Block Valves Under PSV's? 1

[mjpetrag]

I have a natural gas line for a boiler that was built to ASME Section 1 Code. I wanted to know if anyone has any links/advice to see if it is possible to install a block valve under the relief valve.

 

[JLSeagull]

The PSV's are on the fuel not the steam, right?

 

[Ashereng]

A block valve before the PSV to isolate (and change it out)?

If you do, it should be car sealed open as a minimun. Also, it may be a good idea to have a second PSV (with CSO block valve) while you service the other one.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[MortenA]

There not really any need for a block valve unless you have a "tandem" spare PSV. In this case you should interlock the two block valves. If you only have one valve then you will need to shut down the unit for service of the valve - block balve or no block valve.

Best regards

Morten