Inlet piping to PSVs 2

[AtleK]

API says that the pressure drop in the inlet piping to PSVs shall not exceed 3% of the set pressure. Common sense also gives that there should be no pockets in the inlet piping (as liquid accumulation would promote corrosion, possible water hammer effect and possible blockage if solids are present), but I cannot find any mention of in the API standards.

Does anyone know if there is a rule for that?

 

[don1980]

Atlek - inlet and outlet lines should be free-draining (no pockets). You'll find this guidance in API 520 Pt2. See 4.2.4 for the inlet lines, and 5.1 for discharge lines.

A pocket of liquid on the inlet or outlet side can potentially cause a lot of mechanical damage when the relief device opens.

 

[LittleInch]

Also B 31.3 section 322.6.2 refers to the same requirment but only for discharge piping for some reason. May be it asusmes that no one would be stupid enough to design inpet pipiing to a PSV with pockets, but does seem to be a bit of an anomoly.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[AtleK]

Ah, this was great, the references I needed. Thank you, guys.

 

[Latexman]

AtleK,

There's a button for that.

Good luck,
Latexman

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[AtleK]

A star to you, guys!