Design of body flange as per mand appdx 2 clamped using manway clamps 2

[GD_P]

Hello Forum,

Can we design a body flange with manway clamps instead of bolts for clamping, using ASME Sec VIII Div 1, mand appdx 2?
Note: Sealing material - non metallic o rings.
IMO, Bolt PCD shall be replaced by the PCD of clamp contact centre
But where we can find the allowable stress values required for flange calculations, for the clamp material designated / identified by manufacturer as SS 304 for example.

How will you face this situation.
Please do share your opinion.
Thank you in advance.

GD_P

 

[SnTMan]

GD_P, two questions:

1) What's a manway clamp?
2) Have you looked at Appendix 24?

Regards,

Mike

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

Edit: Manway Clamp? Looks like U-2(g) to me

 

[GD_P]

Hello Mike,

Thanks for your response.
Please find the attached images showing the manway clamp & its arrangement on a representative vessel.
Hope this will bring clarity.
So Appdx 24 will not be applicable here, but thank you for telling since i was not aware of this.

GD_P

 

[GD_P]

Hi Mike,

Sorry, I didnt noticed your edited comment.
Yes, it looks like U(2)-g design.
My view towards this
1) Body flange thickness -
In Mand appdx calculations, if I replace the bolt PCD by the PCD of clamp contact centre, i can calculate body flange thickness. But here I need allowable stresses for the clamp. If I can get the allowable stresses of clamps from the manufacturer, this point (view 1) will be completed.
2) Manway clamp compliance with code
The manufacturers link you shared claim that designed to work with ASME code pressure vessels.. But there is no specification covered for such parts, how they can be designed to be inline with ASME code?
Also, as we are responsible for marking U stamp on the completed vessel, how we accept the clamps to comply with code?
Can it be accepted through UG-15 or UG 11-(b) or by some other means?.
Is UG-15 applicable, even if there is no product specification for manway clamps? (Here my thought is to compare the properties of SA 193 with clamp & use allowable stresses of SA 193).




GD_P

 

[SnTMan]

GD_P, rather than futzing around with allowables and so forth, can you just get a rating (Pressure, Temp) from the clamp manufacturer?

You then would only have to design the flange, adapting Apx 2 as you see fit, under U-2(g). There is a case (swlotted bolt holes) under Apx 2 where the flange OD is smaller than the bolt corcle.

Interesting clamps, was not familiar...

Best of luck,

Mike

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

 

[GD_P]

Mike, how the clamp manufacturer can give pressure temperature ratings of the clamps?
The manufacturer will only be supplying the manway clamps. They are not standard fitting like B16.5 flanges, hence he is not aware that how many clamps will be used in the bolted joint?

One more thing, if one can refer the way to accept clamps, which are unidentified material (not covered by any ASME specification or ASTM specification) as per the rules of SEC VIII Div 1, it will be really helpful.
I mentioned above UG-15 & UG-11, but they will not be applicable IMO, as the clamps are not covered by any specification.
I will check the UG-10(c).


GD_P

 

[SnTMan]

GD_P, if your clamp supplier represents the clamps as complying with a given pressure vessel code, said supplier mast have a basis for doing so. I'd think any reputable supplier would be happy to furnish a rating. In this case I'd think the clamps could be shown to meet UG-11(d) (...manufacturers proprietary standard...). I'd think meeting the relevant requirements of UG-11 would not be especially difficult.

If, on the other hand, your supplier cannot or will not furnish a rating, you've got two choices:
1) Your organization can take responsibility for the design and manufacturing of the clamps by perfoming the needed calculations and QC functions, or,
2) Find a different supplier.

Regards,

Mike

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

 

[GD_P]

Hello Mike,

We sincerely admire your efforts for giving us the direction.
Thank you very much.
I will let you know the conclusion once we finalized this with AI.
But honestly, I have not understood how the clamp manufacturer can give pressure temperature ratings of the clamps? When we say rating, I imagine a single component e.g., ASME B16.5 flange, B16.11 fittings etc. which acts individually, along with certain predefined component (for e.g., no of bolts & their grade in case of std flange). And IMO bolt always acts as supportive component, hence how it can have the rating.
Thank you in advance.

GD_P

 

[SnTMan]

GD_P, perhaps load rating is a more applicable term, x lbs @ y deg F, but they should be able to give you something.

Yes, please let us how how it goes.

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

 

[GD_P]

Hello Mike & forum,

we are planning to manufacture the clamp & proof test it as per UG-101(burst test). So when we discussed this with our AI, he is saying 'this method can be used but MAWP has to be established… not the load rating'. Now he is saying this with reference to the purpose of UG-101 as per Sec VIII Div 1 i.e., 'The maximum allowable working pressure for vessels or vessel parts for which the strength cannot be computed with a satisfactory assurance of accuracy (see U-2) shall be established in accordance with the requirements of this paragraph, using one of the test procedures applicable to the type of loading and to the material used in construction.'. So it means, he expect us to proof test each and every vessel (in spite of having identical size clamps). He is right to extent specifically mentioned in the code, but code also address that 'This Division contains mandatory requirements, specific prohibitions, and nonmandatory guidance for pressure vessel materials, design, fabrication, examination, inspection, testing, certification, and pressure relief. The Code does not address all aspects of these activities, and those aspects which are not specifically addressed should not be considered prohibited.Engineering judgment must be consistent with the philosophy of this Division, and such judgments must never be used to overrule mandatory requirements or specific prohibitions of this Division.'. Don't you think that our intention to evaluate the load rating for identical clamps instead of proof testing each vessel is an Engineering judgement, which doesn't overrule mandatory requirements or specific prohibitions of this Division?
Your opinion please.

GD_P

 

[DriveMeNuts]

I think what your AI is saying is that he wants the clamps to be proof tested while attach to its vessel, rather than be attached to a test gig.

I doubt you could put the vessel into service after proof test because it would have bulges from the huge proof test pressure, therefore I don't think your AI is asking you to proof test each vessel. The AI just wants you to sacrifice one vessel and then conduct a regular hydrotest on all future vessels.

You are not just proof testing the clamp. You also need to proof test the custom clamp-flange interface which also doesn't have a calculated pressure rating.

If your vessel is too large and expensive to sacrifice, I would redesign your testing gig so that it replicates the clamp-flange geometry and convince your AI that the vessel will behave identically to the proof test gig. If this is rejected then find another AI.

 

[GD_P]

DriveMeNuts, thank you for your advise.
You are right and with this reference AI is also convinced to use of Test gig. The results of test gig will be MAWP & this MAWP can be used to evaluate the clamp strength.

GD_P

 

[r6155]

You can use a mock-up, in example NPS8 with 4 clamps to test them.

Regards

 

[GD_P]

Okay r6155.

GD_P