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Types of Gaskets for Flanges (Soft, Spiral, Ring Joint)

Learn about the 5 key flange gaskets types (used in the oil and gas industry): non-asbestos gaskets full and raised face (used for low-pressure, low-temperature and non-critical applications), spiral wound gaskets (for higher temperature and pressure oil and gas applications), Ring joint gaskets style R, RX, BX (for RTJ flange faces), Kammprofile and Jacketed gaskets. The article describes the scope of each type of gasket, the dimensions to ASME B16.20 and ASME B16.21, the materials and give some indications to select the right gasket for piping applications.

Table of Content

NON-ASBESTOS GASKET

Non-asbestos gaskets are the simplest type of gasket for flanges and are produced by cutting graphite, organic or inorganic non asbestos sheets into shape (generally, with water jet cutting machines). This type of gaskets for flanges suits low pressure, low temperature, and non-critical piping and plumbing applications.

The two main types of non-asbestos gaskets are the “full face” (FF) for FF flanges and the “flat ring” type for raised face flanges (RF).

 

Non asbestos gasket for flange

 

Non-asbestos gaskets have fully replaced asbestos gaskets for decades as studies demonstrated the risks (for human health) associated with the production, use, and disposal of asbestos materials. The ASME B16.21 specification covers non-asbestos sheet gaskets (types, sheet materials, dimensions, dimensional tolerances, and marking requirements).

 

Full face and ring gasket
The terms, “flat-cut gaskets”, “die-cut gaskets”, “compressed sheet gaskets” and “asbestos-free gaskets” are synonyms to define this low-end family of flange gaskets.
To select the right material for non-asbestos gaskets, multiple factors shall be considered: fluid, temperature, pressure, fugitive emissions laws, and mechanical issues.

NON-ASBESTOS GASKET MATERIALS

 

Materials for soft gaskets

 

The most common materials used to manufacture compressed fiber gaskets are aramid fibers (Kevlar), glass fibers, elastomers, Teflon (PTFE), graphite, neoprene mixed with various binder materials (the most common binder is NBR, i.e. Buna-N):

  • Aramid NBR binder
  • carbon graphite reinforced
  • glass reinforced (steam service gasket)
  • PTFE bi-axially oriented (silica filler)
  • SBR (styrene-butadiene)
  • CR-chloroprene (Neoprene)
  • EPDM gasket (ethylene propylene)
  • fluorocarbon (Viton)
  • graphite
  • BUNA-n-rubber (nitrile, NBR gasket)
  • chlorosulfonated polyethylene (Hypalon gasket)
  • aramid + SBR binder (premium type gasket)
  • graphite + ss316/316l insert
  • PTFE biaxially oriented (with hollow glass microsphere) blue
  • PTFE biaxially oriented (pigment-free)-gray
  • expanded PTFE gasket
  • PTFE joint sealant
  • PTFE envelope slit type
  • PTFE envelope milled type
  • PTFE envelope formed type
  • MICA sheet
  • ceramic fiber

Non-asbestos gaskets can also be coated with graphite, for non-stick and steam resistance, mixed with PTFE for excellent chemical resistance, or with EPDM for potable water applications.

NON-ASBESTOS GASKET DIMENSIONS

Soft Gaskets for ASME B16.5 Flanges

Non-asbestos gaskets dimensions (for ASME B16.5 flanges), in millimeters

soft gaskets sizes

 

NPS d1
(ID)
d2 (GASKET OUTSIDE DIAMETER)
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

All values in millimeters

Soft Gaskets for ASME B16.47 – Series A Flanges

Non-asbestos gaskets dimensions (for ASME B16.47 series A flanges), in millimeters

soft gaskets sizes

 

NPS d1 (ID) d2 (GASKET OUTSIDE DIAMETER)
Class 150 Class 300 Class 400 Class 600
26 660 775 835 832 867
28 711 832 899 892 914
30 762 883 953 946 972
32 813 940 1006 1003 1022
34 864 991 1057 1054 1073
36 914 1048 1118 1118 1130
38 965 1111 1054 1073 1105
40 1016 1162 1114 1127 1156
42 1067 1219 1165 1178 1219
44 1118 1276 1219 1232 1270
46 1168 1327 1273 1289 1327
48 1219 1384 1324 1346 1391
50 1270 1435 1378 1403 1448
52 1321 1492 1429 1454 1499
54 1372 1549 1492 1518 1556
56 1422 1607 1543 1568 1613
58 1473 1664 1594 1619 1664
60 1524 1715 1645 1683 1721

All values in millimeters

Soft Gaskets for ASME B16.47 – Series B Flanges

Non-asbestos gaskets dimensions (for ASME B16.47 series B flanges), in millimeters

soft gaskets sizes

 

NPS d1 (ID) d2 (GASKET OUTSIDE DIAMETER)
Class 150 Class 300 Class 400 Class 600
26 660 725 772 746 765
28 711 776 826 800 819
30 762 827 886 857 879
32 813 881 940 911 933
34 864 935 994 962 997
36 914 987 1048 1022 1048
38 965 1045 1099
40 1016 1095 1149
42 1067 1146 1200
44 1118 1197 1251
46 1168 1256 1318
48 1219 1307 1368
50 1270 1357 1419
52 1321 1408 1470
54 1372 1464 1530
56 1422 1514 1594
58 1473 1580 1656
60 1524 1630 1705

All values in millimeters. Dimensional tolerances:

  • For outside diameter NPS 12 and smaller: +0 / -1.5 mm.; NPS 14 and larger: +0 / -3.0 mm.
  • For inside diameter NPS 12 and smaller: ± 1.5 mm; NPS 14 and larger: ± 3.0 mm

SPIRAL WOUND GASKET

A Spiral wound gasket for flanges features a metal sealing element filled with graphite, PTFE, ceramic fibers and, non-asbestos fibers (fillers). For this reason, spiral wound gaskets are classified as “semi-metallic” gaskets.

The metal component of the spiral wound gasket provides strength to the seal, whereas the fillers enhance the gasket’s conformability and resilience. Inner and outer rings can be added to the core sealing element to facilitate the installation and enhance pressure rating. Spiral wound gaskets with graphite filler are the most commonly sold type.

Flexitallic USA introduced spiral wound gaskets in the petrochemical industry back in 1912 to cope with an increasing demand for leak-proof seals in applications with higher and higher (and fluctuating) temperatures and pressures. Other reputable spiral wound gasket manufacturers are Garlock and Lamons.

Indeed, a spiral wound gasket is designed to withstand, better than other types of flange gaskets, the mechanical stress generated by high temperature and pressure applications. Spiral wound gasket application range, therefore, from oil and gas to power generation.

Spiral wound gasket

The diameter of a spiral wound gasket may range between a few mm up to 5.000 mm, and the spiral wound gasket thicknesses ranges from 3.2, 4.5, 6.4, to 7.2 mm.
A Spiral wound gasket may be ordered in different shapes, such as oblong, rectangular, oval, pear and diamond.

ASME B16.20 is the spiral wound gasket specification.

The round type is, of course, the standard shape for raised face (RF), male-and-female (M&F), and tongue-and-groove flanges (T&G) for petrochemical applications.

SPIRAL WOUND GASKET TYPES

A few different types of spiral wound gaskets exist, depending on:

  • the number of rings (outer and inner)
  • the materials of the inner and the outer ring of the gasket

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 specific codes to designate the different spiral wound gasket types, but the typical designs are recurring regardless of the producer.

The image shows how the different spiral wound gasket types used for flanged joints in piping applications:

types of SW gaskets

SPIRAL WOUND GASKET MATERIALS

 

Section of spiral wound gasket

Spiral Winding Materials

The sealing element of a spiral wound gasket is produced by interleaving plies of alternating metal winding strip combined with a filler material. The formed metal strip in the key sealing element of this type of semi-metallic gasket.

The most common winding materials are:

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

Filler Materials

Filler materials are used to enhance the conformability and the resilience of a spiral wound gasket. The most used filler material is graphite, however, other filler materials may be used depending on the application:

  • Graphite
  • PTFE
  • Ceramic fibers
  • Non-asbestos

Inner and Outer Rings Materials

The inner and the outer rings of a spiral wound gasket may be the same material of the winding core or a different one.

Solid inner rings are required by the ASME B16.20 specification for flanges with pressure rating 900# NPS 24 and larger, 1500# NPS 12 and larger, pressure class 2500#, NPS 4 and larger.

The inner ring improves the pressure rating of the spiral wound gasket, as it provides additional compression to the flanged joint and provides a heat and corrosion barrier protecting the gasket windings and the flanges from erosion.

MECHANICAL PROPERTIES

Spiral Wound Gasket Material
(Commercial Name)
DIN
SPECIFICATION
DIN
MATERIAL NR.
AISI &
UNS
B.S &
ASTM
HARDNESS
HV 10
TEMPERATURE RANGE in 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
Hastelloy 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 GASKET COLORS

Spiral wound gaskets made with different windings and filler materials are easy to spot, as each combination is designated by the application of color codes (the main color designates the winding materials, the stripes indicate the type of filler):

Spiral Wound Gaskets Color Coding

  • Metallic winding materials: the metallic winding material is designated by a solid color identification around the outside edge of the centering, as shown in the image below
  • Non-metallic filler color coding: the gasket filler materials are designated by a number of stripes placed at equal distances around the edge of the centering ring

Spiral Wound Gasket Color Coding

Color Codes for Winding Materials

Metallic Winding Material for Spiral Wound Gasket Abbreviated Winding
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

Color Codes for Filler Materials

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

 

Inconel 600 Inconel 600 Gold
Inconel 625 Inconel 625 Gold
Incoloy 800 Incoloy 800 H / HT White
Incoloy 825 Incoloy 825 White

 

SPIRAL WOUND GASKET MARKING

The illustration shows the typical marking of spiral wound gaskets:

 

Spiral wound gasket marking

 

SPIRAL WOUND GASKETS DIMENSIONS

Class 150

Dimensions of class 150 spiral wound gaskets for ASME B16.5 (in mm.)

 

Spiral wound gaskets dimensions
Spiral wound gaskets dimensions

 

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. 

Class 300

Dimensions of class 300 spiral wound gaskets for ASME B16.5 (in mm.)

Spiral wound gaskets dimensions
Dimensions of spiral wound gaskets

 

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. 

Class 400

Dimensions of class 400 spiral wound gaskets for ASME B16.5 (in mm.)

Spiral wound gaskets dimensions
Dimensions of spiral wound gaskets

 

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. 

Class 600

Dimensions of class 600 spiral wound gaskets for ASME B16.5 (in mm.)

Spiral wound gaskets dimensions
Dimensions of spiral wound gaskets

 

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. 

Class 900

Dimensions of class 900 spiral wound gaskets for ASME B16.5 (in mm.)

Spiral wound gaskets dimensions
Dimensions of spiral wound gaskets

 

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. 

Class 1500

Dimensions of class 1500 spiral wound gaskets for ASME B16.5 (in mm.)

Spiral wound gaskets dimensions
Dimensions of spiral wound gaskets

 

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. 

Class 2500

Dimensions of class 2500 spiral wound gaskets for ASME B16.5 (in mm.)

Spiral wound gaskets dimensions
Dimensions of spiral wound gaskets

 

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. 

RING JOINT GASKETS R, RX, BX

A Ring Joint Gasket (RTJ) provides a strong and durable metal-to-metal seal between two mating RTJ flanges. As the flanges are bolted, the softer material of the ring joint gasket is “squeezed” into the flanges grooves (made of a harder material) and seals the connection very tightly. RTJ gaskets are available in three styles, R (oval, octagonal), RX, and BX.

Ring joint gaskets (RTJ) ensure a long lasting and strong seal for flanges, valves, piping spools and vessels at high pressure and temperatures (which are typical conditions for many petrochemical processes).

RTJ are available in different designs (called “styles”) and dimensions, as illustrated in the picture below (BX, R, and BX).

Ring Joint Gasket Styles

RTJ GASKETS TYPES

R Type Ring Joint Gasket (Oval and Octagonal)

“Style R” is the most common RTJ gasket type. R type ring joint gaskets are available in oval or octagonal cross section and manufactured according to API 6A and ASME B16.20 to suit API 6B and ASME/ANSI B16.5 flanges.

This type of RTJ gasket is machined to tight manufacturing tolerances to ensure correct installation with standard ASME B16.5 and API 6B ring joint faced flanges. “R style” oval and octagonal RTJ gaskets can seal pressures up to 6.250 psi by ASME B16.20 and up to 5.000 psi according to the API 6A pressure ratings.

Type R RTJ gaskets are frequently used for valves covers.

Style RX RTJ Gasket

The RX type RTJ gasket is manufactured according to API 6A and ASME B16.20 to suit API 6B and ASME/ANSI B16.5 flanges.

The RX is a pressure energized version of the R octagonal gasket and fits the R type flat-bottomed groove.

The RX has an increased height and utilizes the internal system pressure to energize and improve the seal as internal pressure increases.

Some RX sizes have a pressure relief hole to equalize pressure on both sides of the sealing faces.

Style BX RTJ Gasket

The BX type RTJ gaskets are manufactured according to API 6A and are suitable for use in high-pressure API 6BX flanges.

The gaskets form a metal to metal seal on assembly and the efficiency improves as internal pressure increases.

All BX sizes have a pressure relief hole to equalize pressure across sealing faces.

RTJ GASKET MATERIALS

The material of RTJ gaskets shall match the flanges material but must have a lower hardness: this to ensure that the gasket, and not the flange, get plastically deformed within the groove of the flange as the two mating flanges are bolted together.

In case a harder material for the ring type joint is used, the groove of the flange would be damaged as the flanges are tightened (the hardness values for ring joint gaskets are given below).

Types of Materials for Ring Joint Gaskets

RTJ GASKET MATERIAL RING ID ASTM GRADE DIN GRADE WKSTOFF NUMBER AISI
GRADE
BS
GRADE
OTHER SPECS
Soft Iron D 1.1003 / 1.0335 Aramco / StW24
LCS S 1.1003 / 1.0335 Aramco / StW24
CS360 LT CS360LT A516 Gr70
4140 4140 UNS G41400 42CrMo4 1.7225 4140
F5 F5 UNS K42544 12CrMo195 1.7362 5Cr 1/2Mo
SS304 S304 S30400 X5CrNi 18 9 1.4301 304 304S15
SS304L S304L S30403 X2CrNi 18 9 1.4306 304L 304SS12
SS309 S309 S30900 X15CrNiSi2012 1.4828 309 309S24
SS310 S310 S31008 XX15CrNiSi2520 1.4841 310 310S24
SS316 S316 S31600 X5CrNiMo18 10 1.4401 316 316S16
SS316L S316L S31603 X2CrNiMo18 10 1.4404 316L 316S11/316S12
SS316L UREA S316UG S31603 X2CrNiMo 18 14 3 1.4435
SS316Ti S316Ti S31635 X10CrNiMoTi1810 1.4571 316Ti 320S31/320S17
SS321 S321 S32100 X10CrNiTi18 9 1.4541 321 321S12
SS347 S347 S34700 X10CrNiNb 18 9 1.455 347 347S51
SS410 S410 S41000 X10Cr13 1.4006 410 410S21
Monel 400 Monel400 N04400 NiCu30Fe 2.436
Inconel 600 INC600 N06600 NiCr15Fe 2.4816
Inconel 625 INC625 N06625 NiCr22Mo9Nb 2.4856
Inconel 718 INC718 N07718
Incoloy 800 INC800 N08800 X5NiCrAlTi31-20 1.4958
Incoloy 800H INC800H N08810 1.4958
Incoloy 825 INC825 N08825 NiCr21Mo 2.4858
904L 904L N08904 X1NiCrMoCu25-20-5 1.4539
F51 F51 S31803 X2CrNiMoN22-5-3 1.4462 2205 /Duplex
F53 F53 S32750 X2CrNiMoN25-7-4 1.441
F55 F55 S32760 X2CrNiMoCuWN 25 7 4 1.4501 Zeron 100
F60 F60 S32205 Duplex
Titanium Ti R 50400 3.7035
17-4PH 17-4PH S17400 1.4542 630
S254 S254 S31254 X1CrNiMoCuN20-18-7 1.4547 F44 / 6Mo
C276 C276 N10276 NiMo16Cr15W 2.4819 Hastelloy
Alloy 28 Alloy28 N08028 X1 NiCrMoCuN 31 27 4 1.4563 SANICRO 28

Mechanical Properties Ring Joint Gaskets Materials

Maximum Hardness of RTJ Gaskets

RTJ Gasket Material

Brinell HRB ID

Soft Iron-S

90 56 D

Low Carbon Steel

120 68 S

4 – 6% Chrome
1/2% Moly

130 72 F5

SS 304 Stainless Steel

160 83 S304

SS 316 Stainless Steel

160 83 S316

SS 347 Stainless Steel

160 83 S347

SS 410 Stainless Steel

170 96 S410

RTJ GASKET DIMENSIONS (ASME B16.20)

Style R Ring Joint Gaskets Dimensions (for ASME B16.5 flanges)

Ring joint gasket sizes

RTJ GASKET RING NUMBER Diameter P Width A Height Oct C Oct R1 NPS / CLASS
Oval B Oct H
R 11 34.14 6.35 11.2 9.7 4.32 1.5 1/2
300 / 600
R 12 39.7 7.95 14.2 12.7 5.23 1.5 1/2
900 / 1500
R 13 42.88 7.95 14.2 12.7 5.23 1.5 3/4
300 / 600
1/2
2500
R 14 44.45 7.95 14.2 12.7 5.23 1.5 3/4
900 / 1500
R 15 47.63 7.95 14.2 12.7 5.23 1.5 1
150
R 16 50.8 7.95 14.2 12.7 5.23 1.5 1
300 / 1500
3/4
2500
R 17 57.15 7.95 14.2 12.7 5.23 1.5
150
R 18 60.33 7.95 14.2 12.7 5.23 1.5
300 / 1500
1
2500
R 19 65.1 7.95 14.2 12.7 5.23 1.5
150
R 20 68.28 7.95 14.2 12.7 5.23 1.5
300 / 1500
R 21 72.24 11.13 17.5 16 7.75 1.5
2500
R 22 82.55 7.95 14.2 12.7 5.23 1.5 2
150
R 23 82.55 11.13 17.5 16 7.75 1.5 2
300 600

2500
R 24 95.25 11.13 17.5 16 7.75 1.5 2
900 / 1500
R 25 101.6 7.95 14.2 12.7 5.23 1.5
150
R 26 101.6 11.13 17.5 16 7.75 1.5
300/ 600
2
2500
R 27 107.95 11.13 17.5 16 7.75 1.5
900 / 1500
R 28 111.13 12.7 19.1 17.5 8.66 1.5
2500
R 29 114.3 7.95 14.2 12.7 5.23 1.5 3
150
R 30
*
117.48 11.13 17.5 16 7.75 1.5 3
300 / 600
R 31 123.83 11.13 17.5 16 7.75 1.5 3
300 / 900
R 32 127 12.7 19.1 17.5 8.66 1.5 3
2500
R 33 131.78 7.95 14.2 12.7 5.23 1.5
150
R 34 131.78 11.13 17.5 16 7.75 1.5
300 / 600
R 35 136.53 11.13 17.5 16 7.75 1.5 3
1500
R 36 149.23 7.95 14.2 12.7 5.23 1.5 4
150
R 37 149.23 11.13 17.5 16 7.75 1.5 4
300 / 900
R 38 157.18 15.88 22.4 20.6 10.49 1.5 4
2500
R 39 161.93 11.13 17.5 16 7.75 1.5 4
1500
R 40 171.45 7.95 14.2 12.7 5.23 1.5 5
150
R 41 180.98 11.13 17.5 16 7.75 1.5 5
300 / 900
R 42 190.5 19.05 25.4 23.9 12.32 1.5 5
2500
R 43 193.68 7.95 14.2 12.7 5.23 1.5 6
150
R 44 193.68 11.13 17.5 16 7.75 1.5 5
1500
R 45 211.15 11.13 17.5 16 7.75 1.5 6
300 / 900
R 46 211.15 12.7 19.1 17.5 8.66 1.5 6
1500
R 47 228.6 19.05 25.4 23.9 12.32 1.5 6
2500
R 48 247.65 7.95 14.2 12.7 5.23 1.5 8
150
R 49 269.88 11.13 17.5 16 7.75 1.5 8
300 / 900
R 50 269.88 15.88 22.4 20.6 10.49 1.5 8
1500
R 51 279.4 22.23 28.7 26.9 14.81 1.5 8
2500
R 52 304.8 7.95 14.2 12.7 5.23 1.5 10
150
R 53 323.85 11.13 17.5 16 7.75 1.5 10
300 900
R 54 323.85 15.88 22.4 20.6 10.49 1.5 10
1500
R 55 342.9 28.58 36.6 35.1 19.81 2.3 10
2500
R 56 381 7.95 14.2 12.7 5.23 1.5 12
150
R 57 381 11.13 17.5 16 7.75 1.5 12
300 900
R 58 381 22.23 28.7 26.9 14.81 1.5 12
1500
R 59 396.88 7.95 14.2 12.7 5.23 1.5 14
150
R 60 406.4 31.75 39.6 38.1 22.33 2.3 12
2500
R 61 419.1 11.13 17.5 16 7.75 1.5 14
300 600
R 62 419.1 15.88 22.4 20.6 10.49 1.5 14
900
R 63 419.1 25.4 33.3 31.8 17.3 2.3 14
1500
R 64 454.03 7.95 14.2 12.7 5.23 1.5 16
150
R 65 469.9 11.13 17.5 16 7.75 1.5 16
300 600
R 66 469.9 15.88 22.4 20.6 10.49 1.5 16
900
R 67 469.9 28.58 36.6 35.1 19.81 2.3 16
1500
R 68 517.53 7.95 14.2 12.7 5.23 1.5 18
150
R 69 533.4 11.13 17.5 16 7.75 1.5 18
300 600
R 70 533.4 19.05 25.4 23.9 12.32 1.5 18
900
R 71 533.4 28.58 36.6 35.1 19.81 2.3 18
1500
R 72 558.8 7.95 14.2 12.7 5.23 1.5 20
150
R 73 584.2 12.7 19.1 17.5 8.66 1.5 20
300 600
R 74 584.2 19.05 25.4 23.9 12.32 1.5 20
900
R 75 584.2 31.75 39.6 38.1 22.33 2.3 20
1500
R 76 673.1 7.95 14.2 12.7 5.23 1.5 24
150
R 77 692.15 15.88 22.4 20.6 10.49 1.5 24
300 600
R 78 692.15 25.4 33.3 31.8 17.3 2.3 24
900
R 79 692.15 34.93 44.5 41.4 24.82 2.3 24
1500

Style R Ring Joint Gaskets Dimensions (for ASME B16.47 Series A flanges)

RTJ GASKET RING NUMBER Dia
P
Width
A
Height Oct
C
Oct
R1
NPS
CLASS
Oval
B
Oct
H
R 93 749.3 19.05 23.9 12.32 1.5 26
300 600
R 94 800.1 19.05 23.9 12.32 1.5 28
300 600
R 95 857.25 19.05 23.9 12.32 1.5 30
300 600
R 96 914.4 22.23 26.9 14.81 1.5 32
300 600
R 97 965.2 22.23 26.9 14.81 1.5 34
300 600
R 98 1022.35 22.23 26.9 14.81 1.5 36
300 600
R 100 749.3 28.58 35.1 19.81 2.3 26
900
R 101 800.1 31.75 38.1 22.33 2.3 28
900
R 102 857.25 31.75 38.1 22.33 2.3 30
900
R 103 914.4 31.75 38.1 22.33 2.3 32
900
R 104 965.2 34.93 41.4 24.82 2.3 34
900
R 105 1022.35 34.93 41.4 24.82 2.3 36
900

Style RX Ring Joint Gaskets Dimensions

RTJ GASKET RING NUMBER 720-960 2900# 3000# 5000# OD HEIGHT WIDTH GASKET Wt. ( kg )
RX20 1 ½ 1 ½ 1 ½ 76.2 19.05 8.74 0.24
RX23 2, 2 1/16 93.27 25.4 11.91 0.52
RX24 2, 2 1/16 2, 2 1/16 105.97 25.4 11.91 0.6
RX25 3 1/8 109.55 19.05 8.74 0.5
RX26 2 ½ , 2 9/16 111.91 25.4 11.91 0.64
RX27 2 ½, 2 9/16 2 ½, 2 9/16 118.26 25.4 11.91 0.68
RX31 3 , 3 1/8 3, 3 1/8 134.54 25.4 11.91 0.78
RX35 3, 3 1/8 147.24 25.4 11.91 0.86
RX37 4 , 4 1/16 4, 4 1/16 159.94 25.4 11.91 0.95
RX39 4, 4 1/16 172.64 25.4 11.91 1.03
RX41 5, 5 1/8 5, 5 1/8 191.69 25.4 11.91 1.15
RX44 5, 5 1/8 204.39 25.4 11.91 1.23
RX45 6, 7 1/16 6, 7 1/16 221.84 25.4 11.91 1.34
RX46 6, 7 1/16 222.25 28.58 13.49 1.66
RX47 8 245.26 41.28 19.84 3.88
RX49 8, 9 8, 9 280.59 25.4 11.91 1.72
RX50 8, 9 283.36 31.75 16.66 2.43
RX53 10, 11 10, 11 334.57 25.4 11.91 2.06
RX54 10, 11 337.34 31.75 16.66 2.92
RX57 12, 13 5/8 12, 13 5/8 391.72 25.4 11.91 2.42
RX63 14 441.73 50.8 27 11.96
RX65 16, 16 3/4 480.62 25.4 11.91 3
RX66 16, 16 3/4 457.99 31.75 16.66 4.25
RX69 18 544.12 25.4 11.91 3.41
RX70 18 550.06 41.28 19.84 9.12
RX73 20, 21 1/4 596.11 31.75 13.49 5.27
RX74 20, 20 3/4 600.86 41.28 19.84 10.01
RX82 1 67.87 25.4 11.91 0.36
RX84 1 ½ 74.22 25.4 11.91 0.4
RX85 2 90.09 25.4 13.49 0.4
RX86 2 ½ 103.58 28.58 15.09 0.81
RX87 3 113.11 28.58 15.09 0.9
RX88 4 139.29 31.75 17.48 1.46
RX89 3 ½ 129.77 31.75 18.26 3.09
RX90 5 174.63 44.45 19.84 7.75
RX91 10 286.94 45.24 30.18 1.5
RX99 8 8 245.67 25.4 11.91 2.2
RX201 1 3/8 51.46 11.3 5.74 0.1
RX205 1 13/16 62.31 11.1 5.56 0.13
RX210 2 9/16 97.64 19.05 9.53 0.35
RX215 4 1/16 140.89 25.4 11.91 0.8

Style BX Ring Joint Gaskets Dimensions

RTJ GASKET RING NUMBER 2000# 3000# 5000# 10000# 15000# 20000# OUTSIDE DIA HEIGHT 
OF THE RING
WIDTH 
OF THE RING
RTJ GASKET 
WEIGHT KG
BX 150 1 11/16 1 11/16 72.19 9.3 9.3 0.13
BX 151 1 13/16 1 13/16 1 13/16 76.4 9.63 9.63 0.15
BX 152 2 1/16 2 1/16 2 1/16 84.68 10.24 10.24 0.19
BX 153 2 9/16 2 9/16 2 9/16 100.94 11.38 11.38 0.29
BX 154 3 1/16 3 1/16 3 1/16 116.84 12.4 12.4 0.4
BX 155 4 1/16 4 1/16 4 1/16 147.96 14.22 14.22 0.55
BX 156 7 1/16 7 1/16 7 1/16 237.92 18.62 18.62 1.87
BX 157 9 9 9 294.46 20.98 20.98 2.97
BX 158 11 11 11 352.04 23.14 23.14 4.35
BX 159 13 5/8 426.72 25.7 25.7 6.53
BX 160 13 5/8 402.59 23.83 13.74 3.06
BX 161 16 ¾ 491.41 28.07 16.21 5.35
BX 162 16 3/4 16 3/4 16 3/4 475.49 14.22 14.22 1.94
BX 163 18 3/4 556.16 30.1 17.37 6.9
BX 164 18 3/4 18 3/4 570.56 30.1 24.59 5.86
BX 165 21 ¼ 624.71 32.03 18.49 8.76
BX 166 21 ¼ 640.03 32.03 26.14 12.82
BX 167 26 3/4 759.36 35.86 13.11 8.53
BX 168 26 3/4 765.25 35.86 16.05 10.54
BX 169 5 1/8 173.51 15.85 12.93 0.73
BX 170 6 5/8 6 5/8 218.03 14.22 14.22 1.03
BX 171 8 9/16 8 9/16 267.44 14.22 14.22 1.24
BX 172 11 5/32 11 5/32 333.07 14.22 14.22 1.56
BX 303 30 30 852.75 37.95 16.97

HOW TO ORDER RING JOINT GASKET

The following tables shows how to select the correct ring joint gasket depending on the flange size (NPS), manufacturing norm (ASME or API) and flange rating:

Style R Ring Joint Gaskets

NOMINAL PIPE SIZE PRESSURE CLASSES
ASME B16.5 API 6B ASME B16.47 Series A
150# 300# – 600# 900# 1500# 2500# 720# – 960# (1) 2000# 3000# 5000# 10000# 150# 300# – 600# 900#
1/2” R-11 R-12 R-12 R-13
3/4” R-13 R-14 R-14 R-16
1” R-15 R-16 R-16 R-16 R-18 R-16 R-16 R-16 R-16 R-82
1 1/4” R-17 R-18 R-18 R-18 R-21 R-18 R-18 R-18 R-18
1 1/2” R-19 R-20 R-20 R-20 R-23 R-20 R-20 R-20 R-20 R-84
2” R-22 R-23 R-24 R-24 R-26 R-23 R-23 R-23 R-24 R-85
2 1/2” R-25 R-26 R-27 R-27 R-28 R-26 R-26 R-26 R-27 R-86
3” R-29 R-31 R-31 R-35 R-32 R-31 R-31 R-31 R-35 R-87
3 1/2” R-33 R-34 R-37 R-89
4” R-36 R-37 R-37 R-39 R-38 R-37 R-37 R-37 R-39 R-88
5” R-40 R-41 R-41 R-44 R-42 R-41 R-41 R-41 R-44 R-90
6” R-43 R-45 R-45 R-46 R-47 R-45 R-45 R-45 R-46
8” R-48 R-49 R-49 R-50 R-51 R-49 R-49 R-49 R-50
10” R-52 R-53 R-53 R-54 R-55 R-53 R-53 R-53 R-54 R-91
12” R-56 R-57 R-57 R-58 R-60 R-57 R-57 R-57 R-57 R-57
14” R-59 R-61 R-62 R-63 R-61 R-61 R-61 R-61 R-62
16” R-64 R-65 R-66 R-67 R-65 R-65 R-65 R-65 R-66
18” R-68 R-69 R-70 R-71 R-69 R-69 R-69 R-69 R-70
20” R-72 R-73 R-74 R-75 R-73 R-73 R-73 R-73 R-74
22” R-80 R-81
24” R-76 R-77 R-78 R-79 R-77 R-78
26” R-93 R-100
28” R-94 R-101
30” R-95 R-102
32” R-96 R-103
34” R-97 R-104
36” R-98 R-105

Style RX Ring Joint Gaskets

NPS PRESSURE RATING
API 6B
720# 960# 2000# 2900# 3000# 5000#
1” RX-82
1 3/8” RX-201
1 1/2” RX-20 RX-20 RX-20 RX-84 RX-20 RX-20
1 13/16″ RX205
2” RX-23 RX-23 RX-23 RX-85 RX-24 RX-24
2 1/2” RX-26 RX-26 RX-26 RX-86 RX-27 RX-27
2 9/16” RX210
3” RX-31 RX-31 RX-31 RX-87 RX-31 RX35
3 1/2” RX-89
4” RX-37 RX-37 RX-37 RX-88 RX-37 RX-39
4 1/16″ RX-215
5” RX-41 RX-41 RX-41 RX-90 RX-41 RX-44
6” RX-45 RX-45 RX-45 RX-45 RX-46
8” RX-49
RX-99 (2)
RX-49 RX-49 RX-49
RX-99 (2)
RX-50
10” RX-53 RX-53 RX-53 RX-91 RX-53 RX-54
12” RX-57 RX-57 RX-57 RX-57
14” RX-63
16” RX-65 RX-65 RX-65 RX-69
18” RX-69 RX-69 RX-69 RX-73
20” RX-73 RX-73 RX-73 RX82

Style BX Ring Joint Gaskets

NPS PRESSURE RATING
API 6BX
2000# 3000# 5000# 10000# 15000# 20000#
1 11/16″ BX-150 BX-150
1 13/16″ BX-151 BX-151 BX-151
2 1/16″ BX-152 BX-152 BX-152
2 9/16″ BX-153 BX-153 BX-153
3 1/16″ BX-154 BX-154 BX-154
4 1/16″ BX-155 BX-155 BX-155
5 1/8″ BX-169
6 5/8″ BX-170 BX-170
7 1/16″ BX-156 BX-156 BX-156
8 9/16″ BX-171 BX-171
9″ BX-157 BX-157 BX-157
11″ BX-158 BX-158 BX-158
11 5/32″ BX-172 BX-172
13 5/8″ BX-160 BX-159 BX-159 BX-159
16 3/4″ BX-161  BX-162 BX-162 BX-162
18 3/4″ BX-163 BX-164 BX-164
21 1/4″ BX-165 BX-166
26 3/4″ BX-167 BX-168
30″ BX-303 BX-303

 

KAMMPROFILE GASKET

KAMMPROFILE GASKET DEFINITION

A Kammprofile gasket is manufactured by applying a sealing layer in non-metallic materials (such as graphite, PTFE-Teflon, ceramic fibers, non-asbestos, Mica, etc) or metallic materials (as aluminum or silver) on both sides of a metal core featuring concentric grooves of 1 mm Cam-Pitch. This sealing product, called also “grooved metal gasket” or “corrugated metal gasket”,  is used for high-pressure and temperature oil & gas applications.

Kammprofile gaskets are used in many industrial, petrochemical, power generation and nuclear installations (to seal flanges, heat exchangers, superheaters and, other pressure equipment) and are preferred to Spiral Wound Gaskets for processes with constant high pressure/temperatures requiring strong bolt-loads and remarkable flanged joints’ resistance.

 

 

kamprofile gasket

 

Kammprofile gaskets fit smooth and stock flange surface finish (3.2 to 6.3 μm Ra, i.e. 125-250 RMS).
The common thickness of a Kammprofile gasket is between 2 and 4 mm (3 mm is the most common specification in petrochemical applications).
A Kammprofile gasket offers several benefits, due to its wide sealing area and construction:

  • May resist temperatures up to approx. 1000°C (the Kammprofile temperature rating depends on the materials of the metal core and the sealing layer)
  • May rate up to 250 bars, which is a considerable pressure rating
  • The gasket does not damage the flange surface, due to the protection offered by the sealing layer
  • The gasket can absorb fluctuations in temperature and pressure
  • It is more tolerant than Spiral Wound Gaskets to improper bolting torques
  • Suits both light and heavyweight flanges, even of large sizes
  • After assembly, the thickness of the sealing material is extremely low (0.1 – 0.2 mm), thus reducing leaks and failure rates
  • The core of a Kammprofile gasket can be re-used after cleaning and fitting the gasket with a new layering material. This is critical for expensive applications, such as heat exchanger gaskets that are made of exotic, expensive, materials (Inconel, Monel, Hastelloy, and Cupronickel).

 

Kamprofile gasket grooved

An outer metallic (integral or floating) ring may be added to the gasket, to facilitate the centering of the gasket during the installation on a flange. The sealing layers protect the flange surface and reinforce the seal.

KAMMPROFILE GASKET TYPES

Kammprofile gaskets are available in two main configurations, parallel root cores/convex root cores, and two designs (with/without loose outer centering ring), as shown in the image below:

Kammprofile Gasket Designs

KAMMPROFILE GASKET MATERIALS

Metal Core Materials

The core material of a Kammprofile gasket shall match the material of the piping system

Kammprofile Core Materials DIN
Designation
DIN Material Number AISI ASTM UNS
Designation
British Standard
Designation
Hardness
HB/HV
Temperature in C°
Min.           Max.
Density in gr/cm3
Soft Iron 90  –  100 –  60 500 7.85
Steel (LCS) RSt. 37.2 1.0038 100  –  130 –  40 500 7.85
Stainless Steel 304 X5 CrNi 1810 1.4301 304 304S15/16/31 130  –  180 -250 550 7.9
Stainless Steel 304 L X2CrNi 1911 1.4306 304L 304S11 130  –  190 -250 550 7.9
Stainless Steel 309 X15CrNiSi 2012 1.4828 309 309S24 130  –  190 -100 1000 7.9
Stainless Steel 316 L(1) X2CrNiMo 1713 1.4404 316L 316S11/13 130  –  190 -100 550 7.9
Stainless Steel 316 Ti X6CrNiMoTi 1712 1.4571 316Ti 320S31 130  –  190 -100 550 7.8
Stainless Steel 321 X6CrNiTi 1810 1.4541 321 321S12/49/87 130  –  190 -250 550 7.9
Stainless Steel 347 X6CrNiNb 1810 1.4550 347 347S31 130  –  190 -250 550 7.9
Aluminium Al 99,5 3.0255 20  –    23 -250 300 2.73
Silver 28* -250 750 10.5
Copper 2.0090 50  –    80 -250 400 8.9
Nickel 200 Ni 99,2 2.4066 N02200 3072-76 NA11 90  –  120 -250 600 8.9
Monel 400 ® NiCu 30 Fe 2.4360 N04400 3072-76 NA13 110  –  150 -125 600 8.8
Inconel 600 ® NiCr 15 Fe 2.4816 N06600 3072-76 NA14 120  –  180 -100 950 8.4
Incoloy 800 ® X10NiCrAITi 3220 1.4876 N08800 3072-76 NA15 140  –  220 -100 850 8.0
Incoloy 825 ® NiCr 21 Mo 2.4858 N08825 3072-76 NA16 120  –  180 -100 450 8.14
Hastelloy B2 ® NiMo 28 2.4617 N10665 170  –  230 -200 450 9.2
Hastelloy C276 ® NiMo16Cr15W 2.4819 N10276 170  –  230 -200 450 8.9
Titanium Ti 99,8 3.7025 110  –  140 -250 350 4.5

Sealing Layer

The most common layer materials for Kammprofile gaskets are graphite and PTFE (Teflon).
The advantages of a graphite layering material are:

  • Excellent gas tightness qualities
  • Non-aging properties
  • Very good chemical resistance
  • Resistance to high (fluctuating) temperatures and pressures

PTFE is also used due to its excellent chemical resistance, resistance to temperatures up to 250°C  and excellent sealing properties for gas applications.

Sealing Layer Material for Kammprofile Temperature in C°
Min.     Max.
Max. operating pressure in Bars Gas tightness Recommended Application
Graphite -200 550 250 Good Aggressive media
PTFE (Teflon ® ) -200 250 100 Good Aggressive media
Non-asbestos -100 250 100 Good Gas and liquids
Silver -200 750 250 Good Aggressive media

KAMMPROFILE GASKET DIMENSIONS

Class 150-400

Kammprofile gasket dimensions for AMSE B16.5 flanges

Kammprofile gasket size

NPS d1 d2 d3
150 300 400
1/2 23 33.3 44.4 50.8 50.8
3/4 28.6 39.7 53.9 63.5 63.5
1 36.5 47.6 63.5 69.8 69.8
44.4 60.3 73 79.4 79.4
52.4 69.8 82.5 92.1 92.1
2 69.8 88.9 101.6 108 108
82.5 101.6 120.6 127 127
3 98.4 123.8 133.4 146.1 146.1
111.1 136.5 158.8 161.9 158.7
4 123.8 154 171.5 177.8 174.6
5 150.8 182.6 193.7 212.7 209.5
6 177.8 212.7 219.1 247.7 244.5
8 228.6 266.7 276.2 304.8 301.6
10 282.6 320.7 336.5 358.8 355.6
12 339.7 377.8 406.4 419.1 415.9
14 371.5 409.6 447.7 482.6 479.4
16 422.3 466.7 511.2 536.6 533.4
18 479.4 530.2 546.1 593.7 590.5
20 530.2 581 603.2 650.9 644.5
24 631.8 682.6 714.4 771.5 765.2

All values in millimeters

Class 600-2500

Kammprofile gasket dimensions for AMSE B16.5 flanges

Kammprofile gasket size

NPS d1 d2 d3
600 900 1500 2500
1/2 23 33.3 50.8 60.3 60.3 66.7
3/4 28.6 39.7 63.5 66.7 66.7 73
1 36.5 47.6 69.8 76.2 76.2 82.5
44.4 60.3 79.4 85.7 85.7 101.6
52.4 69.8 92.1 95.2 95.2 114.3
2 69.8 88.9 108 139.7 139.7 142.8
82.5 101.6 127 161.9 161.9 165.1
3 98.4 123.8 146.1 165.1 171.5 193.7
111.1 136.5 158.7
4 123.8 154 190.5 203.2 206.4 231.7
5 150.8 182.6 238.1 244.5 250.8 276.2
6 177.8 212.7 263.5 285.8 279.4 314.3
8 228.6 266.7 317.5 355.6 349.3 384.1
10 282.6 320.7 369.9 431.8 431.8 473
12 339.7 377.8 454 495.3 517.5 546.1
14 371.5 409.6 488.9 517.5 574.7
16 422.3 466.7 561.9 571.5 638.1
18 479.4 530.2 609.6 635 701.7
20 530.2 581 679.5 695.3 752.4
24 631.8 682.6 787.4 835 898.5

All values in millimeters

JACKETED GASKET

A Jacketed gasket features an inner soft material core and an outer metallic shell. The inner filler material provides resilience to the gasket, whereas the metal jacket protects the inner core of the gasket and withstands the pressure, the temperature, and the corrosion of the process.

Metal jacket gaskets are available with a single or double jacket and are widely used for pumps, valves, pressure vessels, and other mechanical equipment.
A metal jacket gasket requires flat face flanges with a smooth face finish to seal effectively.

The size range and thickness tolerances for this type of gaskets are covered by ASME B16.21 specification:

  • OD: Less than 5,000mm
  • Thickness: 2~8mm with tolerance +0.03 inch. to -0.000 inch (+0.8mm, -0.0mm)

 

Metal jacket gaskets

 

JACKETED GASKET MATERIALS

Metal Jacket Materials

The table shows the most common metals used for jacketed gaskets and the recommended temperature range:

Jacket Materials Hardness HB Temp.℃
Carbon Steel 90 -60~+450
304 (L) 130 -270~+550
316 (L) 130 -270~+550
321 130 -270~+550
Monel 110 -60~+500
Inconel 90 -60~+600
AL 30 -250~+300
CU 80 -250~+400

Inner Core Materials

Metal jacket gaskets have a soft inner core, which may be manufactured in materials as:

  • Non-Asbestos millboard and other non-asbestos materials (aramid, glass fiber, inorganic fibers, etc)
  • CAF
  • Rubber
  • PTFE
  • Graphite

JACKETED GASKET TYPES

The two main types of metal jacketed gasket are the single and the double jacket designs. Besides these two basic types, other designs are available on the market as illustrated below:

Double Jacketed Corrugated Double Jacketed Corrugated
— soft filler

Reduced contact area, enhances compression characteristics, suitable for uneven flanges.
Double Jacketed Corrugated — metal filler Double Jacketed Corrugated
— metal filler

Usually stainless outer casing with soft iron filler ring.
Core material available St. St. -304.316L.321
Soft iron, Monel, Inconel
Single Corrugated — asbestos rope filler Single Corrugated
— asbestos rope filler

Typically used on very poor or pitted flanges, low bolt loading requirement.
Metal Jacket Laminates — soft filler Metal Jacket Laminates
— soft filler

Combines flexible graphite with stainless steel core material
Solid metal ring machined Solid metal ring machined on each contact face to provide a serrated surface finish covered with Graphite.
PTFE Nonas or Asbestos.
Double Jacketed – soft filler Double Jacketed – soft filler
Used on high-temperature pressure applications or where corrosion problems may exist
Single Jacketed – metal filler – partly enclosed Single Jacketed – metal filler
– partly enclosed

Very seldom used, old design. Used in applications where poor or pitted flanges exist on one facing.
Single Jacketed – Soft filler – partly enclosed Single Jacketed – Soft filler
– partly enclosed

Used on narrow flanges
Single Jacketed – Soft filler – open outside edge Single Jacketed – Soft filler
– open outside edge

Used in narrow flanges, protection of filler cleared for by casing
Single Corrugated – no filler Single Corrugated – no filler
Used mainly in valve applications, small recess gap. Sometimes referred to as Taylor ring.

JACKETED GASKET DIMENSIONS

Class 150-400

 

Jacketed gasket dimension
Jacketed gasket dimension

 

NPS d1 d2
150 300 400
1/2 23.8 44.5 50.8 50.8
3/4 31.8 54 63.5 63.5
1 36.5 63.5 69.9 69.9
46 73 79.4 79.4
52.4 82.6 92.1 92.1
2 73.2 101.6 108 108
85.9 120.6 127 127
3 107.8 133.4 146.1 146.1
4 131.8 171.5 177.8 174.7
5 152.4 193.8 212.8 209.5
6 190.5 219.1 247.7 244.5
8 238.3 276.3 304.8 301.7
10 285.8 336.6 358.8 355.6
12 342.9 406.4 419.1 415.9
14 374.7 447.7 482.6 479.5
16 425.5 511.2 536.6 533.4
18 489 546.1 593.7 590.6
20 533.4 603.3 650.9 644.5
24 641.4 714.4 771.6 765.3
NPS d1 150 300 400

Class 600-2500

Jacketed gasket dimensions for AMSE B16.5 flanges

Jacketed gasket dimension

 

NPS d1 d2
600 900 1500 2500
1/2 23.8 50.8 60.4 60.4 66.8
3/4 31.8 63.5 66.7 66.7 73.1
1 36.5 69.9 76.2 76.2 82.5
46 79.4 85.8 85.8 101.6
52.4 92.1 95.3 95.3 114.3
2 73.2 108 139.7 139.7 143
85.9 127 161.9 161.9 165.1
3 107.8 146.1 165.1 171.5 193.8
4 131.8 190.5 203.2 206.5 231.9
5 152.4 238.2 244.6 250.9 276.3
6 190.5 263.6 285.8 279.4 314.5
8 238.3 317.5 355.6 349.3 384.3
10 285.8 396.9 431.8 431.8 473.2
12 342.9 454.1 495.3 517.6 546.1
14 374.7 489 517.6 574.7
16 425.5 562 571.5 638.2
18 489 609.6 635 701.8
20 533.4 679.5 695.5 752.5
24 641.4 787.4 835.1 898.6

HOW TO ORDER A METAL JACKETED GASKET

The following information should be provided to the gasket supplier to order a jacket-gasket properly:

  • Outside diameter
  • Inside diameter (NPS)
  • Shape per standard index
  • Type Number
  • Thickness
  • Materials (metal or metal filler)
  • Bar size
  • Radii
  • Distance from the centerline of the gasket to the centerline of bars

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