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Purging system time delay to produce an alarm or shutdown?

asked Sep 21, 2014 in E&I by sicalamanto (1,560 points)
I am looking at putting together a purging system intended to produce an alarm or shutdown action. What would be the typical industry practice of the time delay before an alarm or shutdown needs to occur?

2 Answers

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answered Sep 22, 2014 by franchaze (1,150 points)
The purging system intended to produce an alarm or shutdown action should incorporate a 0-30 second adjustable time delay before alarm or shutdown.

An initial setting should be 30 seconds.
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answered Sep 22, 2014 by franchaze (1,150 points)

I should also add the followings:

  • Purging system should include overpressure relief
  • If purge and positive pressure ventilation system is used, the system should be designed, fabricated, and installed per ISA S12.4
  • The flowmeters located in areas classified as hazardous shall be certified for installation in the area by UL, FM or other industry accepted authority
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