’s suitability for the conditions. NOTE 2 Changes in temperature and pressure have an influence on the
126 characteristics of the explosive atmosphere including ignitability
127 NOTE 3 IEC TS 60079-43 gives information for equipment used in explosive atmospheres in environmental
128 conditions which include ambient temperatures below –20 °C and additional adverse conditions, including maritime
129 applications.
130 NOTE 4 Reciprocating internal combustion engines are not considered as pressure vessels.
131 NOTE 5 On-going inspection, maintenance and repair aspects play an important role in control of hazardous area
132 installations and the user’s attention is drawn to IEC 60079-17, IEC 60079-19 and IEC 60079-14 and manufacturer’s
133 instructions for further information concerning these aspects.
134 2 Normative references
135 The following documents are referred to in the text in such a way that some or all their content
136 constitutes requirements of this document. For dated references, only the edition cited applies.
137 For undated references, the latest edition of the referenced document (including any
138 amendments) applies.
139 ISO 1813, Belt drives — V-ribbed belts, joined V-belts and V-belts including wide section belts
140 and hexagonal belts — Electrical conductivity of antistatic belts: Characteristics and methods
141 of test
142 ISO 2710-1, Functional safety - Safety instrumented systems for the process industry sector -
143 Part 1: Framework, definitions, system, hardware and application programming requirements
144 ISO 7967-1, Functional safety - Safety instrumented systems for the process industry sector -
145 Part 1: Framework, definitions, system, hardware and application programming requirements
146 ISO 7967-2, Functional safety - Safety instrumented systems for the process industry sector -
147 Part 1: Framework, definitions, system, hardware and application programming requirements
148 ISO 7967-3, Reciprocating internal combustion engines — Vocabulary of components and
149 systems — Part 3: Valves, camshaft drives and actuating mechanisms
150 ISO 7967-4, Reciprocating internal combustion engines Vocabulary of components and systems
151 Part 4: Pressure charging and air/exhaust gas ducting systems
152 ISO 7967-8, Reciprocating internal combustion engines — Vocabulary of components and
153 systems — Part 8: Starting systems
154 ISO 9563, Belt drives Electrical conductivity of antistatic endless synchronous belts
155 Characteristics and test method
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156 ISO 12100, Safety of machinery — General principles for design — Risk assessment and risk
157 reduction
158 ISO 15510, Stainless steels — Chemical composition
159 ISO 17025, General requirements for the competence of testing and calibration laboratories
160 ISO 29463 (all parts), High efficiency filters and filter media for removing particles in air
161 ISO 80079-36, Explosive atmospheres - Part 36: Non-electrical equipment for explosive
162 atmospheres - Basic method and requirements
163 ISO 80079-37, Explosive atmospheres - Part 37: Non-electrical equipment for explosive
164 atmospheres - Non electrical type of protection constructional safety "c", control of ignition
165 source "b", liquid immersion "k"
166 IEC 60034-5, Rotating electrical machines - Part 5: Degrees of protection provided by the
167 integral design of rotating electrical machines (IP code) - Classification
168 IEC 60079-0:2017, Explosive atmospheres - Part 0: Equipment - General requirements
169 IEC 60079-1, Explosive atmospheres - Part 1: Equipment protection by flameproof enclosures
170 "d"
171 IEC 60079-10-1, Explosive atmospheres - Part 10-1: Classification of areas - Explosive gas
172 atmospheres
173 IEC 60079-10-2, Explosive atmospheres - Part 10-2: Classification of areas - Explosive dust
174 atmospheres
175 IEC 60079-14:2014, Explosive atmospheres - Part 14: Electrical installation design, selection
176 and installation of equipment, including initial inspection
177 IEC 60079-25, Explosive atmospheres - Part 25: Intrinsically safe electrical systems
178 IEC 60079-29-1, Explosive atmospheres - Part 29-1: Gas detectors - Performance requirements
179 of detectors for flammable gases
180 IEC 60079-29-2, Explosive atmospheres - Part 29-2: Gas detectors - Selection, installation, use
181 and maintenance of detectors for flammable gases and oxygen
182 IEC 60079-29-3, Explosive atmospheres - Part 29-3: Gas detectors - Guidance on functional
183 safety of fixed gas detection systems
184 IEC TS 60079-32-1, Explosive atmospheres - Part 32-1: Electrostatic hazards - guidance
185 IEC 60079-32-2, Explosive atmospheres - Part 32-2: Electrostatics hazards - Tests
186 IEC 60079-45, Electrical Ignition Systems for Internal Combustion Engines
187 IEC TS 60079-46, Explosive atmospheres - Part 46: Equipment assemblies
188 IEC 60204-1:2016, Safety of machinery - Electrical equipment of machines - Part 1: General
189 requirements
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190 IEC 61340-2-3, Electrostatics - Part 2-3: Methods of test for determining the resistance and
191 resistivity of solid materials used to avoid electrostatic charge accumulation
192 IEC 61508 (all parts), Functional safety of electrical/electronic/programmable electronic safety-
193 related systems
194 IEC 61511 (all parts), Functional safety - Safety instrumented systems for the process industry
195 sector
196 IEC 60529, Degrees of protection provided by enclosures (IP Code)
197 ISO/IEC 80079-38, Explosive atmospheres - Part 38: Equipment and components in explosive
198 atmospheres in underground mines
199 ISO/IEC 80079-49, Explosive atmospheres - Part 49: Flame arresters - Performance
200 requirements, test methods and limits for use
201 EN 1127-2, Explosive atmospheres - Explosion prevention and protection - Part 2: Basic
202 concepts and methodology for mining
203 EN 1822-1, High efficiency air filters (EPA, HEPA and ULPA) - Part 1: Classification,
204 performance testing, marking
205 3 Definitions
206 For the purposes of this document, the terms and definitions given in ISO 2710-1, ISO 7967-1,
207 ISO 7967-2, ISO 7967-3, ISO 7967-4, ISO 7967-8, IEC 60079-0, IEC 60079-10-1, IEC 60079-
208 10-2, ISO 80079-36, ISO 80079-37, ISO/IEC 80079-38 and the following apply.
209 ISO and IEC maintain terminology databases for use in standardization at the following
210 addresses:
211 • IEC Electropedia: available at https://www.electropedia.org/
212 • ISO Online browsing platform: available at https://www.iso.org/obp
213 3.1
214 maximum surface temperature
215 highest temperature that can be attained in service under the most adverse operating conditions
216 (but within the recognized tolerance) by any part or surface of the Ex equipment
217 Note 1 to entry: The maximum surface temperature marked on the equipment includes safety margins depending
218 on the EPL of the equipment.
219 Note 2 to entry: The surface temperature which is relevant can be internal or external depending upon the Type of
220 Protection concerned.
221 Note 3 to entry: For Ex equipment in an explosive dust atmosphere, this temperature occurs on the external surface
222 of the enclosure and can include a defined dust layer condition.
223 Note 4 to entry: This includes exhaust temperature and other fluid temperatures that may come in contact with
224 explosive atmospheres.
225 [SOURCE: IEC 60079-0:2017, 3.57, modified – definition modified and Notes to entry added]
226 3.2
227 maximum exhaust gas temperature
228 highest temperature under the most adverse operating conditions measured at the point where
229 the gas stream first meets the surrounding atmosphere
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230 3.3
231 gas path
232 parts of an engine through which air and exhaust gas passes when the engine is running
233 3.4
234 flame arrester
235 FA
236 device fitted to the opening of an enclosure, or to the connecting pipe work of a system of
237 enclosures, and whose intended function is to allow fluid flow but prevent the transmission of
238 flame
239 3.5
240 closed joint
241 assembly between two parts which is intended to be gas or dust tight or both
242 3.6
243 open joint
244 joint between two parts designed to reduce the heat energy from a gas explosion to the point
245 where it will not ignite a similar external explosive gas mixture
246 3.7
247 spark arrester
248 device, system, or method which controls the emission from an engine exhaust of particles
249 potentially capable of igniting combustible material in the vicinity by virtue of their size and
250 temperature
251 3.8
252 engine control module
253 ECM
254 electronic processor managing the transfer of data between engine sensors, actuators, control
255 elements, and information-storage and display units
256 3.9
257 safety devices
258 devices intended for use inside or outside explosive atmospheres but required for, or
259 contributing to, the safe functioning of equipment and protective systems on the engine with
260 respect to the risks of explosion
261 Note 1 to entry: Safety devices differ from the term devices used in the IEC 61508 and IEC 61511 series. Safety
262 devices are comparable to the terms like "safety-related system (IEC 61508)" or "safety instrumented system
263 (IEC 61511)".
264 Note 2 to entry: In this standard the safety devices are intended to reduce the likelihood of a potential ignition
265 source becoming effective.
266 [SOURCE: ISO 80079-37:2016, modified – "on the engine" and Notes 1 and 2 to entry have
267 been added]
268 3.10
269 performance requirements
270 verifiable requirements related to properties of safety devices and shutdown systems to ensure
271 that the safety function is effective
272 Note 1 to entry: IEC TS 60079-42 includes information for diagnostics, capacity, functionality, response,
273 effectiveness, integrity, reliability, availability, ability to withstand loads and robustness.
274 3.11
275 abnormal combustion
276 unintended or uncontrolled combustion in the engine
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277 3.12
278 explosion protection
279 application of one or more types of protection to minimise the risk of a piece of equipment,
280 apparatus, component, fitting or device causing an ignition of a surrounding explosive gas,
281 vapour, mist or dust atmosphere
282 3.13
283 explosion protected engine
284 engine with measures applied in the construction to prevent it becoming an ignition source when
285 within an explosive atmosphere
286 4 Ignition hazards
287 Specific hazards for engine applications in potentially explosive atmospheres are listed below
288 according to ISO 80079-36.
289 The main sources of ignition are:
290 – hot surfaces;
291 – flames and hot gases;
292 – mechanically generated sparks;
293 – electrically generated arcs and sparks;
294 – static electricity;
295 – stray electric currents;
296 – adiabatic compression.
297 The design specifications for the engine necessary to minimise the likelihood of the ignition of
298 an external potential atmosphere depend on the application and are characterised by:
299 – temperature classification,
300 – presence of flammable gases, or
301 – presence of combustible dust and ventilation effects.
302 5 Safety requirements and measures
303 5.1 For all Equipment Protection Levels (EPLs)
304 5.1.1 General
305 For EPL Mb, EPL Gb and EPL Db engines, normal operating conditions and expected
306 malfunctions shall be taken into account. Rare malfunctions need not be considered (see A.1.1,
307 A.1.2, A.1.3, B.2.1, B.2.2, B.2.3).
308 For EPL Gc and EPL Dc engines, only normal operating conditions need to be considered.
309 Malfunctions need not be considered (see B.2.1).
310 For EPL Mb, if other gases besides firedamp are present, the engine shall comply in addition
311 with 5.3.1 and also EN 1127-2 and ISO/IEC 80079-38
312 For EPL Db and EPL Dc, all hot surfaces shall be designed to reduce the possibility of a dust
313 layer build up. In particular the potential of dust layer build-up in excess of 5 mm shall be
314 avoided ((see also 8.2.3) in the instructions for use).
315 Equipment intended for mines where the atmosphere, in addition to firedamp, might contain
316 flammable gases other than methane, shall be constructed and tested in accordance with the
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317 requirements relating to Group I and to the subdivision of Group II corresponding to the other
318 significant flammable gases. This equipment shall be marked appropriately.
319 Group II engines suitable for potentially explosive atmospheres of gases, vapours or mists shall
320 be subdivided in accordance with IEC 60079-0 using the following Groups:
321 – IIA, a typical gas is propane
322 – IIB, a typical gas is ethylene, or
323 – IIB + H , a typical gas is hydrogen
324 NOTE 1 According to the Scope ethylene oxide is not considered in subdivision IIB and subdivision IIC is not used
325 in this document.
326 NOTE 2: if the machine works in hydrogen atmosphere, chemical corrosion needs to be considered.
327 Group III engines suitable for explosive dust atmospheres shall be subdivided in accordance
328 with IEC 60079-0 using the following Groups:
329 – IIIA: combustible flyings
330 – IIIB: non-conductive dusts, or
331 – IIIC: conductive dusts
332 5.1.2 Ignition hazard assessment
333 A detailed ignition hazard assessment, for the required EPL, shall be undertaken by the
334 manufacturer in accordance with ISO 80079-36. The assessment shall list all the potential
335 ignition sources, that are either effective or likely to become effective.
336 The assessment shall indicate the means used to minimise the likelihood of ignition.
337 See Annex A to Annex D for further information.
338 5.1.3 Joints
339 5.1.3.1 Joint types
340 5.1.3.1.1 General
341 Each joint within the gas path of an explosion-protected internal combustion engine system
342 shall be designated as a closed joint, open joint or liquid immersed joint (Type of Protection
343 "k").
344 5.1.3.1.2 Closed joints
345 A closed joint shall be either a permanent or a separable joint that is gas tight and shall pass
346 the relevant tests in accordance with 7.4, 7.5, 7.6. and 7.7.
347 The following shall apply:
348 a) the faces of the joints shall not be subjected to relative movement which can impair the
349 integrity of the closed joint;
350 b) the flanged connections shall have a metallic or fire-resistant gasket interposed between
351 the faces. If the non-metallic gasket material can affect the type of protection, it shall be
352 subjected to thermal endurance testing as specified in 60079-0:2018, 7.2, prior to testing in
353 7.4, 7.5, 7.6. and 7.7;
354 c) Welded or brazed construction of joints and cemented joints according to IEC 60079 -1 are
355 permitted; and
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356 d) all joints shall be subjected to the tests for the reference pressure as specified in 7.4, 7.5
357 and 7.6. Joints meeting 4 times reference pressure shall be exempt from the flame non-
358 transmission test (7.7) except for welded and cemented joints.
359 5.1.3.1.3 Open joints
360 Open joints shall comply with the flame-path requirements of IEC 60079-1 and shall pass the
361 tests in accordance with 7.4, 7.5. 7.6 and 7.7.
362 A joint with relative movement between the parts shall be an open joint.
363 NOTE 1 An example might be a rotating shaft through the wall of an enclosure is an open joint.
364 Seals may be fitted to open joints to exclude contaminants from the joint, retain non -flammable
365 lubricants or inhibit corrosion. A seal shall not form part of the flame-path.
366 The joint between piston skirts and cylinder bores are exempt from this provision. The following
367 components are also exempt from this requirement, provided they pass the pressure
368 determination, propagation and overpressure tests in accordance with 7.4, 7.5, 7.6 and 7.7 .:
369 a) Valve stems and valve guides;
370 e) Intake and exhaust flame arresters;
371 f) Water or reductant/reactant injection nozzles fitted to cool or clean the exhaust gas stream
372 and system;
373 g) Any turbocharger and any supercharger, where the flame arrester is mounted on the engine
374 inlet side of the turbocharger or supercharger. That is, the intake flame arrester is located
375 as close as possible to the intake valves, if possible after the turbo charger or supercharger
376 and after the intercooler if installed. A position of the flame arrester before the turbo charger
377 or supercharger could be accepted; and
378 h) Fuel injectors.
379 NOTE 2 Overpressure test pressures are often determined by conducting pressure-determination tests (see 8.4.
380 5.1.3.2 94BLiquid immersed joints
381 When a turbocharger is fitted, the joint formed through the bearing assembly between the
382 turbine and the compressor may be designated as a liquid immersed joint. The joint shall comply
383 with the requirements of ISO 80079-37.
384 5.1.4 Electrical systems
385 5.1.4.1 General
386 Electrical equipment shall be explosion-protected in accordance with IEC 60079-0 and shall
387 use explosion protection methods found in the IEC 60079 series of standards with at least the
388 same EPL as the engine.
389 For EPL Gb, Gc, Db and Dc, the requirements of IEC TS 60079-46 for the design, selection,
390 erection, and initial inspection of the electrical installation shall be met.
391 For EPL Mb, the applicable requirements of ISO/IEC 80079-38 shall be met.
392 High voltage ignition systems shall meet the requirements of IEC 60079-45.
393 All components including devices, cables, and enclosures within the installed electrical system
394 of an explosion protected engine shall be able to withstand the temperatures measured during
395 the temperature tests given in 8.3 without damage, deterioration, or failure.
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396 NOTE The relevant electrical safety standards typically include IEC 60204-1 and IEC 60204-11. It is not a
397 requirement of this document that compliance with the relevant industrial standards be verified.
398 5.1.4.2 Protection against damage
399 The electrical system, including cables, shall be protected against damage as identified in the
400 ignition hazard assessment from mechanical impact, vibration, exposure to weather, water,
401 excessive dampness, ultraviolet radiation, corrosive substances, accumulation of dust or
402 debris, steam, oil, grease, fuel, high or low temperatures, high pressure water, or other adverse
403 conditions to which the explosion protected engine may be exposed, either in operation or
404 during maintenance.
405 NOTE IEC 60079-14 and IEC TS 60079-46 provide additional information and guidance to aid meeting the
406 requirements of this subclause.
407 5.1.4.3 Ingress protection
408 The electrical system shall have an ingress protection (IP) meeting the requirements of
409 IEC 60529 or IEC 60034-5 for electrical rotating machinery.
410 5.1.4.4 Cables and wiring systems
411 Engine primary wiring, including cables and connections, are not subject to the requirements in
412 IEC 60079-14. Engine primary wiring must be designed to withstand vibration, service
413 temperature, abrasion, UV exposure, chemical compatibility to which it will be exposed, and be
414 protected from damage including being cut.
415 NOTE 1  It is not a requirement of this standard that compliance with the relevant industrial standards for engine
416 primary wiring be verified.
417 Primary wiring insulation shall be selected based on the associated service temperatures and
418 be rated for the service temperature and voltage to which the wires will be exposed in normal
419 operation. Earth return (utilizing the metallic portions of the engine) circuits are permitted.
420 Engine primary wiring shall be routed such that it is:
421 a) sufficiently supported to minimize deleterious effects
422 b) installed to facilitate inspections.
423 c) not in direct contact with:
424 1) hot surfaces that exceed the wiring assembly temperature rating
425 2) fuel lines
426 3) pneumatic lines
427 4) hydraulic lines.
428 5) abrasive surfaces or sharp edges
429 Engine primary wiring that passes through conduits, partition walls or terminal box walls shall
430 be restrained and protected from abrasion by cable glands, flexible bushings or grommets
431 suitable for the application.
432 If intrinsically safe circuit wiring is used, it may be provided with alternative forms of protection
433 if installed in a manner which guards against potential damage from the environment in which
434 it is installed.
435 NOTE 2 See IEC 60079-11, IEC 60079-14 and IEC 60079-25 for further information on intrinsically safe wiring and
436 systems.
437 5.1.4.5 Protection of cables and wiring harnesses
438 NOTE Further information on intrinsically safe wiring and systems is given in IEC 60079-14 and IEC 60079-25.
439 IEC 60079-14 can be used for the engine wiring harness. The following modifications to the
440 requirements in IEC 60079-14 are permitted for EPL Gc and Dc engines:
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442 a) The engine wiring harness is part of the Ex equipment certificate and not subject to field
443 inspection.
444 b) Where the engine block is used as the earth return, the requirements of IEC 60079-14:2014,
445 6.3.2, 6.3.3, 6.3.4, and 6.3.6 are not applicable.
446 c) An Ex certified engine and its electrical system shall be treated as one item of equipment
447 per IEC 60079-14:2014, 6.3.6.
448 d) A grounded engine block is considered as an equal potential ground per IEC 60079-14:2014,
449 6.4.1.
450 e) Single wires used in engine harnesses are not to be considered easy tear cables . per IEC
451 60079-14:2014, 9.3.1
452 f) Single insulated wires that are mechanically protected (for example nylon braid) do not
453 require conduit. as specified by IEC 60079-14:2014, 9.3.5.
454 NOTE 1 The intent of IEC 60079-14:2014, 9.3.5 is to protect wire from being cut.
455 g) Actuators that do not continuously rotate are not considered rotating electrical machines as
456 defined in IEC 60079-14:2014, Clause 11.
457 h) Intrinsically safe wire may be bundled with other engine wiring if the intrinsically safe wire
458 insulation exceeds the highest rated voltage in the bundle as required in IEC 60079-14:2014
459 16.2.2.5.2,16.2.2.7 and 16.6 . However, an assessment of the hazards involved shall be
460 undertaken to confirm that the intrinsically safe circuit cannot be compromised.
461 NOTE 2 IEC 60079-25 provides additional information and guidance.
462 The first paragraph of IEC 60079-14:2014, 16.2.2.1 does not apply to engine wiring harnesses
463 5.1.4.6 97Bservice temperature
464 Equipment, materials, and components shall be selected taking into consideration the
465 associated service temperatures. Temperature tests are specified in 7.5.
466 5.1.5 Static electricity and bonding requirements
467 5.1.5.1 Equipotential bonding
468 Dangerous, ignitable electrostatic charges can arise on non-conductive surfaces or surfaces
469 made of conductive or dissipative materials that are insulated from the earthing point.
470 For conductive materials, the value of the measured discharge resistance must not exceed
471 10 Ω.
6 9
472 Dissipative materials have a discharge resistance between 10 Ω to 10 Ω.
473 Discharge resistance values >10 Ω indicate non-conductive / non-dissipative materials.
474 The value for the surface resistance must be determined in accordance with 60079-0:2017,
475 26.13 or in accordance with IEC 61340-2-3, in which the correlations are described in detail.
476 The determined value of the surface resistance / discharge resistance must not exceed 10 Ω.
477 5.1.5.2 Electrical resistance to ground
478 The electrical resistance between the engine and the floor or ground shall not exceed 10 Ω.
479 NOTE Further information regarding conductivity of materials is given in IEC TS 60079-32-1 and IEC 60079-32-2.
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480 5.1.5.3 Non-metallic materials
481 5.1.5.3.1 EPL Mb, EPL Gc and EPL Gb
482 Non-metallic materials which are subjected to a foreseeable electrostatic charge generating
483 mechanism shall comply with one of the following:
484 1) The surface resistance of the non- metallic material shall not exceed 10 Ω measured at
485 50 % relative humidity or 10 Ω measured at 30 % relative humidity with a test voltage of
486 500 V ± 5 % and shall be bonded to the chassis in accordance with 5.1.5.
487 2) The non-metallic material shall comply with the requirements for limitation of the transferred
488 charge in accordance with IEC 60079-0:2017, 26.17, with the exclusion of charging the
489 sample with the corona electrode (test with high voltage spray electrode).
490 3) The projected area of the non-metallic material shall not be larger than 100 cm for Group
491 I, IIA or IIB or 20 cm for Group IIB + H . These areas may be multiplied by 4 if the parts
492 are surrounded by conductive frames bonded to the engine frame in accordance with 5.1.5.
493 These areas may be multiplied by 2 if the parts are bordered at the long opposite sides by
494 conductive frames bonded to the engine in accordance with 5.1.5.
495 4) Where the non-metallic material is a coating or layer on an engine-bonded metal surface or
496 on an engine-bonded conductive surface, the thickness of the coating or layer shall not
497 exceed 2 mm for Group I, IIA or IIB and 0,2 mm for Group IIB + H .
498 NOTE 1 Further information is given in IEC TS 60079-32-1 and IEC 60079-32-2.
499 5.1.5.3.2 EPL Dc and EPL Db
500 The requirements for materials, marking and the avoidance of ignition hazards of IEC 60079-
501 0:2017, 8.4 Group III apply.
502 5.1.5.4 Transmission belts
503 Transmission belts shall be dissipative in accordance with an appropriate standard (for example
504 ISO 1813, ISO 9563, IEC TS 60079-32-1 or IEC 60079-32-2). The requirements for limitation
505 of transferred charge in accordance with IEC 60079-0 shall apply.
506 5.1.6 Safety and automation systems
507 5.1.6.1 Safety devices or safety systems
508 Where the ignition hazard assessment specified in 5.1.2 has revealed potential ignition sources
509 the application of safety devices or safety systems may be used to reduce the likelihood of the
510 ignition sources becoming effective. Safety devices or safety systems may be set to alarm and
511 shutdown the engine in response to monitored ignition critical control parameters.
512 The ignition critical control parameters that are monitored by safety devices or safety systems
513 include but are not limited to temperatures, engine speed and pressure. The ignition hazard
514 assessment will determine potential ignition risks and the location for safety devices to monitor
515 ignition control parameters most effectively.
516 NOTE 1 Normal engine operating technical data and tolerances from the engine manufacturer are typically
517 established to use as an input into the ignition hazard assessment.
518 Warning systems (lamps, and audible alarms) shall be designed to avoid operator confusion or
519 misunderstanding about the action required.
520 NOTE 2 An ignition protection device or system could have two or more levels of operation (for example the first
521 level provides a warning to the operator while the second level actuates a shutdown system). The warning could
522 reduce the likelihood of a spurious activation of the ignition protection system.
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523 The operating characteristics of the safety devices intended to be suitable to assist in the control
524 of the specific ignition source in the equipment shall be specified. Examples of factors that
525 should be considered are:
526 – the time taken for a potential ignition source to become effective;
527 – response time of the sensor;
528 – response time of the ignition prevention system / device;
529 – difference in level between the normal parameters and critical parameters (for example
530 normal temperature and critical temperature);
531 – safety factor if considered necessary.
532 5.1.6.2 Safety function
533 5.1.6.2.1 Function of safety systems
534 All monitoring, control, and activation of safety devices for effective ignition source prevention
535 shall function independently of any measurement and control devices required for normal
536 operation and be:
537 – suitable to control the specific ignition source, and
538 – sufficiently reliable for th
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