U-1 Nozzle Description Incomplete

[GoToGuy]

We have some small fluid reservoirs that were designed, built and hydrotested to Section VIII, Div 1. Two of the nozzles welded to the shell are 1/2" IPS pipe. One of the pipes has a 3-piece ball valve flange welded to it, and the other has a reducer, elbow, and threadpiece welded to it.

The U-1 forms do not list the added fittings in line 19; only the 1/2" IPS pipe. The weld records indicate that the fittings were added prior to hydrotest.

Are these U-1 forms incomplete?

Follow-up question: If the manufacturer's U stamp has expired, can the U-1 forms be revised?

Thanks

 

[Caphreak]

The scope of the Section VIII, Div1 can end at the first circumfrential joint where external piping connects (valves, reducers, welding ends).

Those welds could fall under a piping code however.

See U-1(e)(1)

 

[Caphreak]

To more directly answer, my opinion would be that the U-1 is fine stating the nozzles welded directly to the shell, and omitting the connecting piping, as long as the connecting piping falls outside the scope of section VIII, div 1.

I'm not sure on the follow up, but I would hope so.

 

[GoToGuy]

Thanks for your answers/opinions. The Code is a bit mysterious to me.

I forgot to mention that the tanks were manufactured in 2002 and the U-1 forms reference the 2001 Code.

I will look for U-1(e)(1). Do you happen have a page reference (any edition)?

Thanks again.

 

[GoToGuy]

I think I found it in 2004. Is is actually U-1(c)(2)(e)?

 

[trottiey]

No, see the preamble to U-1(c)(2). That just says that Section VIII wasn't written for piping, but you can still stamp it as long as it meets the code.

You see, the manufacturer has some freedom to decide exactly where the pressure vessel ends and the piping begins. There is a minimum boundary defined by U-1(e), i.e. that's the closest point where you can draw that boundary. Where external piping is welded to the vessel, the welding end connection for the first circumferential joint has to considered part of the vessel, and everything beyond that is optional. This manufacturer did not take that option any further than he had to.

(Caveat: I see that this phrase was revised in 2008, and this is the modern version. I don't have an older code handy.)

So it sounds like the U-1 form is fine, but your local regulations may require the piping to meet some other code. If you previously thought that those piping parts were exempted from those other codes because they were within the vessel's jurisdictional boundary, then you may have a problem.