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Mitered Pipe in S8D1?

Mitered Pipe in S8D1?

Mitered Pipe in S8D1?

(OP)
Pretty simple question, are mitered pipe bends allowed in ASME Section VIII Div. 1?  

I have a 30" nozzle which the buyer would like to have a mitered 45° joint in.  After scouring code and the internet, I'm not seeing anything either allowing or prohibiting their use in Section VIII Div 1.  Can I just use the provisions from B31.3 for this joint as an alternative?

Thanks

RE: Mitered Pipe in S8D1?

Section VIII doesn't cover piping, just pressure vessels; that's why you won't find mitered joints there. I you're designing piping, you should use a piping code such as B31.3.

RE: Mitered Pipe in S8D1?

(OP)
I'm designing a nozzle which requires a 45° mitered bend between the nozzle neck and the flange of the nozzle, so within the scope of Div 1 per U-1(e)(1)(c).

RE: Mitered Pipe in S8D1?

*If* you can show valid strength calculations, you can use miters.  Problem is, you will probably go to VIII Div-2 to 'legally' calc it -- skew-angle corner welds as a pressure boundary.

Probably be cheaper to order a custom bent section of pipe and stay in VIII Div-1.

RE: Mitered Pipe in S8D1?

Piping codes basically assume that thermal expansion and other displacements will be taken up by bending of straight sections, so the elbows see minimal stress. This is not such a good assumption for an elbow welded right onto a pressure vessel, and that's the engineering reason why you might not want to put a miter joint there. But as long as you can cram your reasoning within U-2(g) to the satisfaction of your inspector, then you can do anything you want.

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