karthik13:
Yes. The equation for the head is:
A = =0.9286*D^2
where,
A = internal surface area of the ASME F&D head (w/o the straight flange), ft2
D = internal diameter, ft
My reference is: Pressure Vessel Handbook; Eugene F. Megyesy; 8th Edition; Pressure Vessel Handbook Publishing, Inc.
I hope you know how to find the surface of a cylinder, because I'm hoping I don't have to tell you that.
Hope this does it for you.