IEC 62086-1 pdf download – Electrical apparatus for explosive gas atmospheres – Electrical resistance trace heating – Part 1 : General and testing requirements
1scope
This part of lEC 62086 specifies general and testing requirements for electrical resistancetrace heaters for application in explosive gas atmospheres.The standard covers trace heatersthat may comprise either factory- or field- (work-site) assembled units，and which may beseries heating cables，parallel heating cables or heating pads and heating panels that havebeen assembled and/or terminated in accordance with the manufacturer’s instructions.
This standard also includes requirements for termination assemblies and control methodsused with trace heating.The hazardous areas referred to by this standard are those defined inIEC 60079-10.
2Normative references
The following normative documents contain provisions which,through reference in this text,constitute provisions of this part of lEC 62086. For dated references,subsequentamendments to,or revisions of,any of these publications do not apply. However，parties toagreements based on this part of lEC 62086 are encouraged to investigate the possibility ofapplying the most recent editions of the normative documents indicated below. For undatedreferences, the latest edition of the normative document referred to applies.Members of lECand lSo maintain registers of currently valid lnternational Standards.
IEC 60050(151):1978,International Electrotechnical Vocabulary (IEV) – Chapter 151:Electrical and magnetic devices
IEC 60050(426)，International Electrotechnical Vocabulary (IEV) – Chapter 426: Electricalapparatus for explosive atmospheres
IEC 60079-0:1998,Electrical apparatus for explosive gas atmospheres – Part 0: Generalrequirements
IEC 60364-3,Electrical installations of buildings – Part 3: Assessment of general characteristics
3Definitions
For the purpose of this part of lEC 62086, the following definitions as well as the definitionsgiven in IEC 60050(426) and lEC 60079-0 apply.
3.1
ambient temperature
temperature surrounding the object under consideration. Where electrical trace heaters areenciosed in thermal insulation, the ambient temperature is the temperature exterior to suchthermal insulation
3.2
branch circuit
that portion of the wiring installation between the overcurrent device protecting the circuit andthe trace heater unit(s)
3.3
connections(terminations)
3.3.1
cold lead
electrically insulated conductor or conductors used to connect a trace heater to the branchcircuit and designed so that it does not produce significant heat
3.3.2
end termination
termination,which may be heat producing,applied to a trace heater at the end opposite thatwhere the power is supplied
3.3.3
power termination
termination applied to the end of a trace heater at which the power is supplied
3.4
tee
electrical connection of trace heaters, in series or in parallel, to accommodate a tee or branch
3.5
dead leg
segment of process piping segregated from the normal flow pattern for the purpose ofproviding a heat-loss reference
3.6
design loading
minimum power that will meet the design requirements, in the worst conditions,after voltageand resistance tolerances and appropriate safety factors have been considered
3.7
factory fabricated
trace heating cable，tape or device，including the necessary terminations and connections,assembled into units or sets
3.8
field-assembled
trace heaters supplied in bulk with terminating components to be assembled at the work site
3.9
heat loss
energy flow from a pipe, vessel or equipment to its surroundings
3.10
heat sink
part that conducts and dissipates heat away from a workpiece
NOTETypical heat sinks are pipe shoes, pipe supports and items of large mass such as valve actuators or pumpbodies.
3.11
heat-transfer aids
thermally conductive materials，such as metallic foils or heat-transfer compounds used toincrease the heat-transfer efficiency from trace heaters to the workpiece
3.12
heating pad
trace heater comprising series- or parallel-connected elements having sufficient flexibility toconform to the shape of the surface to be heated
3.13
heating panel
non-flexible trace heater comprising series- or parallel-connected elements fabricated toconform to the general shape of the surface to be heated
3.14
high-limit temperature
maximum allowable temperature of the system, including piping, fluid and heating system
3.15
maximum ambient temperature
highest ambient temperature at which the trace heating is operable and should performaccording to specified requirements
3.16
maximum withstand temperature
maximum operating or exposure temperature that will not adversely effect the thermal stabilityof the heater and its component parts
3.17
metallic covering
metal sheath or braid used to provide physical protection for a trace heater，and/or anelectrical earth path
3.18
minimum ambient temperature
lowest ambient temperature specified at which trace heating is operable and performsaccording to specified requirements (and on which heat-loss calculations are based)
3.19
operating voltage
actual voltage applied to the trace heater when in service
3.20
overjacket
continuous layer of insulating material applied outside the metallic sheath, screen orarmouring to protect against corrosion
IEC 62086-1 pdf download – Electrical apparatus for explosive gas atmospheres – Electrical resistance trace heating – Part 1 : General and testing requirements
