Recommended minimum Bolt Torque Values for class 75 spiral wound gaskets with inner ring for Series B flanges.
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 75 | Bolt Torque (ft-lb) |
Bolt Torque (N-m) |
|||
|---|---|---|---|---|---|---|
| No. of Bolts |
Bolt Size (in) |
Min | Max | Min | Max | |
| 26 | 36 | 5/8 | 61 | 113 | 82.7 | 153.2 |
| 28 | 40 | 5/8 | 70 | 113 | 94.9 | 153.2 |
| 30 | 44 | 5/8 | 68 | 113 | 92.2 | 153.2 |
| 32 | 48 | 5/8 | 66 | 113 | 89.5 | 153.2 |
| 34 | 52 | 5/8 | 65 | 113 | 88.1 | 153.2 |
| 36 | 40 | 3/4 | 122 | 204 | 165.4 | 276.6 |
| 38 | 40 | 3/4 | 136 | 204 | 184.4 | 276.6 |
| 40 | 44 | 3/4 | 130 | 204 | 176.3 | 276.6 |
| 42 | 48 | 3/4 | 118 | 204 | 160.0 | 276.6 |
| 44 | 36 | 7/8 | 241 | 330 | 326.8 | 447.4 |
| 46 | 40 | 7/8 | 227 | 330 | 307.8 | 447.4 |
| 48 | 44 | 7/8 | 193 | 330 | 261.7 | 447.4 |
| 50 | 44 | 7/8 | 223 | 330 | 302.3 | 447.4 |
| 52 | 48 | 7/8 | 213 | 330 | 288.8 | 447.4 |
| 54 | 48 | 7/8 | 221 | 330 | 299.6 | 447.4 |
| 56 | 40 | 1 | 349 | 496 | 473.2 | 672.5 |
| 58 | 44 | 1 | 328 | 496 | 444.7 | 672.5 |
| 60 | 44 | 1 | 307 | 496 | 416.2 | 672.5 |
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.