Recommended minimum Bolt Torque Values for class 300 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 300 | Bolt Torque (ft-lb) |
Bolt Torque (N-m) |
|||
|---|---|---|---|---|---|---|
| No. of Bolts |
Bolt Size (in) |
Min | Max | Min | Max | |
| 1/2 | 4 | 1/2 | 15 | 57 | 20.3 | 77.3 |
| 3/4 | 4 | 5/8 | 26 | 106 | 35.3 | 143.7 |
| 1 | 4 | 5/8 | 36 | 113 | 48.8 | 153.2 |
| 1-1/4 | 4 | 5/8 | 39 | 113 | 52.9 | 153.2 |
| 1-1/2 | 4 | 3/4 | 67 | 204 | 90.8 | 276.6 |
| 2 | 8 | 5/8 | 36 | 113 | 48.8 | 153.2 |
| 2-1/2 | 8 | 3/4 | 50 | 198 | 67.8 | 268.5 |
| 3 | 8 | 3/4 | 72 | 204 | 97.6 | 276.6 |
| 4 | 8 | 3/4 | 106 | 204 | 143.7 | 276.6 |
| 5 | 8 | 3/4 | 126 | 204 | 170.8 | 276.6 |
| 6 | 12 | 3/4 | 121 | 204 | 164.1 | 276.6 |
| 8 | 12 | 7/8 | 200 | 330 | 271.2 | 447.4 |
| 10 | 16 | 1 | 209 | 496 | 283.4 | 672.5 |
| 12 | 16 | 1-1/8 | 319 | 737 | 432.5 | 999.2 |
| 14 | 20 | 1-1/8 | 278 | 737 | 376.9 | 999.2 |
| 16 | 20 | 1-1/4 | 416 | 1045 | 564.0 | 1416.8 |
| 18 | 24 | 1-1/4 | 499 | 1045 | 676.6 | 1416.8 |
| 20 | 24 | 1-1/4 | 549 | 1045 | 744.3 | 1416.8 |
| 24 | 24 | 1-1/2 | 857 | 1897 | 1161.9 | 2572.0 |
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.