Recommended minimum Bolt Torque Values for class 150 spiral wound gaskets without 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 150 | Bolt Torque (ft-lb) |
Bolt Torque (N-m) |
|||
|---|---|---|---|---|---|---|
| No. of Bolts |
Bolt Size (in) |
Min | Max | Min | Max | |
| 1/2 | 4 | 1/2 | 11 | 44 | 14.9 | 59.7 |
| 3/4 | 4 | 1/2 | 16 | 57 | 21.7 | 77.3 |
| 1 | 4 | 1/2 | 22 | 57 | 29.8 | 77.3 |
| 1-1/4 | 4 | 1/2 | 24 | 57 | 32.5 | 77.3 |
| 1-1/2 | 4 | 1/2 | 33 | 57 | 44.7 | 77.3 |
| 2 | 4 | 5/8 | 53 | 113 | 71.9 | 153.2 |
| 2-1/2 | 4 | 5/8 | 62 | 113 | 84.1 | 153.2 |
| 3 | 4 | 5/8 | 113 | 113 | 153.2 | 153.2 |
| 4 | 8 | 5/8 | 66 | 113 | 89.5 | 153.2 |
| 5 | 8 | 3/4 | 95 | 204 | 128.8 | 276.6 |
| 6 | 8 | 3/4 | 136 | 204 | 184.4 | 276.6 |
| 8 | 8 | 3/4 | 204 | 204 | 276.6 | 276.6 |
| 10 | 12 | 7/8 | 183 | 330 | 248.1 | 447.4 |
| 12 | 12 | 7/8 | 248 | 330 | 336.2 | 447.4 |
| 14 | 12 | 1 | 309 | 496 | 418.9 | 672.5 |
| 16 | 16 | 1 | 312 | 496 | 423.0 | 672.5 |
| 18 | 16 | 1-1/8 | 505 | 737 | 684.7 | 999.2 |
| 20 | 20 | 1-1/8 | 445 | 737 | 603.3 | 999.2 |
| 24 | 20 | 1-1/4 | 643 | 1045 | 871.8 | 1416.8 |
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.