Check valves in relief path

[spudton]

Are there any rules preventing you from installing check valves into a line that forms the relief path of a vessel protected against fire?
Also, are there any peculiarities with Stoomwezen rules in this case?
Thanks

 

[StoneCold]

spudton
Maybe you should tell us why you want to install the check valves? What are Stoomwezen rules?
The big concern I would have is if you have a relief situation and the check valve is stopping flow coming from somewhere else you could have a large backpressure to deal with.

My two cents.
StoneCold.

 

[svanels]

I guess stoomwezen is an organization that inspect/legislate boilers and steam related issues.

 

[MortenA]

What should the åurpose of such a valve be?

I a relief header all valve should be "closed" (either PSV og BDV's). Thus back-flow cant occur.

A design where check valves are required should be considered redone imho

Best regards

Morten

 

[JimCasey]

WHat's the difference between a relief valve and a check valve? A relief valve IS a check valve with a high cracking pressure.

Don't put anything in the discharge line from a "code" relief valve. It's poor practice if not forbidden by code.

 

[Guidoo]

The "Stoomwezen rules" or Rules for Pressure Vessels sheet A1301 on pressure relief/application of safety valves section 9 just states "The discharge system must be capable of safely discharging the escaping substances". Sounds like an open door to me...

 

[StoneCold]

Sometimes there is a fast moving bus on the other side of the door.
StoneCold

 

[spudton]

Thanks for the replies and apologies for not giving enough detail to make the problem clear.
The system is a serious of liquid filled wash towers. Check valves are installed between the towers to prevent back contamination of one solvent to another. The relief path of the first tower is through the subsequent towers so the check valve is in the relef path but is not the relief device itself.
Guido's response seems to give me the answer I was looking for.
Thanks again.