Requirements for recommissioning ASME Sec VIII pressure vessel

[iangineer]

A pressure vessel was removed from service 4 years ago. Due to some issues that developed from its removal, the plant wants to put it back into service. Are there any particular requirements for recommissioning an ASME VIII PV?

This particular vessel is a liquid knock-out drum for a reciprocating compressor inlet.

I only have the original U-1A form from 1987 (no, we most likely aren't going to buy a new one because of its age). The vessel U-1 shows Full RT and SA-182 F316L material.

With the U-1A form the only documentation we have for it, I would model the vessel to confirm required thicknesses and recommend a hydro test to the original 5438psi.

Let me know if you have any recommendations. Would a hydro even be needed? Maybe just some UT readings?

Thanks in advance.

 

[GD2]

Iangineer,
The immediate thing that comes into mind is to use a post-construction Code like FFS-1/API 579 to verify fitness-for-service. You will also need to look into the local regulatory compliance.
Looks like the vessel was in service for a period of 30 years, which most likely have exceeded the design life.
You need to also check the process data, the parameters and the degradation mechanisms that comes with it.

Your idea of a hydrotest is an universal idea most of plant engineers will do and which ideally confirms any unacceptable flaws after fabrication. What I also suggest is that look into the process and see if there are signs of LTA, degradation of weld joints etc.

The Data Report U-!A and name plate should give you the RT type. Once you have this info, it should give you a fair idea of the required design thickness to do a modelling of the vessel to establish the hydrotest pressure.


GDD
Canada

 

[iangineer]

GD2,

Thank you for the suggestion. I looked through FFS-1, but there are not any flaws in the vessel besides possible general corrosion that has yet to be examined.

Since it has only been 4 years since it was taken out of service and the vessel was externally inspected 5 years ago, I don't think extensive testing is needed. I plan on having the insulation stripped and take thickness readings to confirm good thickness and have the inspectors stick a camera inside to visually check for any issues. I was able to locate the original calculations and GA drawing so that will help save a lot of time.

Let me know if there are any other comments to my plan.

Thanks

 

[EdStainless]

How was it stored?
You mention that it is SS.
You are going to have to do enough inspection to assure that nothing has happened in storage, either corrosion or mechanical damage.
Is there any insulation?

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P.E. Metallurgy, consulting work welcomed

 

[NRP99]

IMO, you need to rerate (possibly rate for less pressure and temperature) vessel since it has completed its intended life. This rerating will be based on API 579/ASME FFS-1 evaluations for whatever general corrosion or other damages that may surface after thorough inspection . Also for how much longer you will keep the vessel in operation further? What will be remaining life? That will be based on these evaluations only.

You need to establish complete structural integrity check/evaluations for whatever damage happened to vessel to be working for next n number of years.

 

[chicopee]

What was the liquid within the tank? Have you had a chance to review the NBIC since you are dealing with an ASME PV. Also do an internal inspection for sign of internal corrosion as alluded by item #1 of EdStainless's comments. Hydro static or a pressure test are either advisable. Be careful with a hydro static test if it is an horizontal tank as cribbing may be warranted. Wall thickness testing is also advisable.
Your statement "... Due to some issues that developed from its removal..." is troublesome. If the issues concerned repair to the vessel pressure parts, there could be a requirement for a repair stamp and an updated data sheet.

 

[iangineer]

Sorry, when i said the vessel was being put back into service "due to some issues that developed from its removal" i meant that some liquid was getting into the compressor and causing damage because there was no longer a liquid knockout drum right at the inlet. A larger drum was added and it was thought that it would be able to do the same thing as the small drum, but it was not as good. There were no issues with the drum being put back into service, the plant just didn't want to route pipe to it after adding the new larger drum.

 

[iangineer]

To close out this thread with what I decided on:

I've requested more information from the vessel owner on how it has been stored. I want to make sure it was dried out and all of the flanges properly closed.

Regardless of the answer, I recommended internal and external visual inspection. Vessel insulation has been removed, so that will be no issue. I also recommended a hydrotest at the original test pressure if no issues are found during the inspection. MIC would be the most concern if water happened to be left in the vessel or if flanges were left improperly covered. If any pitting is observed (not expected), we can UT those spots.

Thank you all for your help and guidance.