Downstream of steam PCV or PRDS, is axial stop essential ?

Posted by: sam

Downstream of steam PCV or PRDS, is axial stop essential ? - 09/14/16 08:56 AM

In any pressure control valve or steam PRDS valve, we notice an axial stop in the downstream piping; PCV or PRDS opening/closing or changing of load is not fast enough like inline PRVs discharging in flare.

Is the provision of axial stop in PCV/PRDS downstream piping not essential due to slow transients generated here ?

If we adopt a robust SOP to keep sparingly working steam PRDS condensate-free before charging steam with sufficient drainage, if not preheating the same with live steam, condensate generated water hammer will not occur, for which we never design the PRDS supporting, will it be sufficient ?

Our existing piping expansion load cases with 1W 1S trains of PRDS do not allow provision of axial stop, due to which I am raising this query to the stress analysts of this forum.
reg,
sam

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Posted by: Ali_Raza_Bashir

Re: Downstream of steam PCV or PRDS, is axial stop essential ? - 09/27/16 01:35 PM

Besides good engineering practice, if we only talk about project piping stress analysis specification, then i have never seen this recommendation in any specification. Contrary to that almost every specification directs us to stop and guide the PRV valve piping.
So if your system is being failed in code, you can take advatge by NOT inserting stop in line.

Regards,
Ali