R stamp requirement? 1

[intaim13]

Hi all,
Is R-Stamp required for replacement of a piece of pipe attached to a weldolet? We have a Div.1 pressure vessel with a weldolet on the bottom for drain. We need to replace in-kind the corroded pipe that is welded on the weldolet. Is there any issue with the Code?
Thanks all experts.

 

[metengr]

The answer to your question depends on the location of the vessel and what rules the regulatory body, or government agency or Jurisdiction enforces. In some locations, only boilers are regulated and pressure vessels are exempt.

With that said, I typically require/recommend welding on pressure retaining items and appurtances under Section VIII or Section I to be performed by an R-Certificate holder.

 

[XL83NL]

Off topic: why was a weldoet used on the PV? It's a typical component for applications on piping...

 

[XL83NL]

Off topic: why was a weldoet used on the PV? It's a typical component for applications on piping...

 

[intaim13]

As I have done a little bit research, I found this in ASME Section VIII Div 1 Paragraph U-1(e)(1) for pressure vessel boundary:
(e) In relation to the geometry of pressure containing parts, the scope of this Division shall include the following:
(1) where external piping; other pressure vessels including heat exchangers; or mechanical devices, such as pumps, mixers, or compressors, are to be connected to the vessel:
(-a) the welding end connection for the first circumferential joint for welded connections;
(-b) the first threaded joint for screwed connections;
(-c) the face of the first flange for bolted, flanged connections;
(-d) the first sealing surface for proprietary connections or fittings;

In my case, I think I will investigate the data book if the drain pipe attached to the weldolet was installed onsite, instead of at the fab shop. I can tell from Para.(e)(1)(a) that replacement of the pipe meets this criteria. The R-stamp will be required?
I forgot to mention it is horizontal vessel, SS material.

 

[moltenmetal]

If it's only the pipe and not the o-let that needs replacement, in my opinion the pipe is part of the piping scope. Welding needs to be done by competent ASME IX welder using qualified procedure, proper NDE and testing of that joint per the piping code etc., but no R stamp paperwork etc. needs to be done.

 

[metengr]

Again, what does the local Jurisdiction require? If the vessel is exempt, you can use an R-Certificate holder except no AI is required to sign the Form R-1. Having a contractor that possesses an R-Certificate at least provides some level of assurance that the welding and NDT will be done correctly and documented. Otherwise, you the owner-user must spell this out for a contractor.

 

[intaim13]

Thank you all!

 

[MJCronin]

Any vessel design drawings available ?

These drawings should clearly note the design limits of the vessel and the limits of the piping system.

MJCronin
Sr. Process Engineer
Venture Engineering & Construction

http://www.VentureEngr.com

 

[jte]

Well, the Jurisdiction can do whatever they want, so clearly it is good to understand the local environment. In most jurisdictions, however, they go along with the scope as set out in VIII-1. It is clear, and easy to verify, that the scope can end at the end of the weldolet, and that the pipe and weld metal belong to the piping (I'll presume B31.3). However, one must be a bit careful: As MJCronin points out, one should check the drawing and U-1. If the U-1 shows the nozzle as a weldolet, that's one thing. If it has any mention of the pipe attached to the weldolet, then it is reasonable to presume that the pipe was added to the scope of VIII-1 by the fabricator and accepted by the AI.

This isn't really any different than the use of half-couplings for socket welded connections, whether directly to an extended body valve or to piping. The fillet weld "belongs" to B31.3, along with the valve or piping.

Grinding out the weld and welding in a new piping component can be done by a qualified piping welder without AI involvement. However, you can't go wrong following metenger's recommendaiton of having vessel qualified welders working with an AI do the job.

Do I allow the use of weldolets in my spec's? No. And I severely restrict the use of half couplings. But they are Code legal when done right and for better or for worse, there are enough of them out there that I'll be dealing with them for the rest of my career.

jt