Recommended minimum Bolt Torque Values for class 150 spiral wound gaskets Series-B flanges 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 | |
| 26 | 36 | 3/4 | 99 | 204 | 134.2 | 276.6 |
| 28 | 40 | 3/4 | 96 | 204 | 130.2 | 276.6 |
| 30 | 44 | 3/4 | 93 | 204 | 126.1 | 276.6 |
| 32 | 48 | 3/4 | 91 | 204 | 123.4 | 276.6 |
| 34 | 40 | 7/8 | 170 | 330 | 230.5 | 447.4 |
| 36 | 44 | 7/8 | 163 | 330 | 221.0 | 447.4 |
| 38 | 40 | 1 | 238 | 496 | 322.7 | 672.5 |
| 40 | 44 | 1 | 269 | 496 | 364.7 | 672.5 |
| 42 | 48 | 1 | 219 | 496 | 296.9 | 672.5 |
| 44 | 52 | 1 | 250 | 496 | 339.0 | 672.5 |
| 46 | 40 | 1-1/8 | 398 | 737 | 539.6 | 999.2 |
| 48 | 44 | 1-1/8 | 334 | 737 | 452.8 | 999.2 |
| 50 | 48 | 1-1/8 | 359 | 737 | 486.7 | 999.2 |
| 52 | 52 | 1-1/8 | 345 | 737 | 467.8 | 999.2 |
| 54 | 56 | 1-1/8 | 294 | 737 | 398.6 | 999.2 |
| 56 | 60 | 1-1/8 | 248 | 737 | 336.2 | 999.2 |
| 58 | 48 | 1-1/4 | 307 | 1045 | 416.2 | 1416.8 |
| 60 | 52 | 1-1/4 | 297 | 1045 | 402.7 | 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.