ASME B16.5 Flange Pressure–Temperature Ratings
A flange class is not a pressure. The maximum allowable working pressure of an ASME B16.5 flange depends on its class, its material group and the design temperature. These tables give the ratings in bar gauge for the material groups most often specified.
To select a class: find your material group, read across from your design temperature, and choose the lowest class whose rating is at or above your design pressure. Mating flanges, valves and gaskets must be suitable for the same rating.
ASME B16.5 Flange Pressure–Temperature Ratings — tables
Material Group 1.1: A105, A350 LF2, A216 WCB
| Temp.°C | Class 150bar | Class 300bar | Class 600bar | Class 900bar | Class 1500bar | Class 2500bar |
|---|---|---|---|---|---|---|
| −29 to 38 | 19.6 | 51.1 | 102.1 | 153.2 | 255.3 | 425.5 |
| 50 | 19.2 | 50.1 | 100.2 | 150.4 | 250.6 | 417.7 |
| 100 | 17.7 | 46.6 | 93.2 | 139.8 | 233.0 | 388.3 |
| 150 | 15.8 | 45.1 | 90.2 | 135.2 | 225.4 | 375.6 |
| 200 | 13.8 | 43.8 | 87.6 | 131.4 | 219.0 | 365.0 |
| 250 | 12.1 | 41.9 | 83.9 | 125.8 | 209.7 | 349.5 |
| 300 | 10.2 | 39.8 | 79.6 | 119.5 | 199.1 | 331.8 |
| 325 | 9.3 | 38.7 | 77.4 | 116.1 | 193.6 | 322.6 |
| 350 | 8.4 | 37.6 | 75.1 | 112.7 | 187.8 | 313.0 |
| 375 | 7.4 | 36.4 | 72.7 | 109.1 | 181.8 | 303.1 |
| 400 | 6.5 | 34.7 | 69.4 | 104.2 | 173.6 | 289.3 |
| 425 | 5.5 | 28.8 | 57.5 | 86.3 | 143.8 | 239.7 |
| 450 | 4.6 | 23.0 | 46.0 | 69.0 | 115.0 | 191.7 |
| 475 | 3.7 | 17.4 | 34.9 | 52.3 | 87.2 | 145.3 |
| 500 | 2.8 | 11.8 | 23.5 | 35.3 | 58.8 | 97.9 |
| 538 | 1.4 | 5.9 | 11.8 | 17.7 | 29.5 | 49.2 |
Material Group 1.9: A182 F11 Cl.2 (also A217 WC6)
| Temp.°C | Class 150bar | Class 300bar | Class 600bar | Class 900bar | Class 1500bar | Class 2500bar |
|---|---|---|---|---|---|---|
| −29 to 38 | 19.8 | 51.7 | 103.4 | 155.1 | 258.6 | 430.9 |
| 50 | 19.5 | 51.7 | 103.4 | 155.1 | 258.6 | 430.9 |
| 100 | 17.7 | 51.5 | 103.0 | 154.4 | 257.4 | 429.0 |
| 150 | 15.8 | 49.7 | 99.5 | 149.2 | 248.7 | 414.5 |
| 200 | 13.8 | 48.0 | 95.9 | 143.9 | 239.8 | 399.6 |
| 250 | 12.1 | 46.3 | 92.7 | 139.0 | 231.8 | 386.2 |
| 300 | 10.2 | 42.9 | 85.7 | 128.6 | 214.4 | 357.1 |
| 325 | 9.3 | 41.4 | 82.6 | 124.0 | 206.6 | 344.3 |
| 350 | 8.4 | 40.3 | 80.4 | 120.7 | 201.1 | 335.3 |
| 375 | 7.4 | 38.9 | 77.6 | 116.5 | 194.1 | 323.2 |
| 400 | 6.5 | 36.5 | 73.3 | 109.8 | 183.1 | 304.9 |
| 425 | 5.5 | 35.2 | 70.0 | 105.1 | 175.1 | 291.6 |
| 450 | 4.6 | 33.7 | 67.7 | 101.4 | 169.0 | 281.8 |
| 475 | 3.7 | 31.7 | 63.4 | 95.1 | 158.2 | 263.9 |
| 500 | 2.8 | 25.7 | 51.5 | 77.2 | 128.6 | 214.4 |
| 538 | 1.4 | 14.9 | 29.8 | 44.7 | 74.5 | 124.1 |
Material Group 1.10: A182 F22 Cl.3 (also A217 WC9)
| Temp.°C | Class 150bar | Class 300bar | Class 600bar | Class 900bar | Class 1500bar | Class 2500bar |
|---|---|---|---|---|---|---|
| −29 to 38 | 19.8 | 51.7 | 103.4 | 155.1 | 258.6 | 430.9 |
| 50 | 19.5 | 51.7 | 103.4 | 155.1 | 258.6 | 430.9 |
| 100 | 17.7 | 51.5 | 103.0 | 154.6 | 257.6 | 429.4 |
| 150 | 15.8 | 50.3 | 100.3 | 150.6 | 250.8 | 418.2 |
| 200 | 13.8 | 48.6 | 97.2 | 145.8 | 243.4 | 405.4 |
| 250 | 12.1 | 46.3 | 92.7 | 139.0 | 231.8 | 386.2 |
| 300 | 10.2 | 42.9 | 85.7 | 128.6 | 214.4 | 357.1 |
| 325 | 9.3 | 41.4 | 82.6 | 124.0 | 206.6 | 344.3 |
| 350 | 8.4 | 40.3 | 80.4 | 120.7 | 201.1 | 335.3 |
| 375 | 7.4 | 38.9 | 77.6 | 116.5 | 194.1 | 323.2 |
| 400 | 6.5 | 36.5 | 73.3 | 109.8 | 183.1 | 304.9 |
| 425 | 5.5 | 35.2 | 70.0 | 105.1 | 175.1 | 291.6 |
| 450 | 4.6 | 33.7 | 67.7 | 101.4 | 169.0 | 281.8 |
| 475 | 3.7 | 31.7 | 63.4 | 95.1 | 158.2 | 263.9 |
| 500 | 2.8 | 28.2 | 56.5 | 84.7 | 140.9 | 235.0 |
| 538 | 1.4 | 18.4 | 36.9 | 55.3 | 92.2 | 153.7 |
Material Group 2.1: A182 F304 / F304H
| Temp.°C | Class 150bar | Class 300bar | Class 600bar | Class 900bar | Class 1500bar | Class 2500bar |
|---|---|---|---|---|---|---|
| −29 to 38 | 19.0 | 49.6 | 99.3 | 148.9 | 248.2 | 413.7 |
| 50 | 18.3 | 47.8 | 95.6 | 143.5 | 239.1 | 398.5 |
| 100 | 15.7 | 40.9 | 81.7 | 122.6 | 204.3 | 340.4 |
| 150 | 14.2 | 37.0 | 74.0 | 111.0 | 185.0 | 308.4 |
| 200 | 13.2 | 34.5 | 69.0 | 103.4 | 172.4 | 287.3 |
| 250 | 12.1 | 32.5 | 65.0 | 97.5 | 162.4 | 270.7 |
| 300 | 10.2 | 30.9 | 61.8 | 92.7 | 154.6 | 257.6 |
| 325 | 9.3 | 30.2 | 60.4 | 90.7 | 151.1 | 251.9 |
| 350 | 8.4 | 29.6 | 59.3 | 88.9 | 148.1 | 246.9 |
| 375 | 7.4 | 29.0 | 58.1 | 87.1 | 145.2 | 241.9 |
| 400 | 6.5 | 28.4 | 56.9 | 85.3 | 142.2 | 237.0 |
| 425 | 5.5 | 28.0 | 56.0 | 84.0 | 140.0 | 233.3 |
| 450 | 4.6 | 27.4 | 54.8 | 82.2 | 137.0 | 228.4 |
| 475 | 3.7 | 26.9 | 53.9 | 80.8 | 134.7 | 224.5 |
| 500 | 2.8 | 26.5 | 53.0 | 79.5 | 132.4 | 220.7 |
| 538 | 1.4 | 24.4 | 48.9 | 73.3 | 122.1 | 203.6 |
Material Group 2.2: A182 F316 / F316H
| Temp.°C | Class 150bar | Class 300bar | Class 600bar | Class 900bar | Class 1500bar | Class 2500bar |
|---|---|---|---|---|---|---|
| −29 to 38 | 19.0 | 49.6 | 99.3 | 148.9 | 248.2 | 413.7 |
| 50 | 18.4 | 48.1 | 96.2 | 144.3 | 240.6 | 400.9 |
| 100 | 16.2 | 42.2 | 84.4 | 126.6 | 211.0 | 351.6 |
| 150 | 14.8 | 38.5 | 77.0 | 115.5 | 192.5 | 320.8 |
| 200 | 13.7 | 35.7 | 71.3 | 107.0 | 178.3 | 297.2 |
| 250 | 12.1 | 33.4 | 66.8 | 100.1 | 166.9 | 278.1 |
| 300 | 10.2 | 31.6 | 63.2 | 94.9 | 158.1 | 263.5 |
| 325 | 9.3 | 30.9 | 61.8 | 92.7 | 154.4 | 257.4 |
| 350 | 8.4 | 30.3 | 60.7 | 91.0 | 151.6 | 252.7 |
| 375 | 7.4 | 29.9 | 59.8 | 89.6 | 149.4 | 249.0 |
| 400 | 6.5 | 29.4 | 58.9 | 88.3 | 147.2 | 245.3 |
| 425 | 5.5 | 29.1 | 58.3 | 87.4 | 145.7 | 242.9 |
| 450 | 4.6 | 28.8 | 57.7 | 86.5 | 144.2 | 240.4 |
| 475 | 3.7 | 28.7 | 57.3 | 86.0 | 143.4 | 238.9 |
| 500 | 2.8 | 28.2 | 56.5 | 84.7 | 140.9 | 235.0 |
| 538 | 1.4 | 25.2 | 50.0 | 75.2 | 125.5 | 208.9 |
Material Group 2.3: A182 F304L / F316L
| Temp.°C | Class 150bar | Class 300bar | Class 600bar | Class 900bar | Class 1500bar | Class 2500bar |
|---|---|---|---|---|---|---|
| −29 to 38 | 15.9 | 41.4 | 82.7 | 124.1 | 206.8 | 344.7 |
| 50 | 15.3 | 40.0 | 80.0 | 120.1 | 200.1 | 333.5 |
| 100 | 13.3 | 34.8 | 69.6 | 104.4 | 173.9 | 289.9 |
| 150 | 12.0 | 31.4 | 62.8 | 94.2 | 157.0 | 261.6 |
| 200 | 11.2 | 29.2 | 58.3 | 87.5 | 145.8 | 243.0 |
| 250 | 10.5 | 27.5 | 54.9 | 82.4 | 137.3 | 228.9 |
| 300 | 10.0 | 26.1 | 52.1 | 78.2 | 130.3 | 217.2 |
| 325 | 9.3 | 25.5 | 51.0 | 76.4 | 127.4 | 212.3 |
| 350 | 8.4 | 25.1 | 50.1 | 75.2 | 125.4 | 208.9 |
| 375 | 7.4 | 24.8 | 49.5 | 74.3 | 123.8 | 206.3 |
| 400 | 6.5 | 24.3 | 48.6 | 72.9 | 121.5 | 202.5 |
| 425 | 5.5 | 23.9 | 47.7 | 71.6 | 119.3 | 198.8 |
| 450 | 4.6 | 23.4 | 46.8 | 70.2 | 117.1 | 195.1 |
Notes
- Working pressures are in bar gauge. Linear interpolation between temperatures is permitted by the standard.
- Group 1.1 includes ASTM A105, A350 LF2 and A216 WCB. Prolonged use of carbon steel above about 425 °C is not recommended because of graphitisation.
- Group 2.3: F304L is not to be used above 425 °C; F316L is rated to 450 °C.
- Ratings are those of the ASME B16.5 metric tables in the 2013 to 2020 editions. Confirm against the edition your project specifies.
- The Group 1.9 (F11 Cl.2) table was cross-checked against the equivalent ASME B16.34 valve ratings; confirm it against the current edition of ASME B16.5 for design.
Reference information compiled from the published standard for convenience. It does not replace the current edition of the governing standard, which takes precedence. Verify critical dimensions and properties before design, purchase or fabrication. Teshi Engineers & Sales Promoters (P) Ltd accepts no liability for errors or omissions.
FAQ
ASME B16.5 pressure–temperature ratings: common questions
What pressure can a Class 150 flange hold?
It depends on material and temperature. An ASTM A105 Class 150 flange is rated 19.6 bar at −29 to 38 °C, 17.7 bar at 100 °C and 13.8 bar at 200 °C.
Is a Class 300 flange rated for 300 psi?
No. Class is a designation, not a pressure. An A105 Class 300 flange is rated 51.1 bar (about 740 psi) at ambient temperature.
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