Bolting Dimensions for API Flanges

5000 lb. W.P.

Nominal Size Inches Gasket API Number Number Of Studs Stud Bolt Size Inches
2-1/16 R24 8 7/8 X 6
2-9/16 R27 8 1 X 6-1/2
3-1/8 R35 8 1-1/8 X 7-1/4
4-1/16 R39 8 1-1/4 X 8
5-1/8 R44 8 1-1/2 X 10
7-1/16 R46 12 1-3/8 X 10-3/4
9 R50 12 1-5/8 X 12
11 R54 12 1-7/8 X 13-3/4
13-5/8 BX160 16 1-5/8 X 12-1/2
16-3/4 BX162 16 1-7/8 X 14-1/2
18-3/4 BX163 20 2 X 17-1/2
21-1/4 BX165 24 2 X 18-3/4