Flange Dimensions Reference

What ASME B16.5 Covers

ASME B16.5 covers pipe flanges and flanged fittings, nominal pipe sizes 1/2 inch through 24 inch, in pressure classes 150, 300, 400, 600, 900, 1500, and 2500. Standard facings include raised face (RF), flat face (FF), ring-type joint (RTJ), tongue and groove (T&G), and large male and female (LMF). Each flange type, size, and class combination has dimensional values for outside diameter, hub diameter, bolt circle, bolt hole diameter, bolt hole count, flange thickness, raised face dimensions, and hub length.

What ASME B16.47 Covers

B16.47 covers large diameter flanges, 26 inch through 60 inch nominal, in two series. Series A (formerly MSS SP-44) is the heavier pattern. Series B (formerly API 605) is the lighter pattern with larger bolt circle. Series A and B are not interchangeable. The project drawing or specification names which series the flange must match.

Dimensions That Drive Quoting

• Outside diameter (OD): the outside dimension across the flange face. Drives bolt circle and physical clearance.
• Bolt circle (BC): the diameter of the circle through the bolt hole centers.
• Bolt hole count and diameter: how many bolts and what size.
• Flange thickness: the dimension from the back face through to the raised face transition.
• Bore: the inside diameter of the flange. Slip-on and weld neck flanges have standard bore tied to schedule of mating pipe.
• Hub length and diameter: applies to weld neck and other hubbed types.

Detailed Tables

For the full ASME B16.5 and B16.47 dimensional tables across every size and class combination, see the texasflange.com dimensional library at texasflange.com/products/flange-dims-weights. The library has type-by-class tables for weld neck, slip-on, blind, threaded, socket weld, and lap joint flanges.

For a specific dimension or to validate a tolerance, call (281) 484-8325 with the line spec.