1、BRITISH STANDARD BS EN 60079-30-2:2007Explosive atmospheres Part 30-2: Electrical resistance traceheating Application guide for design,installation and maintenanceICS 29.260.20g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g
2、3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Incorporating corrigendum September 2010National forewordThis British Standard is the UK implementation of EN 60079-30-2:2007. It is identical to IEC 60079-30-2:2007.It supersedes BS EN 62086-2:2005 which is withdrawn and, t
3、ogether with DD IEC/TS 62395-2:2008, it supersedes BS 6351-2:1983 and BS 6351-3:1983 which are withdrawn.The general and testing requirements previously contained in BS EN 62086-1:2005 and BS 6351-1:1983 are now contained in BS EN 60079-30-1:2007 and BS EN 62395-1:2006.The UK participation in its pr
4、eparation was entrusted by Technical Committee GEL/31, Equipment for explosive atmospheres, to Subcommittee GEL/31/14, Types of protection e and n.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the ne
5、cessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.BS EN 60079-30-2:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 May 2
6、007 BSI 2010Amendments/corrigenda issued since publicationDate Comments 30 September 2010 Supersession text amendedISBN 978 0 580 71372 9EUROPEAN STANDARD EN 60079-30-2 NORME EUROPENNE EUROPISCHE NORM April 2007 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normali
7、sation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 60079-30-2:2007 E ICS 29.260.20 Supersedes EN
8、 62086-2:2005English version Explosive atmospheres - Part 30-2: Electrical resistance trace heating - Application guide for design, installation and maintenance (IEC 60079-30-2:2007) Atmosphres explosives - Partie 30-2: Traage par rsistance lectrique - Guide dapplication pour la conception, linstall
9、ation et la maintenance (CEI 60079-30-2:2007) Explosionsfhige Atmosphre - Teil 30-2: Elektrische Widerstands-Begleitheizungen - Anwendungsleitfaden fr Entwurf, Installation und Instandhaltung (IEC 60079-30-2:2007) This European Standard was approved by CENELEC on 2007-03-01. CENELEC members are boun
10、d to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Ce
11、ntral Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same
12、status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway
13、, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. 2 Foreword The text of document 31/662/FDIS, future edition 1 of IEC 60079-30-2, prepared by IEC TC 31, Equipment for explosive atmospheres, was submitted to the IEC-CENELEC parallel vote and was appr
14、oved by CENELEC as EN 60079-30-2 on 2007-03-01. This European Standard supersedes EN 62086-2:2005. The general revisions and updating to produce EN 60079-30-2:2007 are a result of national comments received. The main technical differences apart from the general revision and updating of EN 62086-2:20
15、05 are as follows: corrections; extensive revision and additions for design and installation recommendations. This standard is to be used in conjunction with EN 60079-30-1:2007, Explosive atmospheres Part 30-1: Electrical resistance trace heating General and testing requirements. The following dates
16、 were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2007-12-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2010-03-01 Annex ZA has been added by CE
17、NELEC. _ Endorsement notice The text of the International Standard IEC 60079-30-2:2007 was approved by CENELEC as a European Standard without any modification. _ BS EN 60079-30-2:2007EN 60079-30-2:2007 (E) 3 CONTENTS 1 Scope 5 2 Normative references .5 3 Terms and definitions 6 4 Application conside
18、rations 6 4.1 General .6 4.2 Corrosive areas .6 4.3 Process temperature accuracy.7 4.4 Installation considerations .7 5 Thermal insulation 8 5.1 General .8 5.2 Selection of insulating material 8 5.3 Selection of weather barrier (cladding) .9 5.4 Selection of economical thickness11 5.5 Double insulat
19、ion.11 6 System design13 6.1 Introduction .13 6.2 Purpose of, and major requirement for, trace heating .13 6.3 Heat loss calculations13 6.4 Heat-up considerations 15 6.5 Heat-loss design safety factor16 6.6 Selection of trace heater16 6.7 Maximum temperature determination20 6.8 Design information.23
20、 6.9 Power system24 6.10 Start-up at low ambient temperatures.25 6.11 Long trace heater runs.25 6.12 Flow pattern analysis.25 6.13 Dead-leg control technique 27 6.14 Chimney effect 27 7 Control and monitoring .27 7.1 General .27 7.2 Mechanical controllers .27 7.3 Electronic controllers .28 7.4 Appli
21、cation suitability.28 7.5 Location of controllers .28 7.6 Location of sensors .28 7.7 Alarm considerations .29 8 Recommendations for installation .31 8.1 Introduction .31 8.2 Preparatory work .31 8.3 Installation of trace heating circuits 32 BS EN 60079-30-2:2007EN 60079-30-2:2007 (E) 4 8.4 Installa
22、tion of control and monitoring equipment.38 8.5 Installation of thermal insulation system (see also Clause 5).43 8.6 Installation of distribution wiring and coordination with branch circuits 45 8.7 Commissioning46 9 Maintenance.47 9.1 General .47 9.2 Fault location.47 9.3 Fault rectification.48 10 R
23、epairs 48 10.1 General .48 10.2 Practicability of repair to electric trace heaters .48 10.3 Repair techniques for electrical trace heaters.49 10.4 Earthing 49 10.5 Testing49 Annex ZA (normative) Normative references to international publications with their corresponding European publications53Figure
24、 1 Thermal insulation Weather-barrier installation.10 Figure 2 Typical temperature profile .12 Figure 3 Equilibrium conditions for workpiece maintenance.18 Figure 4 Equilibrium conditions for upper limit evaluation 19 Figure 5 Heated tank example26 Figure 6 Bypass example.26 Figure 7 Typical install
25、ation of control sensor and sensor for temperature limiting control40 Figure 8 Limiting device sensor on surface of trace heater41 Figure 9 Limiting device sensor as artificial hot spot .42 Table 1 Process types7 Table 2 Pre-installation checks.33 Table 3 Example of pre-commissioning check and trace
26、 heater installation record.50 Table 4 Example of trace heater commissioning record.51 Table 5 Example of maintenance schedule and log record 52 BS EN 60079-30-2:2007EN 60079-30-2:2007 (E) 5 EXPLOSIVE ATMOSPHERES Part 30-2: Electrical resistance trace heating Application guide for design, installati
27、on and maintenance 1 Scope This part of IEC 60079 provides guidance for the application of electrical resistance trace heating systems in areas where explosive gas atmospheres may be present, with the exception of those classified as zone 0. It provides recommendations for the design, installation,
28、maintenance and repair of trace heating equipment and associated control and monitoring equipment. It does not cover devices that operate by induction heating, skin effect heating or direct pipeline heating, nor those intended for stress relieving. This part supplements the requirements specified in
29、 IEC 60079-30-1. 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 60079
30、-0:2004, Electrical apparatus for explosive gas atmospheres Part 0: General requirements IEC 60079-1:2003, Electrical apparatus for explosive gas atmospheres Part 1:Flameproof enclosures “d” IEC 60079-7:2001, Electrical apparatus for explosive gas atmospheres Part 7: Increased safety e IEC 60079-10:
31、2002, Electrical apparatus for explosive gas atmospheres Part 10: Classification of hazardous areas IEC 60079-14:1996, Electrical apparatus for explosive gas atmospheres Part 14: Electrical installations in hazardous areas (other than mines) IEC 60079-17:1996, Electrical apparatus for explosive gas
32、atmospheres Part 17: Inspection and maintenance of electrical installations in hazardous areas (other than mines) IEC 60079-30-1:2006, Explosive atmospheres Part 1: Electrical resistance trace heating General and testing requirementsBS EN 60079-30-2:2007EN 60079-30-2:2007 (E) 6 3 Terms and definitio
33、ns For the purposes of this document, the terms and definitions given in IEC 60079-0, IEC 60079-1 and IEC 60079-7 apply. NOTE Additional terms and definitions applicable to explosive atmospheres can be found in IEC 60050 (426)1. 4 Application considerations 4.1 General This standard supplements the
34、requirements of IEC 60079-14 and IEC 60079-17. Where trace heating systems are to be installed in explosive gas atmospheres, full details of the hazardous area classification(s) (IEC 60079-10) shall be specified. The specification shall state the zone (1 or 2), gas group (IIA, IIB or IIC) and temper
35、ature classification in accordance with IEC 60079-0. Where special considerations apply or where site conditions may be especially onerous, these conditions shall be detailed in the trace heating specification. Where trace heating systems are to be installed on mobile equipment or interchangeable sk
36、id units, the specification for these trace heating systems should accommodate the worst conditions in which the trace heating system may be used. Where any parts of the trace heating system are likely to be exposed, those parts should be suitable for the environment. 4.2 Corrosive areas All compone
37、nts of electric trace heating systems should be examined to verify that they are compatible with any corrosive materials that may be encountered during the lifetime of the system. Trace heating systems operating in corrosive environments have a higher potential for failure than in non-corrosive envi
38、ronments. Deterioration of the thermal insulation system is made worse by corrosion of the weather barrier and the possibility of pipeline and vessel leaks soaking the thermal insulation. Particular attention should be given to the materials of piping systems, as well as the electric trace heating s
39、ystems, as related to the effective earth-leakage/ground-fault return path. The use of non-metallic or lined or coated piping systems may further complicate the earth-leakage/ground-fault return path and special consideration should be given to these piping systems. Earth-leakage/ground-fault return
40、 paths established at the time of installation may become degraded due to corrosion during the operation of the plant. 1IEC 60050-426, International Electrotechnical Vocabulary (IEV) Part 426: Electrical apparatus for explosive atmospheresBS EN 60079-30-2:2007EN 60079-30-2:2007 (E) 7 4.3 Process tem
41、perature accuracy 4.3.1 Type I A Type I process is one for which the temperature should be maintained above a minimum point. Ambient sensing control may be acceptable. Large blocks of power may be controlled by means of a single control device and an electrical distribution panel board. Heat input m
42、ay be provided unnecessarily at times and wide temperature excursions should be tolerable. Energy efficiency may be improved through the use of dead-leg control techniques (see 6.13). 4.3.2 Type II A Type II process is one for which the temperature should be maintained within a moderate band. Contro
43、l by pipeline sensing mechanical thermostats is typical. 4.3.3 Type III A Type III process is one for which the temperature should be controlled within a narrow band. Electronic pipe-sensing controllers using thermocouple or resistance-temperature detector (RTD) units facilitate field (work site) ca
44、libration and provide maximum flexibility in the selection of temperature alarm and monitoring functions. Heat input capability may be provided to preheat an empty pipe or raise the fluid temperature, or both, within a specified range and time interval. Type III systems require strict adherence to f
45、low patterns and thermal insulation systems. 4.4 Installation considerations If failure of any part of the trace heating system can result in a safety or process problem, then the trace heating system may be considered to be a critical component of the total process. The temperature control and circ
46、uit monitoring requirements of an application may be defined according to the temperature control types described in 4.3, together with the circuit monitoring criticality as described in Table 1. Table 1 Process types Desired accuracy of process temperature control Is trace heating a critical compon
47、ent of the process? Above a minimum point Type I Within a moderate band Type II Within a narrow band Type III Yes = Critical (C-) No = Non-critical (NC-) C I NC I C II NC II C III NC III When trace heating is critical to the process, circuit monitoring for correct operation, malfunction alarms, and
48、back-up (redundant) trace heaters should be considered. Spare or back-up controllers can be specified to be automatically activated in the event of a fault being indicated by the monitoring/alarm system. This is sometimes known as “redundancy“. Back-up trace heaters may allow maintenance or repairs
49、to be performed without a process shutdown and may be used to enhance reliability. BS EN 60079-30-2:2007EN 60079-30-2:2007 (E) 8 5 Thermal insulation 5.1 General The selection, installation and maintenance of thermal insulation should be considered a key component in the performance of an electrical trace heating system. The thermal insulation system is normally designed to prevent the majority of heat loss with the trace heating system
