Recommended minimum Bolt Torque Values for class 900 spiral wound gaskets Series-A 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 900 | Bolt Torque (ft-lb) |
Bolt Torque (N-m) |
|||
|---|---|---|---|---|---|---|
| No. of Bolts |
Bolt Size (in) |
Min | Max | Min | Max | |
| 26 | 20 | 2-3/4 | 1814 | 5443 | 2459.5 | 7379.7 |
| 28 | 20 | 3 | 2121 | 6362 | 2875.7 | 8625.7 |
| 30 | 20 | 3 | 2280 | 6839 | 3091.3 | 9272.4 |
| 32 | 20 | 3-1/4 | 2642 | 7926 | 3582.1 | 10746.2 |
| 34 | 20 | 3-1/2 | 3010 | 9030 | 4081.0 | 12243.0 |
| 36 | 20 | 3-1/2 | 3196 | 9587 | 4333.2 | 12998.2 |
| 38 | 20 | 3-1/2 | 3443 | 10329 | 4668.1 | 14004.2 |
| 40 | 24 | 3-1/2 | 3041 | 9123 | 4123.0 | 12369.1 |
| 42 | 24 | 3-1/2 | 3178 | 9535 | 4308.8 | 12927.7 |
| 44 | 24 | 3-3/4 | 3571 | 10713 | 4841.6 | 14524.9 |
| 46 | 24 | 4 | 4006 | 12017 | 5431.4 | 16292.9 |
| 48 | 24 | 4 | 4163 | 12488 | 5644.3 | 16931.5 |
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.