prEN ISO/IEC 80079-41

SLOVENSKI STANDARD
01-junij-2023
Eksplozivne atmosfere - 41. del: Batni motorji z notranjim zgorevanjem (ISO/IEC
DIS 80079-41:2023)
Explosive atmospheres - Part 41: Reciprocating internal combustion engines (ISO/IEC
DIS 80079-41:2023)
Explosionsfähige Atmosphären - Teil 41: Hubkolben-Verbrennungsmotoren (ISO/IEC
DIS 80079-41:2023)
Atmosphères explosives - Partie 41: Moteurs alternatifs à combustion interne (ISO/IEC
DIS 80079-41:2023)
Ta slovenski standard je istoveten z: prEN ISO/IEC 80079-41
ICS:
13.230 Varstvo pred eksplozijo Explosion protection
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 Secretariat: ISO
Voting begins on: Voting terminates on:
2023-04-21 2023-07-14
Explosive atmospheres —
Part 41:
Reciprocating internal combustion engines
ICS: 29.260.20; 27.020
Member bodies are requested to consult relevant national interests in IEC/SC
31M before casting their ballot to the e-Balloting application.
This document is circulated as received from the committee secretariat.
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ISO/IEC DIS 80079-41:2023(E)
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PROVIDE SUPPORTING DOCUMENTATION. © ISO/IEC 2023

ISO/IEC DIS 80079-41:2023(E)
DRAFT INTERNATIONAL STANDARD
ISO/IEC DIS 80079-41
ISO/TMBG Secretariat: ISO
Voting begins on: Voting terminates on:
2023-04-21 2023-07-14
Explosive atmospheres —
Part 41:
Reciprocating internal combustion engines
ICS: 29.260.20; 27.020
Member bodies are requested to consult relevant national interests in IEC/SC
31M before casting their ballot to the e-Balloting application.
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
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© ISO/IEC 2023
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NATIONAL REGULATIONS.
Website: www.iso.org ISO/IEC DIS 80079-41:2023(E)
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ii
© ISO/IEC 2023 – All rights reserved
PROVIDE SUPPORTING DOCUMENTATION. © ISO/IEC 2023

31M/182/CDV – 2 – ISO/IEC 80079-41 © IEC:2023
1 CONTENTS
3 1 Scope . 8
4 2 Normative references . 9
5 3 Definitions . 10
6 4 Ignition hazards . 12
7 5 Safety requirements and/or measures . 13
8 5.1 For all equipment protection levels (EPLs) . 13
9 5.1.1 General . 13
10 5.1.2 Ignition hazard assessment . 13
11 5.1.3 Joints . 14
12 5.1.4 Electrical systems . 14
13 5.1.5 Static electricity and bonding requirements . 16
14 5.1.6 Safety and automation systems . 17
15 5.1.7 Flame arresters . 24
16 5.1.8 Spark arresters . 26
17 5.1.9 Engine gas path configuration . 27
18 5.1.10 Fuel system . 29
19 5.1.11 Mechanically generated sparks . 30
20 5.2 Specific requirements for EPL Mb . 31
21 5.2.1 Maximum temperature . 31
22 5.2.2 Gas path . 31
23 5.2.3 Air intake system . 31
24 5.2.4 Exhaust system . 31
25 5.2.5 Fans and other rotating components . 31
26 5.2.6 Compressed air systems. 31
27 5.3 Specific requirements for EPL Gb and EPL Gc . 32
28 5.3.1 Maximum temperature . 32
29 5.3.2 Configuration of flame arresters & spark arresters . 32
30 5.3.3 Gas path . 33
31 5.3.4 Air intake system . 33
32 5.3.5 Exhaust system . 34
33 5.4 Specific requirements for EPL Db and EPL Dc . 34
34 5.4.1 Maximum temperature . 34
35 5.4.2 Air intake system . 34
36 5.4.3 Exhaust system . 34
37 5.4.4 Cold start devices . 35
38 5.4.5 Mechanically generated sparks . 35
39 5.4.6 Compressed air systems. 35
40 6 EPL Gc gaseous fuelled spark ignited engine . 35
41 6.1 General . 35
42 6.1.1 Differences between spark ignited, gas fuelled engines and
43 compression ignition engines . 35
44 6.1.2 Fuel System . 36
45 6.2 Ignition system . 36
46 6.3 Safe Starting Purge . 36
47 6.3.1 Ventilation . 36

ISO/IEC CDV 80079-41 © IEC:2023 – 3 – 31M/188/CDV
48 6.3.2 Engine starting . 36
49 6.3.3 Engine stopping . 37
50 7 Test setup and testing procedures . 37
51 7.1 General . 37
52 7.2 Documentation . 37
53 7.3 Engine operation . 37
54 7.4 Measuring instruments . 37
55 7.5 Temperature measurement . 37
56 7.5.1 Purpose of the test . 37
57 7.5.2 Test procedure . 37
58 7.5.3 Acceptance criteria . 38
59 7.5.4 (Type) Test report / protocol . 39
60 7.6 Pressure determination . 39
61 7.6.1 General . 39
62 7.6.2 Test procedure . 39
63 7.6.3 (Type) Test report . 42
64 7.7 Over pressure test (Gc, Gb and Mb) . 42
65 7.7.1 General . 42
66 7.7.2 Test procedure static test . 43
67 7.7.3 Test procedure alternative dynamic test . 43
68 7.8 Propagation testing . 45
69 7.8.1 General . 45
70 7.8.2 Test set-up . 45
71 7.8.3 Non-transmission test procedure intake system . 48
72 7.8.4 Non-transmission test procedure exhaust side . 50
73 7.9 Crankcase explosion containment testing . 51
74 7.9.1 General . 51
75 7.9.2 Apparatus . 51
76 7.9.3 Test procedure . 52
77 7.9.4 Acceptance criteria . 52
78 7.9.5 Dry type - spark arrester tests (according to 1834-1:2006, 6.4.2) . 52
79 7.9.6 Liquid type – spark arrester tests . 52
80 7.10 Static electricity / Non-metallic material . 53
81 7.11 Verification engine control, alarms and shutdown . 53
82 7.12 Leak test for ducts . 53
83 8 Instructions . 53
84 8.1 Accompanying documents . 53
85 8.1.1 Group I Mining . 53
86 8.1.2 Group II Flammable gas and vapours . 53
87 8.1.3 Group III Combustible dust . 53
88 8.2 Inspection check list . 54
89 8.2.1 Group I Mining . 54
90 8.2.2 Group II Flammable gas and vapours . 54
91 8.2.3 Group III Combustible dust . 55
92 9 Marking . 55
93 9.1.1 General . 55
94 9.1.2 EPL Mb . 56
95 9.1.3 EPL Gb and EPL Gc . 56
96 9.1.4 EPL Db and EPL Dc . 56

31M/182/CDV – 4 – ISO/IEC 80079-41 © IEC:2023
97 Annex A (informative) Engine conditions and ignition sources – Group I equipment . 57
98 A.1 Engine conditions . 57
99 A.1.1 Normal operating conditions . 57
100 A.1.2 Expected malfunctions . 57
101 A.1.3 Rare malfunctions . 57
102 A.2 Ignition sources . 57
103 A.2.1 Hot surfaces . 57
104 A.2.2 Flame and hot gases . 58
105 A.2.3 Sparks . 58
106 A.2.4 Adiabatic compression . 58
107 Annex B (informative) Engine conditions and ignition sources – Group II and Group III
108 equipment – Flammable gas, vapour and combustible dust atmospheres . 59
109 B.1 General . 59
110 B.2 Engine conditions . 59
111 B.2.1 Normal operating conditions . 59
112 B.2.2 Foreseeable malfunctions . 59
113 B.2.3 Rare malfunctions . 59
114 B.3 Ignition sources . 60
115 B.3.1 Hot surfaces . 60
116 B.3.2 Flame and hot gases . 60
117 B.3.3 Sparks . 60
118 B.3.4 Adiabatic compression . 60
119 Annex C (informative) Ignition hazard assessment for reciprocating internal
120 combustion engines . 61
121 C.1 General requirements . 61
122 C.2 Procedure of ignition hazard assessment . 61
123 C.3 Ignition hazard assessment report . 62
124 Annex D (informative) Identification of Ignition Hazards . 63
125 Annex E (informative) Test reports . 89
126 Annex F (normative) Test set up schematics . 108
127 Annex G (informative) Engine types . 126
129 Figure 1 – Basic gas path configurations . 29
130 Figure 2 – Maximum explosion pressure and Dynamic overpressure test - minimal
131 representation. 41
132 Figure 3 – Non-transmission test . 46
133 Figure F.1 – Explosion pressure on the exhaust side under atmospheric condition in a
134 pressure resistant chamber . 109
135 Figure F.2 – Explosion pressure on the exhaust side under atmospheric condition in a
136 closed pipe . 110
137 Figure F.3 – Flame transmission on the exhaust side under atmospheric conditions in a
138 plastic bag and heated flame arresters . 112
139 Figure F.4 – Flame transmission on the exhaust side under atmospheric conditions in
140 an explosion proof chamber and heated flame arresters . 113
141 Figure F.5 – Flame transmission on the exhaust side under atmospheric conditions
142 with plastic bags . 115
143 Figure F.6 – Explosion pressure on the Intake side under atmospheric conditions . 116

ISO/IEC CDV 80079-41 © IEC:2023 – 5 – 31M/188/CDV
144 Figure F.7 – Explosion pressure on the intake side under overpressure conditions in a
145 plastic bag . 118
146 Figure F.8 – Explosion pressure on the intake side under overpressure conditions in an
147 explosion proof chamber . 119
148 Figure F.9 – Explosion pressure on the intake side under overpressure conditions in a
149 closed pipe . 121
150 Figure F.10 – Flame transmission on the intake side under atmospheric conditions in a
151 plastic bag . 122
152 Figure F.11 – Flame transmission on the intake side under overpressure conditions in
153 an explosion proof chamber . 124
154 Figure F.12 – Flame transmission on the intake side under overpressure conditions in
155 a closed pipe . 125
156 Figure G.1 – Engine types . 127
157 Figure G.2 – Engine types – Fuels used . 128
159 Table 1 – Minimum level of Protection, equipment group, and ingress protection (IP)
160 relationship . 15
161 Table 2 – Minimum integrity for a safety device for ignition source control . 20
162 Table 3 – Alarms and Shutdown . 21
163 Table 4 – Classification of maximum temperatures . 32
164 Table 5 – Configuration of Gb and Gc flame arresters & spark arresters . 33
165 Table 4 – Test mixture for the determination of maximum explosion pressures . 40
166 Table 5 – Test mixtures for Propagation Tests . 47
167 Table D.1 – Possible ignition sources . 63
168 Table D.2 – Gc and Dc example . 65
169 Table D.3 – Gb, Db & Mb example . 76
31M/182/CDV – 6 – ISO/IEC 80079-41 © IEC:2023
173 INTERNATIONAL ELECTROTECHNICAL COMMISSION
174 ____________
176 Explosive atmospheres
178 Part 41: Reciprocating internal combustion engines
180 FOREWORD
181 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
182 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
183 co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
184 in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
185 Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
186 preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
187 may participate in this preparatory work. International, governmental and non-governmental organizations liaising
188 with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
189 Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
190 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
191 consensus of opinion on the relevant subjects since each technical committee has representation from all
192 interested IEC National Committees.
193 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
194 Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
195 Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
196 misinterpretation by any end user.
197 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
198 transparently to the maximum extent possible in their national and regional publications. Any divergence between
199 any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
200 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
201 assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
202 services carried out by independent certification bodies.
203 6) All users should ensure that they have the latest edition of this publication.
204 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
205 members of its technical committees and IEC National Committees for any personal injury, property damage or
206 other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
207 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
208 Publications.
209 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
210 indispensable for the correct application of this publication.
211 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
212 rights. IEC shall not be held responsible for identifying any or all such patent rights.
213 International Standard ISO/IEC 80079-41 has been prepared by ISO/IEC subcommittee 31M:
214 Non-electrical equipment and protective systems for explosive atmospheres.
215 The text of this standard is based on the following documents:
FDIS Report on voting
31M/XX/FDIS 31M/XX/RVD
217 Full information on the voting for the approval of this standard can be found in the report on
218 voting indicated in the above table.
219 This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
220 The committee has decided that the contents of this publication will remain unchanged until the
221 stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to
222 the specific publication. At this date, the publication will be
223 • reconfirmed,
ISO/IEC CDV 80079-41 © IEC:2023 – 7 – 31M/188/CDV
224 • withdrawn,
225 • replaced by a revised edition, or
226 • amended.
228 The National Committees are requested to note that for this publication the stability date
229 is 2020.
230 THIS TEXT IS INCLUDED FOR THE INFORMATION OF THE NATIONAL COMMITTEES AND WILL BE DELETED
231 AT THE PUBLICATION STAGE.
31M/182/CDV – 8 – ISO/IEC 80079-41 © IEC:2023
233 Explosive atmospheres
235 Part 41: Reciprocating internal combustion engines
237 1 0BScope
238 This part of ISO/IEC 80079 specifies the technical requirements for design, construction,
239 testing, marking and the information required for use to avoid or minimise the possibility of
240 ignition which could from reciprocating internal combustion engine intended for use in explosive
241 atmospheres including:
242 • Group I EPL Mb for use in underground workings susceptible to firedamp or combustible
243 dust,
244 • Group II EPL Gb for use in explosive atmospheres of flammable gas and vapour , and
245 • Group III EPL Db for use in explosive atmospheres of combustible dust.
246 • For EPL Gc and Dc engines, only normal operating conditions need to be taken into account.
247 Malfunctions need not be considered (see B.2.1).
248 This part of ISO/IEC 80079 includes those tests of the engine and its ancillary devices that are
249 required to verify compliance with this standard.
250 This part of ISO/IEC 80079 applies to both reciprocating internal combustion engines with
251 compression ignition for EPL Mb, Gb, Gc, Db, Dc and spark ignition engines for EPL Gc. See
252 Annex G.
253 This part of ISO/IEC 80079 does not define requirements relating to the driven machinery and
254 equipment.
255 This part of ISO/IEC 80079 does not apply to
256 • explosive mixtures of vapours and gases, which tend to self-decompose (for example carbon
257 disulphide (CS ), ethylene oxide (C H O), acetylene) or which are chemically unstable;
2 2 4
258 • engines used in areas for the processing, manufacture or storage of explosives;
259 • gasoline and other spark ignited engines where the fuel is injected into the combustion
260 chamber as a liquid; or
261 • high voltage electrical ignition systems.
263 This part of ISO/IEC 80079 solely deals with explosion protection requirements. Requirements
264 on gaseous or particulate exhaust emissions are not covered by this standard.
265 General safety requirements are not included in this International Standard.
266 NOTE 1 General safety requirements (for example those common to internal combustion engines) are covered for
267 the EU in EN 1679-1:1998+A1:2011.
268 This standard does not specify requirements for safety, other than those directly related to the
269 possibility of ignition which can lead to an explosion.
270 The standard atmospheric conditions (relating to the explosion characteristics of the
271 atmosphere) under which it may be assumed that the engine may be operated are:
272 • temperature –20 °C to +60 °C
273 • pressure 80 kPa (0,8 bar) to 110 kPa (1,1 bar); and
274 • air with normal oxygen content, typically 21% v/v.
275 An engine for use outside of the standard atmospheric conditions is to be designed, constructed
276 tested and marked for those conditions. The ignition hazard assessment, ignition, protection
277 provided, additional testing (if necessary) manufacturer’s technical documentation and

ISO/IEC CDV 80079-41 © IEC:2023 – 9 – 31M/188/CDV
278 instructions to the user are intended toclearly demonstrate the engine’s suitability for the
279 conditions.
280 NOTE 2 It is recognised that changes in temperature and pressure have an influence on the characteristics of the
281 explosive atmosphere including ignitability
282 NOTE 3 IEC TS 60079-43 gives information for equipment used in explosive atmospheres in environmental
283 conditions which include ambient temperatures below –20 °C and additional adverse conditions, including maritime
284 applications.
285 NOTE 4 Reciprocating internal combustion engines are not considered as pressure vessels.
286 This standard supplements and modifies the general requirements of IEC 60079-0:2017, as
287 shown in Table 1. Where a requirement of this standard conflicts with a requirement of
288 IEC 60079-0:2017 as far as applicable for Ex engines, the requirement of this standard takes
289 precedence.
290 On-going inspection, maintenance and repair aspects play an important role in control of
291 hazardous area installations and the user’s attention is drawn to IEC 60079-17, IEC 60079-19
292 and manufacturer’s instructions for further information concerning these aspects.
293 2 1BNormative references
294 The following documents, in whole or in part, are normatively referenced in this document and
295 are indispensable for its application. For dated references, only the edition cited applies. For
296 undated references, the latest edition of the referenced document (including any amendments)
297 applies.
298 IEC 60034-5:2020, Rotation electrical machines — Part 5: Degrees of protection provided by
299 the integral design of rotating electrical machines (IP code) — Classification (Amendment 1)
300 IEC 60079-0:2017, Explosive atmospheres — Part 0: Equipment — General requirements
301 IEC 60079-1:2014, Explosive atmospheres — Part 1: Equipment protection by flameproof
302 enclosures "d"
303 IEC 60079-10-1:2020 + COR1:2021, Explosive atmospheres — Part 10-1: Classification of areas
304 — Explosive gas atmospheres
305 IEC 80079-20-1:2017, Explosive atmospheres — Part 20-1: Material characteristics for gas and
306 vapour classification — Test methods and data
307 IEC 60079-29-1:2016, Explosive atmospheres - Part 29-1: Gas detectors - Performance
308 requirements of detectors for flammable gases
309 IEC 60079-29-2:2015, Explosive atmospheres - Part 29-2: Gas detectors - Selection,
310 installation, use and maintenance of detectors for flammable gases and oxygen
311 IEC 60079-29-3:2014, Explosive atmospheres - Part 29-3: Gas detectors - Guidance on
312 functional safety of fixed gas detection systems
313 IEC/TS 60079-42:2019, Explosive atmospheres - Part 42: Electrical Safety Devices for the
314 control of potential ignition sources from Ex-Equipment
315 IEC 60079-45 0F , Explosive Atmospheres – Electrical Ignition Systems for Internal Combustion
316 Engines
317 IEC/TS 60079-46:2017, Explosive atmospheres - Part 46: Equipment assemblies
318 IEC 60204-1:2016, Electrical equipment of industrial machines — Part 1: General requirements
319 IEC 60243-1:2013, Electric strength of insulating materials - Test methods - Part 1: Tests at
320 power frequencies
—————————
In preparation
31M/182/CDV – 10 – ISO/IEC 80079-41 © IEC:2023
321 IEC 60529:1989 + A1:1999 + A2:2013, Degrees of protection provided by enclosures (IP
322 Codes)
323 IEC 61508-1:2010, Functional safety of electrical/electronic/programmable electronic safety-
324 related systems - Part 1: General requirements
325 IEC 61508-2:2010, Functional safety of electrical/electronic/programmable electronic safety-
326 related systems - Part 2: Requirements for electrical/electronic/programmable electronic safety -
327 related systems
328 IEC 61508-4:2010, Functional safety of electrical/electronic/programmable electronic safety-
329 related systems - Part 4: Definitions and abbreviations
330 IEC 61511-1:2016 + COR1:2016 + A1:2017, Functional safety - Safety instrumented systems
331 for the process industry sector - Part 1: Framework, definitions, system, hardware and
332 application programming requirements
333 ISO 1813, Belt drives — V-ribbed belts, joined V-belts and V-belts including wide section belts
334 and hexagonal belts — Electrical conductivity of antistatic belts: Characteristics and methods
335 of test
336 ISO 3046-3:2006, Reciprocating internal combustion engines — Performance — Part 3: Test
337 measurements
338 ISO 12100:2010, Safety of machinery — General principles for design — Risk assessment and
339 risk reduction
340 ISO 15510:2014, Stainless steels — Chemical composition
341 ISO/IEC 80079-49, Flame arresters — Performance requirements, test methods and limits for
342 use
343 ISO 29463 (all parts), High-efficiency filters and filter media for removing particles in air
344 ISO/IEC 80079-20-1:2017, Explosive atmospheres - Part 20-1: Material characteristics for gas
345 and vapour classification - Test methods and data
346 ISO 80079-36:2016, Explosive atmospheres — Part 36: Non-electrical equipment for explosive
347 atmospheres — Basic method and requirements
348 ISO 80079-37:2016, Explosive atmospheres — Part 37: Non-electrical equipment for explosive
349 atmospheres - Non-electrical type of protection constructional safety ''c'', control of ignition
350 sources ''b'', liquid immersion ''k''
351 ISO/IEC 80079-38:2016, Explosive atmospheres — Part 38: Equipment and components in
352 explosive atmospheres in underground mines
353 EN 1822-1:2019, High efficiency air filters (EPA, HEPA and ULPA) — Part 1: Classification,
354 performance testing, marking
355 EN 1834-1:2006, Reciprocating internal combustion engines - Safety requirements for design
356 and construction of engines for use in potentially explosive atmospheres - Part 1: Group II
357 engines for use in flammable gas and vapour atmospheres
358 IEC 61508 (all parts), Functional safety of electrical/electronic/programmable electronic safety-
359 related systems
360 3 2BDefinitions
361 For the purposes of this standard, the definitions in ISO 2710-1:2017, ISO 7967-1, ISO 7967-
362 2:2010, ISO 7967-3, ISO 7967-4, ISO 7967-8, IEC 60079-0, IEC 60079-10-1, IEC 60079-10-2,
363 ISO 80079-36, ISO 80079-37, ISO/IEC 80079-38, and the following definitions apply:

ISO/IEC CDV 80079-41 © IEC:2023 – 11 – 31M/188/CDV
364 3.1
365 maximum surface temperature
367 highest temperature that can be attained in service under the most adverse operating conditions (but
368 within the recognized tolerance) by any part or surface of the equipment, protective system or
369 component that can produce an ignition of the surrounding explosive atmosphere
370 Note 1 to entry: The maximum surface temperature marked on the equipment includes safety margins depending on
371 the EPL of the equipment.
372 Note 2 to entry: The surface temperature which is relevant can be internal or external depending upon the Type of
373 Protection concerned.
374 Note 3 to entry: For Ex Equipment in an explosive dust atmosphere, this temperature occurs on the external surfa ce
375 of the enclosure and can include a defined dust layer condition.,
376 Note 4 to entry: This includes the engine, its fittings, its ancillary equipment including flame
377 arrester, spark arrester, ducts, etc.[SOURCE: IEC 60079-0:2017, modified definitionNotes to
378 entry added]
379 3.2
380 maximum exhaust gas temperature
381 highest temperature under the most adverse operating conditions measured at the point where
382 the gas stream first meets the surrounding atmosphere
383 3.3
384 maximum charge air temperature
385 highest temperature under the most adverse operating conditions measured at the outlet of the
386 boosting device
387 3.4
388 gas path
389 parts of an engine through which air and exhaust gas passes when the engine is running
390 3.5
391 flame arrester
392 FA
393 device fitted to the opening of an enclosure, or to the connecting pipe work of a system of
394 enclosures, and whose intended function is to allow flow but prevent the transmission of flame
395 3.6
396 closed joint
397 assembly between two parts which is intended to be gas or dust tight or both
398 3.7
399 open joint
400 joint between two parts designed to reduce the heat energy from a gas explosion to the point
401 where it will not ignite a similar external explosive gas mixture
402 3.8
403 spark arrester
404 device, system, or method which controls the emission from an engine exhaust of particles
405 potentially capable of igniting combustible material in the vicinity by virtue of their size and
406 temperature
407 3.9
408 engine control module
409 ECM
410 electronic processor managing the transfer of data between engine sensors, actuators, control
411 elements, and information-storage and display units

31M/182/CDV – 12 – ISO/IEC 80079-41 © IEC:2023
412 3.10
413 safety devices
414 devices intended for use inside or outside explosive atmospheres but required for, or
415 contributing to, the safe functioning of equipment and protective systems on the engine with
416 respect to the risks of explosion
417 Note 1 to entry: Safety devices differ from the term devices used in the standards IEC 61508 and IEC 61511.
418 Safety devices are comparable to the terms like “safety-related system (IEC 61508)” or “safety instrumented system
419 (IEC 61511)”.
420 Note 2 to entry: In this standard the safety devices are intended to reduce the likelihood of a potential ignition
421 source becoming effective.
422 [SOURCE: ISO 80079-37:2016, modified – “on the engine” and Note 1 and 2 to entry have been
423 added]
424 3.11
425 performance requirements
426 verifiable requirements related to properties of safety devices and shutdown systems to ensure
427 that the safety function is effective
428 Note 1 to entry: IEC 60079-46 Includes information for diagnostics, capacity, functionality, response, effectiveness,
429 integrity, reliability, availability, ability to withstand loads and robustness.
430 3.12
431 abnormal combustion
432 unintended or uncontrolled combustion in the engine
433 3.13
434 explosion protection
435 application of one or more Types of Protection to minimise the risk of a piece of equipment, apparatus,
436 component, fitting or device causing an ignition of a surrounding explosive gas, vapour, mist or dust
437 atmosphere
438 3.14
439 explosion protected engine
440 engine with measures applied in the construction to prevent it becoming an ignition source for
441 an explosive atmosphere
442 4 3BIgnition hazards
443 Specific hazards for engine applications in potentially explosive atmospheres are listed below
444 according to ISO 80079-36:2016.
445 The main sources of ignition are:
446 • hot surfaces;
447 • flames and hot gases;
448 • mechanically generated sparks;
449 • electrically generated arcs and sparks;
450 • static electricity;
451 • stray electric currents;
452 • adiabatic compression.
453 The design specifications for the engine necessary to minimise the likelihood of the ignition of
454 an external potential atmosphere depend on the application and are characterised by:
455 o temperature classification,
456 o presence of flammable gases, or
457 o presence of combustible dust,
ISO/IEC CDV 80079-41 © IEC:2023 – 13 – 31M/188/CDV
459 5 4BSafety requirements and measures
460 5.1 9BFor all Equipment Protection Levels (EPLs)
461 5.1.1 30BGeneral
462 For EPL Mb, EPL Gb and EPL Db eng
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