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

ANSI 400-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 3 3 R11
3/4 5/8 4 3-1/2 3-1/2 R13
1 5/8 4 3-1/2 3-1/2 R16
1-1/4 5/8 4 3-3/4 3-3/4 R18
1-1/2 3/4 4 4-1/4 4-1/4 R20
2 5/8 8 4-1/4 4-1/4 R23
2-1/2 3/4 8 4-3/4 4-3/4 R26
3 3/4 8 5 5 R31
3-1/2 7/8 8 5-1/2 5-1/2 R34
4 7/8 8 5-1/2 5-1/2 R37
5 7/8 8 5-3/4 5-3/4 R41
6 7/8 12 6 6 R45
8 1 12 6-3/4 6-3/4 R49
10 1-1/8 16 7-1/2 7-1/2 R53
12 1-1/4 16 8 8 R57
14 1-1/4 20 8-1/4 8-1/4 R61
16 1-3/8 20 8-3/4 8-3/4 R65
18 1-3/8 24 9 9 R69
20 1-1/2 24 9-1/2 9-1/2 R73
22 1-5/8 24 10 10-1/2 R81
24 1-3/4 24 10-1/2 11 R77