Isn't ASME Section VIII required?

[thefury]

First, let me explain that I myself am not a mechanical engineer. I am a salesperson who represents a number of companies that produce pressure & vacuum equipment.

I have an application for a vacuum pump where the inlet pressure is 9.7psia and the intention is to discharge at 16.9psig.

In this case I have a discharge water separator and an oil mist eliminator, both on the pressure side, being exposed to pressures greater than 15psig. The inside diameter of each of these vessels exceed 8".

Am I not correct in assuming that both of these vessels are required to be manufactured to ASME Section VII, Div. 1 and stamped accordingly?

Any help would be appreciated.

 

[eliebl]

That would really depend upon the location of installation. If your discharge separator and mist eliminator are open to atmosphere they are not required to meet the ASME code (where I am located) because they cannot contain pressure. They are may be exposed to pressure but if the pump stops the pressure returns to atmospheric.

Regards,
EJL

 

[thefury]

Actually we're recycling helium and the system is a closed loop. Upon leaving the OME, we send the remainder of product back the start of the process.

But if I understand correctly, ASME stamp would not be required (depending on the local requirement) but since the system is closed loop, these vessels should indeed manufactured to code and stamped because they will indeed see pressures above 15psig?

 

[thefury]

Sorry. I thought that by virtue of the fact that I was talking ASME to begin with, that a US installation was a given.

 

[JoeTank]

thefury,
Not only is it a question of whether the state or province requires ASME compliance, but ASME VIII also has a volume criteria. From memory I think it goes something like this...1.5 cubic feet at 600 psi, 2.5 cf at 300 psi and 5 cf at 250 psi. Someone out there will be able to correct my memory, but there is a pressure-volume relationship too.

Joe Tank

 

[proinwv2]

Section VIII is not law in all states of the US either, unfortunately.

Paul

http://www.ostand.com

 

[jte]

JoeTank-

I keep hearing 'bout the volume criteria. Please read the code and let me know if you find it.

thefury-

Yup, sounds like the vessels you describe would fall within the scope of VIII-1, and if they are to be installed in a jurisdiction within the US which requires it (not all do), then they should be stamped. Based on what I've heard so far in this thread, I wouldn't allow them into any facility I was responsible for without a U or UM stamp.

jt

 

[moltenmetal]

> 6" dia, > 1.5 cubic ft volume and operating/relieved at greater than 15 psig- and not merely a piece of pipe connecting to a larger vessel? Then it's a vessel subject to ASME VIII. There are regional exceptions for water heaters, expansion tanks, compressed air receivers below a certain volume, and DOT-regulated transportation devices etc., but your gas-filled process device would almost certainly be seen as a vessel.

In some states, an owner may elect to design an in-line piping component like this in accordance with the applicable piping code rather than as an ASME VIII vessel, or by giving it similar treatment (ie. as a Category H fitting per Canadian CSA B51).

 

[jte]

moltenmetal-

I'm still wondering where the volume limitation (you referred to <1.5 cu.ft.) is coming from. I'm thinking folks are reading U-1(j) and thinking that it is an extension of U-1(c)(2). However, what U-1(j) is about is allowing vessels meeting the volume & pressure criteria listed to be excempt from inspection by an AI and these vessels shall get a UM stamp instead of the U stamp. Unless I'm not reading things right, these vessels are not excempt from the code altogether as they would be if they met one of the criteria of U-1(c)(2).

jt

 

[AravindSujay]

thefury,

you have clearly mentioned "the intention is to discharge at 16.9psig" for the pump and "pressure side, being exposed to pressures greater than 15psig" for the separator and oil eliminator.

To finish simply - As per ASME, pressures >= 15 psig falls under pressure vessel category. Meaning-follow ASME Sec VIII, Div 1.

No confusions.

 

[JoeTank]

jte,
Here's what ASME VIII says about volume related exemptions....

U-1(j) Pressure vessels exclusive of those covered in
U-1(c), U-1(g), U-1(h), and U-1(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)(1) 5 cu ft (0.14 m3) in volume and 250 psi
(1.7 MPa) design pressure; or
U-1(j)(2) 3 cu ft (0.08 m3) in volume and 350 psi
(2.4 MPa) design pressure;
U-1(j)(3) 11?2 cu ft (0.04 m3) in volume and 600 psi
(4.1 MPa) design pressure.

Joe Tank

 

[jte]

JoeTank-

I think we are "violently agreeing" here. The 5, 3, and 1.5 cu.ft. excepmptions are not excemptions from the scope of the Code (listed in U-(2)(c)) but are limits which may allow the deletion of the AI requirement and the "U" stamp gets changed to a "UM" stamp. But they are still "code" vessels.

jt

 

[JoeTank]

jte,
Agreed.
Joe

Joe Tank

 

[thefury]

Thanks to all for the assistance. I'll leave you to your further deliberations...