Reverse flange and opening reinforcement

[cornemo]

Dear all,

In a lot of situations a reverse flange is also acting as opening reinforcement, for example a 48" head with a 10" reverse flange in the top.
I tried to find a reference in ASME VIII how to handle such a situation.
The flange will see stresses due to the fact that is acts as opening reinforcement, and it sees stresses as it is also a flange.

Is there any reference in the code how to calculate such a flange/reinforcement ring?
And how do you handle such a detail?

Thanks in advance for your replies.

 

[SnTMan]

cornemo, if the flange is a studding outlet, see Fig UG-40 (a-2), it appears to me that the two calculations, flange and opening reinforcement are carried out independently. If the flange is not a studding outlet it may not be considered as contributing to opening reinforcement. See UG-40(e)

Regards,

Mike

 

[cornemo]

My issue is that if I carry out both calculations independently that I am using the material 2 times.
First I fully utilize the material for the opening reinforcement giving me maximum allowable stress in the flange.
Secondly I fully utilize the material as a flange, giving me maximum allowable stress in the flange.

There is no combined check although the flange is loaded with two different loads.

 

[SnTMan]

cornemo, yeah understand. These things are often proprietary designs, i.e. Forged Vessel or other suppliers. You give them your design conditions and they design or confirm an existing design.

If designing it yourself, I don't know what else to offer. I'd make the flange design low stressed, and the excess reinforcement area large. How "low"? How "large"? No definitive answer I'm afraid.

Apologies for the late response, distracted

Regards,

Mike

 

[cornemo]

Mike,

that's also how I consider it. Two separate calculations with a lot of margin in both of them.
I hoped that someone would come up with a code case or other reference on how to address this issue in such a way that one can make the design as thin as possible (and still within code limits and safeties of course).