Dimensions of Spiral Wound Gaskets ASME B16.20
used with Raised Face flanges ASME B16.47 series B
OTHER PRESSURE CLASSES
300
| NPS | Inner Ring | Sealing Element | Outer Ring | |
| d1 | d2 | d3 | d4 | |
| 26 | 654.1 | 673.1 | 711.2 | 771.7 |
| 28 | 704.9 | 723.9 | 762 | 825.5 |
| 30 | 755.7 | 774.7 | 812.8 | 886 |
| 32 | 806.5 | 825.5 | 863.6 | 939.8 |
| 34 | 857.3 | 876.3 | 914.4 | 993.9 |
| 36 | 908.1 | 927.1 | 965.2 | 1047.8 |
| 38 | 971.6 | 1009.7 | 1047.8 | 1098.6 |
| 40 | 1022.4 | 1060.5 | 1098.6 | 1149.4 |
| 42 | 1085.9 | 1111.3 | 1149.4 | 1200.2 |
| 44 | 1124 | 1162.1 | 1200.2 | 1251 |
| 46 | 1178.1 | 1216.2 | 1254.3 | 1317.8 |
| 48 | 1231.9 | 1263.7 | 1311.4 | 1368.6 |
| 50 | 1267 | 1317.8 | 1355.9 | 1419.4 |
| 52 | 1317.8 | 1368.6 | 1406.9 | 1470.2 |
| 54 | 1365.3 | 1403.4 | 1454.2 | 1530.4 |
| 56 | 1428.8 | 1479.6 | 1524 | 1593.9 |
| 58 | 1484.4 | 1535.2 | 1573.3 | 1655.8 |
| 60 | 1557.3 | 1589 | 1630.4 | 1706.6 |
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
