Dimensions of Spiral Wound Gaskets ASME B16.20
used with Raised Face flanges ASME B16.47 series A
OTHER PRESSURE CLASSES
150
| NPS | Inner Ring | Sealing Element | Outer Ring | |
| d1 | d2 | d3 | d4 | |
| 26 | 654.1 | 673.1 | 704.9 | 774.7 |
| 28 | 704.9 | 723.9 | 755.7 | 831.9 |
| 30 | 755.7 | 774.7 | 806.5 | 882.7 |
| 32 | 806.5 | 825.5 | 860.6 | 939.8 |
| 34 | 857.3 | 876.3 | 911.4 | 990.6 |
| 36 | 908.1 | 927.1 | 968.5 | 1047.8 |
| 38 | 958.9 | 977.9 | 1019.3 | 1111.3 |
| 40 | 1009.7 | 1028.7 | 1070.1 | 1162.1 |
| 42 | 1060.5 | 1079.5 | 1124 | 1219.2 |
| 44 | 1111.3 | 1130.3 | 1178.1 | 1276.4 |
| 46 | 1162.1 | 1181.1 | 1228.9 | 1327.2 |
| 48 | 1212.9 | 1231.9 | 1279.7 | 1384.3 |
| 50 | 1263.7 | 1282.7 | 1333.5 | 1435.1 |
| 52 | 1314.5 | 1333.5 | 1384.3 | 1492.3 |
| 54 | 1358.9 | 1384.3 | 1435.1 | 1549.4 |
| 56 | 1409.7 | 1435.1 | 1485.9 | 1606.6 |
| 58 | 1460.5 | 1485.9 | 1536.7 | 1663.7 |
| 60 | 1511.3 | 1536.7 | 1587.5 | 1714.5 |
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
