Bolting Dimensions for API Flanges

10,000 lb. W.P.

Nominal Size Inches Gasket API Number Number Of Studs Stud Bolt Size Inches
1-13/16 BX151 8 3/4 X 5
2-1/16 BX152 8 3/4 X 5-1/4
2-9/16 BX153 8 7/8 X 6
3-1/16 BX154 8 1 X 6-3/4
4-1/16 BX155 8 1-1/8 X 8
5-1/8 BX169 12 1-1/8 X 8-3/4
7-1/16 BX156 12 1-1/2 X 11-1/4
9 BX157 16 1-1/2 X 13
11 BX158 16 1-3/4 X 15
13-5/8 BX159 20 1-7/8 X 17-1/4
16-3/4 BX162 24 1-7/8 X 17-1/2
18-3/4 BX164 24 2-1/4 X 22-1/2
21-1/4 BX166 24 2-1/4 X 24-1/2