A blind flange is round plate which has all of the relevant bolt holes but no center hole, and because of this feature this flange is used to close off the ends of a piping systems and pressure vessel openings. It also permits easy access to the interior of a line or vessel once it has been sealed and must be reopened.
Blind Flanges are manufactured without a bore and used to blank off the ends of piping, Valves and pressure vessel openings.
From the standpoint of internal pressure and bolt loading, blind flanges, particularly in the larger sizes, are the most highly stressed flange types.
However, most of these stresses are bending types near the center, and since there is no standard inside diameter, these flanges are suitable for higher pressure temperature applications.
A blind flange is a solid disk used to block off a pipeline or to create a stop. It is machined in the same manner as a regular flange with the mounting holes around the perimeter and the gasket sealing rings machined into the mating surface. The difference is that a blind flange has no opening to allow fluid to pass through. The blind flange can be inserted between two open flanges and used to block off the flow of liquid through a pipeline.
Often a blind flange is inserted into a pipeline when a repair is required further up the line. This allows the flanges down stream to be disconnected without fear of losing liquid. Many times this type of blockade is used when adding another line onto an existing pipeline or when a new valve is being added. This blockade is also used to shut down a line when it is no longer needed.
Without the blind flange it would be difficult to perform maintenance or repairs on a pipeline. The flow would need to be shut off at the nearest valve, which could be miles away from the repair area. Valves are also very expensive and are prone to sticking. The blind flange is a much more cost efficient way of sealing a pipe.
When a pipeline is being constructed, a blind flange is often incorporated into the final length of pipe. This design allows for expansion or continuation of the pipeline by simply adding onto the final flange. This holds true for the addition of tees in the pipeline as well. A tee can be installed and then blocked in order to leave the option of running a pipe at a later date.
The use of flanged pipe has allowed pipelines to be built in a much faster manner than traditional welded seam pipelines. Moreover, it has made the task of repair and sectional replacement a simpler job. Sections of pipe can now be assembled anywhere in the world and shipped to the job site. Once there, they can simply be bolted into place and the pipeline can resume transportation of its liquid cargo.
By utilizing a universal design, any pipe flange in the world can be used in any pipeline as long as the proper diameter is selected. This allows emergency repairs with locally manufactured pieces and eliminates the need to have special parts shipped all over the world.

Application: Blind Flanges are commonly used in petrochemical, pipe engineering, public services & water works.

Dimensions Blind Flanges, ANSI CLASS 150, ASME B16.47 SERIES A, 1/16″ RAISED FACE DATASHEET

  • Dimensions per ASME B16.47 – Large Diameter Steel Flanges: NPS 26 Through NPS 60 Metric/Inch Standard
  • Bolt circle diameters are 1/8 inch larger than bolt diameter.

data bf b16.5 150 300data bf b16.47

Pipe Size

(NPS)

Outside Diameter of Flange

A

Diameter of Raised Face

B

Thickness of Flange

C

Number of Bolt Holes

 

Diameter of Bolt Holes

 

Bolt Circle Diameter

P

Approx Weight

(lb)

26 34 1/4 29 1/2 2 11/16 24 1 3/8 31 3/4 702
28 36 1/2 31 1/2 2 13/16 28 1 3/8 34 833
30 38 3/4 33 3/4 2 15/16 28 1 3/8 36 982
32 41 3/4 36 3 3/16 28 1 5/8 38 1/2 1237
34 43 3/4 38 3 1/4 32 1 5/8 40 1/2 1384
36 46 40 1/4 3 9/16 32 1 5/8 42 3/4 1676
38 48 3/4 42 1/4 3 7/16 32 1 5/8 45 1/4 1819
40 50 3/7 44 1/4 3 9/16 36 1 5/8 47 1/4 2040
42 53 47 3 13/16 36 1 5/8 49 1/2 2381
44 55 1/4 49 4 40 1 5/8 51 3/4 2717
46 57 1/4 51 4 1/16 40 1 5/8 53 1/4 2961
48 59 1/2 53 1/2 10 1/4 44 1 5/8 56 3348
50 61 3/4 55 1/2 4 3/8 44 1 7/8 58 1/4 3716
52 64 57 1/2 4 9/16 44 1 7/8 60 1/2 4156
54 66 1/4 59 1/2 4 3/4 44 1 7/8 62 3/4 4639
56 68 3/4 62 4 7/8 48 1 7/8 65 5132
58 71 64 5 1/16 48 1 7/8 67 1/4 5675
60 73 66 5 3/16 52 1 7/8 69 1/4 6154

Dimensions Blind Flanges, ANSI CLASS 150, ASME B16.47 SERIES B, 1/16″ RAISED FACE DATASHEET

  • Dimensions per ASME B16.47 – Large Diameter Steel Flanges: NPS 26 Through NPS 60 Metric/Inch Standard
  • Bolt circle diameters are 1/8 inch larger than bolt diameter.

data bf b16.5 150 300data bf b16.47

Pipe Size

(NPS)

Outside Diameter of Flange

A

Diameter of Raised Face

B

Thickness of Flange

C

Number of Bolt Holes

 

Diameter of Bolt Holes

 

Bolt Circle Diameter

P

Approx Weight

(lb)

26 30 15/16 28 1 3/4 36 7/8 29 5/16 370
28 32 15/16 30 1 7/8 40 7/8 31 5/16 455
30 34 15/16 32 2 44 7/8 33 5/16 545
32 37 1/16 34 2 1/8 48 7/8 35 7/16 650
34 39 9/16 36 1/4 2 1/42 40 1 37 11/16 785
36 41 5/8 38 1/4 2 5/16 44 1 39 3/4 890
38 44 1/4 40 1/4 2 1/2 40 1 1/8 42 1/8 1090
40 46 1/4 42 1/2 2 5/8 44 1 1/8 44 1/8 1250
42 48 1/4 44 1/2 2 11/16 48 1 1/8 46 1/8 1395
44 50 1/4 46 1/2 2 13/16 52 1 1/8 48 1/8 1580
46 52 13/16 48 5/8 2 15/16 40 1 1/4 50 9/16 1825
48 54 13/16 50 3/4 3 1/16 44 1 1/4 52 9/16 2045
50 56 13/16 52 3/4 3 3/16 48 1 1/4 54 9/16 2285
52 58 13/16 54 3/4 3 5/16 52 1 1/4 56 9/16 2550
54 61 56 3/4 3 7/16 56 1 1/4 58 3/4 2850
56 63 58 3/4 3 9/16 60 1 1/4 60 3/4 3145
58 65 15/16 60 3/4 3 11/16 48 1 3/8 63 7/16 3560
60 67 15/16 63 3 13/16 52 1 3/8 65 7/16 3915

Dimensions Blind Flanges, ANSI CLASS 150, ASME B16.5, 1/16″ RAISED FACE DATASHEET

  • This datasheet is for flanges that have a Raised Face end connection.  Additional in depth information about these kinds of flanges can be found on the Raised Face Flange page.
  • Dimensions per ASME B16.5 – Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
  • Bolt circle diameters are 1/8 inch larger than bolt diameter.

data bf b16.5 150 300data bf b16.5

Pipe Size

(NPS)

Outside Diameter of Flange

A

Diameter of Raised Face

B

Thickness of Flange

C

Number of Bolt Holes

 

Diameter of Bolt Holes

 

Bolt Circle Diameter

P

Approx Weight

(lb)

1/2 3 1/2 1 3/8 7/16 4 5/8 2 3/8 2
3/4 3 7/8 1 11/16 1/2 4 5/8 2 3/4 2
1 4 1/4 2 9/16 4 5/8 3 1/8 2
1 1/4 4 5/8 2 1/2 5/8 4 5/8 3 1/2 2
1 1/2 5 2 7/8 11/16 4 5/8 3 7/8 3
2 6 3 5/8 3/4 4 3/4 4 3/4 3
2 1/2 7 4 1/8 7/8 4 3/4 5 1/2 7
3 7 1/2 5 15/16 4 3/4 6 9
3 1/2 8 1/2 5 1/2 15/16 8 3/4 7 13
4 9 6 3/16 15/16 8 3/4 7 1/2 17
5 10 7 5/16 15/16 8 7/8 8 1/2 20
6 11 8 1/2 1 8 7/8 9 1/2 26
8 13 1/2 10 5/8 1 1/8 8 7/8 11 3/4 45
10 16 12 3/4 1 3/16 12 1 14 1/4 70
12 19 15 1 1/4 12 1 17 110
14 21 16 1/4 1 3/8 12 1 1/8 18 3/4 131
16 23 1/2 18 1/2 1 7/16 16 1 1/8 21 1/4 170
18 25 21 1 9/16 16 1 1/4 22 3/4 209
20 27 1/2 23 1 11/16 20 1 1/4 25 272
22 29 1/2 25 1/4 1 13/16 20 1 3/8 27 1/4 333
24 32 27 1/4 1 7/8 20 1 3/8 29 1/2 411

Dimensions Blind Flanges, ANSI CLASS 150, ASME B16.5, RING TYPE JOINT DATASHEET

This datasheet is for flanges that have a ring type joint (RTJ) end connection.  Additional in depth information about these kinds of flanges can be found on the Ring Type Joint page. 

  • Dimensions per ASME B16.5 – Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
  • Bolt circle diameters are 1/8 inch larger than bolt diameter.

data bf rjf b16.5 150 400data rtj b16.5 150 2500

Pipe Size

(NPS)

Outside Diameter of Flange

A

Thickness of Flange

C

Diameter of Raised Face

T

Diameter of Groove

U

Groove Width

W

Groove Depth

X

Number of Bolt Holes

 

Diameter of Bolt Holes

 

Bolt Circle Diameter

P

1/2
3/4
1 4 1/4 1/2 2 1/2 1 7/8 11/32 1/4 4 5/8 3 1/8
1 1/4 4 5/8 9/16 2 7/8 2 1/4 11/32 1/4 4 5/8 3 1/2
1 1/2 5 5/8 3 1/4 2 9/16 11/32 1/4 4 5/8 3 7/8
2 6 11/16 4 3 1/4 11/32 1/4 4 3/4 4 3/4
2 1/2 7 13/16 4 3/4 4 11/32 1/4 4 3/4 5 1/2
3 7 1/2 7/8 5 1/4 4 1/2 11/32 1/4 4 3/4 6
3 1/2 8 1/2 7/8 6 1/16 5 3/16 11/32 1/4 8 3/4 7
4 9 7/8 6 3/4 5 7/8 11/32 1/4 8 3/4 7 1/2
5 10 7/8 7 5/8 6 3/4 11/32 1/4 8 7/8 8 1/2
6 11 15/16 8 5/8 7 5/8 11/32 1/4 8 7/8 9 1/2
8 13 1/2 1 1/16 10 3/4 9 3/4 11/32 1/4 8 7/8 11 3/4
10 16 1 1/8 13 12 11/32 1/4 12 1 14 1/4
12 19 1 3/16 16 15 11/32 1/4 12 1 17
14 21 1 5/16 16 3/4 15 5/8 11/32 1/4 12 1 1/8 18 3/4
16 23 1/2 1 3/8 19 17 7/8 11/32 1/4 16 1 1/8 21 1/4
18 25 1 1/2 21 1/2 20 3/8 11/32 1/4 16 1 1/4 22 3/4
20 27 1/2 1 5/8 23 1/2 22 11/32 1/4 20 1 1/4 25
22 29 1/2 1 3/4 25 1/2 24 1/4 11/32 1/4 20 1 3/8 27 1/4
24 32 1 13/16 28 26 1/2 11/32 1/4 20 1 3/8 29 1/2

Dimensions Blind Flanges, ANSI CLASS 1500, ASME B16.5, 1/4″ RAISED FACE DATASHEET

This datasheet is for flanges that have a Raised Face end connection.  Additional in depth information about these kinds of flanges can be found on the Raised Face Flange page.

  • Dimensions per ASME B16.5 – Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
  • Bolt circle diameters are 1/8 inch larger than bolt diameter.

data bf b16.5 150 300data bf b16.5

Pipe Size

(NPS)

Outside Diameter of Flange

A

Diameter of Raised Face

B

Thickness of Flange

C

Number of Bolt Holes

 

Diameter of Bolt Holes

 

Bolt Circle Diameter

P

Approx Weight

(lb)

1/2 4 3/4 1 3/8 7/8 4 7/8 3 1/4 4
3/4 5 1/8 1 11/16 1 4 7/8 3 1/2 6
1 5 7/8 2 1 1/8 4 1 4 9
1 1/4 6 1/4 2 1/2 1 1/8 4 1 4 3/8 10
1 1/2 7 2 7/8 1 1/4 4 1 1/8 4 7/8 14
2 8 1/2 3 5/8 1 1/2 8 1 6 1/2 25
2 1/2 9 5/8 4 1/8 1 5/8 8 1 1/8 7 1/2 35
3 10 1/2 5 1 7/8 8 1 1/4 8 48
3 1/2
4 12 1/4 6 3/16 2 1/8 8 1 3/8 9 1/2 73
5 14 3/4 7 5/16 2 7/8 8 1 5/8 11 1/2 142
6 15 1/2 8 1/2 3 1/4 12 1 1/2 12 1/2 159
8 19 10 5/8 3 5/8 12 1 3/4 15 1/2 302
10 23 12 3/4 4 1/4 12 2 19 507
12 26 1/2 15 4 7/8 16 2 1/8 22 1/2 775
14 29 1/2 16 1/4 5 1/4 16 2 3/8 25 975
16 32 1/2 18 1/2 5 3/4 16 2 5/8 27 3/4 1300
18 36 21 6 3/8 16 2 7/8 30 1/2 1750
20 38 3/4 23 7 16 3 1/8 32 3/4 2225
22
24 46 27 1/4 8 16 3 5/8 39 3625

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