...R Stamp Question....yes, another one. 4

[g2ktcf]

So, I have a long history of ASME code work but I got hit with a question that I am not positive of my answer.

ASME Vessel installed in Texas. Owner requires this to be treated as a "code state" even when it is not. Vessel is a column with a nozzle protruding to the inside some 12". Someone wants to weld fittings to the end of that nozzle to divert the flow inside the vessel. While I would not normally consider this to be a pressure boundary, if that nozzle clogs, this could be pressure retaining. Would welding to this nozzle require an R Stamp shop and hydro?

 

[Christine74]

I think it's a bit of a stretch to say that the internal nozzle could become "pressure containing" if the nozzle clogs. Internal welds to non-pressure components generally are not considered to be NBIC Repairs, and even if an R-stamp is deemed necessary such vessels typically would not be hydrotested.

Would a failure of this internal attachment weld compromise the pressure-containing capability of the vessel?


-Christine

 

[g2ktcf]

Would a failure of this internal attachment weld compromise the pressure-containing capability of the vessel?

This is common sense...I never try to mix common sense and ASME code, especially Div 1! I have been bitten too many times.

 

[SnTMan]

I'm with Christine here. But what does the AI (if any) think? What does the owner think?

Regards

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[g2ktcf]

No AI is involved at this point from what I have been told. The owner is the one asking questions so they want to do as little as possible. The question was posed to me by one of their engineers. I was back and forth so I figured I would ask input from others. If I am repairing a vortex breaker or a tray support, the answer is easy. It just hard to me to see pipe and not think of it being pressure retaining in some form.

Thanks!

 

[LittleInch]

A bit difficult without a drawing or sketch, but I don't think any blockage of this extra thing would result in the pipe becoming pressure retaining because it's inside the pressure vessel?

If it was installed originally would it have been part of the pressure vessel design or internal piping?

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

 

[g2ktcf]

Its definitely part of the original PV design. Its a liquid inlet nozzle through the shell above the head seam near bottom of the tank.

 

[david339933]

Standard Designation: BPV Section VIII Div 1
Edition/Addenda:
Para./Fig./Table No:
Subject Description: Section VIII, Division 1 (1998 Edition, 1999 Addenda); U-1(e)(1)(a)
Date Issued: 11/06/2000
Record Number: BC00-596
Interpretation Number : VIII-1-01-09
Question(s) and Reply(ies):

Question: An inlet nozzle extends into the shell of a pressure vessel and makes a welded connection (tack weld) to an internal pipe fitting (malleable cast iron elbow). May this internal weld be considered outside the scope of the Code under U-1(e)(1)(a) of Section VIII, Division l?

Reply: Yes.

 

[weldstan]

Good post David. We performed similar repairs without R-Stamp.

 

[g2ktcf]

Thank you David. I knew I could not be the only person to ask that question. I have passed your code case info along to the proper folks!

Learn something new every single day