Recommended minimum Bolt Torque Values for class 300 spiral wound gaskets with inner ring for Series B 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 300 | Bolt Torque (ft-lb) |
Bolt Torque (N-m) |
|||
|---|---|---|---|---|---|---|
| No. of Bolts |
Bolt Size (in) |
Min | Max | Min | Max | |
| 26 | 32 | 1-1/4 | 376 | 1045 | 509.8 | 1416.8 |
| 28 | 36 | 1-1/4 | 359 | 1045 | 486.7 | 1416.8 |
| 30 | 36 | 1-3/8 | 422 | 1429 | 572.2 | 1937.5 |
| 32 | 32 | 1-1/2 | 551 | 1897 | 747.1 | 2572.0 |
| 34 | 36 | 1-1/2 | 519 | 1897 | 703.7 | 2572.0 |
| 36 | 32 | 1-5/8 | 669 | 2457 | 907.0 | 3331.2 |
| 38 | 36 | 1-5/8 | 646 | 2457 | 875.9 | 3331.2 |
| 40 | 40 | 1-5/8 | 610 | 2441 | 827.0 | 3309.6 |
| 42 | 36 | 1-3/4 | 765 | 3058 | 1037.2 | 4146.1 |
| 44 | 40 | 1-3/4 | 719 | 2876 | 974.8 | 3899.3 |
| 46 | 36 | 1-7/8 | 895 | 3581 | 1213.5 | 4855.2 |
| 48 | 40 | 1-7/8 | 1053 | 3887 | 1427.7 | 5270.1 |
| 50 | 44 | 1-7/8 | 793 | 3171 | 1075.2 | 4299.3 |
| 52 | 48 | 1-7/8 | 754 | 3017 | 1022.3 | 4090.5 |
| 54 | 48 | 1-7/8 | 1035 | 3887 | 1403.3 | 5270.1 |
| 56 | 36 | 2-1/4 | 1524 | 6095 | 2066.3 | 8263.7 |
| 58 | 40 | 2-1/4 | 1216 | 4866 | 1648.7 | 6597.4 |
| 60 | 40 | 2-1/4 | 1369 | 5476 | 1856.1 | 7424.5 |
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.