Cast Iron Flanges - ASME/ANSI Class 125 

ASME/ANSI B16.1 - 1998 - Cast Iron Pipe Flanges and Flanged Fittings - Class 125 Flanges - outside and inside diameters, bolt circles, numbers and diameters of bolts.

Cast Iron Flanges - ASME/ANSI 125 lb 
Pipe Size
(inches)
Outside Diameter
(inches)
Number of Bolt Holes Bolt Hole Diameter
(inches)
Bolt Circle
(inches)
1 4-1/4 4 5/8 3-1/8
1-1/4 4-5/8 4 5/8 3-1/2
1-1/2 5 4 5/8 3-7/8
2 6 4 3/4 4-3/4
2-1/2 7 4 3/4 5-1/2
3 7-1/2 4 3/4 6
3-1/2 8-1/2 8 3/4 7
4 9 8 3/4 7-1/2
5 10 8 7/8 8-1/2
6 11 8 7/8 9-1/2
8 13-1/2 8 7/8 11-3/4
10 16 12 1 14-1/4
12 19 12 1 17
14 21 12 1-1/8 18-3/4
16 23-1/2 16 1-1/8 21-1/4
18 25 16 1-1/4 22-3/4
20 27-1/2 20 1-1/4 25
24 32 20 1-3/8 29-1/2
30 38-3/4 28 1-3/8 36
36 46 32 1-5/8 42-3/4
42 53 36 1-5/8 49-1/2
48 59-1/2 44 1-5/8 56
54 66-1/4 44 2 62-3/4
60 73 52 2 69-1/4
72 86-1/2 60 2 82-1/2
84 99-3/4 64 2-1/4 95-1/2
96 113-1/4 68 2-1/2 108-1/2

                      1) Recommended bolts are 1/8 smaller than the nominal bolt hole diameters shown.

HomeSite TermsOrdering InformationContact UsPlace Order