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Section VIII Div 1 U-1 Interpretation 3

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I quote:

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:
(f) a vessel for containing water under pressure, including those containing air the compression of which serves only as a cushion, when none of the following limitations are exceeded:
(1) a design pressure of 300 psi (2 MPa);
(2) a design temperature of 210 deg. F (99 deg. C)

First, tell me what you think ASME was thinking when they wrote this and then I will tell you our application and then you can tell me if you think this part of ASME applies or not.

TYIA,

heaterguy

 
The thinking is that a failure from harmless liquid stored below its boiling point (at atmos. pressure) would not be significant. An example would be a household water heater. Check on any local regulations which my supersede this.
 
This same issue also parallels how current exemptions had originated for boilers and pressure vessels in many Jurisdictions in the US. A possible answer to this can be found in the recent (Winter, 2006) National Board Bulletin magazine article. The article was written from the perspective of what the early ASME code committee members were thinking when these exemptions were developed for hot water heaters and small boilers.
 
Our application is an ASME pressure vessel made from 12" carbon steel pipe (SA-106B) with a 300# ANSI body flange and 3" 300# ANSI RFWN inlet and outlet flanges. There are some internals, too. The design pressure is 600 psig and the design temperature is 500 deg. F. Water is not stored in the vessel and water passes through the vessel at 80 gpm, 350 deg. F and 450 psig. Does ASME Section VIII, Div. 1 apply?
 
Yes. You have exceeded the exception limitations in U-1 (f) paragraphs 1 and 2.
 
So what does this requote from above mean? "however, any pressure vessel which meets all the applicable requirements of this Division may be stamped with the Code U Symbol".
 
I take it to mean that, even though you don't have to meet the requirements of Section VIII, Division 1, if you do anyway, then you can add the Code Stamp. I.e., you can do more than you have to.

Patricia Lougheed

Please see FAQ731-376 for tips on how to make the best use of the Eng-Tips Forums.
 
So you can have crude oil at for instance 1000 psig and 1000 deg F. or hydrogen or ammonia or whatever, but if it's water, then ASME Section VIII doesn't apply? What is the reasoning here?
 
heaterguy;
The requirements for Code stamping are very clear regarding pressure, volume and temperature. If a pressure vessel you are intending to design and install is located in a Jurisdiction that requires a U-stamp for pressure vessels, one has to comply for operation - this is the law. In some cases where vessels are exempt under Jurisdictions, one can still design and fabricate a vessel that meets the requirements of ASME Section VIII, Div 1 and can be stamped accordingly.
 
I think the answer is that ASME doesn't want people skirting around Section 1 or Section 4 and using Section 8. So these constraints that I listed above have been put into Section 8. However, I also don't think the application listed above applies to Section 1 or Section 4. Having said that I must admit that I know very little about Section 1 or Section 4.
 
Many tanks that would fall under these requirements are built to Section VIII anyway- currently required by my state for hydropneumatic tanks for public water works, for example.

I know I wouldn't want to be in the vicinity when a 299-psi 209 degree tank let go.
 
vpl-Review the second page of the Forward.

heaterguy-Does this thing have valves? Can you isolate it?
Could be considered piping~ See U-1(c)(2),(c),(d),(e).

You must consider the requirments of the local Jurisdiction and see what the locations insurance carrier requires.

If in doubt build it to Code. The Stamp Holder's AIA could help define.
 
No one has explained what I orginally asked.

What is the intent of U-1(c)(2)(f)-(1)&(2)?

My best "guess" at this point is that ASME wants sections 1 or 4 to apply. However, I know very little about those sections. May someone please clarify this for me?
 
I think f1 and f2 are intended to address hydro-pnuematic water tanks.

Steve Braune
Tank Industry Consultants
 
heaterguy
Your questions are very confusing. First you ask for the thinking around 300 psi @ 210F then your application is a piece of pipe 600 psi @ 500F.

I suspect your application can be considered a piping system. Refer U-1(c)(2)(d) and (e).
 
codeeng,

ASME give 300 psi and 210F as not to exceed. My application, for illustration purposes, is 600 psi @ 500F. It is an ASME pressure vessel and does require a code stamp. Still, there has not been a direct answer to my original question, except for Patricia, who answered 1/2 of the original question.

TYIA,

heaterguy
 
heater guy:

This is just my impression, but I think that ASME is giving an "out" for low pressure vessels that contain water. For example: a home water heater. It will contain water and air, will not be above 300 psi and shouldn't be exceeding 210 degrees F (actually I think they're supposed to be set somewhere around 165 to 185F.) So Section VIII doesn't apply to them. And I'm pretty sure that neither do Sections I or IV. But if you go above the limits of U-1(c)(2)(f)-(1)&(2, like in your application, then you DO have to meet the Code.

I also think that this whole issue has been made more complex than it needs to be.

Patricia Lougheed

Please see FAQ731-376 for tips on how to make the best use of the Eng-Tips Forums.
 
It's possible that ASME wasn't thinking of larger vessels when they wrote this, as well. Small hydropneumatic tanks are used on home well pumps, and that may have been what they had in mind, rather than 30,000 gallon tanks.
 
Patricia,

You are my hero!!!

I have been reading this WRONG. Of course the referenced code is a double negative..."are not included when none are exceeded".

But you have correctly stated the obvious and helped resolve this issue, completely.

Thanks,

heaterguy
 
..."Still, there has not been a direct answer to my original question"....

I did answer your original question.
 
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