Hi all:

For flanged piping systems eg: Teflon-lined / glass-lined piping, how critical is modeling the flange thickness. The isos don't consider the flange thicknesses & dimension to C/L of the gasket. I am following dimensions exactly as indicated on isos.

So for the flange, I give it a thickness = gasket thickness with a rigid weight. Is this correct? How critical is the flange thickness in stresses / restraint loads etc. ?

The concern is if I model the flange thickness I have to make up the difference in pipe lengths indicated on the isos. So in that case my model wont match the isos and it's a lot of extra work.

Perhaps this is critical in a large bore piping? NPS>6" ?

Please advise. Also all flanges are rotating lap-joint flanges

Thank you kindly

I would suggest that a lap flange assembly does not add to system stiffness in the way that a weld-neck does and can thus be ignored in that sense. However, you must include the weight of ring and bolts and the correct s.i.f.

Anican12,
Go ask a Piping Material Engineer of a Piping Layout Designer to show you a Catalog and give you an education about "Lap Joint Flanges".