Blind Flange
Blind Flange
A Blind flange is a type of flange used in piping systems to seal the end of a pipe or valve, effectively “closing” the line. It has no opening or hole, and its primary function is to seal the end of a pipe, preventing the flow of fluids. Blind flanges are typically used in maintenance, testing, or when a system is not in use, ensuring that the pipeline is securely closed.
Key Features
- Sealing Function: It blocks the pipe to prevent leakage, providing a tight seal.
- Material Variety: Available in various materials like carbon steel, stainless steel, alloy steel, and others, depending on the system’s requirements.
- Pressure Ratings: Blind flanges come in different pressure ratings (such as ANSI or DIN standards).
- Sizes: They come in a variety of sizes to fit the specific pipe diameter.
Blind Flange Dimensions
Class 150 Blind Flange Dimensions
Size Size Flange Outer RF RF PCD No of Bolt Size Machine Bolt RF Stud Hole Size ISO Stud Weight
in Inch in mm Thick. Dia. Dia. Height Bolts UNC Length Length Size in kg
B A C D E
1/2 15 9.6 90 34.9 2 60.3 4 1/2 50 55 5/8 M14 0.9
3/4 20 11.2 100 42.9 2 69.9 4 1/2 50 65 5/8 M14 0.9
1 25 12.7 110 50.8 2 79.4 4 1/2 55 65 5/8 M14 0.9
1 1/4 32 14.3 115 63.5 2 88.9 4 1/2 55 70 5/8 M14 1.4
1 1/2 40 15.9 125 73 2 98.4 4 1/2 65 70 5/8 M14 1.8
2 50 17.5 150 92.1 2 120.7 4 5/8 70 85 3/4 M16 2.3
2 1/2 65 20.7 180 104.8 2 139.7 4 5/8 75 90 3/4 M16 3.2
3 80 22.3 190 127 2 152.4 4 5/8 75 90 3/4 M16 4.1
3 1/2 90 22.3 215 139.7 2 177.8 8 5/8 75 90 3/4 M16 5.9
4 100 22.3 230 157.2 2 190.5 8 5/8 75 90 3/4 M16 7.7
5 125 22.3 255 185.7 2 215.9 8 3/4 85 95 7/8 M20 9.1
6 150 23.9 280 215.9 2 241.3 8 3/4 85 100 7/8 M20 11.8
8 200 27 345 269.9 2 298.5 8 3/4 90 110 7/8 M20 20.5
10 250 28.6 405 323.8 2 362 12 7/8 100 115 1 M24 32
12 300 30.2 485 381 2 431.8 12 7/8 100 120 1 M24 50
14 350 33.4 535 412.8 2 476.3 12 1 115 135 1 1/8 M27 64
16 400 35 595 469.9 2 539.8 16 1 115 135 1 1/8 M27 82
18 450 38.1 635 533.4 2 577.9 16 1 1/8 125 145 1 1/4 M30 100
20 500 41.3 700 584.2 2 635 20 1 1/8 140 160 1 1/4 M30 130
24 600 46.1 815 692.2 2 749.3 20 1 1/4 150 170 1 3/8 M33 196
Class 300 Blind Flange Dimensions
Size Size Outer Flange RF RF PCD No of Bolt Size Machine Bolt RF Stud Hole Size ISO Stud Weight
in Inch in mm Dia. Thick. Dia. Height Bolts UNC Length Length Size in kg
A B C D E
1/2 15 95 12.7 34.9 2 66.7 4 1/2 55 65 5/8 M14 1.4
3/4 20 115 14.3 42.9 2 82.6 4 5/8 65 75 3/4 M16 1.4
1 25 125 15.9 50.8 2 88.9 4 5/8 65 75 3/4 M16 1.4
1 1/4 32 135 17.5 63.5 2 98.4 4 5/8 70 85 3/4 M16 1.8
1 1/2 40 155 19.1 73 2 114.3 4 3/4 75 90 7/8 M20 2.7
2 50 165 20.7 92.1 2 127 8 5/8 75 90 3/4 M16 3.7
2 1/2 65 190 23.9 104.8 2 149.2 8 3/4 85 100 7/8 M20 5.5
3 80 210 27 127 2 168.3 8 3/4 90 110 7/8 M20 7.3
3 1/2 90 230 28.6 139.7 2 184.2 8 3/4 95 110 7/8 M20 9.6
4 100 255 30.2 157.2 2 200 8 3/4 95 115 7/8 M20 12.3
5 125 280 33.4 185.7 2 235 8 3/4 110 120 7/8 M20 15.9
6 150 320 35 215.9 2 269.9 12 3/4 110 120 7/8 M20 22.7
8 200 380 39.7 269.9 2 330.2 12 7/8 120 140 1 M24 36
10 250 445 46.1 323.8 2 387.4 16 1 140 160 1 1/8 M27 57
12 300 520 49.3 381 2 450.8 16 1 1/8 145 170 1 1/4 M30 84
14 350 585 52.4 412.8 2 514.4 20 1 1/8 160 180 1 1/4 M30 113
16 400 650 55.6 469.9 2 571.5 20 1 1/4 165 190 1 3/8 M33 134
18 450 710 58.8 533.4 2 628.6 24 1 1/4 170 195 1 3/8 M33 181
20 500 775 62 584.2 2 685.8 24 1 1/4 185 205 1 3/8 M33 230
24 600 915 68.3 692.2 2 812.8 24 1 1/2 205 230 1 5/8 M39 359
Class 400 Blind Flange Dimensions
Size in Inch Size in mm Outer Dia. Flange Thick. RF Dia. RF Height PCD No of Bolts Bolt Size UNC RF Stud Length Hole Size ISO Stud Size Weight in kg
A B C D E
1/2 15 95 14.3 34.9 7 66.7 4 1/2 75 5/8 M14 1.5
3/4 20 115 15.9 42.9 7 82.6 4 5/8 90 3/4 M16 1.5
1 25 125 17.5 50.8 7 88.9 4 5/8 90 3/4 M16 1.8
1 1/4 32 135 20.7 63.5 7 98.4 4 5/8 95 3/4 M16 2.3
1 1/2 40 155 22.3 73 7 114.3 4 3/4 110 7/8 M20 3.7
2 50 165 25.4 92.1 7 127 8 5/8 110 3/4 M16 4.6
2 1/2 65 190 28.6 104.8 7 149.2 8 3/4 120 7/8 M20 6.8
3 80 210 31.8 127 7 168.3 8 3/4 125 7/8 M20 9.1
3 1/2 90 230 35 N/A 7 184.2 8 7/8 140 1 M24 13.2
4 100 255 35 157.2 7 200 8 7/8 140 1 M24 15
5 125 280 38.1 185.7 7 235 8 7/8 145 1 M24 20
6 150 320 41.3 215.9 7 269.9 12 7/8 150 1 M24 28
8 200 380 47.7 269.9 7 330 12 1 170 1 1/8 M27 46
10 250 445 54 323.8 7 387.4 16 1 1/8 190 1 1/4 M30 71
12 300 520 57.2 381 7 450.8 16 1 1/4 205 1 3/8 M33 102
14 350 585 60.4 412.8 7 514.4 20 1 1/4 210 1 3/8 M33 132
16 400 650 63.5 469.9 7 571.5 20 1 3/8 220 1 1/2 M36 168
18 450 710 66.7 533.4 7 628.6 24 1 3/8 230 1 1/2 M36 207
20 500 775 69.9 584.2 7 685.8 24 1 1/2 240 1 3/4 M39 266
24 600 915 76.2 692.2 7 812.8 24 1 3/4 265 1 7/8 M45 405
Class 600 Blind Flange Dimensions
Size in Inch Size in mm Outer Dia. Flange Thick. RF Dia. RF Height PCD No of Bolts Bolt Size UNC RF Stud Length Hole Size ISO Stud Size Weight in kg
A B C D E
1/2 15 95 14.3 34.9 7 66.7 4 1/2 75 5/8 M14 1.4
3/4 20 115 15.9 42.9 7 82.6 4 5/8 90 3/4 M16 1.4
1 25 125 17.5 50.8 7 88.9 4 5/8 90 3/4 M16 1.8
1 1/4 32 135 20.7 63.5 7 98.4 4 5/8 95 3/4 M16 2.3
1 1/2 40 155 22.3 73 7 114.3 4 3/4 110 7/8 M20 3.7
2 50 165 25.4 92.1 7 127 8 5/8 110 3/4 M16 4.6
2 1/2 65 190 28.6 104.8 7 149.2 8 3/4 120 7/8 M20 6.8
3 80 210 31.8 127 7 168.3 8 3/4 125 7/8 M20 9.1
3 1/2 90 230 35 N/A 7 184.2 8 7/8 140 1 M24 13.2
4 100 275 38.1 157.2 7 215.9 8 7/8 145 1 M24 18.7
5 125 330 44.5 185.7 7 266.7 8 1 165 1 1/8 M27 31
6 150 355 47.7 215.9 7 292.1 12 1 170 1 1/8 M27 39
8 200 420 55.6 269.9 7 349.2 12 1 1/8 190 1 1/4 M30 64
10 250 510 63.5 323.8 7 431.8 16 1 1/4 215 1 3/8 M33 105
12 300 560 66.7 381 7 489 20 1 1/4 220 1 3/8 M33 134
14 350 605 69.9 412.8 7 527 20 1 3/8 235 1 1/2 M36 161
16 400 685 76.2 469.9 7 603.2 20 1 1/2 255 1 5/8 M39 225
18 450 745 82.6 533.4 7 654 20 1 5/8 275 1 3/4 M42 286
20 500 815 88.9 584.2 7 723.9 24 1 5/8 285 1 3/4 M42 368
24 600 940 101.6 692.2 7 838.2 24 1 7/8 330 2 M48 568
Class 900 Blind Flange Dimensions
Size in Inch Size in mm Outer Dia. Flange Thick. RF Dia. RF Height PCD No of Bolts Bolt Size UNC RF Stud Length Hole Size ISO Stud Size Weight in kg
A B C D E
1/2 15 120 22.3 34.9 7 82.6 4 3/4 110 7/8 M20 1.8
3/4 20 130 25.4 42.9 7 88.9 4 3/4 115 7/8 M20 2.7
1 25 150 28.6 50.8 7 101.6 4 7/8 125 1 M24 3.6
1 1/4 32 160 28.6 63.5 7 111.1 4 7/8 125 1 M24 4.1
1 1/2 40 180 31.8 73 7 123.8 4 1 140 1 1/8 M27 5.9
2 50 215 38.1 92.1 7 165.1 8 7/8 145 1 M24 10.1
2 1/2 65 245 41.3 104.8 7 190.5 8 1 160 1 1/8 M27 16
3 80 240 38.1 127 7 190.5 8 7/8 145 1 M24 13
4 100 290 44.5 157.2 7 235 8 1 1/8 170 1 1/4 M30 24.5
5 125 350 50.8 185.7 7 279.4 8 1 1/4 190 1 3/8 M33 39.5
6 150 380 55.6 215.9 7 317.5 12 1 1/8 190 1 1/4 M30 53
8 200 470 63.5 269.9 7 393.7 12 1 3/8 220 1 1/2 M36 91
10 250 545 69.9 323.8 7 469.9 16 1 3/8 235 1 1/2 M36 132
12 300 610 79.4 381 7 533.4 20 1 3/8 255 1 1/2 M36 189
14 350 640 85.8 412.8 7 558.8 20 1 1/2 275 1 5/8 M39 237
16 400 705 88.9 469.9 7 616 20 1 5/8 285 1 3/4 M42 273
18 450 785 101.6 533.4 7 685.8 20 1 7/8 325 2 M48 367
20 500 855 108 584.2 7 749.3 20 2 350 2 1/8 M52 463
24 600 1040 139.7 692.2 7 901.7 20 2 1/2 440 2 5/8 M64 875
Class 1500 Blind Flange Dimensions
Size in Inch Size in mm Outer Dia. Flange Thick. RF Dia. RF Height PCD No of Bolts Bolt Size UNC RF Stud Length Hole Size ISO Stud Size Weight in kg
A B C D E
1/2 15 120 22.3 34.9 7 82.6 4 3/4 110 7/8 M20 1.8
3/4 20 130 25.4 42.9 7 88.9 4 3/4 115 7/8 M20 2.7
1 25 150 28.6 50.8 7 101.6 4 7/8 125 1 M24 3.7
1 1/4 32 160 28.6 63.5 7 111.1 4 7/8 125 1 M24 4.1
1 1/2 40 180 31.8 73 7 123.8 4 1 140 1 1/8 M27 5.9
2 50 215 38.1 92.1 7 165.1 8 7/8 145 1 M24 10.1
2 1/2 65 245 41.3 104.8 7 190.5 8 1 160 1 1/8 M27 15.9
3 80 265 47.7 127 7 203.2 8 1 1/8 180 1 1/4 M30 21.8
4 100 310 54 157.2 7 241.3 8 1 1/4 195 1 3/8 M33 33
5 125 375 73.1 185.7 7 292.1 8 1 1/2 250 1 5/8 M39 64
6 150 395 82.6 215.9 7 317.5 12 1 3/8 260 1 1/2 M36 75
8 200 485 92.1 269.9 7 393.7 12 1 5/8 290 1 3/4 M42 136
10 250 585 108 323.8 7 482.6 12 1 7/8 335 2 M48 232
12 300 675 123.9 381 7 571.5 16 2 375 2 1/8 M52 314
14 350 750 133.4 412.8 7 635 16 2 1/4 405 2 3/8 M56 443
16 400 825 146.1 469.9 7 704.8 16 2 1/2 445 2 5/8 M64 591
18 450 915 162 533.4 7 774.7 16 2 3/4 495 2 7/8 M72 795
20 500 985 177.8 584.2 7 831.8 16 3 540 3 1/8 M76 1022
24 600 1170 203.2 692.2 7 990.6 16 3 1/2 615 3 5/8 M90 1648
Class 2500 Blind Flange Dimensions
Size in Inch Size in mm Outer Dia. Flange Thick. RF Dia. RF Height PCD No of Bolts Bolt Size UNC RF Stud Length Hole Size ISO Stud Size Weight in kg
A B C D E
1/2 15 135 30.2 34.9 7 88.9 4 3/4 120 7/8 M20 3.2
3/4 20 140 31.8 42.9 7 95.2 4 3/4 125 7/8 M20 3.7
1 25 160 35 50.8 7 108 4 7/8 140 1 M24 5
1 1/4 32 185 38.1 63.5 7 130.2 4 1 150 1 1/8 M27 7.8
1 1/2 40 205 44.5 73 7 146 4 1 1/8 170 1 1/4 M30 10.5
2 50 235 50.9 92.1 7 171.4 8 1 180 1 1/8 M27 18
2 1/2 65 265 57.2 104.8 7 196.8 8 1 1/8 195 1 1/4 M30 25.5
3 80 305 66.7 127 7 228.6 8 1 1/4 220 1 3/8 M33 39
4 100 355 76.2 157.2 7 273 8 1 1/2 255 1 5/8 M39 61.5
5 125 420 92.1 185.7 7 323.8 8 1 3/4 300 1 7/8 M45 102
6 150 485 108 215.9 7 368.3 8 2 345 2 1/8 M52 157
8 200 550 127 269.9 7 438.2 12 2 380 2 1/8 M52 241
10 250 675 165.1 323.8 7 539.8 12 2 1/2 490 2 5/8 M64 470
12 300 760 184.2 381 7 619.1 12 2 3/4 540 2 7/8 M72 575
Blind Flange Weight Chart
Flange Size (inches) Class 150 (lbs) Class 300 (lbs) Class 400 (lbs) Class 600 (lbs) Class 900 (lbs) Class 1500 (lbs) Class 2500 (lbs)
½ 2 2 2 3 4 4 7
¾ 2 3 3 4 6 6 10
1 2 4 4 4 9 9 12
1¼ 3 6 6 6 10 10 18
1½ 4 7 8 8 14 14 25
2 5 8 10 10 25 25 39
2½ 7 12 15 15 32 35 56
3 9 16 20 20 35 48 86
3½ 13 21 29 29 54 73 133
4 17 28 33 41 87 140 223
5 20 37 44 68 115 160 345
6 27 50 61 86 200 302 533
8 47 81 100 140 290 510 1025
10 70 124 155 231 415 775 1464
12 123 185 226 295 520 975
14 140 250 310 378 619 1300
16 180 315 398 527 880 1750
18 220 414 502 665 1107 2225
20 285 515 621 855 2099 3625
22 355 640 720 1000
24 430 800 936 1250
Applications:
- Pipeline Maintenance: Used in situations where the pipeline needs to be temporarily closed.
- Testing: Used during pressure tests to seal off sections of the pipe.
- End Closure: Applied when a pipe needs to be permanently or temporarily sealed.
