Dimensions of Spiral Wound Gaskets ASME B16.20
used with Raised Face flanges ASME B16.47 series A
OTHER PRESSURE CLASSES
300
| NPS | Inner Ring | Sealing Element | Outer Ring | |
| d1 | d2 | d3 | d4 | |
| 26 | 654.1 | 685.8 | 736.6 | 835.2 |
| 28 | 704.9 | 736.6 | 787.4 | 898.7 |
| 30 | 755.7 | 793.8 | 844.6 | 952.5 |
| 32 | 806.5 | 850.9 | 901.7 | 1006.6 |
| 34 | 857.3 | 901.7 | 952.5 | 1057.4 |
| 36 | 908.1 | 955.8 | 1006.6 | 1117.6 |
| 38 | 952.5 | 977.9 | 1016 | 1054.1 |
| 40 | 1003.3 | 1022.4 | 1070.1 | 1114.6 |
| 42 | 1054.1 | 1073.2 | 1120.9 | 1165.4 |
| 44 | 1104.9 | 1130.3 | 1181.1 | 1219.2 |
| 46 | 1152.7 | 1178.1 | 1228.9 | 1273.3 |
| 48 | 1209.8 | 1235.2 | 1286 | 1324.1 |
| 50 | 1244.6 | 1295.4 | 1346.2 | 1378 |
| 52 | 1320.8 | 1346.2 | 1397 | 1428.8 |
| 54 | 1352.6 | 1403.4 | 1454.2 | 1492.3 |
| 56 | 1403.4 | 1454.2 | 1505 | 1543.1 |
| 58 | 1447.8 | 1511.3 | 1562.1 | 1593.9 |
| 60 | 1524 | 1562.1 | 1612.9 | 1644.7 |
General notes..
- Dimensions are in millimeters unless otherwise indicated.
- Image shows a Spiral Wound gasket with Inner - and Outer ring.
- d1 = Inside diameter when Inner ring is used.
- d2 = Inside diameter sealing element when no Inner ring is used.
- d3 = Outside diameter of sealing element.
- d4 = Outside diameter of Outer ring.
- The gasket thickness tolerance is ± 0.13 mm measured across the metallic portion of the gasket, not including the filler, which may protrude slightly beyond the metal.
- The gasket inside diameter tolerance for NPS 26 through NPS 34 is ± 0.8 mm, and the tolerance for NPS 36 through NPS 60 is ± 1.3 mm.
- The gasket outside diameter tolerance for NPS 26 through NPS 60 is ± 1.5 mm.
- The centering ring outside diameter tolerance is ± 0.8 mm.
- The inside diameter tolerance is ± 3.0 mm.
- Thickness of inner and outer ring.. 2.97 mm - 3.33 mm.
- ASME B16.47 Series A flanges NPS 12 through NPS 24 have the same raised face dimensions as ASME B16.5 flanges.
- There are no Class 900 flanges NPS 50 and larger.
Marking of Spiral Wound Gaskets
