Strainer PSV

[maddocks]

We are installing a 16" pipeline strainer ahead of a pressure control valve to keep out the bits that may plug the control valve or valve port. Do I need to install a PSV on the strainer? Are pipeline strainers considered pressure vessels?

 

[dcasto]

Doen't matter, you'll have a PSV on the piping that will cover it.

 

[maddocks]

hmm.....but the strainer will be equipped with block valves and bypass valve so the operators can take it out of service and clean the basket....

 

[dcasto]

I'd still go with administrative controls that require an open vent valve when both the block valves are closed.

 

[maddocks]

hey, that's a good idea.... I can probably handle it with operating procedures in the manual.... and appropriate signage.

 

[dcasto]

I've seen chains and locks used or simple plastic tie wraps. In a similar thing, our pipelines has ASME pig traps. we removed the psv (mainly because the psv must be tested 2 times per year by law and the pig trap was in town). I had a sign made up that read something like this. "This piece of equipment requires a thermal relief path and the valves that must remain open are identified with a red color code. To close this valve a permit must be obtained and an alternate path for thermal rlief must be provided."

The state inspectors we just fine.

 

[CJKruger]

maddocks, I recently had the same problem, and it took me a while to convince the regulators that a PSV is not required.

Seem to recall the key points are:
- Design strainer for pump shut off.
- Only relief case must be fire case.
- Use ASME 8 App M to justify a PSV is not required.