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Technical Library > GASKETS > GASKETS TYPES AND DIMENSIONS > Spiral Wound Gaskets
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SPIRAL WOUND GASKETS


Spiral Wound gaskets are made by combining a metallic winding material with a non-metallic filler material. In this article, we define spiral wound gaskets, illustrate the different available types, the typical materials for the metallic/non-metallic elements and their color coding, and, show the dimensional charts according to ASME B16.20.


 

WHAT ARE SPIRAL WOUND GASKETS?

Spiral wound gaskets are “semi-metallic” gaskets manufactured by combining a metallic material (called the “winding material”) with a non-metallic material (called the “filler material” or “gasket inner material”). The metal component of the spiral wound gasket provides strength and robustness to the seal, whereas the non-metallic component gives great conformability and sealability (resilience).

The dimensions of spiral wound gaskets range from few mm up to 5.000 mm, and the typical thicknesses are 3.2/ 4.5/ 6.4/ 7.2 mm. Spiral wound gaskets are available in different shapes, such as oblong, rectangular, oval, pear and diamond.

 

Spiral wound gaskets

 

Flexitallic USA launched the spiral wound gasket type back in 1912 to cope with an increasing demand for leak-proof sealing solutions in applications with higher and higher temperatures and pressures. Spiral wound gaskets are designed to withstand the mechanical stress generated by severe and fluctuating service conditions on the flanges, the gaskets and the bolting sets of the flanged pipeline joints.

 

flexitallic

 


SPIRAL WOUND GASKETS TYPES

Spiral wound gaskets are available in different configurations depending on the number of rings and material grades combination of the inner rings and the outer rings of the gasket. Semi-metallic gaskets can withstand most operating conditions (pressure and temperature conditions) and are used on raised face flanges (RF), male-and-female flanges (M&F), and tongue-and-groove flanges (T&G). 

Spiral wound gaskets types

  • Type 00: Spiral Wound Gasket without rings: they are used for tongue and groove, male and female flanges.
  • Type 01: Spiral Wound Gasket with inner ring: they are used for male and female or special flange types.
  • Type 10: Spiral Wound Gasket with outer ring: they are used for raised face flanges.
  • Type 101: Spiral Wound Gasket with inner and outer rings: they are used for raised face flanges.
  • Special Section: Spiral Wound Gasket with special rings: they are used for special flanges and special usage.

Each manufacturer, of course, has a specific way of defining the types – however, the configurations are common and are those listed above.

The image shows how the different available types of spiral wound gaskets fit a flanged connection:

types of SW gaskets


SPIRAL WOUND GASKETS MATERIALS

Section of spiral wound gasket

GASKET WINDING MATERIALS

  • SS 304L
  • SS 316L
  • SS 321
  • Titanium
  • Nickel
  • Nickel alloys
  • Duplex

GASKETS FILLER MATERIALS

  • Graphite
  • PTFE
  • Ceramic fibers
  • Non-asbestos

A spiral wound gasket has, as a key sealing element, a formed metal strip. The sealing strips or fillers are usually made of graphite, even if different materials such as PTFE may be used, and the windings are generally made of stainless steel. The gasket is fitted into a steel ring of a specific thickness. When the gasket is fitted with a flange and a bolt load is applied, the steel outer ring of the gasket creates the sealing. To further improve the pressure rating of the spiral wound gasket, a steel ring may be added in the internal part of the gasket (the so-called inner ring). This gives an additional compression and provides a heat and corrosion barrier protecting the gasket windings and the flange from erosion. The inner ring material may be, or not, of the same of the winding metal. The usage of a solid metal inner ring is required by ASME B16.20 for pressure class 900, NPS 24 and larger, pressure class 1500 NPS 12 and larger, pressure class 2500, NPS 4 and larger.

SPIRAL WOUND GASKETS MATERIALS MECHANICAL PROPERTIES

(TRADE NAME)

DIN 

SPECIFICATION

DIN 

MATERIAL NR.

AISI UNS

B.S 

ASTM

HARDNESS 

HV 10*

TEMP. [°C] VOLUMETRIC MASS [G/CM3]
MIN. MAX.
Soft Iron (Armco) 1.1003 90 – 100 -60 500 7.85
Steel (LCS) RSt.37.2 1.0038 100 – 130 -40 500 7.85
Stainless Steel 304 X5CrNi 18 1.4301 304 304S15/16/31 130 – 180 -250 550 7,9
Stainless Steel 304 L X2CrNi 189 1.4306 304L 304S11 130 – 190 -250 550 7,9
Stainless Steel 309 X15CrNiMo 2012 1.4828 309 309S24 130 – 190 -100 1000 7,9
Stainless Steel 316 X5CrNiMo 1810 1.4401 316 316S31/33 130 – 180 -100 550 7,9
Stainless Steel 316 L X2CrNiMo 1810 1.4404 316L 316S11/13 130 – 190 -100 550 7,9
Stainless Steel 316 Ti X10CrNiMoTi 1810 1.4571 316Ti 320S31 130 – 190 -100 550 7,8
Stainless Steel 321 X10CrNiTi 189 1.4541 321 321S12/49/87 130 – 190 -250 550 7,9
Stainless Steel 347 X10CrNiNb 189 1.4550 347 347S31 130 – 190 -250 550 7,9
Nickel 200 Ni 99.2 2,4066 NO2200 3072-76 NA11 90 – 120 -250 600 8,9
Monel 400 NiCu 30 Fe 2.4360 NO4400 3072-76 NA13 110 – 150 -125 600 8,8
Inconel 600 NiCr 15 Fe 2.4816 NO6600 3072-76 NA14 120 – 180 -100 950 8,4
Incoloy 800 X10NiCrAITi 3220 1.4876 NO8800 3072-76 NA15 140 – 220 -100 850 8,4
Incoloy 825 NiCR 21 Mo 2.4858 NO8825 3072-76 NA 16 120 – 180 -100 450 8,14
Hastelloy B2 NMo 28 2.4617 N10665 170 – 230 -200 450 9,2
Hasetlloy C276 ‘NiMo 16Cr15W 2.4819 N10276 170 – 230 -200 450 8.9
Titanium Ti 99,8 3.7025 110 – 140 -250 500 4,5

SPIRAL WOUND GASKETS COLOR CODES

Carbon steel and stainless steel winding materials color code for spiral wound gaskets:

Metallic Material Abbreviated Material Name Color Code
Carbon steel CRS Silver
304 SS 304 Yellow
304 L SS 304 L No color
309 SS 309 No color
316 L SS 316 L Green
347 SS 347 Blue
321 SS 321 Turquoise
Monel 400 MON Orange
Nickel 200 NI Red
Titanium TI Purple
Hastelloy B HAST B Brown
Hastelloy C HAST C Beige

 

Nickel-alloy winding materials color code for spiral wound gaskets:

Inconel 600 INC 600 Gold
Inconel 625 INC 625 Gold
Incoloy 800 IN 800 White
Incoloy 825 IN 825 White

Filler materials color code for spiral wound gaskets:

Polytetrafluoroethylene PTFE White stripe
Mica-graphite Manufacturer’s designation Pink stripe
Flexible graphite F.G. Gray stripe
Ceramic CER Light green stripe

 


MARKINGS ON SPIRAL WOUND GASKETS

The illustration shows the configuration of a typical spiral wound gaskets and the usual manufacturers’ markings:

Spiral wound gasket assembly

 


 

SPIRAL WOUND GASKETS DIMENSIONS

Dimensions of Spiral Wound Gaskets Class 150 (ASME B16.20 for ASME B16.5 RF Flanges)

Spiral wound gaskets sizes

NPS Inner Ring Sealing Element Outer Ring
Inside Diameter (d1) Inside Diameter (d2) Outside Diameter(d3) Outside Diameter (d4)
1/2 14.2 19.1 31.8 47.8
3/4 20.6 25.4 39.6 57.2
1 26.9 31.8 47.8 66.8
38.1 47.8 60.5 76.2
44.5 54.1 69.9 85.9
2 55.6 69.9 85.9 104.9
66.5 82.6 98.6 124
3 81 101.6 120.7 136.7
4 106.4 127 149.4 174.8
5 131.8 155.7 177.8 196.9
6 157.2 182.6 209.6 222.3
8 215.9 233.4 263.7 279.4
10 268.2 287.3 317.5 339.9
12 317.5 339.9 374.7 409.7
14 349.3 371.6 406.4 450.9
16 400.1 422.4 463.6 514.4
18 449.3 474.7 527.1 549.4
20 500.1 525.5 577.9 606.6
24 603.3 628.7 685.8 717.6

NOTES: • All dimensions are in millimeters • Spiral Wound gasket with Inner – and Outer ring • d1 = Inside diameter Inner ring. • d2 = Inside diameter sealing element when no Inner ring is used. • d3 = Outside diameter of sealing element. • d4 = Outside diameter of an Outer ring

The 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 through NPS 24 tolerance is + 1.5 mm – 0.8 mm. • There is 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. 

 

Dimensions of Spiral Wound Gaskets Class 300 (ASME B16.20 for ASME B16.5 RF Flanges)

Spiral wound gaskets sizes

NPS Inner Ring Sealing Element Outer Ring
Inside Diameter (d1) Inside Diameter (d2) Outside Diameter (d3) Outside Diameter (d4)
1/2 14.2 19.1 31.8 54.1
3/4 20.6 25.4 39.6 66.8
1 26.9 31.8 47.8 73.2
38.1 47.8 60.5 82.6
44.5 54.1 69.9 95.3
2 55.6 69.9 85.9 111.3
66.5 82.6 98.6 130.3
3 81 101.6 120.7 149.4
4 106.4 127 149.4 181.1
5 131.8 155.7 177.8 215.9
6 157.2 182.6 209.6 251
8 215.9 233.4 263.7 308.1
10 268.2 287.3 317.5 362
12 317.5 339.9 374.7 422.4
14 349.3 371.6 406.4 485.9
16 400.1 422.4 463.6 539.8
18 449.3 474.7 527.1 596.9
20 500.1 525.6 577.9 654.1
24 603.3 628.7 685.8 774.7

NOTES: • All dimensions are in millimeters • Spiral Wound gasket with Inner – and Outer ring • d1 = Inside diameter Inner ring. • d2 = Inside diameter sealing element when no Inner ring is used. • d3 = Outside diameter of sealing element. • d4 = Outside diameter of an Outer ring

The 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 through NPS 24 tolerance is + 1.5 mm – 0.8 mm. • There is 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. 

 

Dimensions of Spiral Wound Gaskets Class 400 (ASME B16.20 for ASME B16.5 RF Flanges)

Spiral wound gaskets sizes

NPS Inner Ring Sealing Element Outer Ring
Inside Diameter (d1) Inside Diameter (d2) Outside Diameter (d3) Outside Diameter (d4)
1/2 14.2 19.1 31.8 54.1
3/4 20.6 25.4 39.6 66.8
1 26.9 31.8 47.8 73.2
38.1 47.8 60.5 82.6
44.5 54.1 69.9 95.3
2 55.6 69.9 85.9 111.3
66.5 82.6 98.6 130.3
3 81 101.6 120.7 149.4
4 102.6 120.7 149.4 177.8
5 128.3 147.6 177.8 212.9
6 154.9 174.8 209.6 247.7
8 205.7 225.6 263.7 304.8
10 255.3 274.6 317.5 358.9
12 307.3 327.2 374.7 419.1
14 342.9 362 406.4 482.6
16 389.9 412.8 463.6 536.7
18 438.2 469.9 527.1 593.9
20 489 520.7 577.9 647.7
24 590.6 628.7 685.8 768.4

NOTES: • All dimensions are in millimeters • Spiral Wound gasket with Inner – and Outer ring • d1 = Inside diameter Inner ring. • d2 = Inside diameter sealing element when no Inner ring is used. • d3 = Outside diameter of sealing element. • d4 = Outside diameter of an Outer ring

The 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 through NPS 24 tolerance is + 1.5 mm – 0.8 mm. • There is 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. 

 

Dimensions Spiral Wound Gaskets Class 600 (ASME B16.20 for ASME B16.5 RF Flanges)

Spiral wound gaskets sizes

NPS Inner Ring Sealing Element Outer Ring
Inside Diameter (d1) Inside Diameter (d2) Outside Diameter (d3) Outside Diameter (d4)
1/2 14.2 19.1 31.8 54.1
3/4 20.6 25.4 39.6 66.8
1 26.9 31.8 47.8 73.2
38.1 47.8 60.5 82.6
44.5 54.1 69.9 95.3
2 55.6 69.9 85.9 111.3
66.5 82.6 98.6 130.3
3 78.7 101.6 120.7 149.4
4 102.6 120.7 149.4 193.8
5 128.3 147.6 177.8 241.3
6 154.9 174.8 209.6 266.7
8 205.7 225.6 263.7 320.8
10 255.3 274.6 317.5 400.1
12 307.3 327.2 374.7 457.2
14 342.9 362 406.4 492.3
16 389.9 412.8 463.6 565.2
18 438.2 469.9 527.1 612.9
20 489 520.7 577.9 682.8
24 590.6 628.7 685.8 790.7

NOTES: • All dimensions are in millimeters • Spiral Wound gasket with Inner – and Outer ring • d1 = Inside diameter Inner ring. • d2 = Inside diameter sealing element when no Inner ring is used. • d3 = Outside diameter of sealing element. • d4 = Outside diameter of an Outer ring

The 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 through NPS 24 tolerance is + 1.5 mm – 0.8 mm. • There is 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. 

 

Dimensions of Spiral Wound Gaskets Dimensions Class 900 (ASME B16.20 for ASME B16.5 RF Flanges)

Spiral wound gaskets sizes

NPS Inner Ring Sealing Element Outer Ring
Inside Diameter (d1)  Inside Diameter (d2)  Outside Diameter(d3)  Outside Diameter (d4)
1/2 14.2 19.1 31.8 63.5
3/4 20.6 25.4 39.6 69.9
1 26.9 31.8 47.8 79.5
33.3 39.6 60.5 88.9
41.4 47.8 69.9 98.6
2 52.3 58.7 85.9 143
63.5 69.9 98.6 165.1
3 78.7 95.3 120.7 168.4
4 102.6 120.7 149.4 206.5
5 128.3 147.6 177.8 247.7
6 154.9 174.8 209.6 289.1
8 196.9 222.3 257.3 358.9
10 246.1 276.4 311.2 435.1
12 292.1 323.9 368.3 498.6
14 320.8 355.6 400.1 520.7
16 374.7 412.8 457.2 574.8
18 425.5 463.6 520.7 638.3
20 482.6 520.7 571.5 698.5
24 590.6 628.7 679.5 838.2

NOTES: • All dimensions are in millimeters • Spiral Wound gasket with Inner – and Outer ring • d1 = Inside diameter Inner ring. • d2 = Inside diameter sealing element when no Inner ring is used. • d3 = Outside diameter of sealing element. • d4 = Outside diameter of an Outer ring

The 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 through NPS 24 tolerance is + 1.5 mm – 0.8 mm. • There is 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. 

 

Dimensions of Spiral Wound Gaskets Class 1500 (ASME B16.20 for ASME B16.5 RF Flanges)

Spiral wound gaskets sizes

NPS Inner Ring Sealing Element Outer Ring
Inside Diameter (d1)   Inside Diameter (d2)  Outside Diameter(d3)  Outside Diameter (d4)
1/2 14.2 19.1 31.8 63.5
3/4 20.6 25.4 39.6 69.9
1 26.9 31.8 47.8 79.5
33.3 39.6 60.5 88.9
41.4 47.8 69.9 98.6
2 52.3 58.7 85.9 143
63.5 69.9 98.6 165.1
3 78.7 92.2 120.7 174.8
4 97.8 117.6 149.4 209.6
5 124.5 143 177.8 254
6 147.3 171.5 209.6 282.7
8 196.9 215.9 257.3 352.6
10 246.1 266.7 311.2 435.1
12 292.1 323.9 368.3 520.7
14 320.8 362 400.1 577.9
16 374.7 406.4 457.2 641.4
18 425.5 463.6 520.7 704.9
20 476.3 514.4 571.5 755.7
24 577.9 616 679.5 901.7
NOTES: • All dimensions are in millimeters • Spiral Wound gasket with Inner – and Outer ring • d1 = Inside diameter Inner ring. • d2 = Inside diameter sealing element when no Inner ring is used. • d3 = Outside diameter of sealing element. • d4 = Outside diameter of an Outer ring

The 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 through NPS 24 tolerance is + 1.5 mm – 0.8 mm. • There is 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. 

 

Dimensions of Spiral Wound Gaskets Class 2500 (ASME B16.20 for ASME B16.5 RF Flanges)

Spiral wound gaskets sizes

NPS Inner Ring Sealing Element Outer Ring
 Inside Diameter (d1)  Inside Diameter (d2)  Outside Diameter(d3)  Outside Diameter (d4)
1/2 14.2 19.1 31.8 69.9
3/4 20.6 25.4 39.6 76.2
1 26.9 31.8 47.8 85.9
33.3 39.6 60.5 104.9
41.4 47.8 69.9 117.6
2 52.3 58.7 85.9 146
63.5 69.9 98.6 168.4
3 78.7 92.2 120.7 196.9
4 97.8 117.6 149.4 235
5 124.5 143 177.8 279.4
6 147.3 171.5 209.6 317.5
8 196.9 215.9 257.3 387.4
10 246.1 270 311.2 476.3
12 292.1 317.5 368.3 549.4

NOTES: • All dimensions are in millimeters • Spiral Wound gasket with Inner – and Outer ring • d1 = Inside diameter Inner ring. • d2 = Inside diameter sealing element when no Inner ring is used. • d3 = Outside diameter of sealing element. • d4 = Outside diameter of an Outer ring

The 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 through NPS 24 tolerance is + 1.5 mm – 0.8 mm. • There is 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. 

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