Methanol Sphere T-min Calculation

[FIS4224]

I need to perform a t-min calc for a methonal sphere (UG-32f). Where do I find the crown radius of a 24" hemispherical head with a wall thickness of 0.375"? I don't have access to the U1-A form.
I have carried out several semi elliptical head t-min calcs but this is my first hemi-head.
Any and all help would be appreciated. Satic data on the sphere is below:

Manufacturer: Bromley
Year Built: 1999
Size: 24” OD X 0.375” t
MAWP: 400psi at 100F
Material: SA-516-70
No C.A
No RT stamping.

 

[jharris3]

Dude, a hemispherical head doesn't have a knuckle because its a sphere. There is no change in curvature.

 

[FIS4224]

Thanks for taking the time to answer a stupid question...i guess I'll chalk it up to a brain fart.

 

[Duwe6]

Yep, cals's as a pair of hemi heads. Watch out for joint efficieny of the welds, w/o a U-1 you have to derate them a LOT. Have you tried to get a copy of the U-1 from the National Board?

On bigger spheres, don't forget the liquid head pressure. It becomes a large part of the pressure on the lower half of a sphere when you get over 10 - 20 feet in diameter.

 

[jharris3]

Now you make me feel bad because I said "dude"

It wasn't a stupid question.

As for the efficiency, you can come pretty close using the original design information to compare. If the efficiency you use nails the original thickness then you know that what was used in fabrication.

Then take a look at all the inspection data together and decide whether or not API 510 E = 0.7 minimum would be a better choice (if its less than your calculation).

Good luck!