Clarification to ASME Sec 8 Div 1 U-1(e)(3)

[Dave_MECHE]

I am hoping yall can offer some clarity for me. I have a U stamped pressure vessel with a manway on the bottom head that has a nozzle welded to its cover (added for contect). The nozzle is 2" too short. If we cut and weld a new nozzle onto the manway, will that require a R-stamp? There is a differing of opinion at my site. Some people say the code only extends to the manway itself and not the nozzle. I believe the nozzle is part of the manway and therefore covered by U-1(e)(3) and therefore needs an R-stamp for the repair. If it does need an R-stamp do you think it would be acceptable to use 100% x-ray instead of hydrotesting the entire vessel?

Thanks

-Dave

 

[A clark]

Is the Nozzle listed on the Data Report? In my opinion a R Stamp is required, the question of RT instead of a hydro should be discussed with the AI.

 

[chicopee]

OK I am a bit confused, how do you have a nozzle on the manway since a manway would have a cover? Note a replacement nozzle welded on the pressure vessel itself will necessitate full penetration welding and therefore will require a "R" stamp. Get a copy of the NBIC for additional information to any additional inquiry that you may have. My most recent copy is almost 30 years old so it would not be worthwhile to attach relevant pages.

 

[Dave_MECHE]

Sorry for the confusion. The nozzle is welded to the manway cover. U-1(e)(3) specifically talks about the pressure-retaining covers for vessel opening so I thought that was understood. The nozzle is welded to the cover. That is a good call to check the data report and U-1 form.

 

[JStephen]

Can you add 2" thickness of spacer flanges in there and avoid any welding?

 

[Dave_MECHE]

Adding a spacer is not ideal. It adds additional leak points in a service we do not want leak points. We will also be operating a ram valve for drainage purposes through this nozzle so the spacer could effect its operations. After reviewing the data book and U-1, I have advised that this requires a code repair and believe I have sufficient buy in at this point. Thanks for the quick responses.

 

[chicopee]

If I were you, I would contact the manway cover manufacturer as my instinct tells me the manufacturer is not the pressure vessel manufacturer and consequently, the pressure vessel was hydro with a different cover.

 

[Dave_MECHE]

Actually Chicopee, the manway cover is almost always manufactured by the vessel manufacturer since it is covered by the U stamp, which is the case with my vessel. The intention of U-1(e)(3) is to make sure that the manhole cover is properly designed since it is part of the pressure retaining boundary of the vessel and should be installed when a hydro test is performed. At least at my company, we require all permanent covers installed for hydro test and blinds on nozzles that meet the code. We have already called an AI and he bought of on the repair.

 

[Steve-M]

[/the manway cover is almost always manufactured by the vessel manufacturer since it is covered by the U stamp]

Dave, in my experience (however limited it may be), a manway connection designed as an Appendix 2 flange and cover might be fabricated in-house. But, the majority of vessel access points are purchased elliptical manway assemblies (elliptical ring, cover, gasket, yokes and hardware) or ASME B16.5 flanges with blinds.

Your post did not mention the type of manway or cover. If a hydrostatic test of the complete vessel is problematic. Perhaps the AI would allow you to build a fixture to test the cover instead of the full vessel. After all, the point would be to re-test the cover and nozzle weldment, not the entire tank.

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