Sandco Metal Industries is a leading manufacturer of blind flanges(BL). We specialize in producing high quality and close tolerance flanges. A blind flange, also known as blanking flange, is used in sealing an end of the piping system. This is generally used in high pressure applications to cease the flow of gases or liquids from one end. Blind flange is a convenient option to close an end of a pipe in large applications when compared to others due to its ease of access.

1. DIMENSIONS OF BLIND FLANGES/ BL FLANGES
Blind Flange, ANSI Class 150, B16.5
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
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

2. Blind Flange, ANSI Class 300, B16.5
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
Diamet
er
1/2 3 3/4 1/2 2 1 11/32 9/32 7/32 4 5/8 2 5/8
3/4 4 5/8 9/16 2 1/2 1 11/16 11/32 1/4 4 3/4 3 1/4
1 4 7/8 5/8 2 3/4 2 11/32 1/4 4 3/4 3 1/2
1 1/4 5 1/4 11/16 3 1/8 2 3/8 11/32 1/4 4 3/4 3 7/8
1 1/2 6 1/8 3/4 3 9/16 2 11/16 11/32 1/4 4 7/8 4 1/2
2 6 1/2 13/16 4 1/4 3 1/4 15/32 5/16 8 3/4 5
2 1/2 7 1/2 15/16 5 4 15/32 5/16 8 7/8 5 7/8
3 8 1/4 1 1/16 5 3/4 4 7/8 15/32 5/16 8 7/8 6 5/8
3 1/2 9 1 1/8 6 1/4 5 3/16 15/32 5/16 8 7/8 7 1/4
4 10 1 3/16 6 7/8 5 7/8 15/32 5/16 8 7/8 7 7/8
5 11 1 5/16 8 1/4 7 1/8 15/32 5/16 8 7/8 9 1/4
6 12 1/2 1 3/8 9 1/2 8 5/16 15/32 5/16 12 7/8 10 5/8
8 15 1 9/16 11 7/8 10 5/8 15/32 5/16 12 1 13
10 17 1/2 1 13/16 14 12 3/4 15/32 5/16 16 1 1/8 15 1/4
12 20 1/2 1 15/16 16 1/4 15 15/32 5/16 16 1 1/4 17 3/4
14 23 2 1/16 18 16 1/2 15/32 5/16 20 1 1/4 20 1/4

3. Blind Flange, ANSI Class 400, B16.5
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
1/2 3 3/4 9/16 2 1 11/32 9/32 7/32 4 5/8 2 5/8
3/4 4 5/8 5/8 2 1/2 1 11/16 11/32 1/4 4 3/4 3 1/4
1 4 7/8 11/16 2 3/4 2 11/32 1/4 4 3/4 3 1/2
1 1/4 5 1/4 13/16 3 1/8 2 3/8 11/32 1/4 4 3/4 3 7/8
1 1/2 6 1/8 7/8 3 9/16 2 11/16 11/32 1/4 4 7/8 4 1/2
2 6 1/2 1 4 1/4 3 1/4 15/32 5/16 8 3/4 5
2 1/2 7 1/2 1 1/8 5 4 15/32 5/16 8 7/8 5 7/8
3 8 1/4 1 1/4 5 3/4 4 7/8 15/32 5/16 8 7/8 6 5/8
3 1/2 9 1 3/8 6 1/4 5 3/16 15/32 5/16 8 1 7 1/4
4 10 1 3/8 6 7/8 5 7/8 15/32 5/16 8 1 7 7/8
5 11 1 1/2 8 1/4 7 1/8 15/32 5/16 8 1 9 1/4
6 12 1/2 1 5/8 9 1/2 8 5/16 15/32 5/16 12 1 10 5/8
8 15 1 7/8 11 7/8 10 5/8 15/32 5/16 12 1 1/8 13
10 17 1/2 2 1/8 14 12 3/4 15/32 5/16 16 1 1/4 15 1/4
12 20 1/2 2 1/4 16 1/4 15 15/32 5/16 16 1 3/8 17 3/4
14 23 2 3/8 18 16 1/2 15/32 5/16 20 1 3/8 20 1/4
16 25 1/2 2 1/2 20 18 1/2 15/32 5/16 20 1 1/2 22 1/2
18 28 2 5/8 22 5/8 21 15/32 5/16 24 1 1/2 24 3/4
20 30 1/2 2 3/4 25 23 17/32 3/8 24 1 5/8 27

4. Blind Flange, ANSI Class 600, B16.5
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
1/2 3 3/4 9/16 2 1 11/32 9/32 7/32 4 5/8 2 5/8
3/4 4 5/8 5/8 2 1/2 1 11/16 11/32 1/4 4 3/4 3 1/4
1 4 7/8 11/16 2 3/4 2 11/32 1/4 4 3/4 3 1/2
1 1/4 5 1/4 13/16 3 1/8 2 3/8 11/32 1/4 4 3/4 3 7/8
1 1/2 6 1/8 7/8 3 9/16 2 11/16 11/32 1/4 4 7/8 4 1/2
2 6 1/2 1 4 1/4 3 1/4 15/32 5/16 8 3/4 5
2 1/2 7 1/2 1 1/8 5 4 15/32 5/16 8 7/8 5 7/8
3 8 1/4 1 1/4 5 3/4 4 7/8 15/32 5/16 8 7/8 6 5/8
3 1/2 9 1 3/8 6 1/4 5 3/16 15/32 5/16 8 1 7 1/4
4 10 3/4 1 1/2 6 7/8 5 7/8 15/32 5/16 8 1 8 1/2
5 13 1 3/4 8 1/4 7 1/8 15/32 5/16 8 1 1/8 10 1/2
6 14 1 7/8 9 1/2 8 5/16 15/32 5/16 12 1 1/8 11 1/2
8 16 1/2 2 3/16 11 7/8 10 5/8 15/32 5/16 12 1 1/4 13 3/4
10 20 2 1/2 14 12 3/4 15/32 5/16 16 1 3/8 17
12 22 2 5/8 16 1/4 15 15/32 5/16 20 1 3/8 19 1/4
14 23 3/4 2 3/4 18 16 1/2 15/32 5/16 20 1 1/2 20 3/4
16 27 3 20 18 1/2 15/32 5/16 20 1 5/8 23 3/4
18 29 1/4 3 1/4 22 5/8 21 15/32 5/16 20 1 3/4 25 3/4
20 32 3 1/2 25 23 17/32 3/8 24 1 3/4 28 1/2

5. Blind Flange, ANSI Class 900, B16.5
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
1/2 4 3/4 7/8 2 3/8 1 9/16 11/32 1/4 4 7/8 3 1/4
3/4 5 1/8 1 2 5/8 1 3/4 11/32 1/4 4 7/8 3 1/2
1 5 7/8 1 1/8 2 13/16 2 11/32 1/4 4 1 4
1 1/4 6 1/4 1 1/8 3 3/16 2 3/8 11/32 1/4 4 1 4 3/8
1 1/2 7 1 1/4 3 5/8 2 11/16 11/32 1/4 4 1 1/8 4 7/8
2 8 1/2 1 1/2 4 7/8 3 3/4 15/32 5/16 8 1 6 1/2
2 1/2 9 5/8 1 5/8 5 3/8 4 1/4 15/32 5/16 8 1 1/8 7 1/2
3 9 1/2 1 1/2 6 1/8 4 7/8 15/32 5/16 8 1 7 1/2
3 1/2 - - - - - - - - -
4 11 1/2 1 3/4 7 1/8 5 7/8 15/32 5/16 8 1 1/4 9 1/4
5 13 3/4 2 8 1/2 7 1/8 15/32 5/16 8 1 3/8 11
6 15 2 3/16 9 1/2 8 5/16 15/32 5/16 12 1 1/4 12 1/2
8 18 1/2 2 1/2 12 1/8 10 5/8 15/32 5/16 12 1 1/2 15 1/2
10 21 1/2 2 3/4 14 1/4 12 3/4 15/32 5/16 16 1 1/2 18 1/2
12 24 3 1/8 16 1/2 15 15/32 5/16 20 1 1/2 21
14 25 1/4 3 3/8 18 3/8 16 1/2 21/32 7/16 20 1 5/8 22
16 27 3/4 3 1/2 20 5/8 18 1/2 21/32 7/16 20 1 3/4 24 1/4
18 31 4 23 3/8 21 25/32 1/2 20 2 27
20 33 3/4 4 1/4 25 1/2 23 25/32 1/2 20 2 1/8 29 1/2

6. Blind Flange, ANSI Class 1500, B16.5
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
1/2 4 3/4 7/8 2 3/8 1 9/16 11/32 1/4 4 7/8 3 1/4
3/4 5 1/8 1 2 5/8 1 3/4 11/32 1/4 4 7/8 3 1/2
1 5 7/8 1 1/8 2 13/16 2 11/32 1/4 4 1 4
1 1/4 6 1/4 1 1/8 3 3/16 2 3/8 11/32 1/4 4 1 4 3/8
1 1/2 7 1 1/4 3 5/8 2 11/16 11/32 1/4 4 1 1/8 4 7/8
2 8 1/2 1 1/2 4 7/8 3 3/4 15/32 5/16 8 1 6 1/2
2 1/2 9 5/8 1 5/8 5 3/8 4 1/4 15/32 5/16 8 1 1/8 7 1/2
3 10 1/2 1 7/8 6 5/8 5 3/8 15/32 5/16 8 1 1/4 8
3 1/2 - - - - - - - - -
4 12 1/4 2 1/8 7 5/8 6 3/8 15/32 5/16 8 1 3/8 9 1/2
5 14 3/4 2 7/8 9 7 5/8 15/32 5/16 8 1 5/8 11 1/2
6 15 1/2 3 1/4 9 3/4 8 5/16 17/32 3/8 12 1 1/2 12 1/2
8 19 3 5/8 12 1/2 10 5/8 21/32 7/16 12 1 3/4 15 1/2
10 23 4 1/4 14 5/8 12 3/4 21/32 7/16 12 2 19
12 26 1/2 4 7/8 17 1/4 15 29/32 9/16 16 2 1/8 22 1/2

7. Blind Flange, ANSI Class 2500, B16.5
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
1/2 5 1/4 1 3/16 2 9/16 1 11/16 11/32 1/4 4 7/8 3 1/2
3/4 5 1/2 1 1/4 2 7/8 2 11/32 1/4 4 7/8 3 3/4
1 6 1/4 1 3/8 3 1/4 2 3/8 11/32 1/4 4 1 4 1/4
1 1/4 7 1/4 1 1/2 4 2 27/32 15/32 5/16 4 1 1/8 5 1/8
1 1/2 8 1 3/4 4 1/2 3 1/4 15/32 5/16 4 1 1/4 5 3/4
2 9 1/4 2 5 1/4 4 15/32 5/16 8 1 1/8 6 3/4
2 1/2 10 1/2 2 1/4 5 7/8 4 3/8 17/32 3/8 8 1 1/4 7 3/4
3 12 2 5/8 6 5/8 5 17/32 3/8 8 1 3/8 9
3 1/2 - - - - - - - - -
4 14 3 8 6 3/16 22/51 7/16 8 1 5/8 10 3/4
5 16 1/2 3 5/8 9 1/2 7 1/2 21/32 1/2 8 1 7/8 12 3/4
6 19 4 1/4 11 9 25/32 1/2 8 2 1/8 14 1/2
8 21 3/4 5 13 3/8 11 29/32 9/16 12 2 1/8 17 1/4
10 26 1/2 6 1/2 16 3/4 13 1/2 1 3/16 11/16 12 2 5/8 21 1/4