Dimensions Spectacle Blinds – ASME B16.48

Spectacle Blinds

Class 150

NPS Outside Ø
A
Inside Ø
B
Centerline
C
Thickness
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
NPS Outside Ø
A
Inside Ø
B
Centerline
C
Thickness
t
Web Width
W
Spectacle Blinds

Class 300

NPS Outside Ø
A
Inside Ø
B
Centerline
C
Thickness
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
NPS Outside Ø
A
Inside Ø
B
Centerline
C
Thickness
t
Web Width
W
Spectacle Blinds

Class 600

NPS Outside Ø
A
Inside Ø
B
Centerline
C
Thickness
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
NPS Outside Ø
A
Inside Ø
B
Centerline
C
Thickness
t
Web Width
W
Spectacle Blinds

Class 900

NPS Outside Ø
A
Inside Ø
B
Centerline
C
Thickness
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
NPS Outside Ø
A
Inside Ø
B
Centerline
C
Thickness
t
Web Width
W
Spectacle Blinds

Class 1500

NPS Outside Ø
A
Inside Ø
B
Centerline
C
Thickness
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
NPS Outside Ø
A
Inside Ø
B
Centerline
C
Thickness
t
Web Width
W
Spectacle Blinds

Class 2500

NPS Outside Ø
A
Inside Ø
B
Centerline
C
Thickness
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
NPS Outside Ø
A
Inside Ø
B
Centerline
C
Thickness
t
Web Width
W

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 according to 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.

Remark(s) of the Author…

Spectacle Blind with Raised Face

Raised Face Joint Blanks

  • ASME B16.48 says: The gasket seating surface finish and dimensions for raised face line blanks shall be in accordance with ASME B16.5. A raised face may be specified at the option of the purchaser.
  • A Raised Face would add machining time and complexity so the price would be higher. Call this the Bugatti or Rolls Royce of the line blind world.
  • Personally, I have seen that version once or twice somewhere. The version without Raised Face is the default and is used everywhere.