Recommended minimum Bolt Torque Values for class 300 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 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 | 1266 | 572.2 | 1716.5 |
| 32 | 32 | 1-1/2 | 551 | 1653 | 747.1 | 2241.2 |
| 34 | 36 | 1-1/2 | 519 | 1557 | 703.7 | 2111.0 |
| 36 | 32 | 1-5/8 | 669 | 2006 | 907.0 | 2719.8 |
| 38 | 36 | 1-5/8 | 646 | 1938 | 875.9 | 2627.6 |
| 40 | 40 | 1-5/8 | 610 | 1831 | 827.0 | 2482.5 |
| 42 | 36 | 1-3/4 | 765 | 2294 | 1037.2 | 3110.2 |
| 44 | 40 | 1-3/4 | 719 | 2157 | 974.8 | 2924.5 |
| 46 | 36 | 1-7/8 | 895 | 2686 | 1213.5 | 3641.7 |
| 48 | 40 | 1-7/8 | 1053 | 3158 | 1427.7 | 4281.7 |
| 50 | 44 | 1-7/8 | 793 | 2378 | 1075.2 | 3224.1 |
| 52 | 48 | 1-7/8 | 754 | 2263 | 1022.3 | 3068.2 |
| 54 | 48 | 1-7/8 | 1035 | 3106 | 1403.3 | 4211.2 |
| 56 | 36 | 2-1/4 | 1524 | 4571 | 2066.3 | 6197.4 |
| 58 | 40 | 2-1/4 | 1216 | 3649 | 1648.7 | 4947.4 |
| 60 | 40 | 2-1/4 | 1369 | 4107 | 1856.1 | 5568.3 |
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.