PSV in Closed System. 1

[Frank1344]

Good Day Folks,

Do we need to consider PSV Reaction Force in a Closed System Drainage?

I was always under impression that the answer is "NO", but our the Client has asked for it.

I can understand this if we are Discharging to Atmosphere.

Appreciate the help,
Frank

 

[Duwe6]

Not only do you still get 'impulse' from the nozzle-effect of the discharge, but you can get a negative impulse if a discharged 'slug' of liquid hits an elbow while the slug has significant velocity. At my current plant, we have broken off several 1/2"NPT PSV's set at 600 psig, that discharge into a closed-loop discharge header. Probably due to the whiplash from the discharge, then the reversal from hitting a socketweld 90-deg ell 8" later.