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BS EN IEC 60079-0:2018

$215.11

Explosive atmospheres – Equipment. General requirements

Published By Publication Date Number of Pages
BSI 2018 156
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This part of IEC 60079 specifies the general requirements for construction, testing and marking of Ex Equipment and Ex Components intended for use in explosive atmospheres.

The standard atmospheric conditions (relating to the explosion characteristics of the atmosphere) under which it may be assumed that Ex Equipment can be operated are:

  • temperature –20 °C to +60 °C;

  • pressure 80 kPa (0,8 bar) to 110 kPa (1,1 bar); and

  • air with normal oxygen content, typically 21 % v/v.

This part of IEC 60079 and other standards supplementing this standard specify additional test requirements for Ex Equipment operating outside the standard temperature range, but further additional consideration and additional testing may be required for Ex Equipment operating outside the standard atmospheric pressure range and standard oxygen content. Such additional testing may be particularly relevant with respect to Types of Protection that depend on quenching of a flame such as ‘flameproof enclosures “d”’ (IEC 60079-1) or limitation of energy, ‘intrinsic safety “i”’ (IEC 60079-11).

NOTE 1 Although the standard atmospheric conditions above give a temperature range for the atmosphere of -20 °C to +60 °C, the normal ambient temperature range for the Ex Equipment is –20 °C to +40 °C, unless otherwise specified and marked. See 5.1.1. It is considered that –20 °C to +40 °C is appropriate for many items of Ex Equipment and that to manufacture all Ex Equipment to be suitable for a standard atmosphere upper ambient temperature of +60 °C would place unnecessary design constraints.

NOTE 2 Requirements given in this standard result from an ignition hazard assessment made on equipment. The ignition sources taken into account are those found associated with this type of equipment, such as hot surfaces, electromagnetic radiation, mechanically generated sparks, mechanical impacts resulting in thermite reactions, electrical arcing and static electric discharge in normal industrial environments.

NOTE 3 Where an explosive gas atmosphere and a combustible dust atmosphere are, or can be, present at the same time, the simultaneous presence of both often warrants additional protective measures. Additional guidance on the use of Ex Equipment in hybrid mixtures (mixture of a flammable gas or vapour with a combustible dust or combustible flyings) is given in IEC 60079-14.

IEC 60079 does not specify requirements for safety, other than those directly related to the explosion risk.

Ignition sources like adiabatic compression, shock waves, exothermic chemical reaction, selfignition of dust, naked flames and hot gases/liquids, are not addressed by this standard.

NOTE 4 Although outside the scope of this standard, such equipment would typically be subjected to a hazard analysis that identifies and lists all of the potential sources of ignition by the equipment and the measures to be applied to prevent them becoming effective. See ISO/IEC 80079-36.

This document is supplemented or modified by the following parts and technical specifications:

  • IEC 60079-1: Gas – Flameproof enclosures “d”;

  • IEC 60079-2: Gas and dust – Pressurized enclosure “p”;

  • IEC 60079-5: Gas – Powder filling “q”;

  • IEC 60079-6: Gas – Liquid immersion “o”;

  • IEC 60079-7: Gas – Increased safety “e”;

  • IEC 60079-11: Gas and dust – Intrinsic safety “i”;

  • IEC 60079-13: Gas and dust – Equipment protection by pressurized room “p” & artificially ventilated room “v”;

  • IEC 60079-15: Gas – Type of protection “n”;

  • IEC 60079-18: Gas and dust – Encapsulation “m”;

  • IEC 60079-25: Gas and dust – Intrinsically safe electrical systems

  • IEC 60079-26: Gas – Equipment with equipment protection level (EPL) Ga

  • IEC 60079-28: Gas and dust – Protection of equipment and transmission systems using optical radiation

  • IEC 60079-29-1: Gas detectors – Performance requirements of detectors for flammable gases

  • IEC 60079-29-4: Gas detectors – Performance requirements of open path detectors for flammable gases

  • IEC/IEEE 60079-30-1: Gas and dust – Electrical resistance trace heating – General and testing requirements.

  • IEC 60079-31: Dust – Protection by enclosure “t”

  • IEC 60079-33: Gas and dust – Special protection “s”

  • IEC 60079-35-1: Caplights for use in mines susceptible to firedamp – General requirements – Construction and testing in relation to the risk of explosion

  • IEC TS 60079-39: Gas – Intrinsically safe systems with electronically controlled spark duration limitation

  • IEC TS 60079-40: Gas – Requirements for process sealing between flammable process fluids and electrical systems

  • ISO 80079-36: Gas and dust – Non-electrical equipment for explosive atmospheres – Basic method and requirements

This document, along with the additional parts of IEC 60079 mentioned above, is not applicable to the construction of

  • electromedical apparatus,

  • shot-firing exploders,

  • test devices for exploders, and

  • shot-firing circuits.

PDF Catalog

PDF Pages PDF Title
2 undefined
19 English
CONTENTS
25 FOREWORD
32 1 Scope
33 2 Normative references
35 3 Terms and definitions
37 Figures
Figure 1 – Typical battery examples
38 Figure 2 – Typical battery compartment
39 Figure 3 – Typical replaceable battery pack
53 4 Equipment grouping
4.1 General
4.2 Group I
4.3 Group II
4.4 Group III
54 4.5 Equipment for a particular explosive gas atmosphere
5 Temperatures
5.1 Environmental influences
5.1.1 Ambient temperature
5.1.2 External source of heating or cooling
5.2 Service temperature
Tables
Table 1 – Ambient temperatures in service and additional marking
55 5.3 Maximum surface temperature
5.3.1 Determination of maximum surface temperature
5.3.2 Limitation of maximum surface temperature
Table 2 – Classification of maximum surface temperatures for Group II electrical equipment
56 5.3.3 Small component temperature for Group I or Group II electrical equipment
57 5.3.4 Component temperature of smooth surfaces for Group I or Group II electrical equipment
Table 3 – Assessment of temperature classification according to component size
Table 4 – Assessment of temperature classification Component surface area ≥ 20 mm2
58 6 Requirements for all equipment
6.1 General
6.2 Mechanical strength of equipment
6.3 Opening times
59 6.4 Circulating currents in enclosures (e.g. of large electric machines)
6.5 Gasket retention
6.6 Electromagnetic and ultrasonic energy radiating equipment
6.6.1 General
6.6.2 Radio frequency sources
60 6.6.3 Ultrasonic sources
Table 5 – Threshold power
Table 6 – Threshold energy
61 6.6.4 Lasers, luminaires, and other non-divergent continuous wave optical sources
7 Non-metallic enclosures and non-metallic parts of enclosures
7.1 General
7.1.1 Applicability
7.1.2 Specification of materials
62 7.2 Thermal endurance
7.2.1 Tests for thermal endurance
63 7.2.2 Material selection
7.2.3 Alternative qualification of elastomeric sealing O-rings
7.3 Resistance to ultraviolet light
64 7.4 Electrostatic charges on external non-metallic materials
7.4.1 Applicability
7.4.2 Avoidance of a build-up of electrostatic charge for Group I or Group II
65 Table 7 – Limitation of surface areas
66 7.4.3 Avoidance of a build-up of electrostatic charge for Group III
Table 8 – Maximum diameter or width
Table 9 – Limitation of thickness of non-metallic layer
Table 10 – Maximum acceptable transferred charge
67 7.5 Attached external conductive parts
68 8 Metallic enclosures and metallic parts of enclosures
8.1 Material composition
8.2 Group I
8.3 Group II
Table 11 – Maximum capacitance of unearthed conductive parts
69 8.4 Group III
8.5 Copper Alloys
9 Fasteners
9.1 General
70 9.2 Special fasteners
9.3 Holes for special fasteners
9.3.1 Thread engagement
9.3.2 Tolerance and clearance
Figure 4 – Tolerances and clearance for threaded fasteners
71 9.4 Hexagon socket set screws
10 Interlocking devices
11 Bushings
12 (Reserved for future use)
13 Ex Components
13.1 General
Figure 5 – Contact surface under head of fastener with a reduced shank
72 13.2 Mounting
13.3 Internal mounting
13.4 External mounting
13.5 Ex Component certificate
14 Connection facilities
14.1 General
73 14.2 Type of protection
14.3 Creepage and clearance
15 Connection facilities for earthing or bonding conductors
15.1 Equipment requiring earthing or bonding
15.1.1 Internal earthing
15.1.2 External bonding
15.2 Equipment not requiring earthing
15.3 Size of protective earthing conductor connection
74 15.4 Size of equipotential bonding conductor connection
15.5 Protection against corrosion
15.6 Secureness of electrical connections
15.7 Internal earth continuity plate
16 Entries into enclosures
16.1 General
16.2 Identification of entries
Table 12 – Minimum cross-sectional area of PE conductors
75 16.3 Cable glands
16.4 Blanking elements
16.5 Thread adapters
76 16.6 Temperature at branching point and entry point
16.7 Electrostatic charges of cable sheaths
Figure 6 – Cable gland
Figure 7 – Conduit entry
77 17 Supplementary requirements for electric machines
17.1 General
17.2 Ventilation
17.2.1 Ventilation openings
17.2.2 Materials for external fans
17.2.3 Cooling fans of rotating electric machines
78 17.2.4 Auxiliary motor cooling fans
17.2.5 Room ventilating fans
79 17.3 Bearings
18 Supplementary requirements for switchgear
18.1 Flammable dielectric
18.2 Disconnectors
80 18.3 Group I – Provisions for locking
18.4 Doors and covers
19 Reserved for future use
20 Supplementary requirements for external plugs, socket outlets and connectors for field wiring connection
20.1 General
81 20.2 Explosive gas atmospheres
20.3 Explosive dust atmospheres
20.4 Energized plugs
21 Supplementary requirements for luminaires
21.1 General
21.2 Covers for luminaires of EPL Mb, EPL Gb, or EPL Db
82 21.3 Covers for luminaires of EPL Gc or EPL Dc
21.4 Sodium lamps
22 Supplementary requirements for caplights and handlights
22.1 Group I caplights
22.2 Group II and Group III caplights and handlights  
83 23 Equipment incorporating cells and batteries
23.1 General
23.2 Interconnection of cells to form batteries
23.3 Cell types
Table 13 – Primary cells
85 Table 14 – Secondary cells
86 23.4 Cells in a battery
23.5 Ratings of batteries
23.6 Interchangeability
23.7 Charging of primary batteries
23.8 Leakage
23.9 Connections
23.10 Orientation
23.11 Replacement of cells or batteries
87 23.12 Replaceable battery pack
24 Documentation
25 Compliance of prototype or sample with documents
26 Type tests
26.1 General
26.2 Test configuration
26.3 Tests in explosive test mixtures
88 26.4 Tests of enclosures
26.4.1 Order of tests
90 26.4.2 Resistance to impact
91 26.4.3 Drop test
Table 15 – Tests for resistance to impact
92 26.4.4 Acceptance criteria
26.4.5 Degree of protection (IP) by enclosures
93 26.5 Thermal tests
26.5.1 Temperature measurement
95 26.5.2 Thermal shock test
26.5.3 Small component ignition test (Group I and Group II)
96 26.6 Torque test for bushings
26.6.1 Test procedure
Table 16 – Torque to be applied to the stem of bushing used for connection facilities
97 26.6.2 Acceptance criteria
26.7 Non-metallic enclosures or non-metallic parts of enclosures
26.7.1 General
26.7.2 Test temperatures
26.8 Thermal endurance to heat
Table 17 – Thermal endurance test
98 26.9 Thermal endurance to cold
26.10 Resistance to UV light
26.10.1 General
99 26.10.2 Light exposure
26.10.3 Acceptance criteria
26.11 Resistance to chemical agents for Group I equipment
100 26.12 Earth continuity
101 26.13 Surface resistance test of parts of enclosures of non-metallic materials
Figure 8 – Assembly of test sample for earth-continuity test
102 26.14 Measurement of capacitance
26.14.1 General
26.14.2 Test procedure
Figure 9 – Test piece with painted electrodes
103 26.15 Verification of ratings of ventilating fans
26.16 Alternative qualification of elastomeric sealing O-rings
26.17 Transferred charge test
26.17.1 Test equipment
Figure 10 – Compression set of an O-ring
104 26.17.2 Test sample
26.17.3 Test procedure
105 27 Routine tests
28 Manufacturer’s responsibility
28.1 Conformity with the documentation
106 28.2 Certificate
28.3 Responsibility for marking
29 Marking
29.1 Applicability
29.2 Location
29.3 General
107 29.4 Ex marking for explosive gas atmospheres
109 29.5 Ex marking for explosive dust atmospheres
112 29.6 Combined types (or levels) of protection
29.7 Multiple types of protection
29.8 Ga equipment using two independent Gb types (or levels) of protection
29.9 Boundary wall
29.10 Ex Components
113 29.11 Small Ex Equipment and small Ex Components
29.12 Extremely small Ex Equipment and extremely small Ex Components
29.13 Warning markings
114 29.14 Cells and batteries
29.15 Electric machines operated with a converter
Table 18 – Text of warning markings
115 29.16 Examples of marking
118 30 Instructions
30.1 General
119 30.2 Cells and batteries
120 30.3 Electric machines
30.4 Ventilating fans
Table 19 – Example of type-test converter parameters
121 30.5 Cable glands
122 Annexes
Annex A (normative) Supplementary requirements for cable glands
A.1 General
A.2 Constructional requirements
A.2.1 Cable sealing
123 A.2.2 Filling compounds
A.2.3 Clamping
A.2.4 Lead-in of cable
Figure A.1 – Illustration of the terms used for cable glands
124 A.2.5 Release by a tool
A.2.6 Fixing
A.2.7 Degree of protection
A.3 Type tests
A.3.1 Tests of clamping of non-armoured and braided cables
Figure A.2 – Rounded edge of the point of entry of the flexible cable
127 A.3.2 Tests of clamping of armoured cables
128 A.3.3 Type test for resistance to impact
129 A.3.4 Test for degree of protection (IP) of cable glands
Figure A.3 – Example of rig for resistance to impact test
130 A.4 Marking
A.4.1 Marking of cable glands
A.4.2 Identification of cable-sealing rings
A.5 Instructions
132 Annex B (normative) Requirements for Ex Components
Table B.1 – Applicability of clauses to Ex Components
135 Annex C (informative) Example of rig for resistance to impact test
Figure C.1 – Example of rig for resistance to impact test
136 Annex D (informative) Electric machines connected to converters
137 Annex E (informative) Temperature evaluation of electric machines
140 Annex F (informative) Guidance flowchart for tests of non-metallic enclosures or non-metallic parts of enclosures (26.4)
Figure F.1 – Non-metallic enclosures or non-metallic parts of enclosures
141 Annex G (informative) Guidance flowchart for tests of cable glands
142 Annex H (informative) Shaft voltages resulting in motor bearing or shaft brush sparking Discharge energy calculation
H.1 General
H.2 Assessment of the risk of ignition using ignition energy calculation
143 H.3 Shaft voltage determination for a rotating machine
H.4 Capacitance “C” calculation for a rotating machine
Table H.1 – Maximum permitted energy
145 Figure H.1 – Capacitance stored in bearing clearance of sleeve bearing Between journal and outer bearing housing
Figure H.2 – Air-gap between stator and rotor
146 H.5 Energy “E” calculation for a rotating machine
H.6 Assessment using reference curves
Figure H.3 – Typical surfaces that form capacitorsfrom the motor shaft to ground
147 Figure H.4 – Capacitive ignition curves
148 Bibliography
BS EN IEC 60079-0:2018
$215.11