The ASME B16.20 standard, issued by the American Society of Mechanical Engineers (ASME), serves as the authoritative guide for the design, manufacture, and dimensions of spiral-wound gaskets, jacketed gaskets, and ring-joint gaskets used in piping flanges. Selecting gaskets in accordance with this standard is fundamental to ensuring a tight seal at flange connections under conditions involving high temperatures, high pressures, and aggressive media.
In industrial sectors such as petrochemicals, power generation, and energy, the sealing reliability of piping systems is directly linked to operational safety and efficiency. As critical connecting components within piping systems, the sealing performance of flanges relies on another essential component: the flange gasket.
ASME B16.20 Flange Gasket Standard
The full title of the ASME B16.20 standard is *Metallic Gaskets for Pipe Flanges: Spiral-Wound, Jacketed, and Corrugated Metal*. It is used in conjunction with flange standards such as ASME B16.5 (Pipe Flanges and Flanged Fittings) and ASME B16.47 (Large Diameter Steel Flanges), collectively forming a comprehensive system of specifications for flange connections.
This standard specifies in detail:
- Gasket Types: Specifies the structural configurations for various types of gaskets.
- Dimensions and Tolerances: Sets precise requirements for key dimensions—such as inner and outer diameters and thickness—and their permissible deviations to ensure a perfect fit with flange sealing surfaces.
- Material Combinations: Provides guidelines for selecting materials for filler components, metal strips, facing layers, and metal rings.
- Marking and Acceptance: Stipulates product identification methods and inspection criteria.
Selecting gaskets that comply with the ASME B16.20 standard ensures compatibility and interchangeability regarding dimensions and performance with corresponding ASME-standard flanges, which is key to achieving a "standard seal."
Types of Flange Gaskets and Their Suitable Flanges
According to ASME B16.20, flange gaskets are primarily classified into the following categories, each corresponding to specific flange sealing face types and operating conditions:
Spiral Wound Gaskets
- Structure: Formed by the alternating spiral winding of a pre-formed metal strip and a non-metallic filler material (such as graphite, PTFE, ceramic fiber, etc.); typically features inner and outer metal reinforcing rings.
- Applicable Flanges: Primarily used for Raised Face (RF), Female/Male (FM/M), and Tongue/Groove (T/G) flanges.
- Features and Applications: Combines the strength of metal with the elasticity of non-metallic materials, offering excellent compensation capabilities and suitability for a wide range of temperatures and pressures; it is one of the most widely used gasket types in the petrochemical and power generation industries.
Dimensions of Spiral Wound Gaskets for ASME B16.5 Flanges
| Flange Size (NPS) | outer diameter | inner diameter | Outer diameter of the central ring | |||||||||||||
| Class 150300400 600 | Class 9001500 2500 | 150 | 300 | 400 | 600 | 900 | 1500 | 2500 | 150 | 300 | 400 | 600 | 900 | 1500 | 2500 | |
| 1/2 | 31.8 | 31.8 | 19.1 | 19.1 | Class600 | 19.1 | Class1500 | 191 | 19.1 | 47.8 | 54.1 | Class600 | 54.1 | Class1500 | 63.5 | 69.9 |
| 3/4 | 39.6 | 39.6 | 25.4 | 25.4 | Class600 | 25.4 | Class1500 | 25.4 | 25.4 | 57.2 | 66.8 | Class600 | 66.8 | Class1500 | 69.9 | 762 |
| 1 | 47.B | 47.8 | 31.8 | 31.8 | Class600 | 31.8 | Class1500 | 31.8 | 318 | 66.8 | 732 | Class600 | 73.2 | Class1500 | 79.5 | 85.9 |
| 1-1/4 | 60.5 | 60.5 | 47.8 | 47.8 | Class600 | 47.8 | Class1500 | 39.6 | 39.6 | 76.2 | 82.6 | Class600 | 82.6 | Class1500 | 88.9 | 104.9 |
| 1-1/2 | 69.9 | 69.9 | 54.1 | 54.1 | Class600 | 54.1 | Class1500 | 47.8 | 47.8 | 85.9 | 95.3 | Class600 | 95.3 | Class1500 | 98.6 | 117.6 |
| 2 | 85.9 | 85.9 | 69.9 | 69.9 | Class600 | 69.9 | Class1500 | 58.7 | 58.7 | 104.9 | 1.3 | Class600 | 111.3 | Class1500 | 143.0 | 146.1 |
| 2-1/2 | 98.6 | 98.6 | 82.6 | 82.6 | Class600 | 82.6 | Class1500 | 69.9 | 69.9 | 124.0 | 130.3 | Class600 | 130.3 | Class1500 | 165.1 | 168.4 |
| 3 | 120.7 | 120.7 | 101.6 | 101.6 | Class600 | 1016 | 95.3 | 922 | 92.2 | 136.7 | 149.4 | Class600 | 149. | 168.4 | 174.8 | 196.9 |
| 3-1/2 | 133.4 | 114.3 | 114.3 | Class600 | 104.8 | Class1500 | 161.9 | 651 | Class600 | 161.9 | Class1500 | |||||
| 4 | 149.4 | 149.4 | 127.0 | 1270 | 120.7 | 120.7 | 120.7 | 117.6 | 117.6 | 174.8 | 181.1 | 177.8 | 193.8 | 206.5 | 209.6 | 235.0 |
| 5 | 177.8 | 177.8 | 155.7 | 1557 | 147.6 | 147.6 | 147.6 | 143.0 | 143.0 | 196.9 | 215.9 | 212.9 | 241.3 | 247.7 | 254.0 | 279.4 |
| 6 | 2096 | 209.6 | 182.6 | 182.6 | 174.8 | 74.8 | 174.8 | 171.5 | 171.5 | 222.3 | 251.0 | 247.7 | 266.7 | 289.1 | 282.7 | 317.5 |
| 8 | 263.7 | 257.3 | 233.4 | 233.4 | 225.6 | 225.6 | 222.3 | 215.9 | 215.9 | 279.4 | 308.1 | 304.8 | 320.8 | 358.9 | 352.6 | 387.4 |
| 10 | 3175 | 311.2 | 287.3 | 287.3 | 274.6 | 274.6 | 276.4 | 266.7 | 270.0 | 339.9 | 362.0 | 358.9 | 400.1 | 4351 | 4351 | 476.3 |
| 12 | 374.7 | 368.3 | 339.9 | 339.9 | 3272 | 327.2 | 323.9 | 323.93 | 317.5 | 409.7 | 422.4 | 419.1 | 457.2 | 498.6 | 520.7 | 5494 |
| 14 | 406.4 | 4001 | 371.6 | 371.6 | 362.0 | 362.0 | 355.6 | 362.0 | 450.9 | 485.9 | 482.6 | 492.3 | 520.7 | 577.9 | ||
| 16 | 463.6 | 457.2 | 422.4 | 422.4 | 412.8 | 412.8 | 412.8 | 406.4 | 514.4 | 539.8 | 536.7 | 565.2 | 574.8 | 641.4 | ||
| 18 | 5271 | 520.7 | 474.7 | 474.7 | 469.9 | 469.9 | 463.6 | 463.6 | 549.4 | 596.9 | 593.9 | 612.9 | 638.3 | 704.9 | ||
| 20 | 577.9 | 571.5 | 525.5 | 525.5 | 520.7 | 520.7 | 520.7 | 514.4 | 606.6 | 654.1 | 647.7 | 682.8 | 698.5 | 7557 | ||
| 24 | 685.8 | 679.5 | 628.7 | 628.7 | 628.7 | 628.7 | 628.7 | 616.0 | 71,767 | 774.7 | 768.4 | 790.7 | 838.2 | 901.7 | ||
NOTES:
(1)The gasket outside diamete olerance for NPS 1/2 through NPS 8 is ±0.8 mm〔±0.03 in.); for NPS 10 through NPS 24,+1.5mm,-0.8mm(+0.06in,-0.03 in.).
(2) Refer to para.SW-2.5 for required use of inner rings.
(3)The gasket inside diameter tolerance for NPS 1/2 through NPS 8 is±0.4mm(±0.016 in.); for NPS 10 through NPS 24,±0.8mm(±0.03 in.).
(4) The centering-ring outside diameter tolerance is ±0.8mm(±0.03 in.).
(5)There are no Class 400 flanges in NPS 1/2 trough NPS 3-1/2 (use Class 600);Class 900 flanges in NPS 1/2 through NPS 2-1/2 or in NPS 3-1/2 (use Cass1500); Clas1500 flanges in NPS 3-1/2;or Class 2500 flanges in NPS 3-1/2 or NPS 14 and larger.
Dimensions of Spiral Wound Gaskets for ASME B16.47 Series A Flanges
| Flange Size (NPS) | Class150 | Class300 | Class400 | Class600 | Class900 | ||||||||||
| Gasket | Outer diameter of the central ring | Gasket | Outer diameter of the central ring | Gasket | Outer diameter of the central ring | Gasket | Outer diameter of the central ring | Gasket | Outer diameter of the central ring | ||||||
| inner diameter | outer diameter | inner diameter | outer diameter | inner diameter | outer diameter | inner diameter | outer diameter | inner diameter | outer diameter | ||||||
| 26 | 673.1 | 704.9 | 774.7 | 685.8 | 736.6 | 835.2 | 685.8 | 736.6 | 831.9 | 685.8 | 736.6 | 866.9 | 685.8 | 736.6 | 882.7 |
| 28 | 723.9 | 755.7 | 831.9 | 736.6 | 787.4 | 898.7 | 736.6 | 787.4 | 892.3 | 736.6 | 787.4 | 914.4 | 736.6 | 787.4 | 946.2 |
| 30 | 774.7 | 806.5 | 882.7 | 793.8 | 844.6 | 952.5 | 793.8 | 844.6 | 946.2 | 793.8 | 844.6 | 971.6 | 793.8 | 844.6 | 1009.7 |
| 32 | 825.5 | 860.6 | 939.8 | 850.9 | 901.7 | 1006.6 | 850.9 | 901.7 | 1003.3 | 850.9 | 901.7 | 1022.4 | 850.9 | 901.7 | 1073.2 |
| 34 | 876.3 | 911.4 | 990.6 | 901.7 | 952.5 | 1057.4 | 901.7 | 952.5 | 1054.1 | 901.7 | 952.5 | 1073.2 | 901.7 | 952.5 | 1136.7 |
| 36 | 927.1 | 968.5 | 1047.8 | 955.8 | 1006.6 | 1117.6 | 955.8 | 1006.6 | 1117.6 | 955.8 | 1006.6 | 1130.3 | 958.9 | 1009.7 | 1200.2 |
| 38 | 977.9 | 1019.3 | 1111.3 | 977.9 | 1016 | 1054.1 | 971.6 | 1022.4 | 1073.2 | 990.6 | 1041.4 | 1104.9 | 1035.1 | 1085.9 | 1200.2 |
| 40 | 1028.7 | 1070.1 | 1162.1 | 1022.4 | 1070.1 | 1114.6 | 1025.7 | 1076.5 | 1127.3 | 1047.8 | 1098.6 | 1155.7 | 1098.6 | 1149.4 | 1251 |
| 42 | 1079.5 | 1124 | 1219.2 | 1073.2 | 1120.9 | 1165.4 | 1076.5 | 1127.3 | 1178.1 | 1104.9 | 1155.7 | 1219.2 | 1149.4 | 1200.2 | 1301.8 |
| 44 | 1130.3 | 1178.1 | 1276.4 | 1130.3 | 1181.1 | 1219.2 | 1130.3 | 1181.1 | 1231.9 | 1162.1 | 1212.9 | 1270 | 1206.5 | 1257.3 | 1368.6 |
| 46 | 1181.1 | 1228.9 | 1327.2 | 1178.1 | 1228.9 | 1273.3 | 1193.8 | 1244.6 | 1289.1 | 1212.9 | 1263.7 | 1327.2 | 1270 | 1320.8 | 1435.1 |
| 48 | 1231.9 | 1279.7 | 1384.3 | 1235.2 | 1286 | 1324.1 | 1244.6 | 1295.4 | 1346.2 | 1270 | 1320.8 | 1390.7 | 1320.8 | 1371.6 | 1485.9 |
| 50 | 1282.7 | 1333.5 | 1435.1 | 1295.4 | 1346.2 | 1378 | 1295.4 | 1346.2 | 1403.4 | 1320.8 | 1371.6 | 1447.8 | - | - | - |
| 52 | 1333.5 | 1384.3 | 1492.3 | 1346.2 | 1397 | 1428.8 | 1346.2 | 1397 | 1454.2 | 1371.6 | 1422.4 | 1498.6 | - | - | - |
| 54 | 1384.3 | 1435.1 | 1549.4 | 1403.4 | 1454.2 | 1492.3 | 1403.4 | 1454.2 | 1517.7 | 1428.8 | 1479.6 | 1555.8 | - | - | - |
| 56 | 1435.1 | 1485.9 | 1606.6 | 1454.2 | 1505 | 1543.1 | 1454.2 | 1505 | 1568.5 | 1479.6 | 1530.4 | 1612.9 | - | - | - |
| 58 | 1485.9 | 1536.7 | 1663.7 | 1511.3 | 1562.1 | 1593.9 | 1505 | 1555.8 | 1619.3 | 1536.7 | 1587.5 | 1663.7 | - | - | - |
| 60 | 1536.7 | 1587.5 | 1714.5 | 1562.1 | 1612.9 | 1644.7 | 1568.5 | 1619.3 | 1682.8 | 1593.9 | 1644.7 | 1733.6 | - | - | - |
Dimensions of Spiral Wound Gaskets for ASME B16.47B Flanges
| Flange Size (NPS) | Class150 | Class300 | Class400 | Class600 | Class900 | ||||||||||
| Gasket | Outer diameter of the central ring | Gasket | Outer diameter of the central ring | Gasket | Outer diameter of the central ring | Gasket | Outer diameter of the central ring | Gasket | Outer diameter of the central ring | ||||||
| inner diameter | outer diameter | inner diameter | outer diameter | inner diameter | outer diameter | inner diameter | outer diameter | inner diameter | outer diameter | ||||||
| 26 | 673.1 | 698.5 | 725.4 | 673.1 | 711.2 | 771.7 | 666.8 | 698.5 | 746.3 | 663.7 | 714.5 | 765.3 | 692.2 | 749.3 | 838.2 |
| 28 | 723.9 | 749.3 | 776.2 | 723.9 | 762 | 825.5 | 714.5 | 749.3 | 800.1 | 704.9 | 755.7 | 8192 | 743 | 800.1 | 901.7 |
| 30 | 774.7 | 800.1 | 827 | 774.7 | 812.8 | 886 | 765.3 | 806.5 | 857.3 | 778 | 828.8 | 879.6 | 8065 | 8573 | 958.9 |
| 32 | 825.5 | 850.9 | 881.1 | 825.5 | 863.6 | 939.8 | 812.8 | 860.6 | 911.4 | 831.9 | 882.7 | 933.5 | 863.6 | 914.4 | 1016 |
| 34 | 876.3 | 908.1 | 935 | 876.3 | 914.4 | 993.9 | 866.9 | 911.4 | 962.2 | 8B9.0 | 939.8 | 997 | 920.8 | 971.6 | 1073.2 |
| 36 | 927.1 | 958.9 | 987.6 | 927.1 | 965.2 | 1047.8 | 917.7 | 965.2 | 1022.4 | 939.8 | 990.6 | 1047.8 | 946.2 | 997 | 1124 |
| 38 | 974.9 | 1009.7 | 1044.7 | 1009.7 | 1047.8 | 1098.6 | 971.6 | 1022.4 | 1073.2 | 990.6 | 1041.4 | 1104.9 | 1035.1 | 1085.9 | 1200.2 |
| 40 | 1022.4 | 10638 | 1095.5 | 1060.5 | 1098.6 | 11494 | 1025.7 | 1076.5 | 1127.3 | 1047.8 | 1098.6 | 1155.7 | 1098.6 | 1149.4 | 1251 |
| 42 | 1079.5 | 1114.6 | 1146.3 | 1111.3 | 1149.4 | 1200.2 | 1076.5 | 1127.3 | 1178.1 | 1104.9 | 1155.7 | 1219.2 | 1149.4 | 1200.2 | 1301.8 |
| 44 | 1124 | 1165.4 | 1197.1 | 1162.1 | 1200.2 | 1251 | 1130.3 | 1181.1 | 1231.9 | 1162.1 | 1212.9 | 1270 | 1206.5 | 1257.3 | 1368.6 |
| 46 | 1181.1 | 1224 | 1255.8 | 1216.2 | 1254.3 | 1317.8 | 1193.8 | 1244.6 | 1289.1 | 1212.9 | 1263.7 | 1327.2 | 1270 | 1320.8 | 1435.1 |
| 48 | 1231.9 | 1270 | 1306.6 | 1263.7 | 1311.4 | 1368.6 | 1244.6 | 1295.4 | 1346.2 | 1270 | 1320.8 | 1390.7 | 1320.8 | 1371.6 | 1485.9 |
| 50 | 1282.7 | 1325.6 | 1357.4 | 1317.8 | 1355.9 | 1419.4 | 1295.4 | 1346.2 | 1403.4 | 1320.8 | 1371.6 | 1447.8 | - | - | - |
| 52 | 1333.5 | 1376.4 | 1408.2 | 1368.6 | 1406.7 | 1470.2 | 1346.2 | 1397 | 1454.2 | 1371.6 | 1422.4 | 1498.6 | - | - | - |
| 54 | 1384.3 | 1422.4 | 1463.8 | 1403.4 | 1454.2 | 15304 | 1403.4 | 1454.2 | 1517.7 | 1428.8 | 1479.6 | 1555.8 | - | - | - |
| 56 | 1444.8 | 1478 | 1514.6 | 1479.6 | 1524 | 1593.9 | 1454.2 | 1505 | 1568.5 | 1479.6 | 1530.4 | 1612.9 | - | - | - |
| 58 | 1500.1 | 1528.8 | 1579.6 | 1535.2 | 1573.3 | 1655.8 | 1505 | 1555.8 | 1619.3 | 1536.7 | 1587.5 | 1663.7 | - | - | - |
| 60 | 1557.3 | 1586 | 1630.4 | 15890 | 1630.4 | 1706.6 | 1568.5 | 1619.3 | 1682.8 | 1593.9 | 1644.7 | 1733.6 | - | - | - |
Ring Joint Gaskets
- Structure: A ring machined from solid metal into a specific cross-sectional shape (such as oval or octagonal).
- Compatible Flanges: Designed specifically for Ring Type Joint (RTJ) flanges.
- Features and Applications: Provides an all-metal seal, generating extremely high sealing contact pressure through line or surface contact. Suitable for extremely demanding operating conditions—including high temperatures, high pressures, hydrogen service, and thermal cycling—and commonly used in oil production trees, high-pressure heat exchangers, and high-temperature steam piping.
Dimensions of R-Type Ring Joint Gaskets Part 1
| Ring Number | Average Pitch Diameter of Ring P mm (in.) | Wigth of Ring A mm (in.) | Height of Ring mm (in.) | Width of Flat on Octagonal Ring C mm (in.) | Radius in Octagonal Ring Ri mm (in.) | |
| Oval. BOval. B | Octagonal H | |||||
| R-11 | 34.14 (1.344) | 6.35 (0.250) | 11.2 (0.44) | 9.7 (0.38) | 4.32 (0.170) | 1.5 (0.06) |
| R-12 | 39.70 (1.563) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-13 | 42.88 (1.688) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-14 | 44.45 (1.750) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-15 | 47.63 (1.875) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-16 | 50.80 (2.000) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-17 | 57.15 (2.250) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-18 | 60.33 (2.375) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-19 | 65.10 (2.563) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-20 | 68.28 (2.688) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-21 | 72.24 (2.844) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-22 | 82.55 (3.250) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-23 | 82.55 (3.250) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-24 | 95.25 (3.750) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-25 | 101.60 (4.000) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-26 | 101.60 (4.000) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-27 | 107.95 (4.250) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-28 | 111.13 (4.375) | 12.70 (0.500) | 19.1 (0.75) | 17.5 (0.69) | 8.66 (0.341) | 1.5 (0.06) |
| R-29 | 114.30 (4.500) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-30 | 117.48 (4.625) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-31 | 123.83 (4.875) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-32 | 127.00 (5.000) | 12.70 (0.500) | 19.1 (0.75) | 17.5 (0.69) | 8.66 (0.341) | 1.5 (0.06) |
| R-33 | 131.78 (5.188) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-34 | 131.78 (5.188) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-35 | 136.53 (5.375) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-36 | 149.23 (5.875) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-37 | 149.23 (5.875) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-38 | 157.18 (6.188) | 15.88 (0.625) | 22.4 (0.88) | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-39 | 161.93 (6.375) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
Dimensions of R-Type Ring Joint Gaskets Part 2
| Ring Number | Average Pitch Diameter of Ring P mm (in.) | Wigth of Ring A mm (in.) | Height of Ring mm (in.) | Width of Flat on Octagonal Ring C mm (in.) | Radius in Octagonal Ring Ri mm (in.) | |
| Oval. B | Octagonal H | |||||
| R-40 | 171.45 (6.750) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-41 | 180.98 (7.125) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-42 | 190.50 (7.500) | 19.05 (0.750) | 25.4 (1.00) | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-43 | 193.68 (7.625) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-44 | 193.68 (7.625) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-45 | 211.15 (8.313) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-46 | 211.15 (8.313) | 12.70 (0.500) | 19.1 (0.75) | 17.5 (0.69) | 8.66 (0.341) | 1.5 (0.06) |
| R-47 | 228.60 (9.000) | 19.05 (0.750) | 25.4 (1.00) | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-48 | 247.65 (9.750) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-49 | 269.88 (10.625) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-50 | 269.88 (10.625) | 15.88 (0.625) | 22.4 (0.88) | 2.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-51 | 279.40 (11.000) | 22.23 (0.875) | 28.7 (1.13) | 26.9 (1.06) | 14.81 (0.583) | 1.5 (0.06) |
| R-52 | 304.80 (12.000) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-53 | 323.85 (12.750) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-54 | 323.85 (12.750) | 15.88 (0.625) | 22.4 (0.88) | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-55 | 342.90 (13.500) | 28.58 (1.125) | 36.6 (1.44) | 35.1 (1.38) | 19.81 (0.780) | 2.3 (0.09) |
| R-56 | 381.00 (15.000) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-57 | 381.00 (15.000) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-58 | 381.00 (15.000) | 22.23 (0.875) | 28.7 (1.13) | 26.9 (1.06) | 14.81 (0.583) | 1.5 (0.06) |
| R-59 | 396.88 (15.625) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-60 | 406.40 (16.000) | 31.75 (1.250) | 39.6 (1.56) | 38.1 (1.50) | 22.33 (0.879) | 2.3 (0.09) |
| R-61 | 406.40 (16.000) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-62 | 419.10 (16.500) | 15.88 (0.625) | 22.4 (0.88) | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-63 | 419.10 (16.500) | 25.40 (1.000) | 33.3 (1.31) | 31.8 (1.25) | 17.30 (0.681) | 2.3 (0.09) |
| R-64 | 454.03 (17.875) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-65 | 469.90 (18.500) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-66 | 469.90 (18.500) | 15.88 (0.625) | 22.4 (0.88) | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-67 | 469.90 (18.500) | 28.58 (1.125) | 36.6 (1.44) | 35.1 (1.38) | 19.81 (0.780) | 2.3 (0.09) |
| R-68 | 517.53 (20.375) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-69 | 533.40 (21.000) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-70 | 533.40 (21.000) | 19.05 (0.750) | 25.4 (1.00) | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-71 | 533.40 (21.000) | 28.58 (1.125) | 36.6 (1.44) | 35.1 (1.38) | 19.81 (0.780) | 2.3 (0.09) |
| R-72 | 558.80 (22.000) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-73 | 584.20 (23.000) | 12.70 (0.500) | 19.1 (0.75) | 17.5 (0.69) | 8.66 (0.341) | 1.5 (0.06) |
| R-74 | 584.20 (23.000) | 19.05 (0.750) | 254 (1.00) | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-75 | 584.20 (23.000) | 31.75 (1.250) | 39.6 (1.56) | 38.1 (1.50) | 22.33 (0.879) | 2.3 (0.09) |
| R-76 | 673.10 (26.500) | 7.95 (0.313) | 14.2 (0.56) | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
| R-77 | 692.15 (27.250) | 15.88 (0.625) | 22.4 (0.88) | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-78 | 692.15 (27.250) | 25.40 (1.000) | 33.3 (1.31) | 31.8 (1.25) | 17.30 (0.681) | 2.3 (0.09) |
| R-79 | 692.15 (27.250) | 34.93 (1.375) | 44.5 (1.75) | 41.4 (1.63) | 24.82 (0.977) | 2.3 (0.09) |
| R-80 | 615.95 (24.250) | 7.95 (0.313) | - | 12.7 (0.50) | 5.23 (0.206) | 1.5 (0.06) |
Dimensions of R-Type Ring Joint Gaskets Part 3
| Ring Number | Average Pitch Diameter of Ring P mm (in.) | Wigth of Ring A mm (in.) | Height of Ring mm (in.) | Width of Flat on Octagonal Ring C mm (in.) | Radius in Octagonal Ring Ri mm (in.) | |
| Oval. B | Octagonal H | |||||
| R-81 | 635.00 (25.000) | 14.30 (0.563) | … | 19.1 (0.75) | 9.58 (0.377) | 1.5 (0.06) |
| R-82 | 57.15 (2.250) | 11.13 (0.438) | … | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-84 | 63.50 (2.500) | 11.13 (0.438) | … | 16.0(0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-85 | 79.38 (3.125) | 12.70 (0.500) | … | 17.5 (0.69) | 8.66 (0.341) | 1.5 (0.06) |
| R-86 | 90.50 (3.563) | 15.88 (0.625) | … | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-87 | 100.03 (3.938) | 15.88 (0.625) | … | 20.6 (0.81) | 10.49 (0.413) | 1.5 (0.06) |
| R-88 | 123.83 (4.875) | 19.05 (0.750) | … | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-89 | 114.30 (4.500) | 19.05 (0.750) | … | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-90 | 155.58 (6.125) | 22.23 (0.875) | … | 26.9 (1.06) | 14.81 (0.583) | 1.5 (0.06) |
| R-91 | 260.35 (10.250) | 31.75 (1.250) | … | 38.1 (1.50) | 22.33 (0.879) | 2.3 (0.09) |
| R-92 | 228.60 (9.000) | 11.13 (0.438) | 17.5 (0.69) | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-93 | 749.30 (29.500) | 19.05 (0.750) | … | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-94 | 800.10 (31.500) | 19.05 (0.750) | … | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-95 | 857.25 (33.750) | 19.05 (0.750) | … | 23.9 (0.94) | 12.32 (0.485) | 1.5 (0.06) |
| R-96 | 914.40 (36.000) | 22.23 (0.875) | … | 26.9 (1.06) | 14.81 (0.583) | 1.5 (0.06) |
| R-97 | 965.20 (38.000) | 22.23 (0.875) | … | 26.9 (1.06) | 14.81 (0.583) | 1.5 (0.06) |
| R-98 | 1022.35 (40.250) | 22.23 (0.875) | … | 26.9 (1.06) | 14.81 (0.583) | 1.5 (0.06) |
| R-99 | 234.95 (9.250) | 11.13 (0.438) | … | 16.0 (0.63) | 7.75 (0.305) | 1.5 (0.06) |
| R-100 | 749.30 (29.500) | 28.58 (1.125) | … | 35.1 (1.38) | 19.81 (0.780) | 2.3 (0.09) |
| R-101 | 800.10 (31.500) | 31.75 (1.250) | … | 38.1 (1.50) | 22.33 (0.879) | 2.3 (0.09) |
| R-102 | 857.25 (33.750) | 31.75 (1.250) | … | 38.1 (1.50) | 22.33 (0.879) | 2.3 (0.09) |
| R-103 | 914.40 (36.000) | 31.75 (1.250) | … | 38.1 (1.50) | 22.33 (0.879) | 2.3 (0.09) |
| R-104 | 965.20 (38.000) | 34.93 (1.375) | … | 41.4 (1.63) | 24.82 (0.977) | 2.3 (0.09) |
| R-105 | 1022.35 (40.250) | 34.93 (1.375) | … | 41.4 (1.63) | 24.82 (0.977) | 2.3 (0.09) |
GENERAL NOTE: Tolerances:
23 deg= angle,±0 deg 30 min(±1/2 deg)
A=width of ring,±0.20mm(±0.008in.)
B,H= height of ring,+1.3mm,-0.5mm(+0.05 in.,-0.02 in.)
Variation in height throughout the entire circumference of any given ringshall not exceed 0.5mm(0.02 in.) within these tolerances.
C=width of flat on octagonal ring,±0.20mm(±0.008 in.)
P= average pitch diameter of ring,±0.18mm(±0.007 in.]
Ri=radius in ring,±0.5mm(±0.02 in.)
Dimensions of RX-Type Ring Joint Gaskets Part 1
| Ring Number | Outside Diameter of Ring O.D mm (in.) | Width of Ring A mm (in.) | Width of Flat C mm (in.) | Height of Outside Bevel D mm (in.) | Height of Ring H mm (in.) | Radius in Octagonal Ring Ri mm (in.) | Radius in Octagonal Ring Ri mm (in.) |
| RX-20 | 76.20 (3.000) | 8.74 (0.344) | 4.62 (0.182) | 3.18 (0.125) | 19.05 (0.750) | 1.5 (0.06) | - |
| RX-23 | 93.27 (3.672) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1000) | 1.5 (0.06) | - |
| RX-24 | 105.97 (4.172) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-25 | 109.55 (4.313) | 8.74 (0.344) | 4.62 (0.182) | 3.18 (0.125) | 19.05 (0.750) | 1.5 (0.06) | - |
| RX-26 | 111.91 (4.406) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-27 | 118.26 (4.656) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-31 | 134.54 (5.297) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-35 | 147.24 (5.797) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-37 | 159.94 (6.297) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-39 | 172.64 (6.797) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-41 | 191.69 (7.547) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-44 | 204.39 (8.047) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-45 | 221.84 (8.734) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-46 | 222.25 (8.750) | 13.49 (0.531) | 6.68 (0.263) | 4.78 (0.188) | 28.58 (1.125) | 1.5 (0.06) | - |
| RX-47 | 245.26 (9.656) | 19.84 (0.781) | 10.34 (0.407) | 6.88 (0.271) | 41.28 (1.625) | 2.3 (0.09) | - |
| RX-49 | 280.59 (11.047) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1000) | 1.5 (0.06) | - |
| RX-50 | 283.36 (11.156) | 16.66 (0.656) | 8.51 (0.335) | 5.28 (0.208) | 31.75 (1.250) | 1.5 (0.06) | - |
| RX-53 | 334.57 (13.172) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-54 | 337.34 (13.281) | 16.66 (0.656) | 8.51 (0.335) | 5.28 (0.208) | 31.75 (1.250) | 1.5 (0.06) | - |
| RX-57 | 391.72 (15.422) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-63 | 441.73 (17.391) | 27.00 (1.063) | 14.78 (0.582) | 8.46 (0.333) | 50.80 (2.000) | 2.3 (0.09) | - |
| RX-65 | 480.62 (18.922) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-66 | 483.39 (19.031) | 16.66 (0.656) | 8.51 (0.335) | 5.28 (0.208) | 31.75 (1.250) | 1.5 (0.06) | - |
| RX-69 | 544.12 (21.422) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1000) | 1.5 (0.06) | - |
| RX-70 | 550.06 (21.656) | 19.84 (0.781) | 10.34 (0.407) | 6.88 (0.271) | 41.28 (1.625) | 2.3 (0.09) | - |
| RX-73 | 596.11 (23.469) | 13.49 (0.531) | 6.68 (0.263) | 5.28 (0.208) | 31.75 (1.250) | 1.5 (0.06) | - |
Dimensions of RX-Type Ring Joint Gaskets Part 2
| Ring Number | Outside Diameter of Ring O.D mm (in.) | Width of Ring A mm (in.) | Width of Flat C mm (in.) | Height of Outside Bevel D mm (in.) | Height of Ring H mm (in.) | Radius in Octagonal Ring Ri mm (in.) | Hole Size E mm (in.) |
| RX-74 | 600.86 (23.656) | 19.84 (0.781) | 10.34 (0.407) | 6.88 (0.271) | 41.28 (1.625) | 2.3 (0.09) | - |
| RX-82 | 67.87 (2.672) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | 1.5 (0.06) |
| RX-84 | 74.22 (2.922) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | 1.5 (0.06) |
| RX-85 | 90.09 (3.547) | 13.49 (0.531) | 6.68 (0.263) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | 1.5 (0.06) |
| RX-86 | 103.58 (4.078) | 15.09 (0.594) | 8.51 (0.335) | 4.78 (0.188) | 28.58 (1.125) | 1.5 (0.06) | 2.3 (0.09) |
| RX-87 | 113.11 (4.453) | 15.09 (0.594) | 8.51 (0.335) | 4.78 (0.188) | 28.58 (1.125) | 1.5 (0.06) | 2.3 (0.09) |
| RX-88 | 139.29 (5.484) | 17.48 (0.688) | 10.34 (0.407) | 5.28 (0.208) | 31.75 (1.250) | 1.5 (0.06) | 3.0 (0.12) |
| RX-89 | 129.77 (5.109) | 18.26 (0.719) | 10.34 (0.407) | 5.28 (0.208) | 31.75 (1.250) | 1.5 (0.06) | 3.0 (0.12) |
| RX-90 | 174.63 (6.875) | 19.84 (0.781) | 12.17 (0.479) | 7.42 (0.292) | 44.45 (1.750) | 2.3 (0.09) | 3.0 (0.12) |
| RX-91 | 286.94 (11.297) | 30.18 (1.188) | 19.81 (0.780) | 7.54 (0.297) | 45.24 (1.781) | 2.3 (0.09) | 3.0 (0.12) |
| RX-99 | 245.67 (9.672) | 11.91 (0.469) | 6.45 (0.254) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
| RX-201 | 51.46 (2.026) | 5.74 (0.226) | 3.20 (0.126) | 1.45 (0.057) | 11.30 (0.445) | 0.5 (0.02) | - |
| RX-205 | 62.31 (2.453) | 5.56 (0.219) | 3.05 (0.120) | 1.83 (0.072) | 11.10 (0.437) | 0.5 (0.02) | - |
| RX-210 | 97.64 (3.844) | 9.53 (0.375) | 5.41 (0.213) | 3.18 (0.125) | 19.05 (0.750) | 0.8 (0.03) | - |
| RX-215 | 140.89 (5.547) | 11.91 (0.469) | 5.33 (0.210) | 4.24 (0.167) | 25.40 (1.000) | 1.5 (0.06) | - |
GENERAL NOTE: Tolerances:
23 deg=angle,±0 deg, 30 min(±1/2 deg)
A=width of ring,+0.20mm,-0.00 mm(+0.008in.,-0in.)
Variation in width throughout the entire circumference of any ring shall not exceed 0.10mm(0.004 in.) within these tolerances.
C=width of flat,+0.15mm,-0.00 mm(+0.006 in.-0 in.)
D=height of outside bevel,+0.0 mm,-0.76mm(+0 in.,-0.030 in.)
E=hole size,±0.5 mm(±0.02 in.)
H=height of ring,+0.20mm,-0.00 mm(+0.008 in.,-0 in.)
Variation in height throughout the entire circumference of any ring shall not exceed 0.10mm(0.004 in.) within these tolerances.
0.D.= outside diameter of ring,+0.51mm,-0.00 mm(+0.020 in.,-0 in.)
Ri=radius of ring,±0.5 mm(±0.02 in.)
Dimensions of BX-Type Ring Joint Gaskets
| Ring Number | Nominal mm (in.) | Outside Diameter of Ring O.D mm (in.) | Height of Ring H mm (in.) | Width of Ring A mm (in.) | Outside Diameter of Flat O.D.T mm (in.) | Width of Flat C mm (in.) | Hole Size D mm (in.) |
| BX-150 | 43 (1-11/6) | 72.19 (2.842) | 9.30 (0.366) | 9.30 (0.366) | 70.87 (2.790) | 7.98 (0.314) | 1.5 (0.06) |
| BX-151 | 46 (1-13/6) | 76.40 (3.008) | 9.63 (0.379) | 9.63 (0.379) | 75.03 (2.954) | 8.26 (0.325) | 1.5 (0.06) |
| BX-152 | 52 (2-1/16) | 84.68 (3.334) | 10.24 (0.403) | 10.24 (0.403) | 83.24 (3.277) | 8.79 (0.346) | 1.5 (0.06) |
| BX-153 | 65 (2-9/16) | 100.94 (3.974) | 11.38 (0.448) | 11.38 (0.448) | 99.31 (3.910) | 9.78 (0.385) | 1.5 (0.06) |
| BX-154 | 78 (3-1/16) | 116.84 (4.600) | 12.40 (0.488) | 12.40 (0.488) | 115.09 (4.531) | 10.64 (0.419) | 1.5 (0.06) |
| BX-155 | 103 (4-1/16) | 147.96 (5.825) | 14.22 (0.560) | 14.22 (0.560) | 145.95 (5.746) | 12.22 (0.481) | 1.5 (0.06) |
| BX-156 | 179 (7-1/16) | 237.92 (9.367) | 18.62 (0.733) | 18.62 (0.733) | 235.28 (9.263) | 15.98 (0.629) | 3.0 (0.12) |
| BX-157 | 229 (9) | 294.46 (11.593) | 20.98 (0.826) | 20.98 (0.826) | 291.49 (11.476) | 18.01 (0.709) | 3.0 (0.12) |
| BX-158 | 279 (11) | 352.04 (13.860) | 23.14 (0.911) | 23.14 (0.911) | 348.77 (13.731) | 19.86 (0.782) | 3.0 (0.12) |
| BX-159 | 346 (13-5/8) | 426.72 (16.800) | 25.70 (1.012) | 25.70 (1.012) | 423.09 (16.657) | 22.07 (0.869) | 3.0 (0.12) |
| BX-160 | 346 (13-5/8) | 402.59 (15.850) | 23.83 (0.938) | 13.74 (0.541) | 399.21 (15.717) | 10.36 (0.408) | 3.0 (0.12) |
| BX-161 | 422 (16-5/8) | 491.41 (19.347) | 28.07 (1.105) | 16.21 (0.638) | 487.45 (19.191) | 12.24 (0.482) | 3.0 (0.12) |
| BX-162 | 422 (16-5/8) | 475.49 (18.720) | 14.22 (0.560) | 14.22 (0.560) | 473.48 (18.641) | 12.22 (0.481) | 1.5 (0.06) |
| BX-163 | 476 (18-3/4) | 556.16 (21.896) | 30.10 (1.185) | 17.37 (0.684) | 551.89 (21.728) | 13.11 (0.516) | 3.0 (0.12) |
| BX-164 | 476 (18-3/4) | 570.56 (22.463) | 30.10 (1.185) | 24.59 (0.968) | 566.29 (22.295) | 20.32 (0.800) | 3.0 (0.12) |
| BX-165 | 540 (21-1/4) | 624.71 (24.595) | 32.03 (1.261) | 18.49 (0.728) | 620.19 (24.417) | 13.97 (0.550) | 3.0 (0.12) |
| BX-166 | 540 (21-1/4) | 640.03 (25.198) | 32.03 (1.261) | 26.14 (1.029) | 635.51 (25.020) | 21.62 (0.851) | 3.0 (0.12) |
| BX-167 | 680 (26-3/4) | 759.36 (29.896) | 35.86 (1.412) | 13.11 (0.516) | 754.28 (29.696) | 8.03 (0.316) | 1.5 (0.06) |
| BX-168 | 680 (26-3/4) | 765.25 (30.128) | 35.86 (1.412) | 16.05 (0.632) | 760.17 (29.928) | 10.97 (0.432) | 1.5 (0.06) |
| BX-169 | 130 (5-1/8) | 173.51 (6.831) | 15.85 (0.624) | 12.93 (0.509) | 171.27 (6.743) | 10.69 (0.421) | 1.5 (0.06) |
| BX-170 | 168 (6-5/8) | 218.03 (8.584) | 14.22 (0.560) | 14.22 (0.560) | 216.03 (8.505) | 12.22 (0.481) | 1.5 (0.06) |
| BX-171 | 218 (8-9/16) | 267.44 (10.529) | 14.22 (0.560) | 14.22 (0.560) | 265.43 (10.450) | 12.22 (0.481) | 1.5 (0.06) |
| BX-172 | 283 (11-5/32) | 333.07 (13.113) | 14.22 (0.560) | 14.22 (0.560) | 331.06 (13.034) | 12.22 (0.481) | 1.5 (0.06) |
| BX-303 | 762 (30) | 852.75 (33.573) | 37.95 (1.494) | 16.97 (0.668) | 847.37 (33.361) | 11.61 (0.457) | 1.5 (0.06) |
GENERAL NOTE:
(a) Radius, R, shall be 8% to 12% of the gasket height,H.
(b) Tolerances:
23 deg= angle,±0 deg 15 min(±V4 deg)
A=width of ring,+0.20mm,-0.00 mm(+0.008 in.,-0 in.)
Variation in width throughout the entire circumference of any ring shall not exceed 0.10mm(0.004in.) within these tolerances.
C=width of flat,+0.15mm,-0.00 mm(+0.006 in.,-0 in.)
D=hole size,±0.5 mm(±0.02 in.)
H=height of ring,+0.20mm,-0.00 mm(+0.008 in.,-0 in.)
Variation in height throughout the entire circumference of any ring shall not exceed 0.10mm〔0.004in.) within these tolerances.
0.D.= outside diameter of ring,+0.00 mm,-0.15mm(+0 in.,-0.005 in.)
0.D.T.=outside diameter of flat,±0.05 mm(±0.002 in.)
R=radius of ring [see General Note (a)]
Metal Jacketed Gaskets
- Structure: Formed by completely encapsulating a non-metallic filler material (such as graphite or ceramic fiber board) within a soft metal shell (such as copper, aluminum, mild steel, or stainless steel).
- Applicable Flanges: Suitable for various flange facings, including Raised Face (RF) and Flat Face (FF).
- Features and Applications: The metal shell protects the internal filler from media corrosion and mechanical damage while providing good resilience. Commonly used in heat exchangers, valve bonnets, and environments involving corrosive media.
Gasket Dimensions and Tolerances: Key to a Successful Seal
The ASME B16.20 standard imposes strict requirements on gasket dimensions. For example:
For spiral-wound gaskets, the standard specifies the inner diameter (ID), outer diameter (OD), and nominal thickness to ensure compatibility with flanges of various pressure classes and nominal pipe sizes (NPS).
For ring-type joint gaskets, the standard strictly defines the ring width, height, inner and outer diameters, and critical cross-sectional dimensions (such as the diagonal distance for octagonal profiles).
Tolerance ranges are tightly controlled to ensure the gasket fits precisely into the flange sealing groove or seats correctly on the flange face. This prevents installation errors, misalignment, or insufficient sealing contact pressure caused by dimensional deviations, all of which could lead to leakage.
The Important Role of Gaskets in Flange Sealing
Flange sealing is a system comprising the "Flange-Bolt-Gasket" assembly. The flange gasket plays a vital role in this system:
Initial Seal: Under bolt preload, the gasket deforms elastically or plastically, filling microscopic irregularities on the flange sealing faces to create an initial seal.
Operational Seal: When the pipeline experiences internal pressure, temperature changes, or other factors that tend to separate the flanges, the gasket relies on residual compressive stress and its own recovery ability to maintain sufficient sealing stress, preventing media leakage.
Compensation: The gasket can compensate for gap changes caused by temperature fluctuations, mechanical vibration, or minor flange misalignment.
Therefore, a correctly selected, quality-assured, and properly installed ASME B16.20 flange gasket is the most important guarantee of the sealing performance of the entire flange connection.
Wide Range of Applications
Flange gaskets based on the ASME B16.20 standard are widely used across industrial sectors that employ standard flange connections:
- Oil and Gas: Upstream extraction, refining, and long-distance pipelines.
- Chemical and Petrochemical: Various reactors, towers, heat exchangers, and process piping.
- Power Generation: Steam systems in thermal power plants and auxiliary systems in nuclear power plants.
- Shipbuilding: Marine propulsion systems and piping. Other industries: Piping systems for special media in sectors such as papermaking, pharmaceuticals, and food processing.
When selecting ASME B16.20 flange gaskets, it is essential to make the most appropriate choice by considering the flange type, media characteristics, temperature and pressure parameters, and operating conditions, in conjunction with the relevant standard guidelines.
