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Type of Flanges
Class & Size Range
Weld Neck Flanges
Slip On Flanges
Socket Weld Flanges
Lap Joint Flanges
Blind Flanges
Threaded Flanges
ASME B 16.47 A
ASME B16.47 B
WN Flange Bore
Figure 8 Blanks
Ring Joint Facing
AWWA Steel Ring
AWWA Steel hub
Approx Weight
Gaskets
Bolts & Nuts
PL Flanges (EN1092.1)
WN Flanges (EN1092.1)
SO Flanges (EN1092.1)
Th Flanges (EN1092.1)
BL Flanges (EN1092.1)
Backing Rings

Weld Neck Flanges 


















f=2mm on class 150 and 300.
  =7mm on class 400 and higher.

Dimesions of  WN flanges - ASME B16.5 

 Class 150
DN  NPS Overall Diameter  Inside Diameter Thickness of Flange(Min.) Overall Lenght  Diameter at Bevel Diameter of Hub Diameter of Face Number of Bolts Diameter of Bolt Holes  Diameter of Bolt Circle 
　 　 A B C D E F G H I J
15  1/2 90 15.8 9.6 46 21.3 30 34.9 4 15.7 60.3
20  3/4 100 20.9 11.2 51 26.7 38 42.9 4 15.7 69.9
25 1 110 26.6 12.7 54 33.4 49 50.8 4 15.7 79.4
32 1 1/4 115 35.1 14.3 56 42.2 59 63.5 4 15.7 88.9
40 1 1/2 125 40.9 15.9 60 48.3 65 73 4 15.7 98.4
50 2 150 52.5 17.5 62 60.3 78 92.1 4 19.1 120.7
65 2 1/2 180 62.7 20.7 68 73 90 104.8 4 19.1 139.7
80 3 190 77.9 22.3 68 88.9 108 127 4 19.1 152.4
90 3 1/2 215 90.1 22.3 70 101.6 122 139.7 8 19.1 177.8
100 4 230 102.3 22.3 75 114.3 135 157.2 8 19.1 190.5
125 5 255 128.2 22.3 87 141.3 164 185.7 8 22.4 215.9
150 6 280 154.1 23.9 87 168.3 192 215.9 8 22.4 241.3
200 8 345 202.7 27 100 219.1 246 269.9 8 22.4 298.5
250 10 405 254.6 28.6 100 273 305 323.8 12 25.4 362
300 12 485 304.8 30.2 113 323.8 365 381 12 25.4 431.8
350 14 535 - 33.4 125 355.6 400 412.8 12 28.4 476.3
400 16 595 - 35 125 406.4 457 469.9 16 28.4 539.8
450 18 635 - 38.1 138 457 505 533.4 16 31.75 577.9
500 20 700 - 41.3 143 508 559 584.2 20 31.75 635
600 24 815 - 46.1 151 610 663 692.2 20 35.1 749.3
Class 300
DN  NPS Overall Diameter  Inside Diameter Thickness of Flange(Min.) Overall Lenght  Diameter at Bevel Diameter of Hub Diameter of Face Number of Bolts Diameter of Bolt Holes  Diameter of Bolt Circle 
　 　 A B C D E F G H I J
15  1/2 95 15.8 12.7 51 21.3 38 34.9 4 15.7 66.7
20  3/4 115 20.9 14.3 56 26.7 48 42.9 4 19 82.6
25 1 125 26.6 15.9 60 33.4 54 50.8 4 19 88.9
32 1 1/4 135 35.1 17.5 64 42.2 64 63.5 4 19 98.4
40 1 1/2 155 40.9 19.1 67 48.3 70 73 4 22.3 114.3
50 2 165 52.5 20.7 68 60.3 84 92.1 8 19 127
65 2 1/2 190 62.7 23.9 75 73 100 104.8 8 22.3 149.2
80 3 210 77.9 27 78 88.9 117 127 8 22.3 168.3
90 3 1/2 230 90.1 28.6 79 101.6 133 139.7 8 22.3 184.2
100 4 255 102.3 30.2 84 114.3 146 157.2 8 22.3 200
125 5 280 128.2 33.4 97 141.3 178 185.7 8 22.3 235
150 6 320 154.1 35 97 168.3 206 215.9 12 22.3 269.9
200 8 380 202.7 39.7 110 219.1 260 269.9 12 25.4 330.2
250 10 445 254.6 46.1 116 273 321 323.8 16 28.4 387.4
300 12 520 304.8 49.3 129 323.8 375 381 16 31.7 450.8
350 14 585 - 52.4 141 355.6 425 412.8 20 31.7 514.4
400 16 650 - 55.6 144 406.4 483 469.9 20 35 571.5
450 18 710 - 58.8 157 457 533 533.4 24 35 628.6
500 20 775 - 62 160 508 587 584.2 24 35 685.8
600 24 915 - 68.3 167 610 702 692.2 24 41.1 812.8
Class 400
DN  NPS Overall Diameter  Inside Diameter Thickness of Flange(Min.) Overall Lenght  Diameter at Bevel Diameter of Hub Diameter of Face Number of Bolts Diameter of Bolt Holes  Diameter of Bolt Circle 
　 　 A B C D E F G H I J
15  1/2 95 - 14.3 52 21.3 38 34.9 4 15.7 66.7
20  3/4 115 - 15.9 57 26.7 48 42.9 4 19 82.6
25 1 125 - 17.5 62 33.4 54 50.8 4 19 88.9
32 1 1/4 135 - 20.7 67 42.2 64 63.5 4 19 98.4
40 1 1/2 155 - 22.3 70 48.3 70 73 4 22.3 114.3
50 2 165 - 25.4 73 60.3 84 92.1 8 19 127
65 2 1/2 190 - 28.6 79 73 100 104.8 8 22.3 149.2
80 3 210 - 31.8 83 88.9 117 127 8 22.3 168.3
90 3 1/2 230 - 35 86 101.6 133 139.7 8 25.4 184.2
100 4 255 - 35 89 114.3 146 157.2 8 25.4 200
125 5 280 - 38.1 102 141.3 178 185.7 8 25.4 235
150 6 320 - 41.3 103 168.3 206 215.9 12 35.4 269.9
200 8 380 - 47.7 117 219.1 260 269.9 12 28.4 330.2
250 10 445 - 54 124 273 321 323.8 16 31.75 387.4
300 12 520 - 57.2 137 323.8 375 381 16 35.1 450.8
350 14 585 - 60.4 149 355.6 425 412.8 20 35.1 514.4
400 16 650 - 63.5 152 406.4 483 469.9 20 38.1 571.5
450 18 710 - 66.7 165 457 533 533.4 24 38.1 628.6
500 20 775 - 69.9 168 508 587 584.2 24 41.1 685.8
600 24 915 - 76.2 175 610 702 692.2 24 47.8 812.8
Class 600
DN  NPS Overall Diameter  Inside Diameter Thickness of Flange(Min.) Overall Lenght  Diameter at Bevel Diameter of Hub Diameter of Face Number of Bolts Diameter of Bolt Holes  Diameter of Bolt Circle 
　 　 A B C D E F G H I J
15  1/2 95 - 14.3 52 21.3 38 34.9 4 15.7 66.7
20  3/4 115 - 15.9 57 26.7 48 42.9 4 19 82.6
25 1 125 - 17.5 62 33.4 54 50.8 4 19 88.9
32 1 1/4 135 - 20.7 67 42.2 64 63.5 4 19 98.4
40 1 1/2 155 - 22.3 70 48.3 70 73 4 22.3 114.3
50 2 165 - 25.4 73 60.3 84 92.1 8 19 127
65 2 1/2 190 - 28.6 79 73 100 104.8 8 22.3 149.2
80 3 210 - 31.8 83 88.9 117 127 8 22.3 168.3
90 3 1/2 230 - 35 86 101.6 133 139.7 8 25.4 184.2
100 4 275 - 38.1 102 114.3 152 157.2 8 25.4 215.9
125 5 330 - 44.5 114 141.3 189 185.7 8 28.4 266.7
150 6 355 - 47.7 117 168.3 222 215.9 12 28.4 292.1
200 8 420 - 55.6 133 219.1 273 269.9 12 31.75 349.2
250 10 510 - 63.5 152 273 343 323.8 16 35.1 431.8
300 12 560 - 66.7 156 323.8 400 381 20 35.1 489
350 14 605 - 69.9 165 355.6 432 412.8 20 38.1 527
400 16 685 - 76.2 178 406.4 495 469.9 20 41.1 603.2
450 18 745 - 82.6 184 457 546 533.4 20 44.5 654
500 20 815 - 88.9 190 508 610 584.2 24 44.5 723.9
600 24 940 - 101.6 203 610 718 692.2 24 50.8 838.2
Class 900
DN  NPS Overall Diameter  Inside Diameter Thickness of Flange(Min.) Overall Lenght  Diameter at Bevel Diameter of Hub Diameter of Face Number of Bolts Diameter of Bolt Holes  Diameter of Bolt Circle 
　 　 A B C D E F G H I J
15  1/2 120 - 22.3 60 21.3 38 34.9 4 22.3 82.6
20  3/4 130 - 25.4 70 26.7 44 42.9 4 22.3 88.9
25 1 150 - 28.6 73 33.4 52 50.8 4 25.4 101.6
32 1 1/4 160 - 28.6 73 42.2 64 63.5 4 25.4 111.1
40 1 1/2 180 - 31.8 83 48.3 70 73 4 28.4 123.8
50 2 215 - 38.1 102 60.3 105 92.1 8 25.4 165.1
65 2 1/2 245 - 41.3 105 73 124 104.8 8 28.4 190.5
80 3 240 - 38.1 102 88.9 127 127 8 25.4 190.5
100 4 290 - 44.5 114 114.3 159 157.2 8 31.7 235
125 5 350 - 50.8 127 141.3 190 185.7 8 35 279.4
150 6 380 - 55.6 140 168.3 235 215.9 12 31.7 317.5
200 8 470 - 63.5 162 219.1 298 269.9 12 38.1 393.7
250 10 545 - 69.9 184 273 368 323.8 16 38.1 469.9
300 12 610 - 79.4 200 323.8 419 381 20 38.1 533.4
350 14 640 - 85.8 213 355.6 451 412.8 20 41.1 558.8
400 16 705 - 88.9 216 406.4 508 469.9 20 44.4 616
450 18 785 - 101.6 229 457 565 533.4 20 50.8 685.8
500 20 855 - 108 248 508 622 584.2 20 53.8 749.3
600 24 1040 - 139.7 292 610 749 692.2 20 66.55 901.7
Class 1500
DN  NPS Overall Diameter  Inside Diameter Thickness of Flange(Min.) Overall Lenght  Diameter at Bevel Diameter of Hub Diameter of Face Number of Bolts Diameter of Bolt Holes  Diameter of Bolt Circle 
　 　 A B C D E F G H I J
15  1/2 120 - 22.3 60 21.3 38 34.9 4 22.3 82.6
20  3/4 130 - 25.4 70 26.7 44 42.9 4 22.3 88.9
25 1 150 - 28.6 73 33.4 52 50.8 4 25.4 101.6
32 1 1/4 160 - 28.6 73 42.2 64 63.5 4 25.4 111.1
40 1 1/2 180 - 31.8 83 48.3 70 73 4 28.4 123.8
50 2 215 - 38.1 102 60.3 105 92.1 8 25.4 165.1
65 2 1/2 245 - 41.3 105 73 124 104.8 8 28.4 190.5
80 3 265 - 47.7 117 88.9 133 127 8 31.7 203.2
100 4 310 - 54 124 114.3 162 157.2 8 35 241.3
125 5 375 - 73.1 156 141.3 197 185.7 8 41.1 292.1
150 6 395 - 82.6 171 168.3 229 215.9 12 38.1 317.5
200 8 485 - 92.1 213 219.1 292 269.9 12 44.4 393.7
250 10 585 - 108 254 273 368 323.8 12 50.8 482.6
300 12 675 - 123.9 283 323.8 451 381 16 53.8 571.5
350 14 750 - 133.4 298 355.6 495 412.8 16 60.45 635
400 16 825 - 146.1 311 406.4 552 469.9 16 66.55 704.8
450 18 915 - 162 327 457 597 533.4 16 73.15 774.7
500 20 985 - 177.8 356 508 641 584.2 16 79.25 831.8
600 24 1170 - 203.2 406 610 762 692.2 16 91.9 990.6
Class 2500
DN  NPS Overall Diameter  Inside Diameter Thickness of Flange(Min.) Overall Lenght  Diameter at Bevel Diameter of Hub Diameter of Face Number of Bolts Diameter of Bolt Holes  Diameter of Bolt Circle 
　 　 A B C D E F G H I J
15  1/2 135 - 30.2 73 21.3 43 34.9 4 22.3 88.9
20  3/4 140 - 31.8 79 26.7 51 42.9 4 22.3 95.2
25 1 160 - 35 89 33.4 57 50.8 4 25.4 108
32 1 1/4 185 - 38.1 95 42.2 73 63.5 4 28.4 130.2
40 1 1/2 205 - 44.5 111 48.3 79 73 4 31.75 146
50 2 235 - 50.9 127 60.3 95 92.1 8 28.4 171.4
65 2 1/2 265 - 57.2 143 73 114 104.8 8 31.75 196.8
80 3 305 - 66.7 168 88.9 133 127 8 35.1 228.6
100 4 355 - 76.2 190 114.3 165 157.2 8 41.1 273
125 5 420 - 92.1 229 141.3 203 185.7 8 47.8 323.8
150 6 485 - 108 273 168.3 235 215.9 8 53.8 368.3
200 8 550 - 127 318 219.1 305 269.9 12 53.8 438.2
250 10 675 - 165.1 419 273 375 323.8 12 66.55 539.8
300 12 760 - 184.2 464 323.8 441 381 12 73.15 619.1


Tolerances of Welding Neck Flanges ASME B16.5
Outside Diameter (Note) Inside Diameter
 OD≤ 610mm = ± 2.0 mm | > 610 mm= ± 3.0 mm  NPS ≤ 10 = ± 1.0 mm | 12≤ NPS ≤18 = 1.5 mm 
 NPS ≥ 20 = + 3.0 mm / - 1.5 mm
Diameter of Contact Face Diameter of Hub at Base (Note)
 2 mm RF= ± 1 mm  Hub base ≤ 610 mm = ±1.6 mm | Hub base > 610 mm = ± 3.2 mm
 7 mm RF, Tongue & Groove / Male-Female = ± 0.5 mm 　
Diameter of Hub at Point of Welding Drilling
 NPS≤ 5 = + 2.0mm / - 1.0 mm                             
 NPS≥ 6 = + 4.0 mm / - 1.0 mm		  Bolt Circle = ± 1.6 mm | Bolt Hole Spacing = ± 0.8 mm
　 Eccentricity of Bolt Circle with Respect to Facing
　 ≤ 2½ = ± 0.8 mm max. | ≥ 3 = ± 1.6 mm max
Thickness Length through Hub
 NPS≤ 18 = + 3.0 mm / - 0 | NPS≥ 20 = + 5.0 mm / - 0  NPS ≤ 4 = ± 1.5 mm | 5 ≤ NPS ≤12 = + 1.5 mm / - 3.0 mm              
 NPS ≥ 12 = + 3.0 mm / - 5.0 mm 

Note: These tolerances are not listed in ASME B16.5

Genuine knowledge comes from practice - Karl Marx
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