Dear all, I m new in eng tips and

[Gigione]

Dear all,
I m new in eng tips and I need this kind of information: I have to design some branch on one header, we normally deal with small headers (6-8-10-12 inch) and small thickness (std and XS).
Now I have to joint 1" branches (thck XS) with an header 8", sch 120. My collegue told me that there is maximum ratio between header thickness and branch thickness that has to be welded on, but in ASME VIII div.1 I don't find nothing about.
Do someone know something about it and address me to ASME relevant chapter.
Many thanks in advance
Gigione

 

[XL83NL]

Since youre talking about a header and a branch, Im assuming youre talking piping, which would typically be B31.3 (or B31.1). Therefore your reference to VIII-1 doesnt make sense, I think you looking in the wrong direction. Review 304.3.2 of B31.3, directions are in there.

 

[Gigione]

I wrongly use "branch" rather than nozzle. I need ASME VIII div.1 reference, if any. Thank you.

 

[marty007]

ASME does not have any limitations on nozzle thickness vs. shell thickness.

Sometimes you'll find requirements like that in customer specifications. When it comes to cyclic service in particular, I have seen requirements such as "neck thickness not to exceed 2x shell thickness", which tends to reduce peak stresses in the joint. But again, this is not an ASME requirement.

Cheers,

 

[Gigione]

thank you Marty!