Reverse loose metal to metal flange: Appendix Y or Appendix 2-13

[alsy]

Hello all,

Can a reverse loose ring flange, that has metal to metal contact outside of bolt circle be designed per Appendix Y? We have a customer that has provided a design and calculations from App. Y and has asked us to review for compliance. I take App. Y to be for metal to metal regular flange configuration (not reverse). By using App. Y, the customer is getting a much thinner flange (1.1" thick) than by using App. 2-13 which yields approximately 3.3" thick. Attached is a simplified detail of the reverse loose flange in question.

Any insight is appreciated if appendix Y can be used in this situation or if 2-13 shall be used.

If appendix Y is applicable, I would consider this flange a class 3 (a flat blind attaches to the flange in question), category 3 (loose flange without a hub) and proceed with applicable equations for calculations from table Y-6.1

Thanks all!



"Success is not final, failure is not fatal: It is the courage to continue that counts."
Winston S. Churchill

 

[nickelkid]

So the mating flange has an o-ring groove ?

 

[alsy]

Yes, the mating flange (blind) accepts an o-ring.

"Success is not final, failure is not fatal: It is the courage to continue that counts."
Winston S. Churchill

 

[r6155]

In your simplified detail, the distance from the inside surface
of the vessel to the bottom of a drilled hole is insufficient: see UG-43 (g)
Regards
r6155

 

[alsy]

Correct r6155, we have that marked on our review as that minimum distance needs to be 0.25 of wall thickness per UG-43 while meeting thread engagement requirements of stud (there is no corrosion allowance on this product).

Thanks

"Success is not final, failure is not fatal: It is the courage to continue that counts."
Winston S. Churchill

 

[nickelkid]

I am not sure how Appendix Y factors in the o-ring groove in calculating tII or if it does, this should be looked into. Otherwise, your approach appears reasonable.

 

[r6155]

I don´t know design pressure and materials used, but for 43” flange diam. the thickness of 1,1” sound insufficient, and 3,3” excessive.
Consider factor y=0 and m=0 for O-ring gasket
Regards
r6155