Dimensions of Spiral Wound Gaskets ASME B16.20
used with Raised Face flanges ASME B16.5



 
Class 400 - NPS 1/2-24

Class 150 | 300 | 400 | 600 | 900 | 1500 | 2500

Class  400  NPS 1/2-24
NPSInner RingSealing ElementOuter Ring
Inside (d1)
Dia.
Inside (d2)
Dia.
Outside (d3)
Dia.
Outside (d4)
Dia.
1/214.219.131.854.1
3/420.625.439.666.8
126.931.847.873.2
38.147.860.582.6
44.554.169.995.3
255.669.985.9111.3
66.582.698.6130.3
381101.6120.7149.4
4102.6120.7149.4177.8
5128.3147.6177.8212.9
6154.9174.8209.6247.7
8205.7225.6263.7304.8
10255.3274.6317.5358.9
12307.3327.2374.7419.1
14342.9362406.4482.6
16389.9412.8463.6536.7
18438.2469.9527.1593.9
20489520.7577.9647.7
24590.6628.7685.8768.4
NPSInside (d1)
Dia.
Inside (d2)
Dia.
Outside (d3)
Dia.
Outside (d4)
Dia.
Inner RingSealing ElementOuter Ring
 

 

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 2½.
  • There are no class 400 flanges NPS 1/2 thru NPS 3 (use Class 600), class 900 flanges NPS 1/2 thru NPS 2½ (use Class 1500), or class 2500 flanges NPS 14 or larger.
  • The inner ring inside diameters shown for NPS 1¼ thru 2½ 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.

Marking of Spiral Wound Gaskets