ASME Equations for Calculating Shell Thicknesses(Sec VIII, Div 1, UG- 27)

1) Cylindrical shells (Internal pressure & longitudinal seams, Circumferential stress):

When P <= 0.385SE

2) Cylindrical Shells (Internal pressure & circumferential seams, Longitudinal stress):

When P <= 1.25SE

3) Spherical Shells:

When P <= 0.665SE)

E = Joint efficiencyP = Internal design pressureR = Inside radius of the shell (spherical or cylindrical)S = Allowable stresst = Minimum thickness

These equations are also valid for pipes and tubes subjected to internal pressure (Sec VIII, Div 1, UG- 31 )

Head Connections(Sec VIII, Div 1, UG-32)

1) Hemispherical Heads:

2) 2:1 Ellipsoidal Heads:

When P <= 0.665SE LL = Inside crown radius

Most ideal shape for the head L = R (the inside radius of cylindrical shell)

More economical compared to hemispherical heads