Flange chart: Class 150 and Class 300 dimensions, and PN16 vs JIS 10K

How to read the chart

NPS is the nominal pipe size. The flange OD is the outside diameter of the flange plate. The bolt circle, or PCD (pitch circle diameter), is the circle through the centres of the bolt holes. Two flanges bolt together only when the PCD, the number of bolts and the bolt size all match.

For the same pipe size, a Class 300 flange is larger than a Class 150 flange and usually has more or bigger bolts, so the two classes do not bolt together. Weld neck, slip-on, socket weld, threaded and blind flanges of the same class and size share the same OD and drilling.

ASME B16.5 Class 150 flange dimensions

ASME B16.5 Class 300 flange dimensions

Class 150 vs PN16 vs JIS 10K

These are three different flange systems. Class 150 comes from the American standard ASME B16.5 and is drilled in inch dimensions. PN16 comes from the European standard EN 1092-1 and is drilled in metric dimensions with metric bolts. JIS 10K comes from the Japanese standard JIS B2220 and has its own metric drilling.

Although the pressure ratings sound similar, the OD, the bolt circle, the bolt count and the bolt size differ at most sizes. In general a Class 150 flange will not bolt to a PN16 or a JIS 10K flange, and a PN16 flange will not bolt to a JIS 10K flange. Even where a bolt circle comes close, the holes or the bolts may not line up properly, so do not force a mixed joint.

Valves, pumps and equipment from different countries often arrive with different flanges. Before you order, check the marking on the mating flange or the drawing, or measure the OD, the PCD and the bolt holes and send them to us.

• Class 150 or Class 300: ASME B16.5, inch drilling.
• PN10, PN16 or PN25: EN 1092-1, metric drilling.
• 5K, 10K or 16K: JIS B2220, metric drilling.
• Send the standard, the class, PN or K, the size, the flange type and the material with your list.

Flanges and gaskets we list

SS A182 F304/304L and F316/316L and C.S A105 flanges in slip-on (SORF), socket weld (SWRF), weld neck (WNRF), blind and threaded, from ½" to 24", in PN16, CL150 to CL600, and 5K, 10K and 16K. For the joint, we list CNAF, non-metallic and rubber ring gaskets for PN16 and CL150 to CL600, and spiral wound gaskets for PN16 and CL150 to CL600.

Notes

Bolt circle values in mm are the B16.5 inch values converted and rounded to 0.1 mm. Flange OD in mm follows the B16.5 metric values. NPS 3½" and 22" are not shown.

Values per ASME B16.5. Check the mill certificate or drawing before you order.