ANSI B16.5 FORGED FLANGES  Unit: mm
Class 400 Normal Flanges
Nominal Pipe Size Outside Diam Diam of Base of Hub 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
Welding Neck  Slip-on  Lap Joint Counter Bore Min. Welding Neck  Slip-on and Threaded  Lap Joint Bolt Circle Diam Number of  Holes Number of  Holes Diam of Bolts (inch)  Stud Bolt Length Welding Neck Slip-on  and Threaded  Lap Joint Blind
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 95 38.1 35.1 14.2 See Note (1) To be Specified by purchase. 22.4 22.9 23.6 52.3 22.4 22.4 21.3 3 15.7 66.5 4 15.7 ½ 76.2 69.9 76.2 1.36 3.00 0.91 2.00 0.80 1.80 0.91 2.00 ½
¾  117 47.8 42.9 15.7 27.7 28.2 29.0 57.2 25.4 25.4 26.7 3 15.7 82.6 4 19.1 5/8 88.9 82.6 88.9 1.59 3.50 1.36 3.00 1.36 3.00 1.40 3.00 ¾ 
1 124 53.8 50.8 17.5 34.5 35.1 35.8 62.0 26.9 26.9 33.5 3 17.5 88.9 4 19.1 5/8 88.9 82.6 88.9 1.81 4.00 1.59 3.50 1.59 3.50 1.70 3.80 1
1 ¼  133 63.5 63.5 20.6 43.2 43.7 44.5 66.5 28.4 28.4 42.2 4.8 20.6 98.6 4 19.1 5/8 95.3 88.9 95.3 2.50 5.50 2.10 4.60 2.04 4.50 2.27 5.00 1 ¼ 
1 ½  155 69.9 73.2 22.4 49.5 50.0 50.5 69.9 31.8 31.8 48.3 6.4 22.4 114.3 4 22.4 ¾ 108.0 101.6 108.0 3.63 8.00 3.10 6.80 2.95 6.50 3.40 7.50 1 ½ 
2 165 84.1 91.9 25.4 62.0 62.5 63.5 73.2 36.6 36.6 60.5 7.9 28.4 127.0 8 19.1 5/8 108.0 101.6 108.0 4.54 10.00 3.63 8.00 3.63 8.00 4.40 9.70 2
2 ½  191 100.1 104.6 58.4 74.7 75.4 76.2 79.2 41.1 41.1 73.2 7.9 31.8 149.4 8 22.4 ¾ 120.7 114.3 120.7 6.35 14.00 5.44 12.00 4.99 11.00 6.80 15.00 2 ½ 
3 210 117.3 127.0 31.8 90.7 91.4 92.2 82.6 46.0 46.0 88.9 9.7 35.1 168.1 8 22.4 ¾ 127.0 120.7 127.0 8.17 18.00 7.26 16.00 6.35 14.00 8.90 19.60 3
3 ½  229 133.4 139.7 35.1 103.4 104.1 104.9 85.9 49.3 49.3 101.6 9.7 39.6 184.2 8 25.4 7/8 139.7 133.4 139.7 11.80 26.00 9.53 21.00 9.08 20.00 13.17 29.00 3 ½ 
4 254 146.1 157.2 35.1 116.1 116.8 117.6 88.9 50.8 50.8 114.3 11.2 36.6 200.2 8 7/8 7/8 139.7 133.4 139.7 13.61 30.00 10.89 24.00 9.98 22.00 14.40 31.70 4
5 279 177.8 185.7 38.1 143.8 144.5 144.5 101.6 53.8 53.8 141.2 11.2 42.9 235.0 8 25.4 7/8 146.1 139.7 146.1 17.69 39.00 14.07 31.00 13.15 29.00 19.50 43.00 5
6 318 206.2 215.9 41.1 170.7 171.5 171.5 103.1 57.2 57.2 168.4 12.7 46.0 269.7 12 25.4 7/8 152.4 146.1 152.4 22.23 49.00 19.98 44.00 16.78 37.00 27.67 61.00 6
8 381 260.4 269.7 47.8 221.5 222.3 22.3 117.3 68.3 68.3 219.2 12.7 50.8 330.2 12 28.4 1 171.5 165.1 171.5 35.38 78.00 30.40 67.00 26.16 59.00 45.36 100.00 8
10 445 320.5 323.9 53.8 276.4 277.4 276.4 124.0 73.2 101.6 273.1 12.7 55.6 387.4 16 31.8 1 1/8 190.5 184.2 190.5 49.89 110.00 41.28 91.00 43.09 95.00 68.00 150.00 10
12 521 374.7 381.0 57.2 327.2 328.2 328.7 136.7 79.2 108.0 323.9 12.7 60.5 450.9 16 35.1 1 ¼ 203.2 196.9 203.2 72.57 160.00 59.02 130.00 68.95 152.00 98.00 216.00 12
14 584 425.5 412.8 60.5 359.2 360.2 360.4 149.4 84.1 117.3 355.6 12.7 63.5 514.4 20 35.1 1 ¼ 209.6 203.2 209.6 105.69 233.00 81.72 180.00 95.25 210.00 131.66 290.00 14
16 648 482.6 469.9 63.5 410.5 411.2 411.2 152.4 93.7 127.0 406.4 12.7 68.3 571.5 20 38.1 1 3/8 222.3 215.9 222.3 133.30 294.00 106.69 235.00 127.00 280.00 167.00 368.00 16
18 711 533.4 533.4 66.5 461.8 462.3 462.0 165.1 98.6 136.7 457.2 12.7 69.9 628.7 24 38.1 1 3/8 228.6 222.3 228.6 158.90 350.30 129.39 285.30 156.49 345.00 206.57 455.40 18
20 775 587.2 584.2 69.9 513.1 514.4 512.8 168.1 101.6 146.1 508.0 12.7 73.2 685.8 24 41.1 1 ½  241.3 235.0 247.7 193.00 425.50 152.00 335.00 190.51 420.00 261.00 575.40 20
24 914 701.5 692.2 76.2 616.0 616.0 614.4 174.8 114.3 158.8 609.6 12.7 82.6 812.8 24 47.8 1 ¾ 266.7 260.4 279.4 281.48 620.50 231.54 510.50 278.96 615.00 395.00 870.80 24
Notes:
(1) For the inside diameter of pipes (corresponding to Bore (B1) of welding Neck Flanges), refer to page 56.
(2) Class 400 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 rapered 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 3 1/2" are the same as for class 600 Flanges.