Hello all!

I received some vessel calculations that I was asked review and noticed that a correction factor "F" of 0.5 was used to determine the area required for nozzle reinforcement.

What I have is:
300 psig -424 to 100 deg F
6" schedule 40 abutting nozzle SA-312, 304L, located in the center of a 2:1 elliptical head, 71.29" ID, 0.75" thick, 1.5" straight flange length SA-240, 304L

I have not been able to find a way to specify the "F" correction factor in PVElite and when I enter the above element data into PVElite or CodeCalc and run an analysis the "F" factor shown on the output is 1.0. This makes the area required for reinforcement twice that required in the analysis that I am reviewing.

Reading UG-37, I am not sure that this configuration allows the "F" factor reduction. It is a FIG. UW-16.1,(a) configuration and therefore considered an integrally reinforced nozzle, but it is not in a cylindrical shell or cone as the UG-37 "F" correction factor definition states. Can the spherical part of a elliptical head be considered a cylinder?

Any comments or opinions would be appreciated. Actual facts would be even better..

Jim

Hi Jim,

You are correct, reading UG-37 description for "F" factor mentions that:



In my opinion the factor "F" of 0.5 on an elliptical head cannot be used to determine the area required for nozzle reinforcement. In PV Elite the use of the "F" factor is limited to nozzles located on cylindrical sections.