As per the standards followed by some of the consultants, the piping loads on the equipment nozzles should be limited to certain allowable values. These allowable loads are specified in terms of nominal pipe size like, 200D, 250D etc. For radial loads and bending moments, seperate expression are given in terms of 'D'. Some people consider only radial force and B.M. But some other people take shear force and torsion also into account while checking the equipment nozzle qualification.

Can anyone tell me how these expressions are derived? What is the significance of D multiplied by some numerical values? Is it related to any WRC test result?

Please add, whether shear force and torsion are having any considerable effect on the nozzle loads?