Is U-stamp applicable?

[FoxRox]

We are an oil field service pressure vessel manufacturer with a U-stamp. We mostly make heater treaters, gas separators, etc.

We are developing a new product that could be called a "steam boiler". It will be a vessel containing a water-glycol solution with a large heat exchanger mounted in a nozzle. A natural gas burner will be used to flow hot exhaust gas through the heat exchanger to heat the water and create steam that will flow through a closed system of piping to heat another vessel.

Does this fall within the scope of Section VIII Div 1? The scope is a bit contradictory of itself...

U-1(c)(2)(-a) says "those (vessels) within the scope of other Sections are not included in the scope of this Division"

U-1(g)(1) says "Unfired steam boilers shall be constructed in accordance with the rules of Section I or this Division"

U-1(c)(2)(-f) and U-1(h) also have something to say, but I'm not 100% clear on the intent.

What exactly makes a steam boiler "fired" or "unfired"?
Does a U-Stamp encompass S1 (P-Stamp) as well as S8, or is there just this one overlap?
What about Section 4 (H-Stamp) - low pressure boilers? Is the only difference here the pressure? (<15psi) Couldn't I just rate a vessel to 20psi with a U-Stamp if I don't need much pressure?

Someone with some background overlapping different sections of BPVC, please provide some clarity on what section is for what, and whether our U-stamp will suffice for this project.

Thanks!

 

[GenB]

Sect I, S for fired steam applied heat from a burner and produces steam at >15 psig
Sect IV, H for fired boilers and lower temp hot water boilers, applied heat ----- 15 psig or less.
P for power piping does not make Boilers.

in your case at first you are under Sect I, S if you are producing steam >15 psig.or Sect IV,H.vv-
but depending on the application and pressure (you do not mention both) you may be able to mfg to Sect VIII-Div1, U
Why: when you keep your boiler producing steam under a closed system.

 

[metengr]

First, I would submit an Inquiry to ASME Section VIII, Div 1 to have in the event a client requests information regarding your position on the proper ASME Certification mark.

 

[bpv66]

Take a look at UW-2(c) and UW-2(d) of ASME Section VIII, Div. 1. There is also a Code Case that may be applicable in your situation.

 

[FoxRox]

Thank you for the replies.

GenB - Thanks for the clarification on the 'S' for Sect I. The application is for the produced steam to heat liquid in another vessel via a heat exchanger. The "boiler" vessel will be rated for 30" Hg vacuum as well as a pressure rating. It may never exceed 15 psi, depending on the maximum temperature of steam we want to produce (undecided, but certainly not exceeding 300F), but this is part of the question. Rating it to vacuum will drive much if not all of the components/welds to thicknesses that will easily exceed +15 psig per Sect VIII Div 1. If we had only an H-Stamp, we could only rate it to 15 psig, but since we have a U-stamp, can we not just rate the pressure higher - up to the calculated MAWP and rounded down a bit perhaps? It seems to me that anyone with a U-Stamp could easily build vessels that will operate at low pressures and just overrate them - so long as all code rules are satisfied for the given rating, of course. In other words, I don't see anything that would force us into Sect IV. I am still unclear on what would force us into Sect I. How, for example, could I use U-1(g)(1) to stay in Sect VIII Div 1? What heating method/configuration makes a vessel qualify as an "unfired steam boiler"? Why would having a closed system potentially put us in Sect VIII Div 1? I didn't see that in the scope.

Metengr - I have already contacted our AI about the interpretation and scope of our stamp. He is looking into it. It may or may not come to an inquiry to the NB.

 

[metengr]

FoxRox;
It would not be to the NB, the inquiry would be to ASME Section VIII, Div 1 Committee.

 

[FoxRox]

bpv66 - I think UW-2(d) might be the way to go with this. Thanks!

 

[jte]

It would not be to the NB, the inquiry would be to ASME Section VIII, Div 1 Committee.

Strictly speaking, there is no Section VIII Div. 1 committee. I would guess that an inquiry would wind up in VIII Subgroup General Requirements. The Staff Contact listed at that page would be able to handle the request for interpretation and, if not within the scope of SGGR, would forward to the appropriate SG.