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ASME ANSI Flange Sizes

(PETERSEN DOES NOT SELL PIPE OR ASME ANSI FLANGES)

Nominal Pipe Size NPS (inches) Class 150
Diameter of Flange (inches) No. of Bolts Diameter of Bolts (inches) Bolt Circle (inches)
1/4 3-3/8 4 1/2 2-1/4
1/2 3-1/2 4 1/2 2-3/8
3/4 3-7/8 4 1/2 2-3/4
1 4-1/4 4 1/2 3-1/8
1-1/4 4-5/8 4 1/2 3-1/2
1-1/2 5 4 1/2 3-7/8
2 6 4 5/8 4-3/4
2-1/2 7 4 5/8 5-1/2
3 7-1/2 4 5/8 6
3-1/2 8-1/2 8 5/8 7
4 9 8 5/8 7-1/2
5 10 8 3/4 8-1/2
6 11 8 3/4 9-1/2
8 13-1/2 8 3/4 11-3/4
10 16 12 7/8 14-1/4
12 19 12 7/8 17
14 21 12 1 18-3/4
16 23-1/2 16 1 21-1/4
18 25 16 1-1/8 22-3/4
20 27-1/2 20 1-1/8 25
24 32 20 1-1/4 29-1/2
Nominal Pipe Size NPS (inches) Class 300
Diameter of Flange (inches) No. of Bolts Diameter of Bolts (inches) Bolt Circle (inches)
1/4 3-3/8 4 1/2 2-1/4
1/2 3-3/4 4 1/2 2-5/8
3/4 4-5/8 4 5/8 3-1/4
1 4-7/8 4 5/8 3-1/2
1-1/4 5-1/4 4 5/8 3-7/8
1-1/2 6-1/8 4 3/4 4-1/2
2 6-1/2 8 5/8 5
2-1/2 7-1/2 8 3/4 5-7/8
3 8-1/4 8 3/4 6-5/8
3-1/2 9 8 3/4 7-1/4
4 10 8 3/4 7-7/8
5 11 8 3/4 9-1/4
6 12-1/2 12 3/4 10-5/8
8 15 12 7/8 13
10 17-1/2 16 1 15-1/4
12 20-1/2 16 1-1/8 17-3/4
14 23 20 1-1/8 20-1/4
16 25-1/2 20 1-1/4 22-1/2
18 28 24 1-1/4 24-3/4
20 30-1/2 24 1-1/4 27
24 36 24 1-1/2 32
Nominal Pipe Size NPS (inches) Class 400
Diameter of Flange (inches) No. of Bolts Diameter of Bolts (inches) Bolt Circle (inches)
1/4 3-3/8 4 1/2 2-1/4
1/2 3-3/4 4 1/2 2-5/8
3/4 4-5/8 4 5/8 3-1/4
1 4-7/8 4 5/8 3-1/2
1-1/4 5-1/4 4 5/8 3-7/8
1-1/2 6-1/8 4 3/4 4-1/2
2 6-1/2 8 5/8 5
2-1/2 7-1/2 8 3/4 5-7/8
3 8-1/4 8 3/4 6-5/8
3-1/2 9 8 7/8 7-1/4
4 10 8 7/8 7-7/8
5 11 8 7/8 9-1/4
6 12-1/2 12 7/8 10-5/8
8 15 12 1 13
10 17-1/2 16 1-1/8 15-1/4
12 20-1/2 16 1-1/4 17-3/4
14 23 20 1-1/4 20-1/4
16 25-1/2 20 1-3/8 22-1/2
18 28 24 1-3/8 24-3/4
20 30-1/2 24 1-1/2 27
24 36 24 1-3/4 32
Nominal Pipe Size NPS (inches) Class 600
Diameter of Flange (inches) No. of Bolts Diameter of Bolts (inches) Bolt Circle (inches)
1/4 3-3/8 4 1/2 2-1/4
1/2 3-3/4 4 1/2 2-5/8
3/4 4-5/8 4 5/8 3-1/4
1 4-7/8 4 5/8 3-1/2
1-1/4 5-1/4 4 5/8 3-7/8
1-1/2 6-1/8 4 3/4 4-1/2
2 6-1/2 8 5/8 5
2-1/2 7-1/2 8 3/4 5-7/8
3 8-1/4 8 3/4 6-5/8
3-1/2 9 8 7/8 7-1/4
4 10-3/4 8 7/8 8-1/2
5 13 8 1 10-1/2
6 14 12 1 11-1/2
8 16-1/2 12 1-1/8 13-3/4
10 20 16 1-1/4 17
12 22 20 1-1/4 19-1/4
14 23-3/4 20 1-3/8 20-3/4
16 27 20 1-1/2 23-3/4
18 29-1/4 20 1-5/8 25-3/4
20 32 24 1-5/8 28-1/2
24 37 24 1-7/8 33
Nominal Pipe Size NPS (inches) Class 900
Diameter of Flange (inches) No. of Bolts Diameter of Bolts (inches) Bolt Circle (inches)
1/2 4-3/4 4 3/4 3-1/4
3/4 5-1/8 4 3/4 3-1/2
1 5-7/8 4 7/8 4
1-1/4 6-1/4 4 7/8 4-3/8
1-1/2 7 4 1 4-7/8
2 8-1/2 8 7/8 6-1/2
2-1/2 9-5/8 8 1 7-1/2
3 9-1/2 8 7/8 7-1/2
4 11-1/2 8 1-1/8 9-1/4
5 13-3/4 8 1-1/4 11
6 15 12 1-1/8 12-1/2
8 18-1/2 12 1-3/8 15-1/2
10 21-1/2 16 1-3/8 18-1/2
12 24 20 1-3/8 21
14 25-1/4 20 1-1/2 22
16 27-3/4 20 1-5/8 24-1/2
18 31 20 1-7/8 27
20 33-3/4 20 2 29-1/2
24 41 20 2-1/2 35-1/2
Nominal Pipe Size NPS (inches) Class 1500
Diameter of Flange (inches) No. of Bolts Diameter of Bolts (inches) Bolt Circle (inches)
1/2 4-3/4 4 3/4 3-1/4
3/4 5-1/8 4 3/4 3-1/2
1 5-7/8 4 7/8 4
1-1/4 6-1/4 4 7/8 4-3/8
1-1/2 7 4 1 4-7/8
2 8-1/2 8 7/8 6-1/2
2-1/2 9-5/8 8 1 7-1/2
3 10-1/2 8 1-1/8 8
4 12-1/4 8 1-1/4 9-1/2
5 14-3/4 8 1-1/2 11-1/2
6 15-1/2 12 1-3/8 12-1/2
8 19 12 1-5/8 15-1/2
10 23 12 1-7/8 19
12 26-1/2 16 2 22-1/2
14 29-1/2 16 2-1/4 25
16 32-1/2 16 2-1/2 27-3/4
18 36 16 2-3/4 30-1/2
20 38-3/4 16 3 32-3/4
24 46 16 3-1/2 39
Nominal Pipe Size NPS (inches) Class 2500
Diameter of Flange (inches) No. of Bolts Diameter of Bolts (inches) Bolt Circle (inches)
1/2 5-1/4 4 3/4 3-1/2
3/4 5-1/2 4 3/4 3-3/4
1 6-1/4 4 7/8 4-1/4
1-1/4 7-1/4 4 1 5-1/8
1-1/2 8 4 1-1/8 5-3/4
2 9-1/4 8 1 6-3/4
2-1/2 10-1/2 8 1-1/8 7-3/4
3 12 8 1-1/4 9
4 14 8 1-1/2 10-3/4
5 16-1/2 8 1-3/4 12-3/4
6 19 8 2 14-1/2
8 21-3/4 12 2 17-1/4
10 26-1/2 12 2-1/2 21-1/4
12 30 12 2-3/4 24-3/8