Isolation requirement after attaining pressure during Gas leak test

[hvdesai1284]

Dear Experts,
i have gone through a Pressure leak test using ARGON gas for RF pad.No vent was provided only one hole for attaining pressure was made.we have achieved the Gas pressure from Argon cylinder with Gas pressure regulator. pressure gauge was provided in connection at some distance from RF pad & its exact location was in between RF pad and Gas cylinder pressure regulator.In this case we have to provide an additional valve in order to isolate the whole test assembly after attaining test pressure? or Pressure regulator itself will work as a Valve? isolation is necessary in this type of case where gas is provided from cylinder which is having Pressure regulator? pl guide me. any code or spec. is specifying this type of isolation requirement if we go through this type of cylinder & regulator assembly for leak test? In fact as far as i know no code is saying nothing about isolation after attaining pressure. can u guide me if is t available in any code?

Regards,
Hard....

 

[gr2vessels]

The code require maintaining the pressure for a period of time, depending on particular circumstances. Without isolating the pressurized system you cannot determine/locate any leak, since the lost gas through a leak will be continuously replaced from your cylinder. Accordingly, you have to use an isolation valve to maintain the pressure in the RF pad and a pressure gauge to monitor the stability of the gas pressure over time.
Nevertheless, the argon is much heavier than the air or nitrogen, hence is not much value for your leak test. Also, remember the high cost of argon.
Cheers,
gr2vessels