Flanges - ASME/ANSI B16.5 Flanges and Bolt Dimensions - Class 150 to 2500
Diameters and bolt circles for standard ASME B16.5 flanges - 1/4 to 24 inches - Class 150 to 2500.
The pipe size and the required pressure class for the application determine the flange dimensions. According to publications from organizations like ASME, MSS, API, and others, flanges are standardized.
ASME/ANSI B16.5 provides:
weld neck
slip-on
socket weld
threaded
lap joint
blind
Dimensions for weld neck slip-on socket weld threaded lap joint blind flanges for pipes between 1/2" and 24" in classes between 150 and 2500. It should be noted that the ratings use terminology like ASME class xx or API xxxx.
The connected pipe's schedule (thickness) must generally be specified when it is butt welded to the flange. Wall thickness has no bearing on socket welded and threaded connections, which should only need the OD.
|
Nominal Pipe Size NPS (inches) |
Class 150 |
||||
|
Diameter of Flange (inches) |
No. of Bolts |
Diameter of Bolts (inches) |
Diameter of Bolt Holes (inches) |
Bolt Circle (inches) |
|
|
1/4 |
3-3/8 |
4 |
1/2 |
0.62 |
2-1/4 |
|
1/2 |
3-1/2 |
4 |
1/2 |
0.62 |
2-3/8 |
|
3/4 |
3-7/8 |
4 |
1/2 |
0.62 |
2-3/4 |
|
1 |
4-1/4 |
4 |
1/2 |
0.62 |
3-1/8 |
|
1-1/4 |
4-5/8 |
4 |
1/2 |
0.62 |
3-1/2 |
|
1-1/2 |
5 |
4 |
1/2 |
0.62 |
3-7/8 |
|
2 |
6 |
4 |
5/8 |
0.75 |
4-3/4 |
|
2-1/2 |
7 |
4 |
5/8 |
0.75 |
5-1/2 |
|
3 |
7-1/2 |
4 |
5/8 |
0.75 |
6 |
|
3-1/2 |
8-1/2 |
8 |
5/8 |
0.75 |
7 |
|
4 |
9 |
8 |
5/8 |
0.75 |
7-1/2 |
|
5 |
10 |
8 |
3/4 |
0.88 |
8-1/2 |
|
6 |
11 |
8 |
3/4 |
0.88 |
9-1/2 |
|
8 |
13-1/2 |
8 |
3/4 |
0.88 |
11-3/4 |
|
10 |
16 |
12 |
7/8 |
1 |
14-1/4 |
|
12 |
19 |
12 |
7/8 |
1 |
17 |
|
14 |
21 |
12 |
1 |
1.12 |
18-3/4 |
|
16 |
23-1/2 |
16 |
1 |
1.12 |
21-1/4 |
|
18 |
25 |
16 |
1-1/8 |
1.25 |
22-3/4 |
|
20 |
27-1/2 |
20 |
1-1/8 |
1.25 |
25 |
|
24 |
32 |
20 |
1-1/4 |
1.38 |
29-1/2 |
1 inch = 25.4 mm
|
Nominal Pipe Size NPS (inches) |
Class 300 |
||||
|
Diameter of Flange (inches) |
No. of Bolts |
Diameter of Bolts (inches) |
Diameter of Bolt Holes (inches) |
Bolt Circle (inches) |
|
|
1/4 |
3-3/8 |
4 |
1/2 |
0.62 |
2-1/4 |
|
1/2 |
3-3/4 |
4 |
1/2 |
0.62 |
2-5/8 |
|
3/4 |
4-5/8 |
4 |
5/8 |
0.75 |
3-1/4 |
|
1 |
4-7/8 |
4 |
5/8 |
0.75 |
3-1/2 |
|
1-1/4 |
5-1/4 |
4 |
5/8 |
0.75 |
3-7/8 |
|
1-1/2 |
6-1/8 |
4 |
3/4 |
0.88 |
4-1/2 |
|
2 |
6-1/2 |
8 |
5/8 |
0.75 |
5 |
|
2-1/2 |
7-1/2 |
8 |
3/4 |
0.88 |
5-7/8 |
|
3 |
8-1/4 |
8 |
3/4 |
0.88 |
6-5/8 |
|
3-1/2 |
9 |
8 |
3/4 |
0.88 |
7-1/4 |
|
4 |
10 |
8 |
3/4 |
0.88 |
7-7/8 |
|
5 |
11 |
8 |
3/4 |
0.88 |
9-1/4 |
|
6 |
12-1/2 |
12 |
3/4 |
0.88 |
10-5/8 |
|
8 |
15 |
12 |
7/8 |
1 |
13 |
|
10 |
17-1/2 |
16 |
1 |
1.12 |
15-1/4 |
|
12 |
20-1/2 |
16 |
1-1/8 |
1.25 |
17-3/4 |
|
14 |
23 |
20 |
1-1/8 |
1.25 |
20-1/4 |
|
16 |
25-1/2 |
20 |
1-1/4 |
1.38 |
22-1/2 |
|
18 |
28 |
24 |
1-1/4 |
1.38 |
24-3/4 |
|
20 |
30-1/2 |
24 |
1-1/4 |
1.38 |
27 |
|
24 |
36 |
24 |
1-1/2 |
1.62 |
32 |
|
Nominal Pipe Size NPS (inches) |
Class 400 |
||||
|
Diameter of Flange (inches) |
No. of Bolts |
Diameter of Bolts (inches) |
Diameter of Bolt Holes (inches) |
Bolt Circle (inches) |
|
|
1/4 |
3-3/8 |
4 |
1/2 |
0.62 |
2-1/4 |
|
1/2 |
3-3/4 |
4 |
1/2 |
0.62 |
2-5/8 |
|
3/4 |
4-5/8 |
4 |
5/8 |
0.75 |
3-1/4 |
|
1 |
4-7/8 |
4 |
5/8 |
0.75 |
3-1/2 |
|
1-1/4 |
5-1/4 |
4 |
5/8 |
0.75 |
3-7/8 |
|
1-1/2 |
6-1/8 |
4 |
3/4 |
0.88 |
4-1/2 |
|
2 |
6-1/2 |
8 |
5/8 |
0.75 |
5 |
|
2-1/2 |
7-1/2 |
8 |
3/4 |
0.88 |
5-7/8 |
|
3 |
8-1/4 |
8 |
3/4 |
0.88 |
6-5/8 |
|
3-1/2 |
9 |
8 |
7/8 |
1 |
7-1/4 |
|
4 |
10 |
8 |
7/8 |
1 |
7-7/8 |
|
5 |
11 |
8 |
7/8 |
1 |
9-1/4 |
|
6 |
12-1/2 |
12 |
7/8 |
1 |
10-5/8 |
|
8 |
15 |
12 |
1 |
1.12 |
13 |
|
10 |
17-1/2 |
16 |
1-1/8 |
1.25 |
15-1/4 |
|
12 |
20-1/2 |
16 |
1-1/4 |
1.38 |
17-3/4 |
|
14 |
23 |
20 |
1-1/4 |
1.38 |
20-1/4 |
|
16 |
25-1/2 |
20 |
1-3/8 |
1.5 |
22-1/2 |
|
18 |
28 |
24 |
1-3/8 |
1.5 |
24-3/4 |
|
20 |
30-1/2 |
24 |
1-1/2 |
1.62 |
27 |
|
24 |
36 |
24 |
1-3/4 |
1.88 |
32 |
|
Nominal Pipe Size NPS (inches) |
Class 600 |
||||
|
Diameter of Flange (inches) |
No. of Bolts |
Diameter of Bolts (inches) |
Diameter of Bolt Holes (inches) |
Bolt Circle (inches) |
|
|
1/4 |
3-3/8 |
4 |
1/2 |
0.62 |
2-1/4 |
|
1/2 |
3-3/4 |
4 |
1/2 |
0.62 |
2-5/8 |
|
3/4 |
4-5/8 |
4 |
5/8 |
0.75 |
3-1/4 |
|
1 |
4-7/8 |
4 |
5/8 |
0.75 |
3-1/2 |
|
1-1/4 |
5-1/4 |
4 |
5/8 |
0.75 |
3-7/8 |
|
1-1/2 |
6-1/8 |
4 |
3/4 |
0.88 |
4-1/2 |
|
2 |
6-1/2 |
8 |
5/8 |
0.75 |
5 |
|
2-1/2 |
7-1/2 |
8 |
3/4 |
0.88 |
5-7/8 |
|
3 |
8-1/4 |
8 |
3/4 |
0.88 |
6-5/8 |
|
3-1/2 |
9 |
8 |
7/8 |
1 |
7-1/4 |
|
4 |
10-3/4 |
8 |
7/8 |
1 |
8-1/2 |
|
5 |
13 |
8 |
1 |
1.12 |
10-1/2 |
|
6 |
14 |
12 |
1 |
1.12 |
11-1/2 |
|
8 |
16-1/2 |
12 |
1-1/8 |
1.25 |
13-3/4 |
|
10 |
20 |
16 |
1-1/4 |
1.38 |
17 |
|
12 |
22 |
20 |
1-1/4 |
1.38 |
19-1/4 |
|
14 |
23-3/4 |
20 |
1-3/8 |
1.5 |
20-3/4 |
|
16 |
27 |
20 |
1-1/2 |
1.62 |
23-3/4 |
|
18 |
29-1/4 |
20 |
1-5/8 |
1.75 |
25-3/4 |
|
20 |
32 |
24 |
1-5/8 |
1.75 |
28-1/2 |
|
24 |
37 |
24 |
1-7/8 |
2 |
33 |
|
Nominal Pipe Size NPS (inches) |
Class 900 |
||||
|
Diameter of Flange (inches) |
No. of Bolts |
Diameter of Bolts (inches) |
Diameter of Bolt Holes (inches) |
Bolt Circle (inches) |
|
|
1/2 |
4-3/4 |
4 |
3/4 |
0.88 |
3-1/4 |
|
3/4 |
5-1/8 |
4 |
3/4 |
0.88 |
3-1/2 |
|
1 |
5-7/8 |
4 |
7/8 |
1 |
4 |
|
1-1/4 |
6-1/4 |
4 |
7/8 |
1 |
4-3/8 |
|
1-1/2 |
7 |
4 |
1 |
1.12 |
4-7/8 |
|
2 |
8-1/2 |
8 |
7/8 |
1 |
6-1/2 |
|
2-1/2 |
9-5/8 |
8 |
1 |
1.12 |
7-1/2 |
|
3 |
9-1/2 |
8 |
7/8 |
1 |
7-1/2 |
|
4 |
11-1/2 |
8 |
1-1/8 |
1.25 |
9-1/4 |
|
5 |
13-3/4 |
8 |
1-1/4 |
1.38 |
11 |
|
6 |
15 |
12 |
1-1/8 |
1.25 |
12-1/2 |
|
8 |
18-1/2 |
12 |
1-3/8 |
1.5 |
15-1/2 |
|
10 |
21-1/2 |
16 |
1-3/8 |
1.5 |
18-1/2 |
|
12 |
24 |
20 |
1-3/8 |
1.5 |
21 |
|
14 |
25-1/4 |
20 |
1-1/2 |
1.62 |
22 |
|
16 |
27-3/4 |
20 |
1-5/8 |
1.75 |
24-1/2 |
|
18 |
31 |
20 |
1-7/8 |
2 |
27 |
|
20 |
33-3/4 |
20 |
2 |
2.12 |
29-1/2 |
|
24 |
41 |
20 |
2-1/2 |
2.62 |
35-1/2 |
|
Nominal Pipe Size NPS (inches) |
Class 1500 |
||||
|
Diameter of Flange (inches) |
No. of Bolts |
Diameter of Bolts (inches) |
Diameter of Bolt Holes (inches) |
Bolt Circle (inches) |
|
|
1/2 |
4-3/4 |
4 |
3/4 |
0.88 |
3-1/4 |
|
3/4 |
5-1/8 |
4 |
3/4 |
0.88 |
3-1/2 |
|
1 |
5-7/8 |
4 |
7/8 |
1 |
4 |
|
1-1/4 |
6-1/4 |
4 |
7/8 |
1 |
4-3/8 |
|
1-1/2 |
7 |
4 |
1 |
1.12 |
4-7/8 |
|
2 |
8-1/2 |
8 |
7/8 |
1 |
6-1/2 |
|
2-1/2 |
9-5/8 |
8 |
1 |
1.12 |
7-1/2 |
|
3 |
10-1/2 |
8 |
1-1/8 |
1.25 |
8 |
|
4 |
12-1/4 |
8 |
1-1/4 |
1.38 |
9-1/2 |
|
5 |
14-3/4 |
8 |
1-1/2 |
1.62 |
11-1/2 |
|
6 |
15-1/2 |
12 |
1-3/8 |
1.5 |
12-1/2 |
|
8 |
19 |
12 |
1-5/8 |
1.75 |
15-1/2 |
|
10 |
23 |
12 |
1-7/8 |
2 |
19 |
|
12 |
26-1/2 |
16 |
2 |
2.12 |
22-1/2 |
|
14 |
29-1/2 |
16 |
2-1/4 |
2.38 |
25 |
|
16 |
32-1/2 |
16 |
2-1/2 |
2.62 |
27-3/4 |
|
18 |
36 |
16 |
2-3/4 |
2.88 |
30-1/2 |
|
20 |
38-3/4 |
16 |
3 |
3.12 |
32-3/4 |
|
24 |
46 |
16 |
3-1/2 |
3.62 |
39 |
|
Nominal Pipe Size NPS (inches) |
Class 2500 |
||||
|
Diameter of Flange (inches) |
No. of Bolts |
Diameter of Bolts (inches) |
Diameter of Bolt Holes (inches) |
Bolt Circle (inches) |
|
|
1/2 |
5-1/4 |
4 |
3/4 |
0.88 |
3-1/2 |
|
3/4 |
5-1/2 |
4 |
3/4 |
0.88 |
3-3/4 |
|
1 |
6-1/4 |
4 |
7/8 |
1 |
4-1/4 |
|
1-1/4 |
7-1/4 |
4 |
1 |
1.12 |
5-1/8 |
|
1-1/2 |
8 |
4 |
1-1/8 |
1.25 |
5-3/4 |
|
2 |
9-1/4 |
8 |
1 |
1.12 |
6-3/4 |
|
2-1/2 |
10-1/2 |
8 |
1-1/8 |
1.25 |
7-3/4 |
|
3 |
12 |
8 |
1-1/4 |
1.38 |
9 |
|
4 |
14 |
8 |
1-1/2 |
1.62 |
10-3/4 |
|
5 |
16-1/2 |
8 |
1-3/4 |
1.88 |
12-3/4 |
|
6 |
19 |
8 |
2 |
2.12 |
14-1/2 |
|
8 |
21-3/4 |
12 |
2 |
2.12 |
17-1/4 |
|
10 |
26-1/2 |
12 |
2-1/2 |
2.62 |
21-1/4 |
|
12 |
30 |
12 |
2-3/4 |
2.88 |
24-3/8 |
