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Class 150 Blind Flanges

A Blind flange derived it name blind as it is used to blank off a line it does not have a inside bore it is mounted on corresponding flange with the help of Bolt holes matching with that of the other flange. Blind flanges are widely used in testing facilities of vales or Lines being inspected for leakage etc. A blind flange can also be used to close one end of open line. We have the expertise to manufacture Blind flange for varied applications and varied line sizes and materials.

DIMENSIONS OF CLASS 150 FLANGES (ANSI B 16.5) (in mm)
Nominal
Pipe Size
Flange
Dia
'O'
Dia of
Bolt Circle
'A'
Dia of Bolt Holes
'D'
No. of
Holes
Thk of Flange
'C'
Diameter at Weld Bevel Dia of Hub
'E'
Length Through Hub Bore 'B' Dia of
R/F
R
Depth of
Socket
F
Length
of
Threading
S/O & S/W
Y
W/N
Y
L/J
Y
S/O & S/W
B
L/J
B
1/2'' 15 88.9 60.3 15.9 4 11.1 21.3 30.2 15.9 47.6 15.9 22.3 22.9 34.9 9.5 15.9
3/4'' 20 98.4 69.8 15.9 4 12.7 26.7 38.1 15.9 52.4 15.9 27.7 28.2 42.9 11.1 15.9
1'' 25 107.9 79.4 15.9 4 14.3 33.5 49.2 17.5 55.6 17.5 34.5 35.0 50.8 12.7 17.5
1 ¼'' 32 117.5 88.9 15.9 4 15.9 42.2 58.7 20.6 57.1 20.6 43.2 43.7 63.5 14.3 20.6
1 ½'' 40 127.0 98.4 15.9 4 17.5 48.3 65.1 22.2 61.9 22.2 49.5 50.0 73.0 15.9 22.2
2'' 50 152.4 120.6 19.0 4 19.0 60.4 77.8 25.4 63.5 25.4 62.0 62.5 92.1 17.5 25.4
2 ½'' 65 177.8 139.7 19.0 4 22.2 73.1 90.5 28.6 69.8 28.6 74.7 75.4 104.8 19.0 28.6
3'' 80 190.5 152.4 19.0 4 23.8 88.9 107.9 30.2 69.8 30.2 90.7 91.4 127.0 20.6 30.2
3 ½'' 90 216.0 177.8 19.0 8 23.8 101.6 122.2 31.7 71.4 31.7 103.4 104.1 140.0 20.6 31.7
4'' 100 228.6 190.5 19.0 8 23.8 114.3 134.9 33.3 76.2 33.3 116.1 116.8 157.2 23.8 33.3
5'' 125 254.0 215.9 22.2 8 23.8 141.2 163.5 36.5 88.9 36.5 143.8 144.5 185.7 23.8 36.5
6'' 150 279.4 241.3 22.2 8 25.4 168.4 192.1 39.7 88.9 39.7 170.7 171.4 215.9 27.0 39.7
8'' 200 342.9 298.4 22.2 8 28.6 219.2 246.1 44.4 101.6 44.4 221.5 222.2 269.9 31.7 44.4
10'' 250 406.4 361.9 25.4 12 30.2 273.0 304.8 49.2 101.6 49.2 276.3 277.4 323.8 33.3 49.2
12'' 300 482.6 431.8 25.4 12 31.8 323.8 365.1 55.6 114.3 55.6 327.1 328.2 381.0 39.7 55.6
14'' 350 533.4 476.2 28.6 12 34.9 355.6 400.0 57.1 127.0 79.4 359.1 360.2 412.7 41.3 57.1
16'' 400 596.9 539.7 28.6 16 36.5 406.4 457.2 63.5 127.0 87.3 410.5 411.2 469.9 44.4 63.5
18'' 450 635.0 577.8 31.7 16 39.7 457.2 504.8 68.3 139.7 96.8 461.8 462.3 533.4 49.2 68.3
20'' 500 698.5 635.0 31.7 20 42.9 508.0 558.8 73.0 144.5 103.2 513.1 514.3 584.2 54.0 73.0
24'' 600 812.8 749.3 34.9 20 47.6 609.6 663.6 82.5 152.4 111.1 615.9 615.9 692.1 63.5 82.5

Note : Thickness 'C' is inclusive of Raised Face Thickness of 1.65 MM. For Class 150

A class 150 flange can be created from various materials like stainless steel, carbon steel, ductile iron, cast iron, etc and is resistant to abrasion & corrosion with high durability. Flanges such as American standard flanges, British standard flanges and German standard flanges created using above mentioned materials have separate pressure ratings.

The pressure rating of flanges depends on various factors which we will look at in the following section.

Flanges are able to resist different pressure values at different & varied temperatures. With increase in temperature pressure rating of a flange decreases. Let us take an example to illustrate what happens; Class 150 flanges rates to about 270 PSIG (in ambient conditions), at 400 F a PSIG of 180, at 600 F a PSIG of 150 & 75 PSIG at 800 F. So it all depends on the fluid’s operating temperature.