Flanges and Bolt Dimensions - Class 150 to 2500 - ASME/ANSI B16.5

Diameters and bolt circles for standard ASME B16.5 flanges - 1/4 to 24 inches - Class 150 to 2500

Flange dimensions are determined by the pipe size and the pressure class required for the application. Flanges are standardized according publications from organizations like ASME, MSS, API and others.

Ansi B16.5 Welded Neck Raised Face Flange

ASME/ANSI B16.5 provides

  • weld neck
  • slip-on
  • socket weld
  • threaded
  • lap joint
  • blind

flange dimensions for pipes ranging 1/2" to 24" - in classes ranging 150 to 2500.

Nominal Pipe Size
NPS
(inches)
Class 150
Diameter of
Flange
(inches)
No.
of
Bolts
Diameter of
Bolts
(inches)
Diameter of
Bolt Holes
(inches)
Bolt
Circle
(inches)
1/4 3-3/8 4 1/2 0.62 2-1/4
1/2 3-1/2 4 1/2 0.62 2-3/8
3/4 3-7/8 4 1/2 0.62 2-3/4
1 4-1/4 4 1/2 0.62 3-1/8
1-1/4 4-5/8 4 1/2 0.62 3-1/2
1-1/2 5 4 1/2 0.62 3-7/8
2 6 4 5/8 0.75 4-3/4
2-1/2 7 4 5/8 0.75 5-1/2
3 7-1/2 4 5/8 0.75 6
3-1/2 8-1/2 8 5/8 0.75 7
4 9 8 5/8 0.75 7-1/2
5 10 8 3/4 0.88 8-1/2
6 11 8 3/4 0.88 9-1/2
8 13-1/2 8 3/4 0.88 11-3/4
10 16 12 7/8 1 14-1/4
12 19 12 7/8 1 17
14 21 12 1 1.12 18-3/4
16 23-1/2 16 1 1.12 21-1/4
18 25 16 1-1/8 1.25 22-3/4
20 27-1/2 20 1-1/8 1.25 25
24 32 20 1-1/4 1.38 29-1/2
Nominal Pipe Size
NPS
(inches)
Class 300
Diameter of
Flange
(inches)
No.
of
Bolts
Diameter of
Bolts
(inches)
Diameter of
Bolt Holes
(inches)
Bolt
Circle
(inches)
1/4 3-3/8 4 1/2 0.62 2-1/4
1/2 3-3/4 4 1/2 0.62 2-5/8
3/4 4-5/8 4 5/8 0.75 3-1/4
1 4-7/8 4 5/8 0.75 3-1/2
1-1/4 5-1/4 4 5/8 0.75 3-7/8
1-1/2 6-1/8 4 3/4 0.88 4-1/2
2 6-1/2 8 5/8 0.75 5
2-1/2 7-1/2 8 3/4 0.88 5-7/8
3 8-1/4 8 3/4 0.88 6-5/8
3-1/2 9 8 3/4 0.88 7-1/4
4 10 8 3/4 0.88 7-7/8
5 11 8 3/4 0.88 9-1/4
6 12-1/2 12 3/4 0.88 10-5/8
8 15 12 7/8 1 13
10 17-1/2 16 1 1.12 15-1/4
12 20-1/2 16 1-1/8 1.25 17-3/4
14 23 20 1-1/8 1.25 20-1/4
16 25-1/2 20 1-1/4 1.38 22-1/2
18 28 24 1-1/4 1.38 24-3/4
20 30-1/2 24 1-1/4 1.38 27
24 36 24 1-1/2 1.62 32
Nominal Pipe Size
NPS
(inches)
Class 400
Diameter of
Flange
(inches)
No.
of
Bolts
Diameter of
Bolts
(inches)
Diameter of
Bolt Holes
(inches)
Bolt
Circle
(inches)
1/4 3-3/8 4 1/2 0.62 2-1/4
1/2 3-3/4 4 1/2 0.62 2-5/8
3/4 4-5/8 4 5/8 0.75 3-1/4
1 4-7/8 4 5/8 0.75 3-1/2
1-1/4 5-1/4 4 5/8 0.75 3-7/8
1-1/2 6-1/8 4 3/4 0.88 4-1/2
2 6-1/2 8 5/8 0.75 5
2-1/2 7-1/2 8 3/4 0.88 5-7/8
3 8-1/4 8 3/4 0.88 6-5/8
3-1/2 9 8 7/8 1 7-1/4
4 10 8 7/8 1 7-7/8
5 11 8 7/8 1 9-1/4
6 12-1/2 12 7/8 1 10-5/8
8 15 12 1 1.12 13
10 17-1/2 16 1-1/8 1.25 15-1/4
12 20-1/2 16 1-1/4 1.38 17-3/4
14 23 20 1-1/4 1.38 20-1/4
16 25-1/2 20 1-3/8 1.5 22-1/2
18 28 24 1-3/8 1.5 24-3/4
20 30-1/2 24 1-1/2 1.62 27
24 36 24 1-3/4 1.88 32
Nominal Pipe Size
NPS
(inches)
Class 600
Diameter of
Flange
(inches)
No.
of
Bolts
Diameter of
Bolts
(inches)
Diameter of
Bolt Holes
(inches)
Bolt
Circle
(inches)
1/4 3-3/8 4 1/2 0.62 2-1/4
1/2 3-3/4 4 1/2 0.62 2-5/8
3/4 4-5/8 4 5/8 0.75 3-1/4
1 4-7/8 4 5/8 0.75 3-1/2
1-1/4 5-1/4 4 5/8 0.75 3-7/8
1-1/2 6-1/8 4 3/4 0.88 4-1/2
2 6-1/2 8 5/8 0.75 5
2-1/2 7-1/2 8 3/4 0.88 5-7/8
3 8-1/4 8 3/4 0.88 6-5/8
3-1/2 9 8 7/8 1 7-1/4
4 10-3/4 8 7/8 1 8-1/2
5 13 8 1 1.12 10-1/2
6 14 12 1 1.12 11-1/2
8 16-1/2 12 1-1/8 1.25 13-3/4
10 20 16 1-1/4 1.38 17
12 22 20 1-1/4 1.38 19-1/4
14 23-3/4 20 1-3/8 1.5 20-3/4
16 27 20 1-1/2 1.62 23-3/4
18 29-1/4 20 1-5/8 1.75 25-3/4
20 32 24 1-5/8 1.75 28-1/2
24 37 24 1-7/8 2 33
Nominal Pipe Size
NPS
(inches)
Class 900
Diameter of
Flange
(inches)
No.
of
Bolts
Diameter of
Bolts
(inches)
Diameter of
Bolt Holes
(inches)
Bolt
Circle
(inches)
1/2 4-3/4 4 3/4 0.88 3-1/4
3/4 5-1/8 4 3/4 0.88 3-1/2
1 5-7/8 4 7/8 1 4
1-1/4 6-1/4 4 7/8 1 4-3/8
1-1/2 7 4 1 1.12 4-7/8
2 8-1/2 8 7/8 1 6-1/2
2-1/2 9-5/8 8 1 1.12 7-1/2
3 9-1/2 8 7/8 1 7-1/2
4 11-1/2 8 1-1/8 1.25 9-1/4
5 13-3/4 8 1-1/4 1.38 11
6 15 12 1-1/8 1.25 12-1/2
8 18-1/2 12 1-3/8 1.5 15-1/2
10 21-1/2 16 1-3/8 1.5 18-1/2
12 24 20 1-3/8 1.5 21
14 25-1/4 20 1-1/2 1.62 22
16 27-3/4 20 1-5/8 1.75 24-1/2
18 31 20 1-7/8 2 27
20 33-3/4 20 2 2.12 29-1/2
24 41 20 2-1/2 2.62 35-1/2
Nominal Pipe Size
NPS
(inches)
Class 1500
Diameter of
Flange
(inches)
No.
of
Bolts
Diameter of
Bolts
(inches)
Diameter of
Bolt Holes
(inches)
Bolt
Circle
(inches)
1/2 4-3/4 4 3/4 0.88 3-1/4
3/4 5-1/8 4 3/4 0.88 3-1/2
1 5-7/8 4 7/8 1 4
1-1/4 6-1/4 4 7/8 1 4-3/8
1-1/2 7 4 1 1.12 4-7/8
2 8-1/2 8 7/8 1 6-1/2
2-1/2 9-5/8 8 1 1.12 7-1/2
3 10-1/2 8 1-1/8 1.25 8
4 12-1/4 8 1-1/4 1.38 9-1/2
5 14-3/4 8 1-1/2 1.62 11-1/2
6 15-1/2 12 1-3/8 1.5 12-1/2
8 19 12 1-5/8 1.75 15-1/2
10 23 12 1-7/8 2 19
12 26-1/2 16 2 2.12 22-1/2
14 29-1/2 16 2-1/4 2.38 25
16 32-1/2 16 2-1/2 2.62 27-3/4
18 36 16 2-3/4 2.88 30-1/2
20 38-3/4 16 3 3.12 32-3/4
24 46 16 3-1/2 3.62 39
Nominal Pipe Size
NPS
(inches)
Class 2500
Diameter of
Flange
(inches)
No.
of
Bolts
Diameter of
Bolts
(inches)
Diameter of
Bolt Holes
(inches)
Bolt
Circle
(inches)
1/2 5-1/4 4 3/4 0.88 3-1/2
3/4 5-1/2 4 3/4 0.88 3-3/4
1 6-1/4 4 7/8 1 4-1/4
1-1/4 7-1/4 4 1 1.12 5-1/8
1-1/2 8 4 1-1/8 1.25 5-3/4
2 9-1/4 8 1 1.12 6-3/4
2-1/2 10-1/2 8 1-1/8 1.25 7-3/4
3 12 8 1-1/4 1.38 9
4 14 8 1-1/2 1.62 10-3/4
5 16-1/2 8 1-3/4 1.88 12-3/4
6 19 8 2 2.12 14-1/2
8 21-3/4 12 2 2.12 17-1/4
10 26-1/2 12 2-1/2 2.62 21-1/4
12 30 12 2-3/4 2.88 24-3/8

Related Topics

  • Dimensions - Sizes and dimensions of pipes and tubes, and their fittings - inside and outside diameter, weight and more

Related Documents

Tag Search

  • en: ansi asme flanges
  • es: bridas ASME ansi
  • de: ansi ASME Flansche

Search the Engineering ToolBox

- "Search is the most efficient way to navigate the Engineering ToolBox!"

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your SketchUp model with the Engineering ToolBox - SketchUp Extension/Plugin - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro. Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Translate the Engineering ToolBox!
About the Engineering ToolBox!

close