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 | 310 | 156 | 209 | 352 |
| 1'' | 4 | ⅞ | 310 | 249 | 366 | 565 |
| 1¼'' | 4 | ⅞ | 310 | 249 | 366 | 565 |
| 1½'' | 4 | 1 | 310 | 371 | 545 | 842 |
| 2½'' | 8 | 1 | 310 | 371 | 545 | 842 |
| 3'' | 8 | 1 ⅛ | 345 | 599 | 885 | 1372 |
| 4'' | 8 | 1 ¼ | 345 | 835 | 1240 | 1929 |
| 5'' | 8 | 1 ½ | 345 | 1477 | 2209 | 3453 |
| 6'' | 12 | 1 ⅜ | 310 | 1014 | 1511 | 2356 |
| 8'' | 12 | 1 ⅝ | 345 | 1893 | 2839 | 4447 |
| 10'' | 12 | 1 ⅞ | 345 | 2951 | 4444 | 6984 |
| 12'' | 16 | 2 | 345 | 3599 | 5430 | 8545 |
| 14'' | 16 | 2 ¼ | 345 | 5161 | 7813 | 12321 |
| 16'' | 16 | 2 ½ | 345 | 7122 | 10809 | 17077 |
| 18'' | 16 | 2 ¾ | 345 | 9547 | 14520 | 22974 |
| 20'' | 16 | 3 | 345 | 12431 | 18940 | 30005 |
| 24'' | 16 | 3 ½ | 345 | 19888 | 30387 | 48235 |