Welding of a loose ring flange (Appendix "Y" Flange)

[MikeG7]

Referring to the attached diagram, I would like to be sure I have correctly sized the flange welds.

Is the back weld the thickness of the pipe or, per Fig. UW-21 of ASME VIII Div.1, it says the back weld leg distance must be the lesser of 1.4 x tmin or the "hub" but this flange doesn't have a hub.

Thanks

 

[prex]

In this case the hub is the weld itself, so the code is saying that the weld leg cannot be shorter than itself.... In practice you consider the first limitation only.

prex
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[MikeG7]

Thanks Prex. What is the logic of the back weld being 40% bigger?

 

[prex]

Likely because the back weld is a sort of hub that helps in making the flange stiffer.

prex
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