Recommended minimum Bolt Torque Values for class 1500 spiral wound gaskets with inner ring.
Bolt Torque values are specified in ft-lb and N-m.
Bolt torques are based on design bolt stress of 60 ksi and a nut factor (K factor) of 0.18.
| NPS (in) |
Class 1500 | Bolt Torque (ft-lb) |
Bolt Torque (N-m) |
|||
|---|---|---|---|---|---|---|
| No. of Bolts |
Bolt Size (in) |
Min | Max | Min | Max | |
| 1/2 | 4 | 3/4 | 17 | 70 | 23.0 | 94.9 |
| 3/4 | 4 | 3/4 | 28 | 110 | 38.0 | 149.1 |
| 1 | 4 | 7/8 | 43 | 174 | 58.3 | 235.9 |
| 1-1/4 | 4 | 7/8 | 71 | 286 | 96.3 | 387.8 |
| 1-1/2 | 4 | 1 | 111 | 443 | 150.5 | 600.6 |
| 2 | 8 | 7/8 | 70 | 282 | 94.9 | 382.3 |
| 2-1/2 | 8 | 1 | 94 | 378 | 127.4 | 512.5 |
| 3 | 8 | 1-1/8 | 155 | 622 | 210.2 | 843.3 |
| 4 | 8 | 1-1/4 | 242 | 967 | 328.1 | 1311.1 |
| 5 | 8 | 1-1/2 | 375 | 1499 | 508.4 | 2032.4 |
| 6 | 12 | 1-3/8 | 304 | 1215 | 412.2 | 1647.3 |
| 8 | 12 | 1-5/8 | 424 | 1696 | 574.9 | 2299.5 |
| 10 | 12 | 1-7/8 | 583 | 2333 | 790.4 | 3163.1 |
| 12 | 16 | 2 | 653 | 2613 | 885.3 | 3542.8 |
| 14 | 16 | 2-1/4 | 746 | 2982 | 1011.4 | 4043.0 |
| 16 | 16 | 2-1/2 | 1157 | 4628 | 1568.7 | 6274.7 |
| 18 | 16 | 2-3/4 | 1765 | 7062 | 2393.0 | 9574.8 |
| 20 | 16 | 3 | 2125 | 8499 | 2881.1 | 11523.1 |
| 24 | 16 | 3-1/2 | 3286 | 13143 | 4455.2 | 17819.5 |
1] For typical calculation of bolt torque values refer to article: Calculation of Bolt Torque for Flanged Joint Assembly.
2] Bolt Torque values provided in table above are for guidance only. For actual applied torque values follow gasket vendor recommendations.