Spiral Wound Gaskets

Spiral wound gaskets are widely used in the oil & gas industry, particularly in high operating pressure and critical applications.

MSI is a gasket distributor, offering spiral wound gaskets in 304 & 316 stainless steel, along with several special alloys. With sizes ranging from 1/4” to 36", MSI can provide the gaskets required for virturally any project.

Spiral Wound Gaskets—MSI Supply, Inc. Get A Quote


This results in a growing circle of alternating layers of filler material and metal strip. The guide ring of a spiral wound gasket allows for the centering of the sealing element on the flange face, as well as delivers additional radial strength, and acts as a compression limiter. The outer metal ring of a spiral wound gasket holds the windings of the gasket in place and centers the gasket between the flange bolting, aligning the sealing surfaces.

The finished product will resemble the spiral wound gasket image below, with the various components discussed here indicated with labels.

Spiral Wound Gasket Chart

 

Inventory

MSI Supply stocks the following spiral wound gaskets and can often provide them same-day delivery.  MSI can also provide spiral wound gaskets with larger diameters, as well as special alloys (Alloy 20, Monel, Hastelloy, Inconel, Titanium, etc), however these items may be subject to a longer lead time for delivery.

Size Range:

¼” to 36” Diameter

Class:

150 – 2500

Windings:

304 SS, 316 SS

Filler:

Graphite, Teflon

 

Ordering Information

There are some need to know details when purchasing spiral wound gaskets, such as, diameter, pressure rating, series A or B (above NPS 24”), whether there is an inner ring, if so, then material for the inner ring, winding, filler, and outer ring.

Pressure Class

Corresponding to flange pressure classes, spiral wound gaskets are available in 150, 300, 600, 900, 1500, and 2500 pressure classes.  A low-pressure class (I.E. 150#) is made to a low-density construction, with a low number of metallic windings per unit width. High density applications require a more resilient design and a higher number of metallic windings per unit width must be incorporated into the gasket design. Therefore, data sheets do not exist to cover all variations of the spiral wound gasket design. 

Material (Winding and Filler)

Material is identified by the color on the outer edge of the gasket. The stripe along the outer edge denotes filler (graphite, Teflon, etc.). MSI's Spiral Wound Gasket Color Chart shows the different material colors for the outer edge and fillers that the spiral wound gaskets identify by.

Spiral Wound Gasket

Inner Ring (optional)

A spiral wound gasket with an inner ring is common because the inner ring helps prevent what is known as spooling. Spooling can be caused when pressure is applied during bolting, causing the winding to uncoil in the ID of the gasket, causing a lot of problems. This can also happen during the pigging process used when cleaning a pipeline. 

SERIES A VS SERIES B SPIRAL WOUND GASKETS

Large diameter spiral wound gaskets (above NPS 24") can come in either Series A or Series B, which are competing specifications. In most cases the Series A is specified, which can withstand more external loadings than the Series B type. For both series, the dimensions of the spiral wound gaskets are different. From a commercial point of view, the series B type may be selected for piping with a non-critical application.

Dimensional Data

Spiral Wound Gaskets according to ASME B16.21 (2011)

NPS

d1

d2

Class 150

Class 300

Class 400

Class 600

Class 900

1/2

21

48

54

54

54

64

3/4

27

57

67

67

67

70

1

33

67

73

73

73

79

42

76

83

83

83

89

48

86

95

95

95

98

2

60

105

111

111

111

143

73

124

130

130

130.2

165

3

89

137

149

149

149

168

102

162

165

162

162

...

4

114

175

181

178

194

206

5

141

197

216

213

241

248

6

168

222

251

248

267

289

8

219

279

308

305

321

359

10

273

340

362

359

400

435

12

324

410

422

419

457

498

14

356

451

486

483

492

521

16

406

514

540

537

565

575

18

457

549

597

594

613

638

20

508

606

654

648

683

699

24

610

718

775

768

791

838

NPS

d1

Class 150

Class 300

Class 400

Class 600

Class 900

d2

 

General notes:

  • d1 = Inside diameter.
  • d2 = Outside diameter.
  • Dimensional tolerances outside diameter NPS 12 and smaller: +0 / -1.5 mm.
  • Dimensional tolerances outside diameter NPS 14 and larger: +0 / -3.0 mm.
  • Dimensional tolerances inside diameter NPS 12 and smaller: ± 1.5 mm.
  • Dimensional tolerances inside diameter NPS 14 and larger: ± 3.0 mm.
  • Thickness (t) specified by customer.