CLC/TS 62395-2:2010
(Main)Electrical resistance trace heating systems for industrial and commercial applications - Part 2: Application guide for system design, installation and maintenance
Electrical resistance trace heating systems for industrial and commercial applications - Part 2: Application guide for system design, installation and maintenance
Superseded by EN 62395-2:2013
Elektrische Begleitheizungen (Trace-Widerstandsheizungen) für industrielle und gewerbliche Zwecke - Teil 2: Anwendungsleitfaden für Systementwurf, Installation und Wartung
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
Industrijski in komercialni sistemi električnih uporovnih grelnih trakov - 2. del: Vodilo za načrtovanje sistema, namestitev in vzdrževanje (IEC/TS 62395-2:2008)
Ta del IEC 62395 določa podrobna priporočila za načrtovanje, namestitev, vzdrževanje in popravila industrijskih in komercialnih sistemov električnih uporovnih grelnih trakov. Ta tehnična specifikacija ne vključuje ali zagotavlja kakršne koli uporabe v potencialno eksplozivnih atmosferah. Ta specifikacija se nanaša na sledenje grelnim sistemom, ki so sestavljeni bodisi iz v tovarni sestavljenih ali na terenu (lokaciji dela) montiranih enot, ki so lahko serijski kabli za grelce, paralelni kabli za grelce, ploskve ali plošče grelcev, ki so bili montirani in/ali zaključeni v skladu z navodili proizvajalca za povezavo z napetostjo napajanja do in vključno 450 V/750 V. Ta tehnična specifikacija ne zajema indukcijskega gretja in impedančnega gretja ali gretja z učinkom na kožo. Sistemi za sledenje gretju so lahko razvrščeni v skupine različnih tipov namestitev. Te določajo različne zahteve za preskušanje ter so običajno certificirane za določen tip namestitve ali uporabe. Tipične uporabe za različne tipe namestitev so, kot sledi:
a) namestitve cevi, posod in povezane opreme za sledenje ogrevanju. Uporabe
vključujejo:
- varovanje pred zamrzovanjem in vzdrževanje temperature;
- vode za toplo vodo;
- vode za olje in kemične vode;
- sisteme za škropljenje.
b) Namestitve sledenja ogrevanju na področjih, ki so podvržena zunanjim vplivom. Uporabe vključujejo:
- razledenitev streh;
- razledenitev žlebov in odtočnih cevi;
- lovilne bazene in drenažne cevi;
- ogrevanje tračnic.
c) Namestitev z vdelanim sledenjem ogrevanju. Uporabe vključujejo:
- topljenje snega;
- ogrevanje tal;
- preprečevanje širjenja zmrzali;
- podzemne sisteme shranjevanja termalne energije;
- vratne okvirje.
d) Namestitve s sledenjem ogrevanju znotraj napeljave cevi. Uporabe vključujejo:
- topljenje snega - v napeljavi;
- ogrevanje tal – v napeljavi;
- preprečevanje širjenja zmrzali – v napeljavi;
- podzemni sistemi shranjevanja termalne energije – v napeljavi;
- notranje sledenje ogrevanju cevi za pitno vodo;
- zaprte drenažne cevi in prepusti.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-2011
,QGXVWULMVNLLQNRPHUFLDOQLVLVWHPLHOHNWULþQLKXSRURYQLKJUHOQLKWUDNRYGHO
9RGLOR]DQDþUWRYDQMHVLVWHPDQDPHVWLWHYLQY]GUåHYDQMH ,(&76
Electrical resistance trace heating systems for industrial and commercial applications -
Part 2: Application guide for system design, installation and maintenance (IEC/TS 62395-
2:2008)
Elektrische Begleitheizungen (Trace- Widerstandsheizungen) für industrielle und
gewerbliche Zwecke - Teil 2: Anwendungsleitfaden für Systementwurf, Installation und
Wartung (IEC/TS 62395-2:2008)
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 (CEI/TS 62395-2:2008)
Ta slovenski standard je istoveten z: CLC/TS 62395-2:2010
ICS:
25.180.10 (OHNWULþQHSHþL Electric furnaces
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL SPECIFICATION
CLC/TS 62395-2
SPÉCIFICATION TECHNIQUE
November 2010
TECHNISCHE SPEZIFIKATION
ICS 25.180.10
English version
Electrical resistance trace heating systems for industrial and commercial
applications -
Part 2: Application guide for system design, installation and maintenance
(IEC/TS 62395-2:2008)
Systèmes de traçage par résistance Elektrische Begleitheizungen (Trace-
électrique pour applications industrielles et Widerstandsheizungen) für industrielle
commerciales - und gewerbliche Zwecke -
Partie 2: Guide d'application pour la Teil 2: Anwendungsleitfaden für
conception, l'installation et la maintenance Systementwurf, Installation und Wartung
du système (IEC/TS 62395-2:2008)
(CEI/TS 62395-2:2008)
This Technical Specification was approved by CENELEC on 2010-10-25.
CENELEC members are required to announce the existence of this TS in the same way as for an EN and to
make the TS available promptly at national level in an appropriate form. It is permissible to keep conflicting
national standards in force.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia,
Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Management Centre: Avenue Marnix 17, B - 1000 Brussels
© 2010 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TS 62395-2:2010 E
Foreword
This Technical Specification consists of the text of the Technical Specification IEC/TS 62395-2:2008
prepared by IEC TC 27, Industrial electroheating.
It was circulated for voting in accordance with the Internal Regulations, Part 2, Subclause 11.3.3.3 and was
accepted as a CENELEC Technical Specification on 2010-10-25.
The following date was fixed:
– latest date by which the existence of the CLC/TS
has to be announced at national level (doa) 2011-04-25
Annex ZA has been added by CENELEC.
__________
- 3 - CLC/TS 62395-2:2010
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following referenced documents are indispensable for the application 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.
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies.
Publication Year Title EN/HD Year
IEC 60050-841 - International Electrotechnical Vocabulary (IEV) - - -
Part 841: Industrial electroheat
IEC 60519-1 - Safety in electroheat installations - EN 60519-1 -
Part 1: General requirements
IEC 62395-1 2006 Electrical resistance trace heating systems for EN 62395-1 2006
industrial and commercial applications -
Part 1: General and testing requirements
IEC/TS 62395-2
Edition 1.0 2008-06
TECHNICAL
SPECIFICATION
SPÉCIFICATION
TECHNIQUE
Electrical resistance trace heating systems for industrial and commercial
applications –
Part 2: Application guide for system design, installation and maintenance
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
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XC
CODE PRIX
ICS 25.180.10 ISBN 2-8318-9776-9
– 2 – TS 62395-2 © IEC:2008
CONTENTS
FOREWORD.7
INTRODUCTION.9
1 Scope and object.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 .12
4.2.4 Trace heating system design .13
4.2.5 Design information documentation.14
4.3 Thermal system design.14
4.3.1 General .14
4.3.2 Design conditions .14
4.3.3 Thermal insulation .15
4.3.4 Heat loss determination .20
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.29
4.5 Control and monitoring system design .29
4.5.1 General .29
4.5.2 Mechanical controllers.29
4.5.3 Electronic controllers .30
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
4.6 Special design considerations .35
4.6.1 General .35
TS 62395-2 © IEC:2008 – 3 –
4.6.2 Freeze protection systems.35
4.6.3 Sprinkler systems, fire suppression .36
4.6.4 Hot water services/tempered water.36
4.6.5 Specialty lines .37
4.7 Installation .39
4.7.1 General .39
4.7.2 Personnel aspects .39
4.7.3 Preparatory work .40
4.7.4 Preliminary installation of trace heating circuits .40
4.7.5 Insulation resistance test .40
4.7.6 Installation of trace heater systems .41
4.7.7 Installation of control and monitoring equipment .43
4.7.8 Necessary modifications.44
4.7.9 Installation of the thermal insulation system .44
4.7.10 Installation of electrical power .46
4.7.11 Commissioning .46
4.8 Maintenance.47
4.8.1 General .47
4.8.2 Training of maintenance personnel .47
4.8.3 Frequency of inspection.48
4.8.4 Maintenance program documentation .48
4.8.5 Visual evaluation .48
4.8.6 Electrical evaluation .48
4.8.7 Review of the electrical protection system .49
4.9 Repair .49
4.9.1 General .49
4.9.2 Fault location.49
4.9.3 Practicability of repair to electric trace heaters .49
4.9.4 Repair techniques for electrical trace heaters .50
5 Roof and gutter de-icing .50
5.1 Application description .50
5.2 Design information – General .51
5.3 Thermal design .52
5.4 Electrical design.52
5.5 Control and monitoring system design .52
5.6 Special design considerations .53
5.7 Installation .53
5.7.1 General .53
5.7.2 Trace heaters and component mounting .53
5.8 Maintenance.56
5.9 Repair .56
6 Rail heating .57
6.1 Application description .57
6.1.1 Point heating .57
6.1.2 Contact/live rail heating .57
6.1.3 Track heating .57
6.1.4 Catenary/pantograph shoe heating .57
6.2 Design information .58
6.2.1 General .58
– 4 – TS 62395-2 © IEC:2008
6.2.2 Weather data.58
6.2.3 Surface description.58
6.2.4 System design.58
6.2.5 Performance level classification.58
6.3 Thermal design .58
6.3.1 General .58
6.3.2 Typical heating load .59
6.4 Electrical design.59
6.5 Control and monitoring system design .59
6.6 Special design considerations .60
6.6.1 Electrical considerations.60
6.6.2 Finite element analysis .60
6.7 Installation .60
6.8 Maintenance.63
6.9 Repair .63
7 Snow melting.63
7.1 Application description .63
7.2 Design information .64
7.2.1 General .64
7.2.2 Weather data.64
7.2.3 Construction details of workpiece .64
7.2.4 Electrical considerations.64
7.2.5 System performance level .64
7.2.6 Trace heater layout and component mounting .65
7.3 Thermal design – Power output (heat load) determination .69
7.4 Electrical design.69
7.5 Control and monitoring system design .69
7.6 Special design considerations .69
7.7 Installation .70
7.8 Maintenance.70
7.9 Repair .71
8 Floor warming .71
8.1 Application description .71
8.2 Design information .71
8.2.1 General .71
8.2.2 Environmental data.71
8.2.3 Construction details of workpiece .71
8.2.4 Electrical considerations.71
8.2.5 Trace heater layout and component mounting .72
8.3 Thermal design – Heat load determination.73
8.4 Electrical design.74
8.5 Control and monitoring system design .74
8.6 Special design consideration .74
8.7 Installation .74
8.8 Maintenance.75
8.9 Repair .75
9 Frost heave prevention.75
9.1 Application description .75
9.2 Design information .76
TS 62395-2 © IEC:2008 – 5 –
9.2.1 General .76
9.2.2 Construction details of the floor .76
9.2.3 Electrical considerations.76
9.3 Heat load determination .76
9.3.1 General .76
9.3.2 Trace heater layout and component mounting .77
9.4 Electrical design.78
9.5 Control and monitoring system design .78
9.5.1 Control options .78
9.5.2 Monitoring .78
9.6 Special design considerations .78
9.7 Installation .79
9.8 Maintenance.79
9.9 Repair .79
10 Underground thermal energy storage systems.79
10.1 Application description .79
10.2 Design information .79
10.2.1 General .79
10.2.2 Environmental data.80
10.2.3 Construction details of building.80
10.2.4 Electrical considerations.80
10.2.5 Trace heater layout and component mounting .80
10.3 Thermal design – Heat-loss determination.81
10.4 Electrical design.81
10.5 Control and monitoring system design .82
10.6 Special design considerations when trace heaters are located in sand layer .82
10.7 Installation .82
10.7.1 General .82
10.7.2 Installation in sand .82
10.7.3 Installation in concrete.82
10.8 Maintenance.83
10.9 Repair .83
Annex A (informative) Pre-installation checks .84
Annex B (informative) Trace heater commissioning record.85
Annex C (informative) Maintenance schedule and log record .86
Bibliography.87
Figure 1 – Thermal insulation – Weather-barrier installation.17
Figure 2 – Typical temperature profile.19
Figure 3 – Equilibrium conditions for workpiece maintenance.24
Figure 4 – Equilibrium conditions for upper limit evaluation.24
Figure 5 – Heated tank example .34
Figure 6 – Bypass example.35
Figure 7 – Double containment system .38
Figure 8 – Gravity flow piping systems.39
Figure 9 – Ice dam formation .51
Figure 10 – Downspout to underground drain.52
– 6 – TS 62395-2 © IEC:2008
Figure 11 – Roof and gutter trace heater arrangement.54
Figure 12 – Gutter detail .54
Figure 13 – Typical roof mounting methods.55
Figure 14 – Drain detail for flat roof .56
Figure 15 – Typical positioning of point trace heater on stock rail and switch rail .61
Figure 16 – Typical positioning of trace heater on swing nose crossing.61
Figure 17 – Typical clamp lock trace heater .62
Figure 18 – Typical positioning of trace heater on steel and aluminium clad contact
rails .62
Figure 19 – Typical positioning of trace heater in pantograph shoe .63
Figure 20 – Snow melting trace heater embedded in concrete .66
Figure 21 – Snow melting trace heater located in conduit .67
Figure 22 – Expansion joint detail .68
Figure 23 – Snow melting junction box location.68
Figure 24 – Typical floor warming trace heater mounting .73
Figure 25 – Typical floor heating power requirements .74
Figure 26 – Typical frost heave prevention substructure .76
Figure 27 – Frost heave prevention power requirements .77
Figure 28 – Typical underground thermal energy storage system installation .81
Table 1 – Application types.13
Table 2 – Recommendations for monitoring and control – Type II and III control .31
Table 3 – Recommendations for hot water services and tempered water temperatures .37
Table 4 – Possible trace heating load requirements .59
Table 5 – Typical snow melting heat loads.65
TS 62395-2 © IEC:2008 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
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
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
specification when
– the required support cannot be obtained for the publication of an International
Standard, despite repeated efforts, or
– the subject is still under technical development or where, for any other reason, there is
the future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC 62395-2, which is a technical specification, has been prepared by IEC technical
committee 27: Industrial electroheating equipment.
– 8 – TS 62395-2 © IEC:2008
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
27/582/DTS 27/606A/RVC
Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 62395, under the general title Electrical resistance trace heating
systems for industrial and commercial applications, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
TS 62395-2 © IEC:2008 – 9 –
INTRODUCTION
IEC 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 standard has
collated much of this existing work and added considerably to it.
IEC/TS 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 IEC 62395 that, when in normal use, electrical trace heating systems
should 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 62395-1. The construction should include a metallic sheath,
braid, screen or equivalent electrically conductive covering;
b) operating at safe temperatures when designed, installed, and maintained in accordance
with IEC/TS 62395-2;
c) having at least the minimum levels of overcurrent and ground fault protection
requirements in IEC 62395-1 (2006) (4.3).
– 10 – TS 62395-2 © IEC:2008
ELECTRICAL RESISTANCE TRACE HEATING SYSTEMS
FOR INDUSTRIAL AND COMMERCIAL APPLICATIONS –
Part 2: Application guide for system design,
installation and maintenance
1 Scope and object
This part of IEC 62395 provides detailed recommendations for the system design, installation,
maintenance and repair of electrical resistance trace heating systems in industrial and
commercial applications. This technical specification does not include or provide for any
applications in potentially explosive atmospheres.
This specification pertains to trace heating systems that may comprise either factory
constructed or field (work-site) assembled units, and which may be series heater cables,
parallel heater cables, heater pads or heater panels that have been assembled and/or
terminated in accordance with the manufacturer’s instructions for connection to voltage
supplies up to and including 450 V/750 V.
This Technical specification does not cover induction, impedance or skin effect heating.
Trace 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 as
follows:
a) Installations of trace heating on pipes, vessels and associated equipment. Applications
include:
– freeze protection and temperature maintenance;
– hot water lines;
– oil and chemical lines;
– sprinkler systems.
b) Outdoor exposed area installations of trace heating. Applications include:
– roof de-icing;
– gutter and downspout de-icing;
– catch basins and drains;
– rail heating.
c) Installation with embedded trace heating. Applications include:
– snow melting;
– floor warming;
– frost heave prevention;
– underground thermal energy storage systems;
– door frames.
d) Installations with trace heating inside conduit or piping. Applications include:
– snow melting – in conduit;
– floor warming – in conduit;
– frost heave prevention – in conduit;
TS 62395-2 © IEC:2008 – 11 –
– underground thermal energy storage systems – in conduit;
– internal trace heating of potable water lines;
– enclosed drains and culverts.
2 Normative references
The following referenced documents are indispensable for the application 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 60050-841, International Electrotechnical Vocabulary – Part 841: Industrial electroheat
IEC 60519-1, Safety in electroheat installations – Part 1: General requirements
IEC 62395-1:2006, 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 referenced terms and definitions are given in
IEC 60519-1, IEC 62395-1 and IEC 60050-841.
4 Surface heating of vessels and piping systems
4.1 Application description
4.1.1 General
Piping and vessels are often provided with surface-mounted trace heating systems to
maintain water above freezing-point and to maintain process fluids and gases at given
temperature levels. The trace heaters compensate for heat losses to the environment that are
reduced but not eliminated by thermal insulation.
4.1.2 Environmental conditions
Attention should be directed to the surrounding environmental conditions, especially for
systems that are exposed to sunlight (ultraviolet exposure), coastal atmospheres (corrosive
salt spray and high humidity), and chemical atmospheres such as oil refineries and chemical
plants.
Equipment subject to ultraviolet exposure may degrade due to surface oxidation, which can
possibly lead to surface embrittlement and cracking. Corrosive atmospheres can affect the
same exposed surfaces and can accelerate degradation of surfaces that are also susceptible
to ultraviolet exposure. Chemical exposure can affect all equipment, whether covered by
thermal insulation or not.
The trace heating equipment for piping and vessels is often protected from corrosion and
ultraviolet exposure to some degree by the thermal insulation. However, these systems can
have components that are exposed to the environment such as electrical connection
components and weather barrier around the thermal insulation. The selection of trace heating
equipment shall include a review of the suitability of equipment to the expected environmental
conditions.
– 12 – TS 62395-2 © IEC:2008
4.1.3 Trace heating systems considerations
Trace heating systems can range from simple pipe freeze protection in commercial buildings
to large complex piping/vessel systems in industrial facilities. The details required for design
can vary based on the complexity of the application. Control systems and requirements for
monitoring can also vary depending on the control and design requirements.
Trace heating equipment should be chosen that is suitable for the application. For example,
plastic piping typically has only a small range of exposure temperatures. The trace heating
and control system shall keep the piping temperature within the allowed range. Higher
temperature processes shall utilize trace heating and thermal insulation equipment that are
suitable for the maximum exposure temperatures.
Particular attention should be given to the materials of piping systems, as well as the trace
heating systems, as related to an effective earth-leakage/ground-fault return path. The use of
non-metallic, lined or coated piping systems may complicate the earth-leakage/ground-fault
return path. The electrical return paths established at the time of installation may become
degraded due to corrosion during long-term operation.
4.2 Design information – General
4.2.1 General
The requirements for system design varies from simply following installation instructions for
freeze protection to the development of electrical, control and monitoring, and trace heating
system layouts for large, detailed, complex installations such as industrial facilities. While
each design component requires individual treatment, the final system shall be evaluated as
an integration of these component parts.
Trace heating system design shall conform to all IEC requirements for the use of electrical
equipment and with the requirements of this technical specification. Consideration should be
given to the maintenance of the trace heating systems to maintain energy efficiency and to
routine testing of the installed systems for safe and proper operation.
Persons involved in the design and planning of electric trace heating systems should be
suitably trained in all techniques required.
4.2.2 Electrical system design
The evaluation of electrical resistance heating systems
...
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