Forged Flanges – Dimensions

ANSI B16.5

DN 15 to 600 are to ANSI B16.5

DN 750 & 900 are to BS 3293 for Slip-On & Weldneck only

NOMINAL SIZES SHOWN ARE
V DN: SI METRIC TERM
I NPS: ANSI TERM

Note: All dimensions are in millimetres – (mm)

Nominal Size PN20  (CLASS  150) PN50  (CLASS  300) PN100  (CLASS  600) Nominal Size
Dia. of Fig.
O		 Thick- ness of Fig. Min.
C(1)*		 Length Thru Hub Dia. of Bolt Circle Dia. of Bolt Holes No. of Bolts Dia. of Fig.
O		 Thick- ness of Fig. Min.
C(1)*		 Length Thru Hub Dia. of Bolt Circle Dia. of Bolt Holes No. of Bolts Dia. of Fig.
O		 Thick- ness of Fig. Min.
C(1)*		 Length Thru Hub Dia. of Bolt Circle Dia. of Bolt Holes No. of Bolts
V
DN		 I
NPS		 Thrd. Slip-on Soc/ Weld Y(1)* Weld Neck
Y(1)*		 Thrd. Slip-on Soc/ Weld Y(1)* Weld Neck
Y(1)*		 Thrd. Slip-on Soc/ Weld Y(1)* Weld Neck
Y(1)*		 V
DN		 I
NPS
15
20
25
32		 ½
¾ 1
1¼		 90
100
110
115		 11.2
12.7
14.3
15.9		 15.6
15.6
17.6
20.6		 47.6
52.6
55.6
57.6		 60.3
69.9
79.4
88.9		 16
16
16
16		 4
4
4
4		 95
115
125
135		 14.3
15.9
17.5
19.1		 22.6
25.6
26.6
26.6		 52.6
57.6
61.6
65.6		 66.7
82.6
88.9
98.4		 16
19
19
19		 4
4
4
4		 95
115
125
135		 14.3
15.9
17.5
20.7		 22
25
27
29		 52
57
62
67		 66.7
82.6
88.9
98.4		 16
19
19
19		 4
4
4
4		 15
20
25
32		 ½
¾ 1
1¼
40 1½ 125 17.5 22.6 61.6 98.4 16 4 155 20.7 30.6 68.6 114 22 4 155 22.3 32 70 114 22 4 40 1½
50 2 150 19.1 25.6 63.6 121 19 4 165 22.3 33.6 69.6 127 19 8 165 26.4 37 73 127 19 8 50 2
65 2½ 180 22.3 28.6 69.6 140 19 4 190 25.4 38.6 76.6 149 22 8 190 28.6 41 79 149 22 8 65 2½
80 3 190 23.9 30.6 69.6 152 19 4 210 28.6 42.6 79.6 168 22 8 210 31.8 46 83 168 22 8 80 3
90 3½ 215 23.9 31.6 71.6 178 19 8 230 30.2 44.6 80.6 184 22 8 230 35 49 86 184 25 8 90 3½
100 4 230 23.9 33.6 76.6 191 19 8 255 31.8 47.6 85.6 200 22 8 275 38.1 54 102 216 25 8 100 4
125 5 255 23.9 36.6 88.6 216 22 8 280 35 50.6 98.6 235 22 8 330 44.5 60 114 267 28 8 125 5
150 6 280 25.4 39.6 88.6 241 22 8 320 36.6 52.6 98.6 270 22 12 355 47.7 67 117 292 28 12 150 6
200 8 345 28.6 44.6 102 299 22 8 380 41.3 61.6 112 330 25 12 420 55.6 76 133 349 32 12 200 8
250 10 405 30.2 49.6 102 362 25 12 445 47.7 66.6 118 387 28 16 510 63.5 86 152 432 35 16 250 10
300 12 485 31.8 55.6 115 432 25 12 520 50.8 72.6 131 451 32 16 560 66.7 92 156 489 35 20 300 12
350 14 535 35 57.6 127 476 28 12 585 54 76.6 143 514 32 20 605 69.9 94 165 527 38 20 350 14
400 16 595 36.6 63.6 127 540 28 16 650 57.2 82.6 146 572 35 20 685 76.2 106 178 603 41 20 400 16
450 18 635 39.7 68.6 140 578 32 16 710 60.4 88.6 159 629 35 24 745 82.6 117 184 654 44 20 450 18
500 20 700 42.9 72.6 145 635 32 20 775 63.5 95.6 162 686 35 24 815 88.9 127 190 724 44 24 500 20
600 24 815 47.7 82.6 153 749 35 20 915 69.9 107 169 813 41 24 940 102 140 203 838 51 24 600 24
750 30 985 54 89 130 914 35 28 1092 92.1 210 210 997 47.6 28 1130 114 248 248 1022 54 28 750 30
900 36 1170 60.4 95.3 137 1086 41.2 32 1270 105 241 241 1168 53.9 32 1315 124 283 283 1194 67 28 900 36
Nominal Size PN150  (CLASS 900) PN250  (CLASS 1500) PN420  (CLASS 2500) Nominal Size
Dia. of Fig. O Thick-ness of Fi. Min. c(2)+ Length Thru Hub Dia. of Bolt Circle Dia. of Bolt Holes No. of Bolts Dia. of Fig. O Thick-ness of Fi. Min. c(2)+ Length Thru Hub Dia. of Bolt Circle Dia. of Bolt Holes No. of Bolts Dia. of Fig. O Thick-ness of Fi. Min. c(2)+ Length Thru Hub Dia. of Bolt Circle Dia. of Bolt Holes No. of Bolts
v
DN		 I
DN		 Thrd. Slip-on Soc/
Weld Y(2)+		 Weld Neck Y(2)+ Thrd. Slip- on Soc/
Weld Y(2)+		 Weld Neck Y(2)+ Thrd. Slip- on Soc/
Weld Y(2)+		 Weld Neck Y(2)+ v
DN		 I
DN
15 ½ USE PN250 DIMENSIONS IN THESE SIZES 120 22.5 32 60 82.6 22 4 135 30.2 40 73 88.9 22 4 15 ½
20 ¾ 130 25.5 35 70 88.9 22 4 140 31.8 43 79 95.2 22 4 20 ¾
25 1 150 29.0 41 73 101.6 25 4 160 35.0 48 89 108.0 25 4 25 1
32 1¼ 160 29.0 41 73 111.1 25 4 185 38.1 52 95 130.2 29 4 32 1¼
40 1½ 180 32.0 44 83 123.8 28 4 205 44.5 60 111 146.0 32 4 40 1½
50 2 215 38.5 57 102 165.1 25 8 235 50.9 70 127 171.4 29 8 50 2
65 2½ 245 41.5 64 105 190.5 28 8 265 57.2 79 143 196.8 32 8 65 2½
80 3 240 38.1 54 102 190.5 25 8 265 48.0   117 203.2 32 8 305 66.7   168 228.6 35 8 80 3
100 4 290 44.5 70 114 235.0 32 8 310 54.0 124 241.3 35 8 355 76.2 190 273.0 41 8 100 4
125 5 350 50.8 79 127 279.4 35 8 375 73.5 155 292.1 41 8 420 92.1 229 323.8 48 8 125 5
150 6 380 55.6 86 140 317.5 32 12 395 83.0   171 317.5 38 12 485 108.0   273 368.3 54 8 150 6
200 8 470 63.5 102 162 393.7 38 12 485 92.0 213 393.7 44 12 550 127.0 318 438.2 54 12 200 8
250 10 545 69.9 108 184 469.9 38 16 585 108.0 254 482.6 51 12 675 165.1 419 539.8 67 12 250 10
300 12 610 79.4 117 200 533.4 38 20 675 124.0   283 571.5 54 16 760 184.2   464 619.1 73 12 300 12
350 14 640 85.8 130 213 558.8 41 20 750 133.5 298 635.0 60 16             350 14
400 16 705 88.9 133 216 616.0 44 20 825 146.5 311 704.8 67 16             400 16
450 18 785 101.6 152 229 686 51 20 915 162.0   327 774.7 73 16               450 18
500 20 855 108.0 159 248 749 54 20 985 178.0   356 831.8 79 16               500 20
600 24 1040 139.7 203 292 902 67 20 1170 203.5   406 990.6 92 16               600 24
Raised Face Diam. NOMINAL SIZE O.D.
of PIPE
mm		 APPROXIMATE  WELDING  NECK  FLANGE  BORES  –  mm
Alt. Press Ratings mm V
DN		 I
NPS		 SCH.
10		 SCH.
20		 SCH.
30		 STD.
WT		 SCH.
40		 SCH.
60		 EXT.
STG.		 SCH.
80		 SCH.
100		 SCH.
120		 SCH.
140		 SCH.
160		 X.X.
STG.
35 15 ½ 21.3       15.8 < SAME AS STd. WT. >   13.9 < SAME AS EXT. STG. >       11.8 6.4
43
51		 20
25		 ¾
1		 26.7
33.4		       20.9
26.6		   18.9
24.3		       15.5
20.7		 11.0
15.2
64
73		 32
40		 1¼
1½		 42.2
48.3		       35.1
40.9		   32.5
38.1		       29.5
34.0		 22.8
27.9
92
105		 50
65		 2
2½		 60.3
73.0		       52.5
62.7		   49.2
59.0		       42.9
54.0		 38.2
45.0
127
140		 80
90		 3
3½		 88.9
101.6		       77.9
90.1		   73.7
85.4		       66.7 58.4
157
186		 100
125		 4
5		 114.3
141.3		       102.3
128.2		   97.2
122.3		   92.1
115.9		   87.3
109.6		 80.1
103.2
216
270		 150
200		 6
8		 168.3
219.1		   206.4 205.0 154.1
202.7		 198.5 146.3
193.7		 188.9 139.7
182.6		 177.8 131.8
173.1		 124.4
174.6
324
381		 250
300		 10
12		 273.1
323.9		   260.3
311.1		 257.5
307.1		 254.5
304.8		 247.7
295.3		 247.7
298.5		 242.9
288.9		 236.5
281.0		 230.2
273.1		 222.3
266.7		 215.9
257.2		 222.3
273.1
303.2
413
470		 350
400		 14
16		 355.6
406.4		 342.9
393.7		 339.8
390.6		 336.6
387.4		 336.6
387.4		 333.3
381.0		 325.4
373.1		 330.2
381.0		 317.5
363.5		 307.9
354.0		 300.0
344.5		 292.1
333.3		 284.2
325.4		  
533
584		 450
500		 18
20		 457.0
508.0		 444.5
495.3		 441.4
489.0		 434.9
482.6		 438.2
489.0		 428.7
477.8		 419.1
466.8		 431.8
482.6		 409.5
455.6		 398.5
442.9		 387.4
431.8		 377.9
419.1		 366.7
408.0		  
692 600 24 610.0 596.9 590.6 581.1 590.6 574.6 560.4 584.2 547.7 531.8 517.6 504.9 490.5  
857 750 30 762.0 746.2 736.6 730.2 743.0     736.6            
1022 900 36 914.0 898.6 889.0 882.6 882.6 876.3   889.0            

NOTES:
* 1. The 1.6mm Raised Face is included in thickness C(1) and length through hub Y(1). This applies to PN20 and PN50 Pressure Ratings.
= 2. The 6.4mm Raised Face is not included in thickness C(2) and length through hub Y(2). PN100, 150, 250 and 420 Pressure Ratings are regularly furnished with 6.4mm Raised Face which is additional to the flange thickness C(2) and Y(2).
3. Always specify bore when ordering weldneck flanges. Bore dimensions shown opposite also provide inside pipe diameters

LARGE DIAMETER FLANGES ABOVE DN 600
‡ For Blind Flanges refer to ASME B16.47-A (MSS SP44).
BS 3293 covers Slip-On and Weldneck but excludes Blind Flanges.
ASME B16.47-A (MSS SP44) covers Blind and Weldneck but excludes Slip-On Flanges.
BS 3293 Weldneck PN20 flange thickness, C(1), is less than MSS SP44 equivalents.
ASME B16.47-B (API – 605) Dimensions for Large Diameter Flanges vary considerably from both BS 3293 and ASME B16.47-A (MSS SP44) – Details on request