Dear all,
While performing flange leakage calculation of size 16" #150 it is observed that the seating stresses are higher than allowable. As i understand seating stresses gets developed due to initial load at ambeint condition. I found that even with zero external force & moments from piping, this piping fails in seating stresss. can anyone tell me the remedy for such failure like change of gasket type/material.

pls find attached file for refrence.