Recommended minimum Bolt Torque Values for class 400 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 400 | Bolt Torque (ft-lb) |
Bolt Torque (N-m) |
|||
|---|---|---|---|---|---|---|
| No. of Bolts |
Bolt Size (in) |
Min | Max | Min | Max | |
| 26 | 28 | 1-3/8 | 389 | 1166 | 527.4 | 1580.9 |
| 28 | 24 | 1-1/2 | 581 | 1744 | 787.7 | 2364.5 |
| 30 | 28 | 1-1/2 | 633 | 1897 | 858.2 | 2572.0 |
| 32 | 28 | 1-5/8 | 847 | 2457 | 1148.4 | 3331.2 |
| 34 | 32 | 1-5/8 | 733 | 2199 | 993.8 | 2981.4 |
| 36 | 28 | 1-3/4 | 1021 | 3062 | 1384.3 | 4151.5 |
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.