Spectacle Blind Flange ASME B16.48 Manafacturer in China
A spectacle blind flange,also knowns as Figure 8 flanges, is a dual-plate piping component—shaped like a pair of spectacles or figuire 8,—with one solid (blind) plate and one ring-shaped (spacer) plate joined together. It allows you to quickly switch a pipeline or valve between an open (flow) position and a closed (isolation) position without disassembling the flange connection.
ASTM A182 F53 UNS S32750 Spectacle Blind Flange (ASME B16.48)
- Material: ASTM A182 F53 (UNS S32750)Super duplex stainless steel
- Standard: ASME B16.48
- Pressure Classes: 150# – 2500#
- Nominal Sizes: ½″ – 24″
- Face Types: Raised Face (RF), Ring Type Joint (RTJ) Flat Face,(FF)
ASME B16.48 standard for Spectacle blind flange,Paddle Blank and Spacer
This Standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing for operational line blanks in sizes NPS 1/2 through NPS 24 for installation between ASME B16.5 flanges in the 150, 300, 600, 900, 1500, and 2500 pressure classes.
astm a182 f53 material has carbon, manganese, phosphorus, silicon, 24% chromium, 6% nickel, 3% molybdenum and nickel and copper.
astm a182 f53 Chemical composition
Grade | UNS Designation | Composition, % | ||||||||||
ASTM A182 Grade F53 | S32750 | C | Mn | P | S | Si | Ni | Cr | Mo | CbB | Ti | Other Elements |
0.03 | 1.2 | 0.035 | 0.02 | 0.8 | 6.0-8.0 | 24.0-26.0 | 3.0-5.0 | N 0.24-0.32 Cu 0.50 |
Super duplex material ASTM A182 F53 can be used for Oil and gas industry equipment, Offshore platforms, heat exchangers, process and service water systems, fire-fighting systems, injection and ballast water systems, Chemical process industries, heat exchangers, vessels, and piping,
Typical Applications of Super Duplex F53
- Oil & Gas: Wellhead Christmas trees, pipeline isolation, pressure testing.
- Petrochemical: Reactor feed isolation, heat exchanger maintenance.
- Power Generation: Turbine bypass circuits, condenser tube bundle testing.
- Marine & Offshore: Ballast systems, fire-water loops, chemical injection lines.
Dimensions Spectacle Blinds ASME B16.48

Pressure Class 150
NPS | Outside Ø A | Inside Ø B | Center Line C | THK t | Web Width W |
1/2 | 45 | 16 | 60 | 3 | 38 |
3/4 | 54 | 21 | 70 | 3 | 38 |
1 | 64 | 27 | 80 | 3 | 38 |
1.1/4 | 73 | 42 | 90 | 6.4 | 38 |
1.1/2 | 83 | 48 | 100 | 6.4 | 38 |
2 | 102 | 61 | 120 | 6.4 | 51 |
2.1/2 | 107 | 73 | 140 | 6.4 | 51 |
3 | 133 | 89 | 150 | 6.4 | 64 |
3.1/2 | 159 | 102 | 175 | 9.7 | 64 |
4 | 172 | 114 | 190 | 9.7 | 64 |
5 | 194 | 141 | 215 | 9.7 | 76 |
6 | 219 | 168 | 240 | 12.7 | 76 |
8 | 276 | 219 | 300 | 12.7 | 76 |
10 | 337 | 273 | 360 | 15.7 | 102 |
12 | 406 | 324 | 430 | 19.1 | 102 |
14 | 448 | 356 | 475 | 19.1 | 108 |
16 | 511 | 406 | 460 | 22.4 | 108 |
18 | 546 | 457 | 580 | 25.4 | 114 |
20 | 603 | 508 | 635 | 28.4 | 121 |
24 | 714 | 610 | 750 | 31.8 | 140 |
Pressure Class 300
NPS | Outside Ø A | Inside Ø B | Center Line C | THK t | Web Width W |
1/2 | 51 | 16 | 65 | 6.4 | 38 |
3/4 | 64 | 21 | 80 | 6.4 | 38 |
1 | 70 | 27 | 90 | 6.4 | 38 |
1.1/4 | 79 | 42 | 100 | 6.4 | 38 |
1.1/2 | 92 | 48 | 115 | 6.4 | 38 |
2 | 108 | 61 | 125 | 9.7 | 51 |
2.1/2 | 127 | 73 | 150 | 9.7 | 51 |
3 | 146 | 89 | 170 | 9.7 | 64 |
3.1/2 | 162 | 102 | 185 | 12.7 | 64 |
4 | 178 | 114 | 200 | 12.7 | 64 |
5 | 213 | 141 | 235 | 15.7 | 76 |
6 | 248 | 168 | 270 | 15.7 | 76 |
8 | 305 | 219 | 330 | 22.4 | 76 |
10 | 359 | 273 | 385 | 25.4 | 102 |
12 | 419 | 324 | 450 | 28.4 | 102 |
14 | 483 | 356 | 515 | 31.8 | 108 |
16 | 536 | 406 | 570 | 38.1 | 108 |
18 | 594 | 457 | 630 | 41.1 | 114 |
20 | 651 | 508 | 685 | 44.5 | 121 |
24 | 772 | 610 | 810 | 50.8 | 140 |
Pressure Class 600
NPS | Outside Ø A | Inside Ø B | Center Line C | THK t | Web Width W |
1/2 | 51 | 16 | 65 | 6.4 | 38 |
3/4 | 64 | 21 | 80 | 6.4 | 38 |
1 | 70 | 27 | 90 | 6.4 | 57 |
1.1/4 | 79 | 37 | 100 | 9.7 | 57 |
1.1/2 | 92 | 43 | 115 | 9.7 | 67 |
2 | 108 | 55 | 125 | 9.7 | 57 |
2.1/2 | 127 | 67 | 150 | 12.7 | 67 |
3 | 146 | 83 | 170 | 12.7 | 67 |
3.1/2 | 159 | 96 | 185 | 15.7 | 76 |
4 | 191 | 108 | 215 | 15.7 | 76 |
5 | 238 | 135 | 265 | 19.1 | 86 |
6 | 264 | 162 | 290 | 22.4 | 86 |
8 | 318 | 212 | 350 | 28.4 | 95 |
10 | 397 | 265 | 430 | 35.1 | 105 |
12 | 454 | 315 | 490 | 41.1 | 105 |
14 | 489 | 346 | 525 | 44.5 | 114 |
16 | 562 | 397 | 605 | 50.8 | 124 |
18 | 610 | 448 | 655 | 53.8 | 133 |
20 | 679 | 497 | 725 | 63.5 | 133 |
24 | 787 | 597 | 840 | 73.2 | 152 |
Pressure Class 900
NPS | Outside Ø A | Inside Ø B | Center Line C | THK t | Web Width W |
1/2 | 60 | 16 | 80 | 6.4 | 38 |
3/4 | 67 | 21 | 90 | 6.4 | 41 |
1 | 76 | 27 | 100 | 6.4 | 57 |
1.1/4 | 86 | 37 | 110 | 9.7 | 57 |
1.1/2 | 95 | 43 | 125 | 9.7 | 67 |
2 | 140 | 55 | 165 | 12.7 | 57 |
2.1/2 | 162 | 67 | 190 | 12.7 | 67 |
3 | 165 | 83 | 190 | 15.7 | 67 |
4 | 203 | 108 | 235 | 19.1 | 76 |
5 | 244 | 135 | 280 | 22.4 | 86 |
6 | 286 | 162 | 320 | 25.4 | 86 |
8 | 356 | 212 | 395 | 35.1 | 95 |
10 | 432 | 265 | 470 | 41.1 | 105 |
12 | 495 | 315 | 535 | 47.8 | 105 |
14 | 518 | 346 | 560 | 53.8 | 114 |
16 | 572 | 397 | 615 | 60.5 | 124 |
18 | 635 | 448 | 685 | 66.5 | 133 |
20 | 696 | 497 | 750 | 73.2 | 133 |
24 | 835 | 597 | 900 | 88.9 | 152 |
Pressure Class 1500
NPS | Outside Ø A | Inside Ø B | Center Line C | THK t | Web Width W |
1/2 | 61 | 16 | 80 | 6.4 | 38 |
3/4 | 67 | 21 | 90 | 9.7 | 41 |
1 | 76 | 27 | 100 | 9.7 | 64 |
1.1/4 | 86 | 35 | 110 | 9.7 | 64 |
1.1/2 | 95 | 41 | 125 | 12.7 | 70 |
2 | 140 | 53 | 165 | 12.7 | 70 |
2.1/2 | 162 | 63 | 190 | 15.7 | 76 |
3 | 172 | 78 | 205 | 19.1 | 76 |
4 | 206 | 102 | 240 | 22.4 | 89 |
5 | 251 | 128 | 290 | 28.4 | 89 |
6 | 279 | 154 | 320 | 35.1 | 89 |
8 | 349 | 203 | 395 | 41.1 | 102 |
10 | 432 | 255 | 480 | 50.8 | 114 |
12 | 518 | 303 | 570 | 60.5 | 114 |
14 | 575 | 333 | 635 | 66.5 | 127 |
16 | 638 | 381 | 705 | 76.2 | 133 |
18 | 702 | 429 | 775 | 85.9 | 146 |
20 | 752 | 478 | 830 | 95.3 | 152 |
24 | 899 | 575 | 990 | 111.3 | 178 |
Pressure Class 2500
NPS | Outside Ø A | Inside Ø B | Center Line C | THK t | Web Width W |
1/2 | 67 | 16 | 90 | 9.7 | 38 |
3/4 | 73 | 21 | 95 | 9.7 | 41 |
1 | 83 | 27 | 110 | 9.7 | 64 |
1.1/4 | 102 | 35 | 130 | 12.7 | 64 |
1.1/2 | 114 | 41 | 145 | 15.7 | 70 |
2 | 143 | 53 | 170 | 15.7 | 70 |
2.1/2 | 165 | 63 | 195 | 19.1 | 76 |
3 | 194 | 78 | 230 | 22.4 | 76 |
4 | 232 | 102 | 275 | 28.4 | 89 |
5 | 276 | 128 | 325 | 35.1 | 89 |
6 | 314 | 154 | 370 | 41.1 | 89 |
8 | 384 | 198 | 440 | 53.8 | 102 |
10 | 473 | 248 | 540 | 66.5 | 114 |
12 | 546 | 289 | 620 | 79.2 | 114 |
General notes..
- Dimensions are in millimeters unless otherwise indicated.
- D = Hole size (where required) should be the same as the flange bolt hole. In practice, these dimensions have been rounded round off upwards.
- Wt = Thickness of the web (or tie bar) should be 6 mm minimum, or equal to Thickness (t) if less than 6 mm.
- Spectacle Blinds should be made from a plate or forging specification, approved for use by ASME B31.3, of essentially the same chemical composition as the mating flanges and piping involved.
- Spectacle Blinds ASME B16.48 may be used for installation between ASME B16.5 flanges
- Depending on a customer specification, some dimensions can be different from what on this page is defined.