Indicates how the value of hoop stress should be calculated.
ID
Compute hoop stress according to Pd/2t, where d is the internal diameter of the pipe.
OD
Compute hoop stress according to Pd/2t, where d is the outer diameter of the pipe.
Mean
Compute hoop stress according to Pd/2t, where d is the average or mean diameter of the pipe.
Lamé
Compute maximum hoop stress according to Lamé's solution: s = P(Ro2+Ri2)/(Ro2-Ri2).