oSIST prEN IEC 60079-2:2022

SLOVENSKI STANDARD
oSIST prEN IEC 60079-2:2022
01-november-2022
Eksplozivne atmosfere - 2. del: Zaščita opreme z nadtlakom "p"
Explosive atmospheres - Part 2: Equipment protection by pressurized enclosure "p"
Explosionsgefährdete Bereiche - Teil 2: Geräteschutz durch Überdruckkapselung "p"
Atmosphères explosives - Partie 2: Protection du matériel par enveloppe à surpression
interne "p"
Ta slovenski standard je istoveten z: prEN IEC 60079-2:2022
ICS:
29.260.20 Električni aparati za Electrical apparatus for
eksplozivna ozračja explosive atmospheres
oSIST prEN IEC 60079-2:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN IEC 60079-2:2022

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oSIST prEN IEC 60079-2:2022
31/1636/CDV

COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60079-2 ED7
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2022-09-02 2022-11-25
SUPERSEDES DOCUMENTS:
31/1560/CD, 31/1565A/CC

IEC TC 31 : EQUIPMENT FOR EXPLOSIVE ATMOSPHERES
SECRETARIAT: SECRETARY:
United Kingdom Mr Tom Stack
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:


Other TC/SCs are requested to indicate their interest, if any, in this
CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.

This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of which they
are aware and to provide supporting documentation.

TITLE:
Explosive atmospheres - Part 2: Equipment protection by pressurized enclosure "p"

PROPOSED STABILITY DATE: 2028

NOTE FROM TC/SC OFFICERS:
Due to the translation period (ISO/IEC DIR 1:2022 A.5.1) the CDV for IEC 60079-2 ED7 ‘Explosive atmospheres
- Part 2: Equipment protection by pressurized enclosure "p"’ is due to be circulated from 2022 -08-26 to 2022-11-
18. So unfortunately the ballot result and comments would be late for the meetings in San Francisco.

Copyright © 2022 International Electrotechnical Commission, IEC. All rights reserved. It is permitted to download this
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
permission in writing from IEC.

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oSIST prEN IEC 60079-2:2022
31/1636/CDV – 2 – IEC CDV 60079-2 © IEC:2022

It is possible to extract any votes/comments that have been submitted on a ballot prior to it closing so NC's are
encouraged to submit comments before the October meeting if possible. Any comments that have been submitted
on the ballot will be reviewed by MT 60079-2. Note these comments will be anonymised to not indicate actual
voting by an NC.

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oSIST prEN IEC 60079-2:2022
IEC CDV 60079-2 © IEC:2022 – 3 – 31/1636/CDV
1 CONTENTS
2
3 FOREWORD . 8
4 INTRODUCTION . 15
5 1 Scope . 16
6 2 Normative references . 26
7 3 Terms and definitions . 26
8 4 Levels of Protection . 29
9 5 Constructional requirements for pressurized enclosures . 32
10 5.1 Enclosure . 32
11 5.1.1 General . 32
12 5.1.2 Level of protection “pyb” . 32
13 5.1.3 Level of protection “pzc” that incorporates EPL Gc equipment. . 32
14 5.2 Materials . 32
15 5.3 Doors and covers . 32
16 5.3.1 General . 32
17 5.3.2 Group I pressurized enclosures . 33
18 5.3.3 Group I pressurized enclosures with static pressurization . 33
19 5.3.4 Group II and Group III pressurized enclosures . 33
20 5.3.5 Group II and Group III pressurized enclosures with static pressurization. 33
21 5.3.6 Group II and Group III Level of Protection “pxb” . 33
22 5.3.7 Group II and Group III Door and Cover warning . 33
23 5.4 Mechanical strength . 33
24 6 Constructional requirements for pressurized equipment . 34
25 6.1 Group I and Group II Apertures, and partitions . 34
26 6.2 Group I and Group II Internal components, compartments, and enclosures . 34
27 6.3 Apertures for Static Pressurization . 35
28 6.4 Insulating materials for Group I equipment . 35
29 6.5 Spark and particle barriers . 35
30 6.6 Thermal Protection Sensors of Electric machines. 35
31 6.7 Bypass or Override function . 35
32 7 Temperature limits . 36
33 7.1 General . 36
34 7.2 For Level of Protection “pxb” or Level of Protection “pyb” . 36
35 7.3 For Level of Protection “pzc” . 37
36 8 Safety devices and safety control functions of pressurization control systems
37 (except for static pressurization) . 37
38 8.1 General . 37
39 8.2 Provider of safety devices . 38
40 8.3 Pressurization Control Systems . 38
41 8.3.1 General . 38
42 8.3.2 For Level of Protection ”pzc”. . 39
43 8.3.3 For Level of Protection ”pyb”. . 39
44 8.3.4 For Level of Protection ”pxb”. . 39
45 8.3.5 Evaluated as Ex associated equipment . 39
46 8.4 Group I and Group II Purging for Level of Protection “pxb” . 40

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47 8.5 Group I or Group II − Purging criteria . 40
48 8.6 Group III – Cleaning . 41
49 8.7 Requirements when a minimum flow rate required . 41
50 8.8 Safety devices to detect minimum pressurization overpressure . 42
51 8.9 Value of pressurization overpressure and maximum overpressure . 43
52 8.10 Pressurizing multiple enclosures . 43
53 8.11 Safety devices on doors and covers . 44
54 8.12 Equipment that may remain energized . 44
55 8.13 Equipment permitted within Level of Protection “pyb” . 44
56 9 Safety provisions and safety devices for static pressurization . 44
57 9.1 Suitability of safety devices for hazardous area . 44
58 9.2 Protective gas . 44
59 9.3 Internal sources of release . 44
60 9.4 Group I and Group II Filling procedure . 44
61 9.5 Group III Filling Procedure . 44
62 9.6 Safety devices . 45
63 9.7 Equipment that may remain energized . 45
64 9.8 Overpressure . 45
65 10 Supply of protective gas . 45
66 10.1 Backup supply . 45
67 10.2 Independent supplies . 45
68 10.3 Type of gas . 45
69 10.4 Temperature . 46
70 11 Pressurized equipment with an internal source of release . 46
71 11.1 General . 46
72 11.2 Release conditions . 48
73 11.2.1 No release . 48
74 11.2.2 Limited release of a gas or vapour . 48
75 11.2.3 Limited release of a liquid . 48
76 11.3 Design requirements for the containment system . 48
77 11.3.1 General design requirements . 48
78 11.3.2 Infallible containment system . 49
79 11.3.3 Containment system with a limited release . 49
80 11.4 Protective gas and pressurizing techniques when there is an internal source
81 of release. 50
82 11.4.1 General . 50
83 11.4.2 Pressurization with leakage compensation . 50
84 11.4.3 Pressurization with dilution flow . 51
85 11.4.4 Limited release of a liquid . 51
86 11.5 Ignition-capable equipment . 51
87 11.6 Internal hot surfaces . 52
88 12 Cells and batteries within pressurized equipment. . 52
89 12.1 General Requirements . 52
90 12.2 Cells or Battery used for memory backup applications . 52
91 12.3 Other cell and battery types . 53
92 12.4 Cell and Battery Related Warnings . 53
93 12.4.1 General . 53
94 12.4.2 Relevant to EPL Mb, Gb or Db without other protection . 53
95 12.4.3 Relevant to EPL Gc or Dc without other protection . 53

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96 12.4.4 Otherwise protected . 53
97 13 Type Verification and Tests . 54
98 13.1 General . 54
99 13.2 Determining the maximum overpressure rating . 54
100 13.3 Maximum overpressure test . 54
101 13.4 Leakage test . 54
102 13.4.1 Other than static pressurization . 54
103 13.4.2 Static pressurization . 55
104 13.5 Purging and dilution flow tests . 55
105 13.5.1 General . 55
106 13.5.2 Criteria for compliance where the protective gas is air . 55
107 13.5.3 Criteria for compliance where the protective gas is inert . 55
108 13.6 Purging test for pressurized equipment with no internal source of release
109 and filling procedure test for static pressurization . 56
110 13.6.1 General . 56
111 13.6.2 Pressurized equipment where the protective gas is air . 56
112 13.6.3 Pressurized equipment where the protective gas is inert . 56
113 13.6.4 Pressurized equipment where the protective gas may be either air or an
114 inert gas with a density equal to air 10 % . 56
115 13.6.5 Filling procedure test for a pressurized equipment protected by static
116 pressurization . 56
117 13.7 Purging and dilution flow tests for a pressurized equipment with an internal
118 source of release . 57
119 13.7.1 Test gas . 57
120 13.7.2 Pressurized equipment where the flammable substance has less than
121 2 % (v/v) oxygen and the protective gas is inert . 57
122 13.7.3 Pressurized equipment with pressurization by continuous flow,
123 containment system with less than 21 % (v/v) oxygen and the protective
124 gas is inert . 57
125 13.7.4 Pressurized equipment where the flammable substance is not a liquid,
126 pressurization by continuous flow and the protective gas is air . 58
127 13.8 Verification of minimum pressurization overpressure . 58
128 13.9 Tests for an infallible containment system . 59
129 13.9.1 Overpressure test . 59
130 13.9.2 Infallibility test . 59
131 13.10 Overpressure test for a containment system with a limited release . 59
132 13.11 Pressurization Control Systems . 59
133 14 Routine tests . 60
134 14.1 Functional test . 60
135 14.2 Leakage test . 60
136 14.3 Tests for an infallible containment system . 60
137 14.4 Test for a containment system with a limited release . 60
138 15 Marking . 60
139 15.1 General . 60
140 15.2 Identifying as pressurized . 60
141 15.3 Supplementary marking . 60
142 15.4 Internal source of release . 61
143 15.5 Static pressurization . 61
144 15.6 Pressurization control systems evaluated as Ex associated equipment . 61
145 15.7 Inert gas . 61

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146 15.8 Internal flammable substance . 62
147 15.9 Warning markings . 62
148 16 Schedule Drawings . 63
149 17 Instructions . 63
150 Annex A (informative) Design considerations for pressurized equipment that have
151 containment systems where the flammable material is a liquid. 65
152 A.1 General . 65
153 A.2 Classification of material state . 65
154 A.3 Design recommendations . 65
155 A.3.1 Flashing liquids . 65
156 A.3.2 Pooling liquids . 65
157 A.3.3 Leak Detection . 66
158 A.3.4 Isolation of flammable lines . 66
159 A.3.5 Drain & vent connections . 66
160 A.3.6 Flame detectors . 66
161 A.4 Dilution vs leakage compensation . 66
162 A.5 Information to User . 66
163 Annex B (informative) Examples of functional sequence diagram . 67
164 Annex C (Informative) Examples of the changes in pressure in ducts and enclosures . 69
165 Annex D (informative)  Information to be provided to the user . 74
166 D.1 General . 74
167 D.2 Ducting of protective gas . 74
168 D.2.1 Location of inlet . 74
169 D.2.2 Ducting between pressurized equipment and inlet . 74
170 D.2.3 Outlets for protective gas . 74
171 D.2.4 Additional purge time to account for ducting . 75
172 D.2.5 Temperature of protective gas at the inlet . 75
173 D.3 Power for protective gas supply . 75
174 D.4 Static pressurization . 75
175 D.5 Pressurized Equipment with a containment system . 75
176 D.6 Pressurized Equipment maximum overpressure . 75
177 Annex E (normative)  Classification of the type of release within pressurized
178 equipment . 76
179 E.1 General . 76
180 E.2 No normal release, no abnormal release . 76
181 E.3 No normal release, limited abnormal release . 76
182 E.4 Limited normal release . 76
183 Annex F (informative)  Examples for the use of the dilution volume concept . 78
184 Annex G . 80
185 G.1 Safety device(s) and control function(s) evaluation . 80
186 Bibliography . 83
187 Figure 1 – Determination of Level of Protection . 30
188 Figure 2 - Determination of protection level and protective gas for equipment with
189 internal release . 47
190
191 Figure B.1 – State diagram of a leakage-compensation pressurization control system . 67
192 Figure C.1 – Protective gas outlet . 70

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193 Figure C.2 – Pressurized enclosures with leakage compensation, enclosures without
194 moving parts . 71
195 Figure C.3 – Pressurized enclosures with leakage compensation, rotating electrical
196 machine with an internal cooling fan . 72
197 Figure C.4 – Pressurized enclosure with a leakage compensation, rotating electrical
198 machine with an external cooling fan . 73
199 Figure F.1 – Diagram showing the use of the dilution volume concept to simplify the
200 purge and dilution flow test requirements . 78
201 Figure F.2 – Diagram showing the use of the infallible containment system concept to
202 simplify the purging and dilution flow requirements around ICE . 79
203 Figure F.3 – Diagram showing the use of internal partitions around the potential source
204 of release to simplify the purging and dilution flow requirements around ICE located
205 outside the partitions . 79
206
207 Table 1 - Applicability of specific clauses of IEC 60079-0 . 16
208 Table 2 - Design criteria based upon Level of Protection. 31
209 Table 3 – Internal volumes that do not require purging. . 34
210 Table 4 – Conditions for the determination of maximum surface temperature in electric
211 machines . 36
212 Table 5 – Control functions based upon Level of Protection . 37
213 Table 6 - Purging test requirements . 41
214 Table 7 – Equipment Protection Levels permitted within the dilution area based upon
215 the Level of Protection of the pressurized equipment . 51
216 Table 8 – Text of warning markings . 62
217 Table B.1 – Truth table of a leakage-compensation purge control system . 67
218 Table G.1 – Example of evaluation of pressurization control system elements for
219 control function . 80
220
221
222

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223 INTERNATIONAL ELECTROTECHNICAL COMMISSION
224 ____________
225
226 EXPLOSIVE ATMOSPHERES –
227
228 Part 2: Equipment protection by pressurization “p”
229
230
231
232 FOREWORD
233 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
234 all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
235 co-operation on all questions concerning standardization
...