Bolting Dimensions for ANSI Flanges all sizes as per ANSI B16.5-1988

ANSI 900-lb Flanges

Nominal Pipe Size Diameter of Studs No.
Of
Studs
Stud Bolt Length Ring
Joint Gasket No.
Raised Face Ring Joint
Inches Inches Inches Inches
1/2 3/4 4 4 4-1/4 R12
3/4 3/4 4 4-1/4 4-1/2 R14
1 7/8 4 4-3/4 5 R16
1-1/4 7/8 4 5 5 R18
1-1/2 1 4 5-1/4 5-1/2 R20
2 7/8 8 5-1/2 5-3/4 R24
2-1/2 1 8 6-1/4 6-1/4 R27
3 7/8 8 5-1/2 5-3/4 R31
4 1-1/8 8 6-1/2 6-3/4 R37
5 1-1/4 8 7-1/2 7-1/2 R41
6 1-1/8 12 7-1/2 7-3/4 R45
8 1-3/8 12 8-1/2 8-3/4 R49
10 1-3/8 16 9 9-1/4 R53
12 1-3/8 20 9-3/4 10 R57
14 1-1/2 20 10-1/2 11 R62
16 1-5/8 20 11 11-1/2 R66
18 1-7/8 20 12-3/4 13-1/4 R70
20 2 20 13-1/2 14-1/4 R74
24 2-1/2 20 17 18 R78