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 SizePN20  (CLASS  150)PN50  (CLASS  300)PN100  (CLASS  600)Nominal Size
Dia. of Fig.
O
Thick- ness of Fig. Min.
C(1)*
Length Thru HubDia. of Bolt CircleDia. of Bolt HolesNo. of BoltsDia. of Fig.
O
Thick- ness of Fig. Min.
C(1)*
Length Thru HubDia. of Bolt CircleDia. of Bolt HolesNo. of BoltsDia. of Fig.
O
Thick- ness of Fig. Min.
C(1)*
Length Thru HubDia. of Bolt CircleDia. of Bolt HolesNo. 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
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
4012517.522.661.698.416415520.730.668.611422415522.3327011422440
50215019.125.663.612119416522.333.669.612719816526.43773127198502
6518022.328.669.614019419025.438.676.614922819028.6417914922865
80319023.930.669.615219421028.642.679.616822821031.84683168228803
9021523.931.671.617819823030.244.680.618422823035498618425890
100423023.933.676.619119825531.847.685.620022827538.1541022162581004
125525523.936.688.62162282803550.698.623522833044.5601142672881255
150628025.439.688.624122832036.652.698.6270221235547.76711729228121506
200834528.644.610229922838041.361.6112330251242055.67613334932122008
2501040530.249.6102362251244547.766.6118387281651063.586152432351625010
3001248531.855.6115432251252050.872.6131451321656066.792156489352030012
350145353557.612747628125855476.6143514322060569.994165527382035014
4001659536.663.6127540281665057.282.6146572352068576.2106178603412040016
4501863539.768.6140578321671060.488.6159629352474582.6117184654442045018
5002070042.972.6145635322077563.595.6162686352481588.9127190724442450020
6002481547.782.6153749352091569.91071698134124940102140203838512460024
7503098554891309143528109292.121021099747.62811301142482481022542875030
90036117060.495.3137108641.2321270105241241116853.93213151242832831194672890036
Nominal SizePN150  (CLASS 900)PN250  (CLASS 1500)PN420  (CLASS 2500)Nominal Size
Dia. of Fig. OThick-ness of Fi. Min. c(2)+Length Thru HubDia. of Bolt CircleDia. of Bolt HolesNo. of BoltsDia. of Fig. OThick-ness of Fi. Min. c(2)+Length Thru HubDia. of Bolt CircleDia. of Bolt HolesNo. of BoltsDia. of Fig. OThick-ness of Fi. Min. c(2)+Length Thru HubDia. of Bolt CircleDia. of Bolt HolesNo. 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
15½USE PN250 DIMENSIONS IN THESE SIZES12022.5326082.622413530.2407388.922415½
20¾13025.5357088.922414031.8437995.222420¾
25115029.04173101.625416035.04889108.0254251
3216029.04173111.125418538.15295130.229432
4018032.04483123.828420544.560111146.032440
50221538.557102165.125823550.970127171.4298502
6524541.564105190.528826557.279143196.832865
80324038.154102190.525826548.0 117203.232830566.7 168228.6358803
100429044.570114235.032831054.0124241.335835576.2190273.04181004
125535050.879127279.435837573.5155292.141842092.1229323.84881255
150638055.686140317.5321239583.0 171317.53812485108.0 273368.35481506
200847063.5102162393.7381248592.0213393.74412550127.0318438.254122008
2501054569.9108184469.93816585108.0254482.65112675165.1419539.8671225010
3001261079.4117200533.43820675124.0 283571.55416760184.2 464619.1731230012
3501464085.8130213558.84120750133.5298635.06016      35014
4001670588.9133216616.04420825146.5311704.86716      40016
45018785101.61522296865120915162.0 327774.77316       45018
50020855108.01592487495420985178.0 356831.87916       50020
600241040139.720329290267201170203.5 406990.69216       60024
Raised Face Diam.NOMINAL SIZEO.D.
of PIPE
mm
APPROXIMATE  WELDING  NECK  FLANGE  BORES  –  mm
Alt. Press Ratings mmV
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.
3515½21.3   15.8< SAME AS STd. WT. > 13.9< SAME AS EXT. STG. >   11.86.4
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

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
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
88.9
101.6
   77.9
90.1
 73.7
85.4
   66.758.4
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
 206.4205.0154.1
202.7
198.5146.3
193.7
188.9139.7
182.6
177.8131.8
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
 
69260024610.0596.9590.6581.1590.6574.6560.4584.2547.7531.8517.6504.9490.5 
85775030762.0746.2736.6730.2743.0  736.6      
102290036914.0898.6889.0882.6882.6876.3 889.0      

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