Butt weld - Single bevel or double bevel

[Greg80]

Hi
I would like to know is there any part in the Div 1 code that specifies when single bevel butt weld can be used to weld head to shell?
I mean by single bevel butt weld: that a pipe will be butt-welded to a SE head. The head has bevel 37.5 but the pipe is plain end has no bevel.
Both the head and the pipe has 1/4" THK.

Can this joint be considered UW-11 type 2 ? (a backing ring will be used).
I already saw many heads welded to pipes using single bevel but I would like to check the code requirement to evaluate my case.

Please check the attached sketch for more detail:

Any help is much appreciated

Thanks

 

[Don56]

See UW-13 (b)(1). A butt weld is acceptable to attach heads to shells. The Code odes not specify bevel details for it.

 

[weldstan]

There is no such requirement in ASME VIII, Div.1. It is up to the manufacturer. designer to make the call based on economics and accessibility.

 

[gr2vessels]

Look up on ASME VIII-1, Table UW-12 to see where you can place your joint. It could be a Type (1) under the proviso of UW-35. The ends with or without weld preparation make no difference to the quality of weld, for 1/4" thickness, even without backing strip. You'll need however a suitable WPS/PQR.