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Pressure vessel Body flange calculation DIV 2

Pressure vessel Body flange calculation DIV 2

Pressure vessel Body flange calculation DIV 2

Need your help.i got datasheet from client need to design Division 2 vessel.

ID : 2320
length shell : 6245
Internal pressure : 165 Bars
External Pressure : FV
Temperature : 70/70
Head Type : Body flange (Top),Hemispherical Head (Bottom)
material head and shell : SA 516 GR.70
body flange material " SA.350 LF.2 CL.1

When i come out in PV elite. requirement thickness body flange is 500 mm thickness. have other way how to reduced thickness of body flange?

Thank You so much if can help me to solve this problem

RE: Pressure vessel Body flange calculation DIV 2

You are leaving out a lot of information. What type of flange? Weld neck? Slip On? What type gasket are you using? Dimensions? bolt size and material?

What part is driving the thickness requirement? Seating condition? Operating condition? Flange rigidity?

RE: Pressure vessel Body flange calculation DIV 2

I'm not very familiar with ASME VIII-2 Part 4, but this is going to be a monster flange at that pressure and diameter.

The best way to reduce flange thickness in general is to make your bolt circle diameter as small as possible.

Because of your pressure however, you're going to be running into bolt spacing issues. Really the only thing you can do is try to find the strongest bolts allowable by code, and use them to reduce your bolt circle diameter as much as possible.

Other than that, you'd have to step outside of the rules of Part 4 and design a specialised closure. One example would be something like a Greyloc closure, but I don't know if that's practical at your diameter.

Another option could be some sort of breech-lock style threaded closure? Depends on the geometry of your equipment...

Good luck!

RE: Pressure vessel Body flange calculation DIV 2


Sorry if i miss information.
Orientation : Vertical
flange type : proposed to used weld neck type
gasket : ring joint ss and nickel base alloy
dimension and bolt size : depend what the design calculation can pass
material of bolt and nuts : SA-193-B7M/SA 194-2HM

Thank You sir for your reply


Yes your right.
i will get monster flange. but if i changed to used quick opening closure type i will step out from design code also?

RE: Pressure vessel Body flange calculation DIV 2

Also be aware that depending on the bolt size that you're using you might need
hydraulic tensioning therefore your studs should be longer by the thickness
of one extra nut on one side.
Usually bolting of 1.5" and higher requires the use of hydraulic tensioners.

You could also try and use alternative design codes for flange design like:
BS EN 1591-1:2013

EN 13445 Annex G

but what the outcome would be in comparison to ASME VIII-2 - I have absolutely no idea.

RE: Pressure vessel Body flange calculation DIV 2

Quote (pepiji)

if i changed to used quick opening closure type i will step out from design code also?

ASME VIII-2 addresses quick opening closures in paragraph 4.8. Unfortunately this paragraph doesn't provide specific design formulas, so you're probably left with Part 5 (FEA).

RE: Pressure vessel Body flange calculation DIV 2

I suggest design for top head similar to ASME VIII Div 1 Figure 1-6 (d)
Stud screwed through shell flange and fitted with single nut in top head flange.
Hydraulic tensioner shall be applied in set of four studs (minimum) at same time . Particular specification is required.
My experience was: Reactor Pressure Vessel (nuclear), 76 stud 220 mm diameter with special design of nuts (no hexagonal).


RE: Pressure vessel Body flange calculation DIV 2

Double check the B7M stud bolt material, as that material doesn't seem to make sense for external bolting.

B7M studs have a lower allowable stress than B7 studs, so using them will result in a larger diameter/more expensive flange.


RE: Pressure vessel Body flange calculation DIV 2

I prefer the standard EN 1591-1 or EN13445 Annex G.
Or we should push the ASME BPVC adopting the methord " the leakage Behavior of Gaskets in Flanged Connections".
Unfortunately, after so many years, nothing has happened. Leaving us behind the europeans.

RE: Pressure vessel Body flange calculation DIV 2


Leaving us behind the europeans.

I wouldnt say that, but: have you considered becoming a voluntary ASME committee member, such to participate and help in making changes?

RE: Pressure vessel Body flange calculation DIV 2

Dear XL83NL ,
Sorry my schedule is always full. I just hope our association can absorb some foreign more advanced experience.

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