Calculating Wall Thickness and Bolt Diameter for a Spherical Pressure Vessel

[mattyboson12]

A spherical pressure vessel of internal diameter 2m is constructed by bolting together two hemispherical domes with flanges. Assuming that the number of bolts used to join the two hemispheres together is 12, determine the wall thickness of the dome and the diameter of the bolts, if the maximum applied pressure is 0.7MPa, the maximum stress in the spherical shell is 50MPa and the maximum stress in the bolts is 200MPa.

I really don't where to start with this question so was wondering if anyone could give me any hints. I know that for a thin sphere the membrane stress is σ=(internal pressure*mean radius)/(2*thickness)

 

[paisiello2]

Maybe try to plug in some numbers and see what information you have or missing.