ASME Interpretation : Pipe vs. Vessel

[seasar]

I remember reading once about an interpretation in section VIII that defined when section VIII applies and when B31.3 applies and it said that essentially if used as a pipe it is B31.3, if used as a vessel it is section VIII. I have a new "vessel" that will be used in service up to 30psig, will be made out of 8" sched 40 pipe and will be used as a vessel...therefore it needs to be certified as a pressure vessel, correct?
Anyone know where I can find this interpretation?

Thanks,

 

[metengr]

I have a new "vessel" that will be used in service up to 30psig, will be made out of 8" sched 40 pipe and will be used as a vessel...therefore it needs to be certified as a pressure vessel, correct?

No, not necessarily. Review the Scope of ASME Section VIII, Div 1, specifically U-1(c)2 and (h). Piping by design should convey fluids.

 

[seasar]

metengr,

to clarify...my "vessel" will be used as a vessel. It will contain a variable amount of liquid, level switches to determine when to allow it to fill and when to drain it, smaller piping for inlet/outlet/equalizing/etc.
Per U1(c)2 ...which serve such purposes as mixing, separating, snubbing, distributing...etc.
Mine will be used as a surge tank...its only association with piping is that it will be made of one.

 

[seasar]

...I meant U-1(C)5

 

[metengr]

seasar;
Well, you found your answer. I'll throw another request that you can follow-up on - check with your local Jurisdiction as to what they recommend for this vessel. The reason is this - you should design and fabricate the vessel to ASME Section VIII, Div 1 but your local Jurisdiction has the final say regarding registration, inspection and issuance of an operating certificate for this vessel.

 

[jte]

seasar-

In your original post you stated that you vaguely recalled an Interpretation which dealt with this. I suspect you may be referring to Int. VIII-1-04-47 in which the question is basically “If I build a vessel out of pipe and end caps but I don’t meet any of the exemptions in U-1(c)(2), is it out of the scope?” to which the reply is “No.”

jt

 

[rustbuster]

It could also be classified as a Category H fitting.

 

[seasar]

Thanks for all the replies...I'm going to keep this as a pressure vessel, I think it is the better fit.

I need to get an updated copy of section VIII, I my 1992 copy doesn't have the 2004 interpretation referenced above or section h in the intro.

 

[JohnGP]

If it looks like a duck, walks like a duck, and quacks like a duck......, then it must be a duck!

I'm blown away by the fact that the 1992 edition of ASME VIII is still being used for design - I agree it's time to get a new version.

 

[seasar]

The 92 edition is a desk reference for me. The contractors I pay to stamp the vessel should use the most current.

 

[JohnGP]

Fair enough.