6.3　Calculations for Equivalent Design Pressure of Girth Flanges

6.3.1　Where the column sections are flange connected,the internal pressure,external moment and axial force shall be all considered,and the design pressure for flanges(or the nominal pressure of standard flanges)shall be not less than the equivalent design pressure,pc,calculated by Equation(5).

where　pc—equivalent design pressure for the flange,MPa;

M—external moment,including the maximum moment at flanged joint(i.e.,the sum of the moment resulting from wind load or seismic load and eccentric load and the moment resulting from piping thrust force applied on the flanged joint),N·mm;

DG—diameter of the center circle under hold-down force of a gasket(to GB 150),mm;

F—external axialforce(tensile force only),N;

p—internal design pressure,static liquid head shall be includedif necessary,MPa.