IEC/IEEE 62395-2:2024

Electrical resistance trace heating systems for industrial and commercial applications - Part 2: Application guide for system design, installation and maintenance

IEC/IEEE 62395-2:2024 provides detailed recommendations for the system design, installation, maintenance and repair of electrical resistance trace heating systems in industrial and commercial applications. This document does not include or provide for any applications in potentially explosive atmospheres.
This standard cancels and replaces IEC 62395-2:2013. This edition constitutes a technical revision.
This standard includes the following significant technical changes with respect to IEC 62395-2:2013:
a) Design considerations for trace heating on sprinkler systems have been expanded and a figure has been added to illustrate how to avoid undue shadowing of spray patterns from insulated sprigs close to sprinkler heads;
b) Specific details of design considerations for trace heating for emergency eyewash units and safety showers have been added.
This document is published as an IEC/IEEE Dual Logo standard.

Systèmes de traçage par résistance électrique pour applications industrielles et commerciales - Partie 2: Guide d'application pour la conception, l'installation et la maintenance du système

General Information

• Status: Published
• Publication Date: 26-Jun-2024
• ICS: 25.180.10 - Electric furnaces
• Technical Committee: TC 27 - Industrial electroheating and electromagnetic processing
• Drafting Committee: JWG 34 - TC 27/JWG 34
• Current Stage: PPUB - Publication issued
• Start Date: 27-Jun-2024
• Completion Date: 17-May-2024

Relations

• Replaces: IEC 62395-2:2013 - Electrical resistance trace heating systems for industrial and commercial applications - Part 2: Application guide for system design, installation and maintenance
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC/IEEE 62395-2 ®
Edition 1.0 2024-06
INTERNATIONAL
STANDARD
colour
inside
Electrical resistance trace heating systems for industrial and commercial
applications –
Part 2: Application guide for system design, installation and maintenance

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IEC/IEEE 62395-2 ®
Edition 1.0 2024-06
INTERNATIONAL
STANDARD
colour
inside
Electrical resistance trace heating systems for industrial and commercial

applications –
Part 2: Application guide for system design, installation and maintenance

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.180.10 ISBN 978-2-8322-8826-9

– 2 – IEC/IEEE 62395-2:2024 © IEC/IEEE 2024
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 11
3 Terms and definitions . 11
4 Surface heating of vessels and piping systems . 11
4.1 Application description . 11
4.1.1 General . 11
4.1.2 Environmental conditions . 11
4.1.3 Trace heating systems considerations . 12
4.2 Design information – General . 12
4.2.1 General . 12
4.2.2 Electrical system design . 12
4.2.3 Control and monitoring . 13
4.2.4 Trace heating system design . 14
4.2.5 Design information documentation . 14
4.3 Thermal system design . 14
4.3.1 General . 14
4.3.2 Design conditions . 15
4.3.3 Thermal insulation . 15
4.3.4 Heat loss determination . 19
4.3.5 Design safety factor . 21
4.3.6 Heat-up considerations . 21
4.3.7 Selection of trace heater . 22
4.3.8 Design calculations . 25
4.3.9 Theoretical sheath temperature calculations – Metallic pipe applications . 25
4.3.10 Theoretical sheath temperature calculations – Non-metallic pipe
applications . 26
4.3.11 Design documentation . 27
4.3.12 Start-up at low ambient temperatures . 28
4.3.13 Long trace heater circuits . 28
4.3.14 Chimney effect . 28
4.4 Electrical design . 28
4.5 Control and monitoring system design . 29
4.5.1 General . 29
4.5.2 Mechanical temperature controllers . 29
4.5.3 Electronic temperature controllers . 29
4.5.4 Application suitability . 30
4.5.5 Location of controllers . 31
4.5.6 Location of sensors . 31
4.5.7 Alarm considerations . 32
4.5.8 Integrated control . 33
4.5.9 Flow pattern analysis . 33
4.5.10 Dead-leg control technique . 35
4.5.11 Monitoring requirements for fire sprinkler systems . 35
4.6 Special design considerations . 35
4.6.1 General . 35

4.6.2 Freeze protection systems . 35
4.6.3 Sprinkler systems, fire suppression. 36
4.6.4 Hot water services/tempered water . 37
4.6.5 Safety shower design requirements . 38
4.6.6 Specialty lines . 38
4.7 Installation . 40
4.7.1 General . 40
4.7.2 Personnel aspects . 40
4.7.3 Preparatory work . 41
4.7.4 Preliminary installation of trace heating circuits . 41
4.7.5 Pre-installation insulation resistance test . 41
4.7.6 Installation of trace heater systems . 42
4.7.7 Installation of control and monitoring equipment . 44
4.7.8 Necessary modifications . 45
4.7.9 Installation of the thermal insulation system . 45
4.7.10 Installation of electrical power . 47
4.7.11 Commissioning . 47
4.8 Maintenance . 48
4.8.1 General . 48
4.8.2 Training of maintenance personnel . 49
4.8.3 Frequency of inspection . 49
4.8.4 Maintenance program documentation . 49
4.8.5 Visual evaluation . 49
4.8.6 Electrical evaluation. 50
4.8.7 Review of the electrical protection system . 50
4.9 Repair . 50
4.9.1 General . 50
4.9.2 Fault location . 50
4.9.3 Practicability of repair to electric trace heaters . 51
4.9.4 Repair techniques for electrical trace heaters . 51
5 Roof and gutter deicing . 52
5.1 Application description . 52
5.2 Design information – General . 52
5.3 Thermal design . 53
5.4 Electrical design . 53
5.5 Control and monitoring system design . 53
5.6 Special design considerations . 54
5.7 Installation . 54
5.7.1 General . 54
5.7.2 Trace heaters and component mounting . 54
5.8 Maintenance . 57
5.9 Repair . 57
6 Rail heating . 57
6.1 Application description . 57
6.1.1 General . 57
6.1.2 Switch point heating9 . 58
6.1.3 Contact/live rail heating . 58
6.1.4 Track heating . 58
6.1.5 Catenary/pantograph shoe heating . 58

– 4 – IEC/IEEE 62395-2:2024 © IEC/IEEE 2024
6.2 Design information . 59
6.2.1 General . 59
6.2.2 Weather data . 59
6.2.3 Rail system description . 59
6.2.4 System design . 59
6.3 Thermal design . 60
6.3.1 Heating load determination . 60
6.3.2 Typical heating load . 60
6.4 Electrical design . 60
6.5 Control and monitoring system design . 60
6.6 Special design considerations . 61
6.6.1 Electrical considerations . 61
6.6.2 Finite element analysis . 61
6.7 Installation . 61
6.7.1 General . 61
6.7.2 Point heating . 62
6.7.3 Swing nose crossing . 62
6.7.4 Clamp lock heating . 63
6.7.5 Contact/live rail heating and track heating . 63
6.7.6 Catenary/pantograph shoe heating . 64
6.8 Maintenance . 64
6.9 Repair . 64
7 Snow melting . 64
7.1 Application description . 64
7.2 Design information . 65
7.2.1 General . 65
7.2.2 Weather data . 65
7.2.3 Construction details of workpiece . 65
7.2.4 Electrical considerations . 65
7.2.5 System performance level . 65
7.2.6 Trace heater layout and component mounting . 66
7.3 Thermal design – Power output (heat load) determination . 69
7.4 Electrical design . 70
7.5 Control and monitoring system design . 70
7.6 Special design considerations . 70
7.7 Installation . 71
7.8 Maintenance . 71
7.9 Repair . 71
8 Floor warming . 72
8.1 Application description . 72
8.2 Design information . 72
8.2.1 General . 72
8.2.2 Environmental data . 72
8.2.3 Construction details of workpiece . 72
8.2.4 Electrical considerations . 72
8.2.5 Trace heater layout and component mounting . 72
8.3 Thermal design – Heat load determination . 74
8.4 Electrical design . 75
8.5 Control and monitoring system design . 75

8.6 Special design consideration . 75
8.7 Installation . 76
8.8 Maintenance . 76
8.9 Repair . 76
9 Frost heave prevention . 76
9.1 Application description . 76
9.2 Design information . 77
9.2.1 General . 77
9.2.2 Construction details of the floor . 77
9.2.3 Electrical considerations . 77
9.3 Heat load determination . 77
9.3.1 General . 77
9.3.2 Trace heater layout and component mounting . 79
9.4 Electrical design . 79
9.5 Control and monitoring system design . 79
9.5.1 Control options . 79
9.5.2 Monitoring . 79
9.6 Special design considerations . 79
9.7 Installation . 80
9.8 Maintenance . 80
9.9 Repair . 80
10 Underground thermal energy storage systems . 80
10.1 Application description . 80
10.2 Design information . 81
10.2.1 General . 81
10.2.2 Environmental data . 81
10.2.3 Construction details of building . 81
10.2.4 Electrical considerations . 81
10.2.5 Trace heater layout and component mounting . 81
10.3 Thermal design – Heat-loss determination . 82
10.4 Electrical design . 82
10.5 Control and monitoring system design . 82
10.6 Special design considerations when trace heaters are located in sand layer . 83
10.7 Installation . 83
10.7.1 General . 83
10.7.2 Installation in sand . 83
10.7.3 Installation in concrete . 83
10.8 Maintenance . 84
10.9 Repair . 84
Annex A (informative) Pre-installation checks . 85
Annex B (informative) Trace heater commissioning record . 86
Annex C (informative) Maintenance schedule and log record . 87
Bibliography . 88

Figure 1 – Thermal insulation – Weather-barrier installation . 17
Figure 2 – Typical temperature profile . 19
Figure 3 – Equilibrium conditions for workpiece maintenance . 24

– 6 – IEC/IEEE 62395-2:2024 © IEC/IEEE 2024
Figure 4 – Equilibrium conditions for upper limit evaluation . 24
Figure 5 – Heated tank example . 34
Figure 6 – Bypass example . 34
Figure 7 – Fire sprinkler sprig: tapered thermal insulation . 37
Figure 8 – Double containment system . 39
Figure 9 – Gravity flow piping systems . 40
Figure 10 – Ice dam formation . 52
Figure 11 – Downspout to underground drain . 53
Figure 12 – Roof and gutter trace heater arrangement . 55
Figure 13 – Gutter detail . 55
Figure 14 – Typical roof mounting methods . 56
Figure 15 – Drain detail for flat roof. 57
Figure 16 – Typical positioning of point trace heater on stock rail and switch rail . 62
Figure 17 – Typical positioning of trace heater on swing nose crossing . 62
Figure 18 – Typical clamp lock trace heater . 63
Figure 19 – Typical positioning of trace heater on steel and aluminium clad contact rails . 63
Figure 20 – Typical positioning of trace heater in pantograph shoe . 64
Figure 21 – Snow melting trace heater embedded in concrete. 67
Figure 22 – Snow melting trace heater located in conduit . 68
Figure 23 – Expansion joint detail . 69
Figure 24 – Snow melting junction box location . 69
Figure 25 – Typical floor warming trace heater mounting . 74
Figure 26 – Typical floor heating power requirements . 75
Figure 27 – Typical frost heave prevention substructure . 77
Figure 28 – Frost heave prevention power requirements . 78
Figure 29 – Typical underground thermal energy storage system installation . 82

Table 1 – Trace heater and surface heater types and related attributes . 10
Table 2 – Application types . 13
Table 3 – Recommendations for monitoring and control – Type II and III control . 31
Table 4 – Recommendations for hot water services and tempered water temperatures . 37
Table 5 – Minimum values of Insulation resistance. 42
Table 6 – Typical snow melting heat loads . 66

ELECTRICAL RESISTANCE TRACE HEATING SYSTEMS
FOR INDUSTRIAL AND COMMERCIAL APPLICATIONS –

Part 2: Application guide for system design, installation and maintenance

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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Users of this standard are expressly advised that determination of the validity of any patent rights, and the risk
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IEC/IEEE 62395-2 was prepared by IEC technical committee 27: Industrial electroheating and
electromagnetic, in cooperation with the Petroleum & Chemical Industry Committee of the IEEE
Industrial Applications Society, under the IEC/IEEE Dual Logo Agreement between IEC and
IEEE. It is an International Standard.

– 8 – IEC/IEEE 62395-2:2024 © IEC/IEEE 2024
This document is published as an IEC/IEEE Dual Logo standard.
This standard cancels and replaces IEC 62395-2:2013. This edition constitutes a technical
revision.
This standard includes the following significant technical changes with respect to
IEC 62395-2:2013:
a) Design considerations for trace heating on sprinkler systems have been expanded and a
figure has been added to illustrate how to avoid undue shadowing of spray patterns from
insulated sprigs close to sprinkler heads;
b) Specific details of design considerations for trace heating for emergency eyewash units and
safety showers have been added.
The text of this International Standard is based on the following IEC documents:
Draft Report on voting
27/1183/FDIS 27/1185/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with the rules given in the ISO/IEC Directives, Part 2,
available at www.iec.ch/members_experts/refdocs. The main document types developed by IEC
are described in greater detail at www.iec.ch/publications/.
This standard is intended to be used in conjunction with IEC/IEEE 62395-1.
A list of all parts in the IEC 62395 series, under the general title Electrical resistance trace
heating systems for industrial and commercial applications, can be found on the IEC website.
The IEC Technical Committee and IEEE Technical Committee have decided that the contents
of this document will remain unchanged until the stability date indicated on the IEC website
under webstore.iec.ch in the data related to the specific document. At this date, the document
will be
• reconfirmed,
• withdrawn, or
• revised.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

INTRODUCTION
IEC/IEEE 62395-1 provides the essential requirements and testing appropriate to electrical
resistance trace heating equipment used in industrial and commercial applications. While some
of this work already exists in national or international standards, this document has collated
much of this existing work and added considerably to it.
IEC/IEEE 62395-2 provides detailed recommendations for the system design, installation,
maintenance and repair of electrical resistance trace heating systems in industrial and
commercial applications which can include piping, vessels, roofs and concrete slab heating
applications.
It is the objective of the IEC/IEEE 62395 series that, when in normal use, electrical trace heating
systems operate safely under their defined conditions of use, by
a) employing heaters of the appropriate construction so as to meet the test criteria and
requirements detailed in IEC/IEEE 62395-1. The construction includes a metallic sheath,
braid, screen or equivalent electrically conductive covering;
b) operating at safe temperatures when designed, installed, and maintained in accordance with
IEC/IEEE 62395-2;
c) having at least the minimum levels of overcurrent and earth-fault protection required in
IEC/IEEE 62395-1 and IEC/IEEE 62395-2.

– 10 – IEC/IEEE 62395-2:2024 © IEC/IEEE 2024
ELECTRICAL RESISTANCE TRACE HEATING SYSTEMS
FOR INDUSTRIAL AND COMMERCIAL APPLICATIONS –

Part 2: Application guide for system design, installation and maintenance

1 Scope
This part of IEC/IEEE 62395 provides detailed recommendations for the system design,
installation, maintenance and repair of electrical resistance trace heating systems in industrial
and commercial applications. This document does not include or provide for any applications in
potentially explosive atmospheres.
This document pertains to trace heating systems that can comprise either factory fabricated or
field-assembled (work-site) units, and which can be series or parallel trace heaters, or surface
heaters (heater pads or heater panels) that have been assembled and/or terminated in
accordance with the manufacturer's instructions.
The products covered by this document are intended to be installed by persons who are suitably
trained in the techniques required and that only trained personnel carry out especially critical
work, such as the installation of connections and terminations. Installations are intended to be
carried out under the supervision of a qualified person who has undergone supplementary
training in electric trace heating systems.
This document does not cover induction, impedance or skin effect heating.
Trace heating systems and surface heating systems can be grouped into different types of
installations. These are characterized by different requirements for testing and are usually
certified for a specific type of installation or application. Typical applications for the different
types of installation are shown in Table 1.
Table 1 – Trace heater and surface heater types and related attributes
Trace heater type Intended installations Examples of installations Required attributes
A Insulated surfaces Hot water lines Dielectric, thermal,
(including pipe) Freeze protection mechanical, moisture
Grease lines exclusion, and performance
Fuel oil lines characteristics verification
Pre-insulated pipe
Sprinkler system verification
Below grade trace heating
(if specified for use)
Sprinkler systems
B Outdoor exposed areas Roof deicing Dielectric, thermal,
Gutter and downspouts deicing mechanical, moisture
Catch basins and drains exclusion, and performance
Rail heating systems characteristics verification
Increased moisture
resistance
UV and condensation
resistance
Resistance to cutting
Abrasion resistance
Tension test
Rail system tests (if specified
for use)
Trace heater type Intended installations Examples of installations Required attributes
C Installations with Embedded snow melting Dielectric, thermal,
embedded trace heating Embedded frost heave protection mechanical, moisture
Embedded floor warming exclusion, and performance
Embedded energy storage characteristics verification
systems
Resistance to cutting
Embedded door frames
Resistance to crushing
D Installations with trace Embedded snow melting Dielectric, thermal,
heater inside conduit or Embedded frost heave protection mechanical, moisture
piping Embedded floor warming exclusion, and performance
Embedded energy storage characteristics verification
systems
Increased moisture
Embedded door frames
resistance (pressurized or
Internal trace heating for freeze
non-pressurized)
protection of potable water lines
Enclosed drains and culverts
Pull-strength evaluation
NOTE Trace heating systems intended for use in explosive atmospheres are the subject of IEC/IEEE 60079-30-1
and IEC/IEEE 60079-30-2.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC/IEEE 62395-1:2024, Electrical resistance trace heating systems for industrial and
commercial applications – Part 1: General and testing requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC/IEEE 62395-1 apply.
ISO, IEC and IEEE maintain terminology databases for use in standardization at the following
addresses:
 IEC Electrope
...