ASME Standards for Checking Standard Flanges

Dear Guest,

Per ASME B&P Vessel Code Section VIII, Division 1 Addenda 2009b to 2007 Edition paragraph UG-11(a)(2), the Pressure/Temperature ratings within B16.5 (and other allowable "standard parts" per UG-44) are acceptable. Therefore, no need to check per Appendix 2 unless you modify the flange.

Typically, internal corrosion does not affect the flange thickness. However the (cylinder) neck of the weld neck shall be checked for this corrosion and shall have the same bore as the attached pipe. For external corrosion that would decrease the flange thickness, maybe you could mame a drawing/specification that requires a B16.5 flange with a heavier flange thickness that is still within the tolerances of B16.5.