Dear all

To be honest,my question has little to do with caesar ii.
i am rather confused why the caculated wall thickness by b31.3 is so thicker than B16.39.
Take an example,in LNG industry,the caculated TP304 thickness under 1.86MpaG is about 2.1mm,with manufacure factor considered and errosion factor ignored, but the selected sch10s is 3.76mm.
Can anyone give light on this difference ,best regard and many thanks.