Dimensions in Inches Weld Neck Flanges & Stud Bolts according to ASME B16.5

Weld Neck flange

Important  Information

Class 150

NPS DIA
D
THK
B
DIA
A
DIA
OD
HEIGHT
H
DIA
K
DIA
L
NO OF
BOLT
HOLES
DIA
STUD
BOLTS
LENGTH
STUD
BOLTS
1/2 3.5 0.38 1.19 0.84 1.81 2.38 5/8 4 1/2 2.25
3/4 3.88 0.44 1.5 1.05 2 2.75 5/8 4 1/2 2.5
1 4.25 0.5 1.94 1.32 2.12 3.12 5/8 4 1/2 2.5
1.1/4 4.62 0.56 2.31 1.66 2.19 3.5 5/8 4 1/2 2.75
1.1/2 5 0.62 2.56 1.9 2.38 3.88 5/8 4 1/2 2.75
2 6 0.69 3.06 2.38 2.44 4.75 3/4 4 5/8 3.25
2.1/2 7 0.81 3.56 2.88 2.69 5.5 3/4 4 5/8 3.5
3 7.5 0.88 4.25 3.5 2.69 6 3/4 4 5/8 3.5
3.1/2 8.5 0.88 4.81 4 2.75 7 3/4 8 5/8 3.5
4 9 0.88 5.31 4.5 2.94 7.5 3/4 8 5/8 3.5
5 10 0.88 6.44 5.56 3.44 8.5 7/8 8 3/4 3.75
6 11 0.94 7.56 6.63 3.44 9.5 7/8 8 3/4 4
8 13.5 1.06 9.69 8.63 3.94 11.75 7/8 8 3/4 4.25
10 16 1.12 12 10.75 3.94 14.25 1 12 7/8 4.5
12 19 1.19 14.38 12.75 4.44 17 1 12 7/8 4.75
14 21 1.31 15.75 14 4.94 18.75 1.1/8 12 1 5.25
16 23.5 1.38 18 16 4.94 21.25 1.1/8 16 1 5.25
18 25 1.5 19.88 18 5.44 22.75 1.1/4 16 1.1/8 5.75
20 27.5 1.62 22 20 5.62 25 1.1/4 20 1.1/8 6.25
24 32 1.81 26.12 24 5.94 29.5 1.3/8 20 1.1/4 6.75

Class 300

NPS DIA
D
THK
B
DIA
A
DIA
OD
HEIGHT
H
DIA
K
DIA
L
NO OF
BOLT
HOLES
DIA
STUD
BOLTS
LENGTH
STUD
BOLTS
1/2 3.75 0.5 1.5 0.84 2 2.62 5/8 4 1/2 2.5
3/4 4.62 0.56 1.88 1.05 2.19 3.25 3/4 4 5/8 3
1 4.88 0.62 2.12 1.32 2.38 3.5 3/4 4 5/8 3
1.1/4 5.25 0.69 2.5 1.66 2.5 3.88 3/4 4 5/8 3.25
1.1/2 6.12 0.75 2.75 1.9 2.63 4.5 7/8 4 3/4 3.5
2 6.5 0.81 3.31 2.38 2.69 5 3/4 8 5/8 3.5
2.1/2 7.5 0.94 3.94 2.88 2.94 5.88 7/8 8 3/4 4
3 8.25 1.06 4.62 3.5 3.06 6.62 7/8 8 3/4 4.25
3.1/2 9 1.12 5.25 4 3.13 7.25 7/8 8 3/4 4.25
4 10 1.19 5.75 4.5 3.32 7.88 7/8 8 3/4 4.5
5 11 1.31 7 5.56 3.82 9.25 7/8 8 3/4 4.75
6 12.5 1.38 8.12 6.63 3.82 10.62 7/8 12 3/4 4.75
8 15 1.56 10.25 8.63 4.32 13 1 12 7/8 5.5
10 17.5 1.81 12.62 10.75 4.56 15.25 1.1/8 16 1 6.25
12 20.5 1.94 14.75 12.75 5.06 17.75 1.1/4 16 1.1/8 6.75
14 23 2.06 16.75 14 5.56 20.25 1.1/4 20 1.1/8 7
16 25.5 2.19 19 16 5.69 22.5 1.3/8 20 1.1/4 7.5
18 28 2.31 21 18 6.19 24.75 1.3/8 24 1.1/4 7.75
20 30.5 2.44 23.12 20 6.32 27 1.3/8 24 1.1/4 8
24 36 2.69 27.62 24 6.56 32 1.5/8 24 1.1/2 9

 

Class 400

NPS DIA
D
THK
B
DIA
A
DIA
OD
HEIGHT
H
DIA
K
DIA
L
NO OF
BOLT
HOLES
DIA
STUD
BOLTS
LENGTH
STUD
BOLTS
1/2 3.75 0.56 1.5 0.84 2.06 2.62 5/8 4 1/2 3
3/4 4.62 0.62 1.88 1.05 2.25 3.25 3/4 4 5/8 3.5
1 4.88 0.69 2.12 1.32 2.44 3.5 3/4 4 5/8 3.5
1.1/4 5.25 0.81 2.5 1.66 2.62 3.88 3/4 4 5/8 3.75
1.1/2 6.12 0.88 2.75 1.9 2.75 4.5 7/8 4 3/4 4.25
2 6.5 1 3.31 2.38 2.88 5 3/4 8 5/8 4.25
2.1/2 7.5 1.12 3.94 2.88 3.12 5.88 7/8 8 3/4 4.75
3 8.25 1.25 4.62 3.5 3.25 6.62 7/8 8 3/4 5
3.1/2 9 1.38 5.25 4 3.38 7.25 1 8 7/8 5.5
4 10 1.38 5.75 4.5 3.5 7.88 1 8 7/8 5.5
5 11 1.5 7 5.56 4 9.25 1 8 7/8 5.75
6 12.5 1.62 8.12 6.63 4.06 10.62 1 12 7/8 6
8 15 1.88 10.25 8.63 4.62 13 1.1/8 12 1 6.75
10 17.5 2.12 12.62 10.75 4.88 15.25 1.1/4 16 1.1/8 7.5
12 20.5 2.25 14.75 12.75 5.38 17.75 1.3/8 16 1.1/4 8
14 23 2.38 16.75 14 5.88 20.25 1.3/8 20 1.1/4 8.25
16 25.5 2.5 19 16 6 22.5 1.1/2 20 1.3/8 8.75
18 28 2.62 21 18 6.5 24.75 1.1/2 24 1.3/8 9
20 30.5 2.75 23.12 20 6.62 27 1.5/8 24 1.1/2 9.5
24 36 3 27.62 24 6.88 32 1.7/8 24 1.3/4 10.5

Class 600

NPS DIA
D
THK
B
DIA
A
DIA
OD
HEIGHT
H
DIA
K
DIA
L
NO OF
BOLT
HOLES
DIA
STUD
BOLTS
LENGTH
STUD
BOLTS
1/2 3.75 0.56 1.5 0.84 2.06 2.62 5/8 4 1/2 3
3/4 4.62 0.62 1.88 1.05 2.25 3.25 3/4 4 5/8 3.5
1 4.88 0.69 2.12 1.32 2.44 3.5 3/4 4 5/8 3.5
1.1/4 5.25 0.81 2.5 1.66 2.62 3.88 3/4 4 5/8 3.75
1.1/2 6.12 0.88 2.75 1.9 2.75 4.5 7/8 4 3/4 4.25
2 6.5 1 3.31 2.38 2.88 5 3/4 8 5/8 4.25
2.1/2 7.5 1.12 3.94 2.88 3.12 5.88 7/8 8 3/4 4.75
3 8.25 1.25 4.62 3.5 3.25 6.62 7/8 8 3/4 5
3.1/2 9 1.38 5.25 4 3.38 7.25 1 8 7/8 5.5
4 10.75 1.5 6 4.5 4 8.5 1 8 7/8 5.75
5 13 1.75 7.44 5.56 4.5 10.5 1.1/8 8 1 6.5
6 14 1.88 8.75 6.63 4.62 11.5 1.1/8 12 1 6.75
8 16.5 2.19 10.75 8.63 5.25 13.75 1.1/4 12 1.1/8 7.5
10 20 2.5 13.5 10.75 6 17 1.3/8 16 1.1/4 8.5
12 22 2.62 15.75 12.75 6.12 19.25 1.3/8 20 1.1/4 8.75
14 23.75 2.75 17 14 6.5 20.75 1.1/2 20 1.3/8 9.25
16 27 3 19.5 16 7 23.75 1.5/8 20 1.1/2 10
18 29.25 3.25 21.5 18 7.25 25.75 1.3/4 20 1.5/8 10.75
20 32 3.5 24 20 7.5 28.5 1.3/4 24 1.5/8 11.25
24 37 4 28.25 24 8 33 2 24 1.7/8 13

Class 900

NPS DIA
D
THK
B
DIA
A
DIA
OD
HEIGHT
H
DIA
K
DIA
L
NO OF
BOLT
HOLES
DIA
STUD
BOLTS
LENGTH
STUD
BOLTS
1/2 4.75 0.88 1.5 0.84 2.38 3.25 7/8 4 3/4 4.25
3/4 5.12 1 1.75 1.05 2.75 3.5 7/8 4 3/4 4.5
1 5.88 1.12 2.06 1.32 2.88 4 1 4 7/8 5
1.1/4 6.25 1.12 2.5 1.66 2.88 4.38 1 4 7/8 5
1.1/2 7 1.25 2.75 1.9 3.25 4.88 1.1/8 4 1 5.5
2 8.5O 1.5 4.12 2.38 4 6.5 1 8 7/8 5.75
2.1/2 9.62 1.62 4.88 2.88 4.12 7.5 1.1/8 8 1 6.25
3 9.5 1.5 5 3.5 4 7.5 1 8 7/8 5.75
4 11.5 1.75 6.25 4.5 4.5 9.25 1.1/4 8 1.1/8 6.75
5 13.75 2 7.5 5.56 5 11 1.3/8 8 1.1/4 7.5
6 15 2.19 9.25 6.63 5.5 12.5 1.1/4 12 1.1/8 7.5
8 18.5 2.5 11.75 8.63 6.38 15.5 1.1/2 12 1.3/8 8.75
10 21.5 2.75 14.5 10.75 7.25 18.5 1.1/2 16 1.3/8 9.25
12 24 3.12 16.5 12.75 7.88 21 1.1/2 20 1.3/8 10
14 25.25 3.38 17.75 14 8.38 22 1.5/8 20 1.1/2 10.75
16 27.75 3.5 20 16 8.5 24.25 1.3/4 20 1.5/8 11.25
18 31 4 22.25 18 9 27 2 20 1.7/8 12.75
20 33.75 4.25 24.5 20 9.75 29.5 2.1/8 20 2 13.75
24 41 5.5 29.5 24 11.5 35.5 2.5/8 20 2.1/2 17.25

 

Class 1500

NPS DIA
D
THK
B
DIA
A
DIA
OD
HEIGHT
H
DIA
K
DIA
L
NO OF
BOLT
HOLES
DIA
STUD
BOLTS
LENGTH
STUD
BOLTS
1/2 4.75 0.88 1.5 0.84 2.38 3.25 7/8 4 3/4 4.25
3/4 5.12 1 1.75 1.05 2.75 3.5 7/8 4 3/4 4.5
1 5.88 1.12 2.06 1.32 2.88 4 1 4 7/8 5
1.1/4 6.25 1.12 2.5 1.66 2.88 4.38 1 4 7/8 5
1.1/2 7 1.25 2.75 1.9 3.25 4.88 1.1/8 4 1 5.5
2 8.5O 1.5 4.12 2.38 4 6.5 1 8 7/8 5.75
2.1/2 9.62 1.62 4.88 2.88 4.12 7.5 1.1/8 8 1 6.25
3 10.5 1.88 5.25 3.5 4.62 8 1.1/4 8 1.1/8 7
4 12.25 2.12 6.38 4.5 4.88 9.5 1.3/8 8 1.1/4 7.75
5 14.75 2.88 7.75 5.56 6.12 11.5 1.5/8 8 1.1/2 9.75
6 15.5 3.25 9 6.63 6.75 12.5 1.1/2 12 1.3/8 10.25
8 19 3.62 11.5 8.63 8.38 15.5 1.3/4 12 1.5/8 11.5
10 23 4.25 14.5 10.75 10 19 2 12 1.7/8 13.25
12 26.5 4.88 17.75 12.75 11.12 22.5 2.1/8 16 2 14.75
14 29.5 5.25 19.5 14 11.75 25 2.3/8 16 2.1/4 16
16 32.5 5.75 21.75 16 12.25 27.75 2.5/8 16 2.1/2 17.5
18 36 6.38 23.5 18 12.88 30.5 2.7/8 16 2.3/4 19.5
20 38.75 7 25.25 20 14 32.75 3.1/8 16 3 21.25
24 46 8 30 24 16 39 3.5/8 16 3.1/2 24.25

 

Class 2500

NPS DIA
D
THK
B
DIA
A
DIA
OD
HEIGHT
H
DIA
K
DIA
L
NO OF
BOLT
HOLES
DIA
STUD
BOLTS
LENGTH
STUD
BOLTS
1/2 5.25 1.19 1.69 0.84 2.88 3.5 7/8 4 3/4 4.75
3/4 5.5 1.25 2 1.05 3.12 3.75 7/8 4 3/4 5
1 6.25 1.38 2.25 1.32 3.5 4.25 1 4 7/8 5.5
1.1/4 7.25 1.5 2.88 1.66 3.75 5.12 1.1/8 4 1 6
1.1/2 8 1.75 3.12 1.9 4.38 5.75 1.1/4 4 1.1/8 6.75
2 9.25 2 3.75 2.38 5 6.75 1.1/8 8 1 7
2.1/2 10.5 2.25 4.5 2.88 5.62 7.75 1.1/4 8 1.1/8 7.75
3 12 2.62 5.25 3.5 6.62 9 1.3/8 8 1.1/4 8.75
4 14 3 6.5 4.5 7.5 10.75 1.5/8 8 1.1/2 10
5 16.5 3.62 8 5.56 9 12.75 1.7/8 8 1.3/4 11.75
6 19 4.25 9.25 6.63 10.75 14.5 2.1/8 8 2 13.5
8 21.75 5 12 8.63 12.5 17.25 2.1/8 12 2 15
10 26.5 6.5 14.75 10.75 16.5 21.25 2.5/8 12 2.1/2 19.25
12 30 7.25 17.38 12.75 18.25 24.38 2.7/8 12 2.3/4 21.25

Notes:

  • Dimensions are in inches unless otherwise indicated.
  • The length of the Stud Bolt does not include the height of the chamfers (points).
  • ID = Depending on the wall thickness of the pipe, must be specified by the purchaser.

 

Measuring lengths of Stud Bolts and Hex bolts

Dimensional Tolerances of Weld Neck Flanges ASME B16.5

Outside Diameter

≤24 = 1.6 mm (0.06 in)

>24 = ±3.2 mm (±0.12 in)

Inside Diameter

≤10
±0.8 mm (±0.03 in)

12 thru 18
1.6 mm (0.06 in)

≥20
+3.2 mm / -1.6 mm
(±0.12 in / -0.06 in)

Welding bevel

1 mm (0.03 in)
2 mm (0.07 in)
6 mm (0.23 in)

Diameter Contact Face

1.6 mm RF (0.06 in)
±0.8 mm (±0.03 in)

6.35 mm RF (0.25 in)
±0.4 mm (±0.01 in)

Tongue & Groove
±0.4 mm (±0.01 in)

Male-Female
±0.4 mm (±0.01 in)

Diameter Hub at Base

≤24
1.6 mm (0.06 in)

>24
±3.2 mm (±0.12 in)

Diameter Hub at Point of Welding

≤5
+2.4 mm / -0.8 mm
(±0.09 in / -0.03 in)

≥6
+4.0 mm / -0.8 mm
(+0.15 in / -0.03 in)

Drilling

Bolt Circle
1.6 mm (0.06 in)

Bolt Hole Spacing
±0.8 mm (±0.03 in)

Eccentricity Bolt Circle with Respect to Facing

≤2.1/2
0.8 mm max (0.03 in max)

≥3
1.6 mm max (0.06 in max)

Thickness

≤18
+3.2 mm / -0 (+0.12 in / -0)

≥20
+4.8 mm / -0 (+0.18 in / -0)

Length thru Hub

≤10
1.6 mm (0.06 in)

≥12
±3.2 mm (±0.12 in)