AWWA Flange for ASME VIII, Div 1 Service 3

[engpes]

I have an AWWA table 4 class E flange that we are planning to use on a 42" OD vessel. The flange is a 42" 125# slip on flange per AWWA table 4 class E. My design pressure is 150 psi @ 200 F and is SA105 material.

I tried analyzing as an ASME VIII, Division 1, Appendix 2 flange, but it did not meet code requirements (mainly the flange thickness).

My question is as follows:

1.) Can you use a AWWA Table 4 Class E flange for ASME VIII, Division 1 pressure vessel service?
2.) If it does not meet the Appendix 2 requirements, can the 275 psi rating per AWWA Table 4 class E be valid for ASME VIII, Div 1? This is built and rated by Texas Flange.
3.) Would I need to run an ASME VIII, Div 2, part 5 design by analysis approach for div 1 service to determine the adequacy for service on a pressure vessel?

Thank you in advance for your help!

 

[SnTMan]

engpes, 1) No, unless you can justify it per Apx 2. See UG-44.
2) No
3) Possibly, you would have to get the client, your AI and any other interested parties to buy-in.

Why not just use a B16.47 flange, or an Appendix 2 flange and make your life simple?

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[mk3223]

IMO, as the flange material, thickness, construction, etc. are complied with the ASME BPVC requirements and the pressure-temperature design conditions, an AWWA flange can be used for the ASME vessel.
Agreed with SnTMan, B16.47 flange is a good choice for the vessel.

 

[SnTMan]

mk3223,just so we're clear, an AWWA flange may not be used per its AWWA ratings under Sec VIII, Div. 1. Again, see UG-44. It would need to meet calculations under Apx 2.

"The world is full of things you can buy. Not all of them are suitable for use in Code pressure vessels."

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

Edit typo

 

[engpes]

For spacing reasons a B16.47 makes things difficult for this application.

If the div 2, part 5 analysis method works and would the flange be adequate for service?

On a side note, why do standard ansi flanges B16.5 not meet the appendix 2 design requirements in some sizes?

 

[SnTMan]

engpes, last question first, B16.5 flanges are often "overbolted" as compared to Apx 2, therefore the thickness often fails. Same as with your AWWA flange I'd guess.

Your first question, I'd say yeah, under U-2(g) if all the involved parties permitted it.

So why not just design, to Apx 2, a slip on flange per the AWWA dimensions you desire. Make the thickness comply with Apx 2. Burn ID / OD from plate, machine the gasket face, drill the bolt circle, weld it on. Be done.

Regards,

Mike



The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[BJI]

To clarify point 3, I would say no, not where the design of the flange is already covered under division 1. Also, if it doesn't pass the division 1 calculations then it does not meet U-2(g) IMO.

 

[SnTMan]

BJI, good points.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[engpes]

Where is U-2(g) located in VIII? What section would it fall under?

 

[david339933]

What about using App. Y - thickness required would be reduced.

 

[david339933]

U2(g) is before section UG....pgs 1 - 6.

 

[JStephen]

I was thinking that AWWA flanges were normally cut from flat plate (not forged, not rolled from bar)- but check into the fabrication to see if that's an issue.
AWWA flanges are typically flat-faced, used with full face gaskets.
I believe some of the flange suppliers (possibly Texas flange) also have flanges available made to ASME B16.47 geometry, but in a slip-on configuration- that'd fall under App. 2 also.

 

[mk3223]

In the VIII-1, U-2(g) is in the "Introduction" before the "Subsections":

(g) This Division of Section VIII does not contain rules to cover all details of design and construction. Where complete details are not given, it is intended that the Man- ufacturer, subject to the acceptance of the Inspector, shall provide details of design and construction which will be as safe as those provided by the rules of this Division.

 

[marty007]

Agree with BJI, Div2 Part 5 would NOT be acceptable.

U-2(g):

(g) This Division of Section VIII does not contain rules to cover all details of design and construction. Where complete details are not given, it is intended that the Manufacturer, subject to the acceptance of the Inspector, shall provide details of design and construction which will be as safe as those provided by the rules of this Division.​

So first question, are complete details for the design of slip-on flanges given in VIII-1? The answer is yes, Appendix 2 provides complete rules for the design of slip-on flanges.

Even if you did perform an FEA and convinced yourself of the results (interpreting FEA results for a flange is non-trivial), you are still trying to justify a thinner flange than would be calculated using Appendix 2. So, you would fail the second test of U-2(g); your flange would be thinner than an Appendix 2 designed flange, so would not be as safe as a flange designed using the rules of Division 1.

If your connecting piping uses AWWA flanges, then I would design a custom flange using Appendix 2. You can design a ring flange that matches the OD and bolt pattern of the AWWA flange. It may be thicker than a standard AWWA flange, but this can be made up

 

[engpes]

Ok I agree with BJI. We are going to go with a 42" 150# RF SO, but this large size is not covered in ASME B16.47. However, a 42" 150# RF SO flange does not meet the Appendix 2 requirements due to flange thickness (viii bolting requirements for 1.5" stud).

Is my only option to increase the SO flange thickness to meet appendix 2?

Or can I us div 2, part 5?

After this discussion and research I think div 2, part 5 may not be allowable?

 

[pdiculous963]

No, you cannot use Div. 2 part 5 as many others have said. In Division 1, if there is a rule for a component it must be followed. U-2(g) is only applicable when the Code does not provide rules. You will need to design a flange which meets the requirements of Appendix 2.

 

[TGS4]

That's right. There exists rules in VIII-1, so those must be followed first. Only if rules don't exist, then can you apply U-2(g).

 

[engpes]

TGS$ & PDICULOUS963 - Thank you. I agree.

So just to confirm, I would have to increase the flange thickness of the 42" 150# RF SO flange to meet the appendix to requirements.

Out of curiosity, why is there a size 42" 150# RF SO size if not good for ASME VIII? Is this only good for B31.3?

 

[TGS4]

Different design codes with different committee members, and different design margins. And different purposes.

 

[BJI]

If permitted by site hot works and the required coating system, what about using a butt weld connection as the battery limit of the vessel and keep the flanges in the piping scope?