Explosive atmospheres - Part 14: Electrical installations design, selection and erection

IEC 60079-14:2013 contains the specific requirements for the design, selection, erection and initial inspection of electrical installations in, or associated with, explosive atmospheres. Where the equipment is required to meet other environmental conditions, for example, protection against ingress of water and resistance to corrosion, additional protection requirements may be necessary. The requirements of this standard apply only to the use of equipment under standard atmospheric conditions as defined in IEC 60079-0. For other conditions, additional precautions may be necessary, and the equipment should be certified for these other conditions. For example, most flammable materials and many materials which are normally regarded as non-flammable might burn vigorously under conditions of oxygen enrichment. These requirements are in addition to the requirements for installations in non-hazardous areas. This standard applies to all electrical equipment including fixed, portable, transportable and personal, and installations, permanent or temporary. No account is taken in this Standard of the toxic risks that are associated with flammable gases, liquids and dusts in concentrations that are usually very much less than the lower explosive limit. In locations where personnel may be exposed to potentially toxic concentrations of flammable material, appropriate precautions should be taken. Such precautions are outside the scope of this Standard. This fifth edition cancels and replaces the fourth edition published in 2007. This edition constitutes a technical revision. Refer to the document's Foreward for a listing of the specific revisions and additional Notes. Key words: requirements for the design, selection, erection and initial inspection of electrical installations in explosive atmospheres.
The contents of the corrigendum of January 2016, the interpretation sheet 1 of February 2017 and March 2020 have been included in this copy.

Atmosphères explosives - Partie 14: Conception, sélection et construction des installations électriques

L'IEC 60079-14:2013 contient les exigences spécifiques de conception, de sélection, de construction et d'inspection initiale applicables aux installations électriques situées ou en relation avec des atmosphères explosives. Lorsque le matériel est tenu de satisfaire à d'autres conditions environnementales, par exemple, la protection contre la pénétration de l'eau et la résistance à la corrosion, des exigences de protection supplémentaires peuvent être nécessaires. Les exigences de la présente norme s'appliquent uniquement à l'utilisation de matériels dans des conditions atmosphériques normalisées telles que définies dans la CEI 60079-0. Pour d'autres conditions, des précautions complémentaires peuvent être nécessaires, et il convient de certifier le matériel pour ces mêmes conditions. Par exemple, la plupart des matières inflammables et beaucoup de matières normalement réputées ininflammables sont susceptibles de brûler violemment dans des conditions enrichies en oxygène. Ces exigences complètent celles relatives aux installations dans les emplacements non dangereux. La présente norme est applicable à tout matériel électrique fixe, portable, transportable et personnel et aux installations permanentes ou temporaires. La présente norme ne tient pas compte des risques toxiques associés aux gaz, liquides et poussières inflammables présents dans des concentrations habituellement bien inférieures à la limite inférieure d'explosivité. Sur les sites où le personnel peut être exposé à des concentrations potentiellement toxiques de matières inflammables, il convient de prendre des précautions appropriées. Ces précautions ne relèvent pas du domaine d'application de la présente norme. Cette cinquième édition annule et remplace la quatrième édition parue en 2007, dont elle constitue une révision technique. Reportez-vous à l'Avant-propos du document pour obtenir une liste des révisions spécifiques et billets supplémentaires. Mots clès: exigences de conception, de sélection, de construction et d'inspection initiale applicables aux installations électriques situées ou en des atmosphères explosives.
Le contenu du corrigendum de janvier 2016, la feuille d'interprétation 1 de février 2017 et de mars 2020 a été pris en considération dans cet exemplaire.

General Information

Status
Published
Publication Date
27-Nov-2013
Current Stage
PPUB - Publication issued
Start Date
28-Nov-2013
Completion Date
28-Nov-2013
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IEC 60079-14
Edition 5.0 2013-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Explosive atmospheres –
Part 14: Electrical installations design, selection and erection
Atmosphères explosives –
Partie 14: Conception, sélection et construction des installations électriques
IEC 60079-14:2013
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60079-14
Edition 5.0 2013-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Explosive atmospheres –
Part 14: Electrical installations design, selection and erection
Atmosphères explosives –
Partie 14: Conception, sélection et construction des installations électriques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XG
ICS 26.260.20 ISBN 978-2-8322-1276-9

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 60079-14:2013/ISH1:2017
 IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
IEC 60079-14
Edition 5.0 2013-11
EXPLOSIVE ATMOSPHERES –
Part 14: Electrical installations design, selection and erection
INTERPRETATION SHEET 1

This interpretation sheet has been prepared by subcommittee 31J: Classification of hazardous

areas and installation requirements, of IEC technical committee 31: Equipment for explosive

atmospheres.
The text of this interpretation sheet is based on the following documents:
ISH Report on voting
31J/268/ISH 31J/270/RVD

Full information on the voting for the approval of this interpretation sheet can be found in the

report on voting indicated in the above table.
___________
INTERPRETATION SHEET

Interpretation sheet for IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical

installations design, selection and erection

Following decision No 1 of the SC 31J meeting in Frankfurt in 2016, the issuing of an

Interpretation Sheet for IEC 60079-14:2013 was requested, in order to clarify the issues

relating to the installation of the converter supply or reduced voltage starting of electric

motors.
Details of interpretation:

Interpretation of sub clauses 11.2.1 b), 11.2.2 b), 11.3.5 b), 11.4.1 b) 11.4.2 b), 11.5.1 b),

11.5.2 b), 11.6.1 b) and 11.6.2 b) for Motors with converter supply or reduced voltage

starting

The motor has not been type-tested for this duty as a unit in association with the converter.

In this case, means (or equipment) for direct temperature control by embedded temperature

sensors specified in the motor documentation or other effective measures for limiting the

surface temperature of the motor housing shall be provided. The effectiveness of the

temperature control shall take into consideration power, speed range, torque and frequency

for the duty required and shall be verified and documented. The action of the protective

device shall cause the motor to be electrically disconnected.”
ICS 26.260.20
IEC 60079-14:2013-11/ISH1:2017-02(en-fr)
---------------------- Page: 4 ----------------------
IEC 60079-14:2013/ISH1:2017 – 3 –
 IEC 2017
Question

Is physical disconnection, such as a switch (circuit breaker) or contactor, required to

accomplish the intent of this requirement ?
Interpretation

The intention of this requirement is to protect the machine from excessive surface

temperatures.

Any action within the control circuit for the motor that accomplishes one of the following

satisfactorily meets the intent of this requirement:
• direct physical disconnection resulting in no output voltage to the motor, or,

• control circuit intervention such as ceasing modulation, resulting in the motor not

operating.

NOTE In this case, voltage to a motor may still exist, but the motor does not operate.

---------------------- Page: 5 ----------------------
IEC 60079-14:2013/ISH2:2020 – 1 –
 IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
IEC 60079-14
Edition 5.0 2013-11
EXPLOSIVE ATMOSPHERES –
Part 14: Electrical installations design, selection and erection
INTERPRETATION SHEET 2

This interpretation sheet has been prepared by subcommittee 31J: Classification of hazardous

areas and installation requirements, of IEC technical committee 31: Equipment for explosive

atmospheres.
The text of this interpretation sheet is based on the following documents:
DISH Report on voting
31J/302/DISH 31J/303/RVDISH

Full information on the voting for the approval of this interpretation sheet can be found in the

report on voting indicated in the above table.
___________
Background

With changes to the Type of Protection designations in the IEC 60079 Series, a number of

these Type of Protection designations are not identified in the current edition of

IEC 60079-14. This may create confusion for end users regarding the correct application of

equipment with these Types of Protection.
Question

How should equipment be marked with new Type of Protection designations be handled in

accordance with IEC 60079-14?
Interpretation

Equipment marked with new Type of Protection designations shall be applied in accordance

with IEC 60079-14 requirements based on the following points and IEC 60079-14:2013,

Table 2.
ICS 26.260.20
IEC 60079-14:2013-11/ISH2:2020-03(en)
---------------------- Page: 6 ----------------------
– 2 – IEC 60079-14:2013/ISH2:2020
 IEC 2020
• Ex "eb" should be treated as equivalent to Ex "e"
• Ex "ec" should be treated as equivalent to Ex "nA"
• Ex "db" should be treated as equivalent to Ex "d"

• Ex "dc" requirements should be based on Ex "d" requirements but is only suitable for

EPL Gc
• Ex "ob" should be treated as equivalent to Ex "o"

• Ex "oc" requirements should be based on Ex "o" requirements but is only suitable for

EPL Gc
---------------------- Page: 7 ----------------------
– 2 – 60079-14 © IEC:2013
CONTENTS

FOREWORD ......................................................................................................................... 11

INTRODUCTION ................................................................................................................... 16

1 Scope ............................................................................................................................ 18

2 Normative references .................................................................................................... 19

3 Terms and definitions .................................................................................................... 20

3.1 General ............................................................................................................ 20

3.2 Hazardous areas .............................................................................................. 21

3.3 Flameproof enclosure ...................................................................................... 22

3.4 Increased safety .............................................................................................. 22

3.5 Intrinsic safety ................................................................................................. 23

3.6 Intrinsic safety parameters ............................................................................... 24

3.7 Pressurization .................................................................................................. 24

3.8 Type of protection “n” ....................................................................................... 24

3.9 oil-immersion “o” .............................................................................................. 25

3.10 powder filling “q” .............................................................................................. 25

3.11 encapsulation “m” ............................................................................................ 25

3.12 protection by enclosure “t” ............................................................................... 25

3.13 Electrical supply systems ................................................................................. 25

3.14 Equipment ....................................................................................................... 25

3.15 radio frequency identification RFID ................................................................. 26

4 General ......................................................................................................................... 26

4.1 General requirements ...................................................................................... 26

4.2 Documentation ................................................................................................. 27

4.3 Initial inspection ............................................................................................... 28

4.4 Assurance of conformity of equipment.............................................................. 28

4.4.1 Equipment with certificates according to IEC standards .................. 28

4.4.2 Equipment without certificates according to IEC standards ............. 28

4.4.3 Selection of repaired, second hand or existing equipment ............... 29

4.5 Qualifications of personnel ............................................................................... 29

5 Selection of equipment .................................................................................................. 29

5.1 Information requirements ................................................................................. 29

5.2 Zones .............................................................................................................. 30

5.3 Relationship between equipment protection levels (EPLs) and zones ............... 30

5.4 Selection of equipment according to EPLs ....................................................... 30

5.4.1 General .......................................................................................... 30

5.4.2 Relationship between EPLs and types of protection ........................ 30

5.4.3 Equipment for use in locations requiring EPL “Ga” or “Da” .............. 32

5.4.4 Equipment for use in locations requiring EPL “Gb” or “Db” .............. 32

5.4.5 Equipment for use in locations requiring EPL “Gc” or “Dc” .............. 32

5.5 Selection according to equipment grouping ...................................................... 32

5.6 Selection according to the ignition temperature of the gas, vapour or dust

and ambient temperature ................................................................................. 33

5.6.1 General .......................................................................................... 33

5.6.2 Gas or vapour ................................................................................. 33

5.6.3 Dust ................................................................................................ 34

5.7 Selection of radiating equipment ...................................................................... 36

5.7.1 General .......................................................................................... 36

---------------------- Page: 8 ----------------------
60079-14 © IEC:2013 – 3 –

5.7.2 Ignition process .............................................................................. 36

5.8 Selection of ultrasonic equipment .................................................................... 36

5.8.1 General .......................................................................................... 36

5.8.2 Ignition process .............................................................................. 37

5.9 Selection to cover external influences .............................................................. 37

5.10 Selection of transportable, portable and personal equipment ........................... 38

5.10.1 General .......................................................................................... 38

5.10.2 Transportable and portable equipment ............................................ 39

5.10.3 Personal equipment ........................................................................ 39

5.11 Rotating electrical machines ............................................................................ 39

5.11.1 General .......................................................................................... 39

5.11.2 Environmental Factors for “Ex” machine installation ........................ 40

5.11.3 Power and accessory connections, grounding ................................. 40

5.11.4 Motors fed from a converter supply ................................................. 41

5.11.5 Switching motors above 1kV ........................................................... 41

5.12 Luminaires ....................................................................................................... 42

5.13 Plugs and socket outlets .................................................................................. 42

5.13.1 General .......................................................................................... 42

5.13.2 Specific requirements for explosive dust atmospheres .................... 42

5.13.3 Location.......................................................................................... 42

5.14 Cells and batteries ........................................................................................... 42

5.14.1 Charging of secondary cells and batteries ...................................... 42

5.14.2 Ventilation ...................................................................................... 43

5.15 RFID tags ........................................................................................................ 43

5.15.1 General .......................................................................................... 43

5.15.2 Passive RFID tags .......................................................................... 43

5.15.3 Mounting RFID tags ........................................................................ 43

5.16 Gas detection equipment ................................................................................. 43

6 Protection from dangerous (incendive) sparking ............................................................ 44

6.1 Light metals as construction materials ............................................................. 44

6.2 Danger from live parts ...................................................................................... 44

6.3 Danger from exposed and extraneous conductive parts ................................... 44

6.3.1 General .......................................................................................... 44

6.3.2 TN type of system earthing ............................................................. 45

6.3.3 TT type of system earthing ............................................................. 45

6.3.4 IT type of system earthing .............................................................. 45

6.3.5 SELV and PELV systems ................................................................ 45

6.3.6 Electrical separation ....................................................................... 45

6.3.7 Non Ex electrical equipment above hazardous areas ...................... 45

6.4 Potential equalization ....................................................................................... 46

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

6.4.2 Temporary bonding ......................................................................... 47

6.5 Static electricity ............................................................................................... 47

6.5.1 General .......................................................................................... 47

6.5.2 Avoidance of a build-up of electrostatic charge on
construction and protecting parts for locations requiring EPL

“Ga”, “Gb” and “Gc” ........................................................................ 47

6.5.3 Avoidance of a build-up of electrostatic charge on
construction and protecting parts for locations requiring EPL

“Da”, “Db” and “Dc” ......................................................................... 49

---------------------- Page: 9 ----------------------
– 4 – 60079-14 © IEC:2013

6.6 Lightning protection ......................................................................................... 49

6.7 Electromagnetic radiation ................................................................................. 49

6.7.1 General .......................................................................................... 49

6.7.2 Radio frequency received in hazardous areas ................................. 49

6.8 Cathodically protected metallic parts ................................................................ 50

6.9 Ignition by optical radiation .............................................................................. 50

7 Electrical protection ....................................................................................................... 51

8 Switch-off and electrical isolation ................................................................................... 51

8.1 General ............................................................................................................ 51

8.2 Switch-off ......................................................................................................... 51

8.3 Electrical isolation ............................................................................................ 51

9 Cables and wiring systems ............................................................................................ 52

9.1 General ............................................................................................................ 52

9.2 Aluminium conductors ...................................................................................... 52

9.3 Cables ............................................................................................................. 52

9.3.1 General .......................................................................................... 52

9.3.2 Cables for fixed installations ........................................................... 52

9.3.3 Flexible cables for fixed installations (excluding intrinsically

safe circuits) ................................................................................... 53

9.3.4 Flexible cables supplying transportable and portable

equipment (excluding intrinsically safe circuits) .............................. 53

9.3.5 Single insulated wires (excluding intrinsically safe circuits) ............. 54

9.3.6 Overhead lines ............................................................................... 54

9.3.7 Avoidance of damage ..................................................................... 54

9.3.8 Cable surface temperature.............................................................. 54

9.3.9 Resistance to flame propagation ..................................................... 54

9.4 Conduit systems .............................................................................................. 55

9.5 Additional requirements ................................................................................... 56

9.6 Installation requirements .................................................................................. 56

9.6.1 Circuits traversing a hazardous area ............................................... 56

9.6.2 Terminations ................................................................................... 56

9.6.3 Unused cores ................................................................................. 56

9.6.4 Openings in walls ........................................................................... 56

9.6.5 Passage and collection of flammables ............................................ 56

9.6.6 Accumulation of dust ...................................................................... 57

10 Cable entry systems and blanking elements .................................................................. 57

10.1 General ............................................................................................................ 57

10.2 Selection of cable glands ................................................................................. 57

10.3 Connections of cables to equipment ................................................................. 58

10.4 Additional requirements for entries other than Ex “d”, Ex “t” or Ex “nR” ............ 59

10.5 Unused openings ............................................................................................. 59

10.6 Additional requirements for type of protection “d” – Flameproof

enclosures ....................................................................................................... 59

10.6.1 General .......................................................................................... 59

10.6.2 Selection of cable glands ................................................................ 60

10.7 Additional requirements for type of protection “t” – Protection by

enclosure ......................................................................................................... 60

10.8 Additional requirements for type of protection “nR” – Restricted breathing

enclosure ......................................................................................................... 61

---------------------- Page: 10 ----------------------
60079-14 © IEC:2013 – 5 –

11 Rotating electrical machines .......................................................................................... 61

11.1 General ............................................................................................................ 61

11.2 Motors with type of protection “d” – Flameproof enclosures .............................. 61

11.2.1 Motors with a converter supply ....................................................... 61

11.2.2 Reduced-voltage starting (soft starting) .......................................... 62

11.3 Motors with type of protection “e” – Increased safety ....................................... 62

11.3.1 Mains-operated ............................................................................... 62

11.3.2 Winding temperature sensors ......................................................... 63

11.3.3 Machines with rated voltage greater than 1 kV ................................ 64

11.3.4 Motors with converter supply .......................................................... 64

11.3.5 Reduced-voltage starting (soft starting) .......................................... 64

11.4 Motors with type of protection “p” and “pD” – Pressurized enclosures .............. 64

11.4.1 Motors with a converter supply ....................................................... 64

11.4.2 Reduced-voltage starting (soft starting) .......................................... 65

11.5 Motors with type of protection “t” – Protection by enclosures supplied at

varying frequency and voltage ......................................................................... 65

11.5.1 Motors with a converter supply ....................................................... 65

11.5.2 Reduced-voltage starting (soft starting) .......................................... 66

11.6 Motors with type of protection “nA” – Non-sparking .......................................... 66

11.6.1 Motors with converter supply .......................................................... 66

11.6.2 Reduced-voltage starting (soft starting) .......................................... 66

11.6.3 Machines with rated voltage greater than 1 kV ................................ 66

12 Luminaires ..................................................................................................................... 67

13 Electric heating systems ................................................................................................ 67

13.1 General ............................................................................................................ 67

13.2 Temperature monitoring ................................................................................... 67

13.3 Limiting temperature ........................................................................................ 68

13.4 Safety device ................................................................................................... 68

13.5 Electrical trace heating systems ....................................................................... 69

14 Additional requirements for type of protection “d” – Flameproof enclosures ................... 69

14.1 General ............................................................................................................ 69

14.2 Solid obstacles ................................................................................................ 70

14.3 Protection
...

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