Recommended minimum Torque Values are in N-m.
Torque values are applicable for Bolt Materials - ASTM A193 B7, B16 & ASTM A320 L7.
BOLT TORQUING
| Flange NPS |
No of Bolts |
Bolt size |
Bolt Stress (MPa) |
Torque N-m μ=0.09 Copperslip |
Torque N-m μ=0.14 Chesterton Nickel |
Torque N-m μ=0.225 Unlubricated |
|---|---|---|---|---|---|---|
| ½'' | 4 | ¾ | 276 | 139 | 203 | 313 |
| ¾'' | 4 | ¾ | 276 | 139 | 203 | 313 |
| 1'' | 4 | ⅞ | 276 | 221 | 325 | 502 |
| 1¼'' | 4 | ⅞ | 276 | 221 | 325 | 502 |
| 1½'' | 4 | 1 | 276 | 330 | 485 | 748 |
| 2'' | 8 | ⅞ | 276 | 221 | 325 | 502 |
| 2½'' | 8 | 1 | 276 | 330 | 485 | 748 |
| 3'' | 8 | ⅞ | 310 | 249 | 366 | 565 |
| 4'' | 8 | 1 ⅛ | 310 | 539 | 797 | 1235 |
| 5'' | 8 | 1 ¼ | 310 | 752 | 1116 | 1736 |
| 6'' | 12 | 1 ⅛ | 310 | 539 | 797 | 1235 |
| 8'' | 12 | 1 ⅜ | 310 | 1014 | 1511 | 2356 |
| 12'' | 20 | 1 ⅜ | 310 | 1014 | 1511 | 2356 |
| 14'' | 20 | 1 ½ | 345 | 1477 | 2209 | 3453 |
| 16'' | 20 | 1 ⅝ | 345 | 1893 | 2839 | 4447 |
| 18'' | 20 | 1 ⅞ | 345 | 2951 | 4444 | 6984 |
| 20'' | 20 | 2 | 345 | 3599 | 5430 | 8545 |
| 24'' | 20 | 2 ½ | 310 | 6410 | 9728 | 15369 |