IEC/IEEE 60079-30-1:2025

IEC/IEEE 60079-30-1 ®
Edition 2.0 2025-09
INTERNATIONAL
STANDARD
REDLINE VERSION
Explosive atmospheres -
Part 30-1: Electrical resistance trace heating - General and testing requirements
ICS 29.260.20  ISBN 978-2-8327-0727-2

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CONTENTS
FOREWORD . 4
INTRODUCTION . 1
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 10
4 General requirements . 14
4.1 Applicability of IEC 60079-0 . 17
4.2 General . 27
4.3 Mechanical strength . 28
4.4 Terminations and connections. 28
4.5 Circuit protection requirements for branch circuits . 28
4.6 Temperature requirements . 29
4.6.1 General . 29
4.6.2 Stabilized design . 29
4.6.3 Controlled design . 30
5 Testing . 31
5.1 Type tests . 33
5.1.1 General . 33
5.1.2 Dielectric test . 33
5.1.3 Electrical insulation resistance test . 34
5.1.4 Flammability test . 34
5.1.5 Impact test. 36
5.1.6 Deformation test . 39
5.1.7 Cold bend test . 40
5.1.8 Water resistance test . 42
5.1.9 Integral components' resistance to water test . 43
5.1.10 Verification of rated output . 43
5.1.11 Thermal stability of electrical insulating material . 46
5.1.12 Thermal performance test . 46
5.1.13 Determination of maximum sheath temperature . 48
5.1.14 Verification of start-up current . 54
5.1.15 Verification of the electrical resistance of electrically conductive
covering . 58
5.1.16 Outdoor exposureUV and condensation test . 58
5.1.17 Connection Integrity (integral components) . 59
5.2 Routine tests . 61
5.2.1 Dielectric test . 61
5.2.2 Verification of rated output . 61
6 Marking . 61
6.1 Product markings for trace heaters . 61
6.2 Markings for Field assembled components . 62
6.3 Product markings for high temperature limiters and temperature controllers . 62
7 Documentation requirements . 62
7.1 General . 62
7.2 Circuit design documentation . 63
7.3 Trace heating system documentation . 63
7.3.1 General . 63
7.3.2 For trace heating systems according to the product classification
method . 63
7.3.3 For trace heating systems according to stabilized design method . 63
7.3.4 For trace heating systems according to controlled design method . 63
7.4 Instructions for installation of trace heating system . 64
7.5 Instructions for commissioning . 65
7.6 Instructions for maintenance / repair or modification . 65
Annex A (informative) Type test matrix for EPLs Gb/Gc/Db/Dc (refer to IEC 60079-14
for the relationship of EPLs to Zones) . 66
Annex B (informative) Checklist for installation . 68
Annex C (normative) Trace heater product design verification methodology . 69
C.1 General . 69
C.2 Design methodology and selection of trace heaters . 69
C.3 Stabilized design calculations . 69
C.4 Trace heater performance and equilibrium conditions . 70
C.5 Heat loss calculations . 72
C.6 Heat loss design safety factor . 73
C.7 Maximum temperature determination . 73
C.7.1 Theoretical pipe and sheath temperature calculations - Metallic
applications . 73
C.7.2 Theoretical vessel and sheath temperature calculations - Metallic
applications . 74
C.7.3 Sheath temperature - metallic applications utilizing a temperature limiter
control sensing the trace heater sheath or an artificial hot spot . 76
C.7.4 Theoretical sheath temperature calculations - Non-metallic applications . 76
C.7.5 Sheath temperature - Non-metallic applications utilizing a temperature
limiter control sensing the trace heater sheath or an artificial hot spot . 78
Annex D (normative) Calculation methodology for coverage of electrically conductive
covering . 79
Annex E (normative) Applications of trace heating in empty conduit . 80
E.1 General . 80
E.2 Maximum sheath temperature - trace heating internal to conduit . 80
E.3 Pull-strength test. 80
E.4 Rated output . 80
E.5 Verification of start-up current . 81
Annex F (normative) Requirements for Division 1 and Division 2 trace heating systems . 82
F.1 Application . 82
F.2 General . 82
F.3 Terminations and connections. 82
F.4 Control and temperature requirements . 82
F.4.1 General . 82
F.4.2 Stabilized design . 82
F.4.3 Controlled design . 83
F.4.4 Requirements for protective device in Divisions 1 and 2 . 83
F.5 Type tests . 83
F.5.1 Division 1 trace heating equipment . 83
F.5.2 Division 2 trace heating equipment . 84
F.6 Marking . 84
F.7 Instructions - Installation requirements . 84
Annex G (normative) Type test matrix for Division 1 and 2 explosive atmospheres . 86
Bibliography . 89

Figure 1 – Flammability test . 36
Figure 2 – Example of room temperature impact test .
...