Dimensions of Spiral Wound Gaskets ASME B16.20
used with Raised Face flanges ASME B16.47 series B
OTHER PRESSURE CLASSES
400
| NPS | Inner Ring | Sealing Element | Outer Ring | |
| d1 | d2 | d3 | d4 | |
| 26 | 654.1 | 666.8 | 698.5 | 746.3 |
| 28 | 701.8 | 714.5 | 749.3 | 800.1 |
| 30 | 752.6 | 765.3 | 806.5 | 857.3 |
| 32 | 800.1 | 812.8 | 860.6 | 911.4 |
| 34 | 850.9 | 866.9 | 911.4 | 962.2 |
| 36 | 898.7 | 917.7 | 965.2 | 1022.4 |
| 38 | 952.5 | 971.6 | 1022.4 | 1073.2 |
| 40 | 1000.3 | 1025.7 | 1076.5 | 1127.3 |
| 42 | 1051.1 | 1076.5 | 1127.3 | 1178.1 |
| 44 | 1104.9 | 1130.3 | 1181.1 | 1231.9 |
| 46 | 1168.4 | 1193.8 | 1244.6 | 1289.1 |
| 48 | 1206.5 | 1244.6 | 1295.4 | 1346.2 |
| 50 | 1257.3 | 1295.4 | 1346.2 | 1403.4 |
| 52 | 1308.1 | 1346.2 | 1397 | 1454.2 |
| 54 | 1352.6 | 1403.4 | 1454.2 | 1517.7 |
| 56 | 1403.4 | 1454.2 | 1505 | 1568.5 |
| 58 | 1454.2 | 1505 | 1555.8 | 1619.3 |
| 60 | 1517.7 | 1568.5 | 1619.3 | 1682.8 |
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
