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The ANSI 900/1500 Spiral Wound Gaskets available from this page are made using the commonly used WR construction. They are made from a combination of a Carbon Steel Outer Ring, 316 Stainless Steel Windings and a flexible Graphite Filler.
Our Spiral Wound Gasket Naming Convention.Before proceeding with more information on spiral wound gasket performance capabilities and sizing, we thought it may be a good idea to explain the word-salad of a product name. Each part is explained below:
Style WR Spirals are made with a sealing component (metallic windings and a flexible, non-metallic filler) and an additional, solid metal outer ring.
The outer ring (also known as a centring ring or guide ring) centres the gasket on the flange and sits flush with the bolts. It also acts as an anti-blowout device, provides radial support to the sealing components and acts as a compression stop to prevent the windings and filler being crushed due to over tightening of the bolts.
Most commonly, outer rings are produced from mild steel or stainless steel but can be produced from other metals when required. The spiral wound gaskets listed on this page all feature a Carbon Steel Guide Ring with 316 Stainless Steel Windings and a Flexible Graphite Filler.
Each of the above stands for one of the materials used for making this spiral. Specifically,
CS = Carbon Steel, Used for the Outer Ring of the Gasket.
316 = 316 Stainless Steel, Used for the Windings on the Spiral.
Graph = Flexible Graphite. Used as a filler between the layers of Windings to assist with compression and sealing.
All Spiral Wound Gaskets from Swift Supplies are colour coded in accordance with ASME B16.20 requirements (with the exception of style W (windings only spirals) as colour coding is not practical).
The colour code key is included below. Since this page features CS-316-Graph spirals, all will have the outside face of their guide ring painted green (316L SS Windings) with grey strips (flexible graphite filler).
| Metallic Winding Materials | ||||
| Material | Colour | Material | Colour | |
| 304 Stainless Steel | Yellow | Incoloy | White | |
| 316L Stainless Steel | Green | Titanium | Purple | |
| 317L Stainless Steel | Maroon | Alloy 20 | Black | |
| 347 Stainless Steel | Blue | Carbon Steel | Silver | |
| 321 Stainless Steel | Tourquoise | Hastelloy "B" | Brown | |
| Monel | Orange | Hastelloy "C" | Beige | |
| Inonel | Gold | Phos. Bronze | Copper | |
| Nickel | Red | |||
| Non-Metallic Filler Materials | |
| Material | Colour (Applied as Stripes) |
| PTFE | White |
| Ceramic | Light Green |
| Flexible Graphite | Grey |
| Phyllosilicate (HTG) | Light Blue |
Our spiral wound gaskets to suit standard (i.e. non-custom) flanges each have their size, style and material information stamped onto them (again, excluding style W as there is nowhere to stamp).
The image below provides an overview of the information stamped on each spiral.
All Dimensions below are given in millimeters (mm).
| Flange Nominal Bore |
Imperial Short-Hand |
Windings Inside Diameter |
Windings Outside Diameter |
Outer Ring Outside Diameter |
Matches Table |
|---|---|---|---|---|---|
| 15NB | 1/2" | 19.1 | 31.8 | 47.6 | N/A |
| 20NB | 3/4" | 25.4 | 39.7 | 57.2 | N/A |
| 25NB | 1" | 31.8 | 47.6 | 66.7 | N/A |
| 32NB | 1 1/4" | 47.6 | 60.3 | 76.2 | N/A |
| 40NB | 1 1/2" | 54 | 69.9 | 85.7 | N/A |
| 50NB | 2" | 69.9 | 85.7 | 104.8 | N/A |
| 65NB | 2 1/2" | 82.6 | 98.4 | 123.8 | N/A |
| 80NB | 3" | 101.6 | 120.7 | 136.5 | N/A |
| 90NB* | 3 1/2" | 114.3 | 133.4 | 161.9 | N/A |
| 100NB | 4" | 127 | 149.2 | 174.6 | N/A |
| 125NB | 5" | 155.6 | 177.8 | 196.9 | N/A |
| 150NB | 6" | 182.6 | 209.6 | 222.3 | N/A |
| 200NB | 8" | 233.4 | 263.5 | 279.4 | N/A |
| 250NB | 10" | 287.3 | 317.5 | 339.7 | N/A |
| 300NB | 12" | 339.7 | 374.7 | 409.6 | N/A |
| 350NB | 14" | 371.5 | 406.4 | 450.9 | N/A |
| 400NB | 16" | 422.3 | 463.6 | 514.4 | N/A |
| 450NB | 18" | 474.7 | 527.1 | 549.3 | N/A |
| 500NB | 20" | 525.5 | 577.9 | 606.4 | N/A |
| 600NB | 24" | 628.7 | 685.8 | 717.6 | N/A |
*Not officially included in ASME B16.20 specification.
All Dimensions below are given in millimeters (mm).
| Flange Nominal Bore |
Imperial Short-Hand |
Windings Inside Diameter |
Windings Outside Diameter |
Outer Ring Outside Diameter |
Matches Table |
|---|---|---|---|---|---|
| 15NB | 1/2" | 19.1 | 31.8 | 54 | ANSI 600 |
| 20NB | 3/4" | 25.4 | 39.7 | 66.7 | ANSI 600 |
| 25NB | 1" | 31.8 | 47.6 | 73 | ANSI 600 |
| 32NB | 1 1/4" | 47.6 | 60.3 | 82.6 | ANSI 600 |
| 40NB | 1 1/2" | 54 | 69.9 | 95.3 | ANSI 600 |
| 50NB | 2" | 69.9 | 85.7 | 111.1 | ANSI 600 |
| 65NB | 2 1/2" | 82.6 | 98.4 | 130.2 | ANSI 600 |
| 80NB | 3" | 101.6 | 120.7 | 149.2 | ANSI 600 |
| 90NB* | 3 1/2" | 114.3 | 133.4 | 165.1 | N/A |
| 100NB | 4" | 127 | 149.2 | 181 | N/A |
| 125NB | 5" | 131.8 | 155.6 | 177.8 | N/A |
| 150NB | 6" | 182.6 | 209.6 | 250.8 | N/A |
| 200NB | 8" | 233.4 | 263.5 | 308 | N/A |
| 250NB | 10" | 287.3 | 317.5 | 362 | N/A |
| 300NB | 12" | 339.7 | 374.7 | 422.3 | N/A |
| 350NB | 14" | 371.5 | 406.4 | 485.8 | N/A |
| 400NB | 16" | 422.3 | 463.6 | 539.8 | N/A |
| 450NB | 18" | 474.7 | 527.1 | 596.9 | N/A |
| 500NB | 20" | 525.5 | 577.9 | 654.1 | N/A |
| 600NB | 24" | 628.7 | 685.8 | 774.7 | N/A |
*Not officially included in ASME B16.20 specification.
All Dimensions below are given in millimeters (mm).
| Flange Nominal Bore |
Imperial Short-Hand |
Windings Inside Diameter |
Windings Outside Diameter |
Outer Ring Outside Diameter |
Matches Table |
|---|---|---|---|---|---|
| 15NB | 1/2" | 19.1 | 31.8 | 54 | ANSI 300 |
| 20NB | 3/4" | 25.4 | 39.7 | 66.7 | ANSI 300 |
| 25NB | 1" | 31.8 | 47.6 | 73 | ANSI 300 |
| 32NB | 1 1/4" | 47.6 | 60.3 | 82.6 | ANSI 300 |
| 40NB | 1 1/2" | 54 | 69.9 | 95.3 | ANSI 300 |
| 50NB | 2" | 69.9 | 85.7 | 111.1 | ANSI 300 |
| 65NB | 2 1/2" | 82.6 | 98.4 | 130.2 | ANSI 300 |
| 80NB | 3" | 101.6 | 120.7 | 149.2 | ANSI 300 |
| 90NB* | 3 1/2" | 114.3 | 133.4 | 161.9 | N/A |
| 100NB | 4" | 127 | 149.2 | 193.7 | N/A |
| 125NB | 5" | 131.8 | 155.6 | 241.3 | N/A |
| 150NB | 6" | 182.6 | 209.6 | 266.7 | N/A |
| 200NB | 8" | 233.4 | 263.5 | 320.7 | N/A |
| 250NB | 10" | 287.3 | 317.5 | 400.1 | N/A |
| 300NB | 12" | 339.7 | 374.7 | 457.2 | N/A |
| 350NB | 14" | 371.5 | 406.4 | 492.1 | N/A |
| 400NB | 16" | 422.3 | 463.6 | 565.2 | N/A |
| 450NB | 18" | 474.7 | 527.1 | 612.8 | N/A |
| 500NB | 20" | 525.5 | 577.9 | 682.6 | N/A |
| 600NB | 24" | 628.7 | 685.8 | 790.6 | N/A |
*Not officially included in ASME B16.20 specification.
All Dimensions below are given in millimeters (mm).
| Flange Nominal Bore |
Imperial Short-Hand |
Windings Inside Diameter |
Windings Outside Diameter |
Outer Ring Outside Diameter |
Matches Table |
|---|---|---|---|---|---|
| 15NB | 1/2" | 19.1 | 31.8 | 63.5 | ANSI 1500 |
| 20NB | 3/4" | 25.4 | 39.7 | 69.9 | ANSI 1500 |
| 25NB | 1" | 31.8 | 47.6 | 79.4 | ANSI 1500 |
| 32NB | 1 1/4" | 47.6 | 60.3 | 88.9 | ANSI 1500 |
| 40NB | 1 1/2" | 54 | 69.9 | 98.4 | ANSI 1500 |
| 50NB | 2" | 69.9 | 85.7 | 142.9 | ANSI 1500 |
| 65NB | 2 1/2" | 82.6 | 98.4 | 165.1 | ANSI 1500 |
| 80NB | 3" | 101.6 | 120.7 | 168.3 | N/A |
| 90NB* | 3 1/2" | 114.3 | 133.4 | 190.5 | N/A |
| 100NB | 4" | 127 | 149.2 | 206.4 | N/A |
| 125NB | 5" | 131.8 | 155.6 | 247.7 | N/A |
| 150NB | 6" | 182.6 | 209.6 | 288.9 | N/A |
| 200NB | 8" | 233.4 | 263.5 | 358.8 | N/A |
| 250NB | 10" | 287.3 | 317.5 | 435 | N/A |
| 300NB | 12" | 339.7 | 374.7 | 498.5 | N/A |
| 350NB | 14" | 371.5 | 406.4 | 520.7 | N/A |
| 400NB | 16" | 422.3 | 463.6 | 574.7 | N/A |
| 450NB | 18" | 474.7 | 527.1 | 638.2 | N/A |
| 500NB | 20" | 525.5 | 577.9 | 698.5 | N/A |
| 600NB | 24" | 628.7 | 685.8 | 838.2 | N/A |
*Not officially included in ASME B16.20 specification.
All Dimensions below are given in millimeters (mm).
| Flange Nominal Bore |
Imperial Short-Hand |
Windings Inside Diameter |
Windings Outside Diameter |
Outer Ring Outside Diameter |
Matches Table |
|---|---|---|---|---|---|
| 15NB | 1/2" | 19.1 | 31.8 | 63.5 | ANSI 900 |
| 20NB | 3/4" | 25.4 | 39.7 | 69.9 | ANSI 900 |
| 25NB | 1" | 31.8 | 47.6 | 79.4 | ANSI 900 |
| 32NB | 1 1/4" | 47.6 | 60.3 | 88.9 | ANSI 900 |
| 40NB | 1 1/2" | 54 | 69.9 | 98.4 | ANSI 900 |
| 50NB | 2" | 69.9 | 85.7 | 142.9 | ANSI 900 |
| 65NB | 2 1/2" | 82.6 | 98.4 | 165.1 | ANSI 900 |
| 80NB | 3" | 101.6 | 120.7 | 174.6 | N/A |
| 90NB* | 3 1/2" | 114.3 | 133.4 | 187.3 | N/A |
| 100NB | 4" | 127 | 149.2 | 209.6 | N/A |
| 125NB | 5" | 131.8 | 155.6 | 254 | N/A |
| 150NB | 6" | 182.6 | 209.6 | 282.6 | N/A |
| 200NB | 8" | 233.4 | 263.5 | 352.4 | N/A |
| 250NB | 10" | 287.3 | 317.5 | 435 | N/A |
| 300NB** | 12" | 339.7 | 374.7 | 520.7 | N/A |
| 350NB** | 14" | 371.5 | 406.4 | 577.9 | N/A |
| 400NB** | 16" | 422.3 | 463.6 | 641.4 | N/A |
| 450NB** | 18" | 474.7 | 527.1 | 704.9 | N/A |
| 500NB** | 20" | 525.5 | 577.9 | 755.7 | N/A |
| 600NB** | 24" | 628.7 | 685.8 | 901.7 | N/A |
*Not officially included in ASME B16.20 specification.
** Not reccommended. A spiral with an inner ring (style WRIR) is suggested for this size and pressure rating.
| SKU | SWM000304B01-900-1500 |
|---|