I´m analyzing a tank right now with three huge 30" nozzles very close. The Pipe is 36" and the tanks is going to settle 2" during lifetime. I initially ran the analysis with this conditions and specify some spring hangers and a ball joints as client request. My client comments asked me to include the unrestrained nozzle rotation due to thermal expansion and product head. The tank is really big and this angle is 1.5º degrees. The pipe now is having overstresses and deflects almost 4" near the nozzle.

I always include the nozzle stiffnesses Kr, Kl and Kc according to API 650 App. P, the thermal expansion displacements at nozzle-pipe junction and settlement displacements if necessary, but including this angle is giving me hard time to make this pipe pass the analysis.

How real is this angle for my analysis, I mean, 1.5 degres rotation is huge in a 36" pipe. The unrestrained condition on the tank is important here? My nozzle is not unrestrained, the pipe is flanged to it.