Dimensions of Spiral Wound Gaskets ASME B16.20
used with Raised Face flanges ASME B16.47 series A
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.
he 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.
