Procedure 2-9 Design of Flat Heads

C = attachment factor D = long span of noncircular heads, in. d = diameter of circular heads or short span of non-circular heads, in. 

E = joint efficiency (Cat. A seam only) t = length of straight flange measured from tangent line, in. 

P = internal pressure psi r = inside corner radius of head, in. 

S = code allowable stress, tension, psi t = minimum required thickness of head, in. tf = thickness of flange of forged head, in. th = thickness of head, in. 

Z = factor, dependent on d/D ratio Qo = shear force per unit length, Ih/in. 

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