This section covers dimensions of ring joint facings for all pressure classes. ASME B16.5 covers ring joint flange facing dimensions for class 150, class 300, class 400, class 600, class 900, class 1500 and class 2500. Dimensions in this section are specific to ring joint facings. For other dimensions of flanges such as flange thickness, bolt circle diameters and bolt hole diameters, refer to the section on the applicable Flange Dimensions.