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

ANSI 300-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 1/2 4 2-1/2 3 R11
3/4 5/8 4 3 3-1/4 R13
1 5/8 4 3-1/4 3-1/4 R16
1-1/4 5/8 4 3-1/4 3-3/4 R18
1-1/2 3/4 4 3-1/2 4 R20
2 5/8 8 3-1/2 4-1/4 R23
2-1/2 3/4 8 4 4-1/2 R26
3 3/4 8 4-1/4 5 R31
3-1/2 3/4 8 4-1/4 5 R34
4 3/4 8 4-1/2 5-1/4 R37
5 3/4 8 4-3/4 5-1/4 R41
6 3/4 12 4-3/4 5-3/4 R45
8 7/8 12 5-1/2 6-1/4 R49
10 1 16 6-1/4 7-1/4 R53
12 1-1/8 16 6-3/4 7-1/2 R57
14 1-1/8 20 7 7-3/4 R61
16 1-1/4 20 7-1/2 8-1/4 R65
18 1-1/4 24 7-3/4 8-1/2 R69
20 1-1/4 24 8-1/4 9-1/4 R73
22 1-1/2 24 8-3/4 9-3/4 R81
24 1-1/2 24 9-1/4 10-1/4 R77