Recommended minimum Bolt Torque Values for class 900 spiral wound gaskets with inner ring for Series A 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 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 | 7257 | 2459.5 | 9839.2 |
| 28 | 20 | 3 | 2121 | 8482 | 2875.7 | 11500.0 |
| 30 | 20 | 3 | 2280 | 9118 | 3091.3 | 12362.3 |
| 32 | 20 | 3-1/4 | 2642 | 10568 | 3582.1 | 14328.3 |
| 34 | 20 | 3-1/2 | 3010 | 12040 | 4081.0 | 16324.0 |
| 36 | 20 | 3-1/2 | 3196 | 12782 | 4333.2 | 17330.1 |
| 38 | 20 | 3-1/2 | 3443 | 13772 | 4668.1 | 18672.3 |
| 40 | 24 | 3-1/2 | 3041 | 12164 | 4123.0 | 16492.2 |
| 42 | 24 | 3-1/2 | 3178 | 12714 | 4308.8 | 17237.9 |
| 44 | 24 | 3-3/4 | 3571 | 14284 | 4841.6 | 19366.5 |
| 46 | 24 | 4 | 4006 | 16022 | 5431.4 | 21722.9 |
| 48 | 24 | 4 | 4163 | 16650 | 5644.3 | 22574.4 |
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.