Bolting Dimensions for API Flanges

15,000 lb. W.P.

Nominal Size Inches Gasket API Number Number Of Studs Stud Bolt Size Inches
1-13/16 BX151 8 7/8 X 5-1/2
2-1/16 BX152 8 7/8 X 6
2-9/16 BX153 8 1 X 6-3/4
3-1/16 BX154 8 1-1/8 X 7-1/2
4-1/16 BX155 8 1-3/8 X 9-1/4
5-1/8 BX169 12 1-1/2 X 11-1/2
7-1/16 BX156 16 1-1/2 X 12-3/4
9 BX157 16 1-7/8 X 15-3/4
11 BX158 20 2 X 19-1/4
13-5/8 BX159 20 2-1/4 X 21-1/4
18-3/4 BX164 20 3 X 26-3/4