ANSI B16.5 FORGED FLANGES  Unit: mm
Class 900 Normal Flanges
Nominal Pipe Size Outside Diam Diam  O.D. of Raised face Thick-ness  BORE LENGTH THRU HUB Diam of Hub of Bevel Radius of Filet thread length Drilling Bolting Approximate Weight Nominal Pipe Size
Bolt Circle Diam Number of Holes Diam of Holes Diam of Bolts (inch)  Stud Bolt Length Welding Neck Sip-on and Threaded Lap Joint Blind
of Base of Hub Welding Neck  Slip-on  Lap Joint Counter Bore Min.  Welding Neck  Slip-on Threaded  Lap 
Joint 0.25 Raised Face Male female tongue-Groove Ring Joint
D X G t B1 B2 B3 B T1 T2 T3 A R Q Kg Ib Kg Ib Kg Ib Kg Ib
½ 121 38.1 35.1 22.4 See Note (1) to be Specified by purchaser. 22.4 22.9 23.6 60.5 31.8 31.8 21.3 3 22.4 82.6 4 22.4 ¾  108.0 101.6 108.0 2.10 4.60 1.81 4.00 1.81 4.00 1.90 4.20 ½
¾  130 44.5 42.9 25.4 27.7 28.2 29.0 69.9 35.1 35.1 26.7 3 25.4 88.9 4 22.4 ¾ 114.3 108.0 114.3 2.72 6.00 2.40 5.30 2.30 5.00 2.70 6.00 ¾ 
1 149 52.3 50.8 28.4 34.5 35.1 35.8 73.2 41.1 41.1 33.5 3 28.4 101.6 4 25.4 7/8 127.0 120.7 127.0 3.86 8.50 3.41 7.50 3.40 7.50 4.09 9.00 1
1 ¼  159 63.5 63.5 28.4 43.2 43.7 44.5 73.2 41.1 41.1 42.2 4.8 30.2 111.3 4 25.4 7/8 127.0 120.7 127.0 4.54 10.00 4.10 9.00 4.09 9.00 4.54 10.00 1 ¼ 
1 ½  178 69.9 73.2 31.8 49.5 50.0 50.5 82.6 44.5 44.5 48.3 6.4 31.8 124.0 4 28.4 1 139.7 133.4 139.7 5.90 13.00 5.45 12.00 5.40 11.90 5.90 13.00 1 ½ 
2 216 104.6 91.9 38.1 62.0 62.5 63.5 101.6 57.2 57.2 60.5 7.9 38.1 165.1 8 25.4 7/8 146.1 139.7 146.1 10.89 24.00 9.98 22.00 9.53 21.00 11.34 25.00 2
2 ½  244 124.0 104.6 41.1 74.7 75.4 76.2 104.6 63.5 63.5 73.2 7.9 47.8 190.5 8 28.4 1 158.8 152.4 158.8 16.33 36.00 15.80 34.80 13.15 29.00 16.00 35.30 2 ½ 
3 241 127.0 127.0 38.1 90.7 91.4 92.2 101.6 53.8 53.8 88.9 9.7 14.1 190.5 8 25.4  7/8 146.1 139.7 146.1 15.00 33.00 11.80 26.00 11.34 25.00 13.17 29.00 3
4 292 158.8 157.2 44.5 116.1 116.8 117.6 114.3 69.9 69.9 114.3 11.2 47.8 235.0 8 31.8 1 1/8 171.5 165.1 171.5 23.13 51.00 23.20 51.00 22.60 48.50 24.50 54.00 4
5 349 190.5 185.7 50.8 143.8 144.5 144.5 127.0 79.2 79.2 141.2 11.2 53.8 279.4 8 35.1 1 ¼ 190.5 184.2 190.5 38.50 84.90 37.65 83.00 36.74 81.00 39.46 87.00 5
6 381 235.0 215.9 55.6 170.7 171.5 171.5 139.7 85.9 85.9 168.4 12.7 57.2 317.5 12 31.8 1 1/8 190.5 184.2 196.9 49.89 110.00 48.30 106.50 47.50 104.70 51.50 113.50 6
8 470 298.5 269.7 63.5 221.5 222.3 222.3 162.1 101.6 114.3 219.2 12.7 63.5 393.7 12 38.1 1 3/8 222.3 215.9 222.3 79.45 175.00 75.00 166.30 86.00 189.60 89.00 106.20 8
10 546 368.3 323.9 69.9 276.4 277.4 276.4 184.2 108.0 127.0 273.1 12.7 71.4 469.9 16 38.1 1 3/8 235.0 228.6 235.0 118.04 260.00 111.13 245.00 125.64 277.00 131.54 290.00 10
12 610 419.1 381.0 79.2 327.2 328.2 328.7 200.2 117.3 142.7 323.9 12.7 76.2 533.4 20 38.1 1 3/8 254.0 247.7 254.0 157.00 346.00 146.00 321.80 167.00 368.00 187.00 412.30 12
14 641 450.9 412.8 85.9 359.2 360.2 360.4 212.9 130.0 155.4 355.6 12.7 82.6 558.8 20 41.1 1 ½ 273.1 266.7 292.1 181.60 400.40 172.36 380.00 180.07 397.00 224.07 494.00 14
16 705 508.0 469.9 88.9 410.5 411.2 411.2 215.9 133.4 165.1 406.4 12.7 85.9 616.0 20 44.5 1 5/8 285.8 279.4 298.5 224.73 495.50 192.95 425.40 211.11 465.40 272.40 600.50 16
18 787 565.2 533.4 101.6 461.8 462.3 462.0 228.6 152.4 190.5 457.2 12.7 88.9 685.8 20 50.8 1 7/8 323.9 317.5 333.6 308.72 680.60 272.40 600.50 295.10 650.60 385.90 850.80 18
20 857 622.3 584.2 105.0 513.1 514.4 512.8 247.7 158.8 209.6 508.0 12.7 91.9 749.3 20 53.8 2 349.3 342.9 362.0 376.82 830.70 331.42 730.60 367.74 810.70 488.00 1076.00 20
24 1041 749.3 692.2 139.7 616.0 616.0 614.4 292.1 203.2 266.7 609.6 12.7 101.6 901.7 20 66.5 2 ½ 438.2 431.8 457.2 685.00 1510.00 632.00 1393.30 700.00 1543.00 905.00 1995.00 24
Notes:
(1) For the inside diameter of pipes (corresponding to Bore (B1) of welding Neck Flanges), refer to page 56.
(2) Class 900 flanges except lap Joint will be furnished with 0.25" (6.35mm) raised, face which is not included in Thickness (t)
 and length through Hub (T1), (T2)
(3) For Slip-on, Threaded and lap joint Flanges, the hubs can be shaped either vertical from base to top or tapered within the limits of 7 degrees.
(4) Blind Flanges may be made with the same hub as that used for slip-on Flanges or without hub.
(5) The gasket surface and backside (bearing surface for bolting) are made parallel within 1 degree, to accomplish parallelism.
spot facing is carried out according to MSS SP-9 without reducing thickness(t).
(6) Dimensions of size 1/2" through 2 1/2" are the same as for class 1500 Flanges.