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UCP skid mounted or in the local control room?

asked Nov 2, 2014 in E&I by Normandy (21,040 points)

A client specifies the following equipment items to be mounted on a common baseplate:

  • Driver
  • Gearbox (if applicable)
  • Driven equipment
  • All auxiliaries (i.e. lube oil system, seal systems, etc.) including Unit Control Panel (UCP)

If the client specifies the electrical equipment to a Zone I standard, and if the UCP is skid mounted then they would have to be housed in “Exd”  or “Exp” enclosures.

Is this a typical arrangement and does it create any design problem?

1 Answer

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answered Nov 2, 2014 by lilianlope (2,360 points)

That requirement would create the following challenges:

  • Panel maintenance means opening a control enclosure with some contents not suitable for a Zone I or Zone II environment.
  • Detailed troubleshooting after an alarm in the control room means the operator has to go outside to the UCP on the local equipment skid.
  • Alarm acknowledgements and resets would have to be enabled from remote use which is dangerous.
  • No ventilation/cooling for panel heat rejected components.
  • Exposure to weather and heat due to solar input.
  • Zone I rated touch screen HMI’s are rare.  (An Exd or Exp mouse and keyboard is more rare.)

The following packages such as below should be put in the Local Engine Room with its Unit Control Panel (UCP):

  • VRU Compressor
  • Booster Compressor
  • HP Compressor
  • Export Compressor
  • Turbine Generators
  • Water Injection Pumps
  • Seawater treatment module