Hydro test of pressure vessel with scaffolding inside

[SJmetallurgist]

Dear friends,
one of our fabricator is insisting on conducting hydrotest on a vessel at shop (designed to ASME Sec VIII), with scaffolding fixed inside. they do not intend to remove the scaffolding.
Can someone throw some clarity on this, how decision to be taken OR pros & cons be established

 

[LittleInch]

What is it holding up?

Of its just access to do things after hydro I can't see too many issues but the devil is in the detail. Any drawings?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

As long as it doesn't float away I don't see a problem.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[r6155]

Perhaps it can be useful for applying surface protection or for in-service inspection.

Regards

 

[SJmetallurgist]

@LittleInch - drawings wont be able to share due to proprietary issues. But got yr point.
@ironic metallurgist & r6155: the main concern I find is that the packing/pads used to fix scaffolding inside the vessel should not mask a leak in the vessel. also, scaffolding pipes are hollow, not sure whether its safe to have a pressurized water around hollow pipes.

Thanks all of you

 

[gtaw]

If the ends of the pipe scaffold are not sealed, the pressure inside the pipe will be the same as the pressure inside the vessel. If the pads are welded such that the weld is only part way around the perimeter, water will enter and exit under the pads. Any leaks that are through the pressure boundary of the vessel will allow water to leak through and observed during the test. Just make sure the welds securing the pads are discontinuous.

Best regards - Al

 

[r6155]

Avoid inside pads.

Regards

 

[Stallionbreed]

What was the fabricator's reason?

As others have pointed out, you have to check to make sure the scaffolding is secured. Are the pads and scaffold rated for the pressure?

Is there a liner or coating inside the equipment? if so, make sure the scaffold doesn't damage that during the test.

 

[Dhurjati Sen]

There is no Inspection Code like API or something belonging to the client that govern this construction?

If no, then the manufacturer is quite noble not to put anything else inside the vessel apart from scaffolding and going ahead with hydrotest.

Hope they remove the scaffolding without resorting to any hot job or grinding or even cold cutting.

Also pray that an internal inspection is carried out after scaffolding removal.

DHURJATI SEN