Dimensions Spiral Wound Gaskets ASME B16.20

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.
• Thickness of inner and outer ring.. 2.97 mm - 3.33 mm.
• Thickness sealing element.. 4.45 mm.
• Tolerance Outside diameter for NPS 1/2 through NPS 8 is ± 0.8 mm; for NPS 10 trough NPS 24 tolerance is + 1.5 mm - 0.8 mm.
• ASME B16.20 does not covers class 400 flanges up to NPS 3 and class 900 flanges up to NPS 2.1/2.
• There are no class 400 flanges NPS 1/2 thru NPS 3 (use Class 600), class 900 flanges NPS 1/2 thru NPS 2.1/2 (use Class 1500), or class 2500 flanges NPS 14 or larger.
• The inner ring inside diameters shown for NPS 1.1/4 thru 2.1/2 in class 1500 and 2500 will produce inner ring widths of 0.12 inches, a practical minimum for production purposes.
• ASME B16.20 which covers spiral wound gaskets requires the use of solid metal inner rings in.. Pressure Class 900, nominal pipe sizes 24 and larger, Pressure Class 1500 from nominal pipe sizes 12 and larger, Pressure Class 2500 from nominal pipe sizes 4 and larger and all PTFE filled gaskets.