ASME Section VIII Pressure Vessel Made from Piping Components

[josephYETI]

I've got a code issue at work with regards to making a condensate drain tank. The tank is made out of 2 pipe caps and a 1-1/2' section of pipe, all 8" nominal diameter, schedule 40, with 1" NPT half couplings as inlets and outlets, and a 4" ANSI 150# pipe flange on top that's met by a blind flange with two 1/4" NPT couplings on it. All of the piping components are rated for a working pressure of at least 150 PSI. Total volume is 5.25 gallons, working pressure is 80 PSIG, material is carbon steel.

My question is whether ASME Section VIII applies to a vessel of this size. While it's clear that if Section VIII did apply towards it, it would only require a UM stamp and would not need inspection by AIs as per U-1(j)(3), it looks like U-1(c)(2)(e) excludes piping components entirely. How does that play for pressure vessels manufactured exclusively from piping components? Has anyone had any experience with this?

I know, of course, that local regulations may have a different say outside of standard Section VIII requirements, but I'm wondering with regards to ASME standards. Relevant code is quoted below.

U-1(c)(2) Based on the Committee’s
consideration, the following classes of
vessels are not included in the scope of this
Division; however, any pressure vessel
which meets all the applicable requirements
of this Division may be stamped with the
Code U Symbol:
(e) piping components, such as pipe,
flanges, bolting, gaskets, valves, expansion
joints, fittings, and the pressure containing
parts of other components, such as strainers
and devices which serve such purposes as
mixing, separating, snubbing, distributing,
and metering or controlling flow, provided
that pressure containing parts of such
components are generally recognized as
piping components or accessories;

U-1(j) Pressure vessels exclusive of those
covered in U-l(c), U-l(g), U-l(h), and U-l(i)
that are not required by the rules of this
Division to be fully radiographed, which are
not provided with quick actuating closures
(see UG-35), and that do not exceed the
following volume and pressure limits may
be exempted from inspection by Inspectors,
as defined in UG-91, provided that they
comply in all other respects with the
requirements of this Division:
U-1(j)(3) 1½ cu ft (0.04 m3) in volume
and 600 psi (4.1 MPa) design pressure.

 

[marty007]

I don't have experience using this clause directly, but one aspect that would give me pause is the 4" pipe flange.

How is the 4" pipe flange connecting to the vessel? I'm guessing it is in-line through an opening in the head. If so, I would now consider the head to be a modified component that would require calculations to check for opening reinforcement (is a repad required?).

If however a standard 8x4 reducer were used and the flange welded to this, nothing would be a modified component and you'd be able to use the base ratings of every component.

Just my thoughts, I'd be interested in other poster's views.

Cheers,
Marty

 

[josephYETI]

Marty,

Thanks, that's an excellent point. I was planning to do it inline but that does make sense from both a code and manufacturing standpoint to use a 8x4 conc reducer.

 

[SnTMan]

iseabury, your path for exempting this vessel from Sec VIII, Div 1 would be thru either U-1(c)(2)(f) or (h), rather than U-1(c)(2)(e). Vessels falling under U-1(j) are exempted from inspection only, and as you noted are stamped UM.

U-1(c)(2)(e) is concerned with the purpose of the assembly, i.e. conveying of fluids, rather than what is it made of, i.e. piping components.

Of course it may be contracturally required to meet all applicable provisions of Sec VIII, Div. 1, that is, exemptions under U-1(c) would not apply.

Regards,

Mike

 

[GenB]

pipe components are used to fab many vessels. if your item is used as a vessel, in the US, it shall be stamped designator U or UM if applicable.