IEC Electrical Trace Heating Installation in Process Plants

PURPOSE – This technical engineering specification defines the minimum requirements for the installation of electrical trace heating systems.

2.  IEC Electrical Trace Heating Installation in Process Plants

This technical specification applies to electrical trace heating systems on process plants. This article is limited to the use of electrical trace heating systems for the prevention of freezing or coagulation of fluids, or the malfunction of equipment during normal operation, by application of self-limiting type electric trace heating cables to process plant.

2.3      The supply and installation of thermal insulation is not discussed here.

3. RELATED DOCUMENTS
4. 3.1      Air Products Engineering Documents
5. All equipment covered by this article shall be according to the requirements of the latest edition of the following documents:
6. Shipment and Packing Specification for Consolidating Warehouses and Direct Export Shipping
7. 4GN90001E                         Winterisation of Piping, Equipment, Vessels, and Instrumentation
8. VDR                                    Vendor Documentation requirements form
9. STANDARD ELEC 0002          Electrical Installation Details
10. 3.2      British Standards Institute (BSI)
11. All equipment for installation in the European Union shall be according to the requirements of the latest edition of the following documents:
12. BS EN 60079-14    Electrical apparatus for explosive gas atmospheres
13. Part 14:  Electrical installations in hazardous areas (other than mines)
14. BS 6351: Part 1     Electrical surface heating: Specification for electric surface heating devices
15. BS 6351: Part 2     Electrical surface heating: Guide to the design of electric surface heating systems
16. BS 6351: Part 3     Electrical surface heating: Code of practice for the installation, testing and maintenance of electric surface heating systems
17. 3.3      European Council/Commission Legislative Documents (EC)
18. All equipment for installation in the European Union shall be according to the requirements of the latest edition of the following documents:
19. 73/23/EEC       Council Directive on the Harmonization of the Laws of Member States Relating to Electrical Equipment Designed for Use within Certain Voltage Limits
20. 2004/108/EC   Council Directive on the Approximation of the Laws of the Member StatesRelating to Electromagnetic Compatibility
21. 3.4      International Electrotechnical Commission (IEC)
22. All equipment covered by this specification shall be according to the requirements of the latest edition of the following documents:
23. 60079             Electrical apparatus for explosive gas atmospheres
24. 60800             Heating cables with a rated voltage of 300/500 V for comfort heating and prevention of ice formation
25. 3.5      China National Standards (GB)
26. Equipment for final installation in the People’s Republic of China shall conform to the following standards, where applicable.
27. GB 1207          Voltage transformers
28. GB 1208          Current transformers
29. GB 6995          Markings for electric cables and wires
30. GB 13539        General requirements for low-voltage fuses
31. GB 14048        Low-voltage switchgear and controlgear
32. GB 3836.15     Electrical apparatus for explosive gas atmospheres Part 15: Electrical installation in hazardous areas (other than mines)
33. GB 16847        Requirements for protective current transformers for transient performance
34. GB 16916        Residual current operated circuit-breakers without integral overcurrent protection for household and similar uses
35. GB 16917        Residual current operated circuit-breakers with integral overcurrent protection for household and similar uses (RCBO)
36. GB/T 7676       Direct acting indicating analogue electrical measuring instruments and their accessories
37. GB/T 4728.7    Switchgear, controlgear and protective devices
38. GB/T 14598     Electrical relays
39. GB/T 17627     High-voltage test techniques for low voltage equipment
40. 4. DEVIATIONS
41. 4.1      No deviations from this specification shall be permitted without the written approval of
42. Air Products. The supplier may list exceptions in their quotation for Air Products’ consideration and approval. Without an exceptions list, Air Products will assume the supplier fully complies with this specification.
43. 5. GENERAL REQUIREMENTS
44. 5.1      Installation Climatic Conditions
45. Note:   The installation shall guarantee complete protection against the ingress of water when installed in the open without additional protection. This shall include provision to prevent the ingress of moisture during transit of materials/equipment from the contractor’s works and storage before installation on site.
46. The following types of equipment/materials shall be provided by the contractor for the installation of the electric trace heating system.
47. 5.2.1      Cables
48. Frost protection circuit thermostats shall be supplied by the contractor for automatic control of the trace heating distribution board. In addition, all other types of process control thermostats or thermocouples shall be supplied by the contractor.
49. Distribution boards shall be supplied by Air Products unless stated to the contrary.
50. Minimum Cable Size:  The minimum size of power cable to be used shall be 2.5 mm2. Cable shall be 600/1000 V grade polyvinyl chloride (PVC) or cross-linked polyethylene (XLPE) insulated, stranded copper conductors, wire or tape armored, and PVC sheathed to IEC standards.
51. 6. DRAWING AND DATA
52. 6.1       Electrical Trace Heating Design:   Air Products will design the complete electrical trace heating system up to and including the distribution boards. All necessary information to complete the installation work shall be obtained by the contractor from the drawings and documents attached to the technical specification.
53. 6.2      Isometric Drawings
54. 6.3.1   Company will provide standard drawings showing the typical installation of electrical trace heating cables for the following:
55. 6.3.2   In addition, Air Products will provide standard drawings showing the installation details of junction boxes and termination requirements of electrical trace heating cables.
56. 6.4.1   Air Products will supply project-specific, one line diagrams of each distribution board showing the following:
57. 6.5.1   Air Products will supply a simplified layout identifying the location of the trace heating distribution board and the power cable route to the first electrical trace heating box for each power circuit. The contractor shall be responsible for determining the cable routes from this point on a “site run” principle.
58. 6.5.2   The contractor shall mark up the Air Products layout drawings, showing the “As-Built” location of the junction boxes and an interconnection diagram of the junction boxes.
59. FIELD TESTING AND INSPECTION

1. The contractor shall perform all tests listed in Appendix A. The test results shall be completed and approved by the contractor’s Quality Assurance (QA) department, then handed to the Air Products construction supervisor for acceptance.
2. Field testing of insulation resistance and continuity shall be performed with a 500 V megger.
3. Insulation resistance from one conductor to shield shall not be less than 10 Megohms, irrespective of the heating cable length.
4. The Air Products construction supervisor shall verify that the heating system is being installed according to the required installation specifications, project specifications, and cable manufacturer’s instructions. If there is a conflict, Air Products shall require the contractor to obtain approval of the installation from the trace heating cable manufacturer at the contractor’s expense.
5. The contractor may provide their own quality control and test/inspection sheets as an alternative to those identified in paragraph 7.1 above, subject to the approval of Air Products Electrical Design Department.

8. EMC AND LOW VOLTAGE DIRECTIVES

All equipment for final installation in the European Union shall be CE marked for compliance with 73/23/EEC, 2004/108/EC and the Supplier shall provide a Declaration of Conformance or Certificate of Incorporation as applicable for the equipment supplied.

Appendix A

Electrical Trace Heating Installation Test Certificate