ANSI B16.5 Class 300 Flanges Dimensions
ANSI B 16.5 DIMENSIONS OF CLASS 300 FLANGES in mm
Nominal
Pipe Size
Flange
Dia
‘O’
Dia of
Bolt Circle
‘A’
Dia of Bolt Holes
‘D’
No. of
Holes
Thickness of Flange
‘C’
Diameter at Weld Bevel Dia of Hub
‘E’
Length Through Hub Bore ‘B’ Dia of
R/F
R
Depth of
Socket
F
Length
of
Threading
S/O & S/W
Y
W/N
Y
L/J
Y
S/O & S/W
B
L/J
B
1/2” 15 95.2 66.7 15.9 4 14.3 21.3 38.1 22.2 52.4 22.2 22.3 22.9 34.9 9.5 15.9
3/4” 20 117.5 82.5 19.0 4 15.9 26.7 47.6 25.4 57.1 25.4 27.7 28.2 42.9 11.1 15.9
1” 25 123.8 88.9 19.0 4 17.5 33.5 54.0 27.0 61.9 27.0 34.5 35.0 50.8 12.7 17.5
1 ¼” 32 133.3 98.4 19.0 4 19.0 42.2 63.5 27.0 65.1 27.0 43.2 43.7 63.5 14.3 20.6
1 ½” 40 155.6 114.3 22.2 4 20.6 48.3 69.8 30.2 68.3 30.2 49.5 50.0 73.0 15.9 22.2
2” 50 165.1 127.0 19.0 8 22.2 60.4 84.1 33.3 69.8 33.3 62.0 62.5 92.1 17.5 25.4
2 ½” 65 190.5 149.2 22.2 8 25.4 73.1 100.0 38.1 76.2 38.1 74.7 75.4 104.8 19.0 28.6
3” 80 209.5 168.3 22.2 8 28.6 88.9 117.5 42.9 79.4 42.9 90.7 91.4 127.0 20.6 30.2
3 ½” 90 228.5 184.2 22.2 8 30.2 101.6 133.4 44.5 81.0 44.5 103.4 104.1 140.0 20.6 31.7
4” 100 254.0 200.0 22.2 8 31.8 114.3 146.0 47.6 85.7 47.6 116.1 116.8 157.2 23.8 33.3
5” 125 279.4 234.9 22.2 8 34.9 141.2 177.8 50.8 98.4 50.8 143.8 144.5 185.7 36.5
6” 150 317.5 269.9 22.2 12 36.5 168.4 206.4 52.4 98.4 52.4 170.7 171.4 215.9 39.7
8” 200 381.0 330.2 25.4 12 41.3 219.2 260.3 61.9 111.1 61.9 221.5 222.2 269.9 44.4
10” 250 444.5 387.3 28.6 16 47.6 273.0 320.7 66.7 117.5 95.2 276.3 277.4 323.8 49.2
12” 300 520.7 450.8 31.7 16 50.8 323.8 374.6 73.0 130.2 101.6 327.1 328.2 381.0 55.6
14” 350 584.2 514.3 31.7 20 54.0 355.6 425.4 76.2 142.9 111.1 359.1 360.2 412.7 57.1
16” 400 647.7 571.5 34.9 20 57.2 406.4 482.6 82.5 146.0 120.6 410.5 411.2 469.9 63.5
18” 450 711.2 628.5 34.9 24 60.3 457.2 533.4 88.9 158.7 130.2 461.8 462.3 533.4 68.3
20” 500 774.7 685.8 34.9 24 63.5 508.0 587.4 95.2 161.9 139.7 513.1 514.3 584.2 73.0
24” 600 914.4 812.8 41.3 24 69.8 609.6 701.7 106.4 168.3 152.4 615.9 615.9 692.1 82.5