Explosive atmospheres - Part 11: Equipment protection by intrinsic safety "i"

This part of IEC 60079 specifies the construction and testing of intrinsically safe apparatus intended for use in an explosive atmosphere, and for associated apparatus which is intended for connection to intrinsically safe circuits which enter such atmospheres. This Type of Protection is applicable to electrical equipment in which the electrical circuits themselves are incapable of causing ignition of a surrounding explosive atmosphere. This includes electrical equipment which contains circuits that are intrinsically safe only under certain conditions, for example under battery supply with mains supply removed. This standard is also applicable to electrical equipment or parts of electrical equipment located outside the explosive atmosphere or protected by another Type of Protection listed in IEC 60079-0, where the intrinsic safety of the electrical circuits in the explosive atmosphere may depend upon the design and construction of such electrical equipment or parts of such electrical equipment. The electrical circuits exposed to the explosive atmosphere are assessed for use in such an atmosphere by applying this standard. This standard applies to sensors connected to intrinsically safe circuits but does not apply to the protection of catalytic elements for Group IIC or Group IIB + H2. The requirements for intrinsically safe systems are provided in IEC 60079-25. This standard supplements and modifies the general requirements of IEC 60079-0, except as indicated in Table 1. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard takes precedence. Unless otherwise stated, the requirements in this standard are applicable to both intrinsically safe apparatus and associated apparatus, and the generic term "apparatus" is used throughout the standard. As this standard applies only to electrical equipment, the term "equipment" used in the standard always means “electrical equipment”. This standard applies to apparatus for use under the atmospheric conditions of IEC 60079-0 with additional requirements for for use at lower atmospheric pressures in the range from 60 kPa (0,6 bar), up to 110 kPa (1,1 bar). [...]

Explosionsgefährdete Bereiche - Teil 11: Geräteschutz durch Eigensicherheit "i"

Atmosphères explosives - Partie 11: Protection de l'équipement par sécurité intrinsèque "i"

Eksplozivne atmosfere - 11. del: Zaščita opreme z lastno varnostjo "i"

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Not Published
Current Stage
4020 - Enquiry circulated
Due Date
06-Nov-2020
Completion Date
06-Nov-2020

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SLOVENSKI STANDARD
oSIST prEN 60079-11:2021
01-januar-2021
Eksplozivne atmosfere - 11. del: Zaščita opreme z lastno varnostjo "i"
Explosive atmospheres - Part 11: Equipment protection by intrinsic safety "i"
Explosionsgefährdete Bereiche - Teil 11: Geräteschutz durch Eigensicherheit "i"

Atmosphères explosives - Partie 11: Protection de l'équipement par sécurité intrinsèque

"i"
Ta slovenski standard je istoveten z: prEN 60079-11:2020
ICS:
29.260.20 Električni aparati za Electrical apparatus for
eksplozivna ozračja explosive atmospheres
oSIST prEN 60079-11:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 60079-11:2021
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oSIST prEN 60079-11:2021
31G/327/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60079-11 ED7
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2020-11-06 2021-01-29
SUPERSEDES DOCUMENTS:
31G/291/CD, 31G/297A/CC
IEC SC 31G : INTRINSICALLY-SAFE APPARATUS
SECRETARIAT: SECRETARY:
United Kingdom Mr Nicholas Ludlam
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:
TC 18,SC 31J
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 11: Equipment protection by intrinsic safety "i"
PROPOSED STABILITY DATE: 2026
NOTE FROM TC/SC OFFICERS:

The attached CDV includes significant changes from Edition 6 including a restructure and new technical

elements. It is requested that NCs hold any new items until completion of Edition 7.

Copyright © 2020 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 60079-11:2021

The list of 'significance of differences' in the Foreword will be circulated as a separate INF document.

Due to the nature of changes between this CDV and IEC 60079-11 Ed 6 a redline comparison is not

being circulated.
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oSIST prEN 60079-11:2021
31G/327/CDV – 2 – IEC CDV 60079-11  IEC:2020
2 CONTENTS

3 FOREWORD ......................................................................................................................... 10

4 1 Scope ............................................................................................................................ 13

5 2 Normative references .................................................................................................... 24

6 3 Terms, definitions and abbreviated terms ...................................................................... 25

7 3.1 Terms and definitions............................................................................................ 25

8 3.2 Abbreviated terms ................................................................................................. 29

9 4 Grouping, classification and Levels of Protection of apparatus ...................................... 30

10 5 Levels of Protection and ignition compliance requirements ............................................ 30

11 5.1 General ................................................................................................................. 30

12 5.2 Conditions for assessment .................................................................................... 31

13 5.2.1 General ......................................................................................................... 31

14 5.2.2 Level of Protection "ia" .................................................................................. 31

15 5.2.3 Level of Protection "ib" .................................................................................. 32

16 5.2.4 Level of Protection “ic” ................................................................................... 32

17 5.2.5 Non-shock hazard equipment or systems ....................................................... 32

18 5.3 Spark ignition compliance ..................................................................................... 33

19 5.3.1 General ......................................................................................................... 33

20 5.3.2 Levels of Protection “ia” and “ib” .................................................................... 34

21 5.3.3 Level of Protection “ic” ................................................................................... 34

22 5.3.4 Application of safety factors ........................................................................... 34

23 5.3.5 Circuits without controlled semiconductor limitation ....................................... 35

24 5.3.6 Circuits with controlled semiconductor limitation ............................................ 35

25 5.4 Thermal ignition compliance.................................................................................. 36

26 5.4.1 General ......................................................................................................... 36

27 5.4.2 Temperature of small components for Group I and Group II ........................... 37

28 5.4.3 Wiring within intrinsically safe apparatus for Group I and Group II ................. 37

29 5.4.4 PCB tracks for Group I and Group II .............................................................. 38

30 5.4.5 Intrinsically safe apparatus and component temperature for dusts ................. 40

31 5.5 Simple apparatus .................................................................................................. 40

32 6 Apparatus construction .................................................................................................. 41

33 6.1 General ................................................................................................................. 41

34 6.2 Enclosures ............................................................................................................ 41

35 6.2.1 General ......................................................................................................... 41

36 6.2.2 Apparatus complying with Table 7 ................................................................. 42

37 6.2.3 Apparatus complying with Table 8 or Table 9 ................................................. 42

38 6.2.4 Enclosures for Group IIIC intrinsically safe apparatus .................................... 42

39 6.3 Connection facilities for external circuits ............................................................... 43

40 6.3.1 Terminals ...................................................................................................... 43

41 6.3.2 Plugs and sockets ......................................................................................... 45

42 6.3.3 Permanently connected cable ........................................................................ 45

43 6.3.4 Connections and accessories for intrinsically safe apparatus when

44 located in the non-hazardous area ................................................................. 46

45 6.4 Internal connections and connectors ..................................................................... 47

46 6.4.1 General ......................................................................................................... 47

47 6.4.2 Infallible connections ..................................................................................... 47

48 6.4.3 Connectors for internal connections, plug-in cards and components .............. 49

49 6.4.4 Earth conductors and connections ................................................................. 49

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50 6.5 Separation of conductive parts .............................................................................. 49

51 6.5.1 Separations on which intrinsic safety depends ............................................... 49

52 6.5.2 Separation distances according to Table 7 .................................................... 50

53 6.5.3 Reduced separation distances ....................................................................... 50

54 6.5.4 Failure of separations .................................................................................... 51

55 6.5.5 Voltage between conductive parts ................................................................. 57

56 6.5.6 Types of separation ....................................................................................... 57

57 6.5.7 Composite separations .................................................................................. 64

58 6.5.8 Printed circuit board assemblies .................................................................... 65

59 6.5.9 Separation by metal parts .............................................................................. 66

60 6.5.10 Separation by non-metallic insulating partitions ............................................. 67

61 6.5.11 Insulation of internal wiring ............................................................................ 67

62 6.6 Encapsulation ....................................................................................................... 67

63 6.6.1 General ......................................................................................................... 67

64 6.6.2 Encapsulation used for the exclusion of explosive atmospheres .................... 69

65 6.6.3 Mechanical protection to avoid access to parts .............................................. 71

66 6.6.4 Encapsulation used for protection of a fuse. .................................................. 71

67 6.6.5 Encapsulation used to provide separation ...................................................... 71

68 6.6.6 Encapsulation used to enhance the rating of protective components .............. 72

69 6.6.7 Free space within the encapsulation .............................................................. 72

70 6.7 Specification of coating, encapsulation and moulding materials ............................ 73

71 6.7.1 General ......................................................................................................... 73

72 6.7.2 Coating materials .......................................................................................... 73

73 6.7.3 Materials used for encapsulation ................................................................... 74

74 6.7.4 Plastic materials used for moulding ............................................................... 74

75 6.8 Protection against polarity reversal ....................................................................... 74

76 6.9 Dielectric strength requirement ............................................................................. 74

77 7 Characteristics and failure of components and assemblies ............................................ 75

78 7.1 Rating of components on which intrinsic safety depends ....................................... 75

79 7.2 Failure of components .......................................................................................... 75

80 7.3 Manufacturing variation ......................................................................................... 75

81 7.4 Resistors .............................................................................................................. 76

82 7.4.1 General ......................................................................................................... 76

83 7.4.2 Resistors on which intrinsic safety depends ................................................... 76

84 7.5 Capacitors ............................................................................................................ 77

85 7.5.1 General ......................................................................................................... 77

86 7.5.2 Capacitors on which intrinsic safety depends ................................................. 77

87 7.5.3 Blocking capacitors ........................................................................................ 78

88 7.5.4 Infallible filter capacitors ................................................................................ 78

89 7.6 Inductors and windings ......................................................................................... 78

90 7.6.1 General ......................................................................................................... 78

91 7.6.2 Inductors on which intrinsic safety depends ................................................... 79

92 7.6.3 Infallibly insulated inductors ........................................................................... 79

93 7.6.4 Damping windings ......................................................................................... 80

94 7.6.5 Common mode choke coils (EMI suppression filters) ..................................... 80

95 7.7 Semiconductors .................................................................................................... 80

96 7.7.1 General ......................................................................................................... 80

97 7.7.2 Semiconductors on which intrinsic safety depends......................................... 81

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98 7.7.3 Transient effects on semiconductors on which intrinsic safety depends ......... 81

99 7.7.4 Semiconductors in shunt voltage limiters ....................................................... 82

100 7.7.5 Shunt assembly on which intrinsic safety depends ......................................... 82

101 7.7.6 Infallible assemblies on which intrinsic safety depends .................................. 82

102 7.7.7 Semiconductor current limiters ...................................................................... 83

103 7.8 Transformers ........................................................................................................ 83

104 7.8.1 General ......................................................................................................... 83

105 7.8.2 Transformers on which intrinsic safety depends ............................................. 83

106 7.8.3 Construction of transformers on which intrinsic safety depends ..................... 83

107 7.8.4 Protective measures for transformers on which intrinsic safety depends

108 for Levels of Protection “ia” and “ib” ............................................................... 84

109 7.8.5 Requirements for transformers for Level of Protection “ic” ............................. 85

110 7.9 Relays .................................................................................................................. 85

111 7.9.1 General ......................................................................................................... 85

112 7.9.2 Relays on which intrinsic safety depends ....................................................... 85

113 7.10 Signal isolators ..................................................................................................... 86

114 7.10.1 General ......................................................................................................... 86

115 7.10.2 Signal isolators on which intrinsic safety depends.......................................... 86

116 7.10.3 Signal isolators between intrinsically safe and non-intrinsically safe

117 circuits ........................................................................................................... 87

118 7.10.4 Signal isolators between separate intrinsically safe circuits ........................... 87

119 7.11 Fuses ................................................................................................................... 87

120 7.12 Primary and secondary cells and batteries ............................................................ 88

121 7.12.1 General ......................................................................................................... 88

122 7.12.2 Construction of cells and batteries used in intrinsically safe apparatus .......... 89

123 7.12.3 Electrolyte leakage ........................................................................................ 89

124 7.12.4 Ventilation ..................................................................................................... 89

125 7.12.5 Cell voltages .................................................................................................. 90

126 7.12.6 Batteries in equipment protected by other Types of Protection ....................... 90

127 7.12.7 Batteries used and replaced in explosive atmospheres .................................. 90

128 7.12.8 Replaceable batteries used but not replaced in explosive atmospheres ......... 90

129 7.12.9 External contacts for charging batteries ......................................................... 91

130 7.13 Piezo-electric devices ........................................................................................... 91

131 7.14 Cells for the detection of gases ............................................................................. 91

132 7.14.1 Electrochemical ............................................................................................. 91

133 7.14.2 Catalytic ........................................................................................................ 91

134 7.15 Supercapacitors .................................................................................................... 91

135 7.16 Thermal devices ................................................................................................... 92

136 7.16.1 General ......................................................................................................... 92

137 7.16.2 Thermal devices used to limit temperature ..................................................... 92

138 7.16.3 Thermal devices used to limit current ............................................................ 93

139 8 Supplementary requirements for specific apparatus ....................................................... 94

140 8.1 Diode safety barriers ............................................................................................. 94

141 8.1.1 General ......................................................................................................... 94

142 8.1.2 Construction .................................................................................................. 94

143 8.2 FISCO apparatus .................................................................................................. 94

144 9 Type verifications and type tests ................................................................................... 94

145 9.1 Spark ignition test ................................................................................................. 94

146 9.1.1 General ......................................................................................................... 94

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147 9.1.2 Spark test apparatus and its use.................................................................... 95

148 9.1.3 Test gas mixtures and spark test apparatus calibration current ...................... 95

149 9.2 Spark ignition assessment using reference curves and tables ............................... 96

150 9.2.1 General ......................................................................................................... 96

151 9.2.2 Assessment of simple resistive circuit ............................................................ 97

152 9.2.3 Assessment of simple capacitive circuits ....................................................... 97

153 9.2.4 Assessment of Simple Inductive Circuits ...................................................... 100

154 9.2.5 Determination of maximum external inductance to resistance ratio

155 (L /R ) for resistance limited power source .................................................. 100

o o

156 9.2.6 Circuits with both inductance and capacitance ............................................. 101

157 9.3 Temperature tests ............................................................................................... 102

158 9.4 Dielectric strength tests ...................................................................................... 102

159 9.5 Determination of parameters of loosely specified components ............................ 102

160 9.6 Tests for cells, batteries and supercapacitors ..................................................... 103

161 9.6.1 General ....................................................................................................... 103

162 9.6.2 Electrolyte leakage test for cells, batteries and supercapacitors .................. 103

163 9.6.3 Spark ignition and surface temperature of cells, batteries or

164 supercapacitors ........................................................................................... 104

165 9.6.4 Battery container pressure tests .................................................................. 105

166 9.7 Qualification of reduced distances for solid insulation and distance through

167 casting compound ............................................................................................... 106

168 9.7.1 General ....................................................................................................... 106

169 9.7.2 Preconditioning ............................................................................................ 106

170 9.7.3 AC power frequency voltage test ................................................................. 107

171 9.7.4 Partial discharge test ................................................................................... 107

172 9.8 Mechanical tests ................................................................................................. 108

173 9.8.1 Casting compound ....................................................................................... 108

174 9.8.2 Determination of the acceptability of fuses requiring encapsulation ............. 108

175 9.8.3 Partitions ..................................................................................................... 109

176 9.8.4 Cable pull test ............................................................................................. 109

177 9.9 Tests for intrinsically safe apparatus containing piezoelectric devices ................. 109

178 9.10 Type tests for components protected by time dependent current limitation .......... 109

179 9.11 Current carrying capacity of infallible printed circuit board connections ............... 110

180 9.12 Transformer tests ................................................................................................ 111

181 9.12.1 General ....................................................................................................... 111

182 9.12.2 Mains transformers for Level of Protection “ia” and “ib” ................................ 111

183 9.12.3 Transformers galvanically isolated from the mains supply for Levels of

184 Protection “ia” and “ib” ................................................................................. 112

185 9.12.4 Transformers for Level of Protection “ic” ...................................................... 112

186 9.13 Isolator tests ....................................................................................................... 112

187 9.13.1 General ....................................................................................................... 112

188 9.13.2 Thermal conditioning and dielectric test ....................................................... 112

189 9.13.3 Dielectric and short-circuit test .................................................................... 113

190 9.14 Differential Leakage current tests for signal isolators .......................................... 114

191 9.15 Determination of storable energy in common mode chokes ................................. 115

192 9.16 Tests for PTCs .................................................................................................... 116

193 10 Routine verifications and tests ..................................................................................... 116

194 10.1 Routine tests for diode safety barriers ................................................................. 116

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195 10.1.1 Completed barriers ...................................................................................... 116

196 10.1.2 Diodes for 2-diode “ia” barriers .................................................................... 116

197 10.2 Routine tests for transformers ............................................................................. 116

198 10.2.1 Levels of Protection “ia” and “ib” .................................................................. 116

199 10.2.2 Level of Protection “ic” ................................................................................. 117

200 10.3 Routine verification ............................................................................................. 117

201 11 Marking ....................................................................................................................... 118

202 11.1 Intrinsically safe apparatus and associated apparatus......................................... 118

203 11.1.1 General ....................................................................................................... 118

204 11.1.2 Electrical parameters ................................................................................... 118

205 11.1.3 FISCO ......................................................................................................... 118

206 11.1.4 Marking of connection facilities .................................................................... 118

207 11.1.5 Non-hazardous area accessory ................................................................... 118

208 11.2 Warning markings ............................................................................................... 119

209 12 Instructions .................................................................................................................. 119

210 12.1 General ............................................................................................................... 119

211 12.2 Specific Conditions of Use .................................................................................. 119

212 Annex A (normative) Spark ignition reference curves ......................................................... 121

213 Annex B (normative) Spark test apparatus for intrinsically safe circuits .............................. 149

214 B.1 Principle ............................................................................................................. 149

215 B.2 Spark test apparatus ........................................................................................... 149

216 B.3 Spark test apparatus sensitivity .......................................................................... 150

217 B.4 Preparation and cleaning of tungsten wires ......................................................... 150

218 B.5 Conditioning a new cadmium disc ....................................................................... 150

219 B.6 Limitations of the spark test apparatus ................................................................ 151

220 B.7 Modification of spark test apparatus for use at higher currents ............................ 151

221 Annex C (informative) Measurement of creepage distances, clearances and

222 separation distances through casting compound and through solid insulation .............. 156

223 C.1 Clearances and separation distances through casting compound and

224 through solid insulation ....................................................................................... 156

225 C.2 Creepage distances ............................................................................................ 157

226 C.3 Examples for the application of an ambient pressure correction factor ................ 158

227 Annex D (normative) Excess transient energy test ............................................................. 160

228 D.1 Int
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