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 | ½ | 276 | 40 | 59 | 90 |
| ¾'' | 4 | ½ | 276 | 40 | 59 | 90 |
| 1'' | 4 | ½ | 276 | 40 | 59 | 90 |
| 1¼'' | 4 | ½ | 276 | 40 | 59 | 90 |
| 1½'' | 4 | ½ | 276 | 40 | 56 | 90 |
| 2'' | 4 | ⅝ | 276 | 79 | 116 | 178 |
| 2½'' | 4 | ⅝ | 276 | 79 | 116 | 178 |
| 3'' | 4 | ⅝ | 276 | 79 | 116 | 178 |
| 4'' | 8 | ⅝ | 276 | 79 | 116 | 178 |
| 5'' | 8 | ¾ | 276 | 139 | 203 | 313 |
| 6'' | 8 | ¾ | 276 | 139 | 203 | 313 |
| 8'' | 8 | ¾ | 276 | 139 | 203 | 313 |
| 10'' | 12 | ⅞ | 276 | 221 | 325 | 502 |
| 12'' | 12 | ⅞ | 276 | 221 | 325 | 502 |
| 14'' | 12 | 1 | 276 | 330 | 485 | 748 |
| 16'' | 16 | 1 | 276 | 330 | 485 | 748 |
| 18'' | 16 | 1 ⅛ | 276 | 479 | 708 | 1098 |
| 20'' | 20 | 1 ⅛ | 276 | 479 | 708 | 1098 |
| 24'' | 20 | 1 ¼ | 276 | 668 | 992 | 1543 |