Limitations on Nozzle Reinforcement
Limitations on Nozzle Reinforcement
(OP)
Hey everybody,
I'm analyzing a horizontal vessel with a large (24") tangential nozzle that is throwing the Div. 2 deficiency, referencing 4.5.2 which says that if the ratio is greater than 1.5 then you need to design by analysis. Therefore I'm doing FEA - but I'm still getting high stresses (~40 ksi) close to the nozzle even with a small repad modeled. The nozzle is pretty close to the head (~6 inches) so there's only so much room for more reinforcement.
My question is, does ASME (or API 510 for that matter) limit how close a reinforcement pad can get to a head-to-shell seam? What about just putting a rectangular plate on that section of shell, basically a big thick square repad?
Thanks in advance. I'm new to this forum and it's been super useful so far.
I'm analyzing a horizontal vessel with a large (24") tangential nozzle that is throwing the Div. 2 deficiency, referencing 4.5.2 which says that if the ratio is greater than 1.5 then you need to design by analysis. Therefore I'm doing FEA - but I'm still getting high stresses (~40 ksi) close to the nozzle even with a small repad modeled. The nozzle is pretty close to the head (~6 inches) so there's only so much room for more reinforcement.
My question is, does ASME (or API 510 for that matter) limit how close a reinforcement pad can get to a head-to-shell seam? What about just putting a rectangular plate on that section of shell, basically a big thick square repad?
Thanks in advance. I'm new to this forum and it's been super useful so far.





RE: Limitations on Nozzle Reinforcement
To directly answer your question, no, I cannot think of any rules which limit extending the pad into a head, although I believe many would consider it to be poor practice. Generally, rectangular pads would not be considered a good alternative either, perhaps they could be shown to be acceptable with very generous corners. However, if it were my vessel I would first opt to relocate the nozzle, or if that was not possible, look to use an integrally thickened nozzle and/or insert plate. Optionally, the non-linear plastic collapse options in Part 5 such as limit load or elastic plastic analysis could be performed. Don't forget the other required checks in Part 5 (local failure, buckling, fatigue, and ratcheting).
RE: Limitations on Nozzle Reinforcement