My first post:

I am looking at a 16" overhead line going from the top of a 80 foot tall, 1/4" thick 4' diamter Zirconium column to an Air Cooler.

A question I have always wondered. Is it accurate to model the column as deflecting in a wind case, with the Air Cooler remaining perfectly rigid? Does the structure itself tend to sway in the wind too?

Also, for API 661 qualifications of the Air Cooler, do I need to qualify the nozzle loads with the operating wind loads as well?

At just 1/2" column deflection, my Air Cooler nozzle API 661 allowables are exceeded. The nozzles pass in the thermal design load case. I modeled the Column in PVElite and at the design wind condition of 130 mph, I get 3 1/2" deflection. At 50 mph, I get the 1/2" deflection.

(I apply the deflection as equivalent forces acting on the Column in my model, so that I am not "forcing" the pipe to deflect at 3 1/2", but I am allowing it to resist the wind load.)