I thought that I clearly answered that by saying that I used the 4.0 safety factor.
I figured out what I was doing wrong. I had added head pressure. This is a propane tank and most likely designed without it. I took it off, now it works.
I'm calculating a nozzle addition and trying to replicate the original vessel thickness for a Section VIII Div 1 vessel built in 1961.
Using the 4.0 safety factor and formula from UG-27 I'm getting a result just short of being acceptable. Vessel was fully radiographed so I'm using an...