This section covers dimensions of ASME B16.5 Weld Neck Flanges for all pressure classes. ASME B16.5 covers Weld Neck Flange dimensions for class 150, class 300, class 400, class 600, class 900, class 1500 and class 2500. Dimensions in this section are specific to RF Weld Neck Flanges. For dimensions of flanges with ring joint facings such as pitch diameter of groove, depth of groove, refer to the section on Ring Joint Flange Dimensions.