Recommended minimum Bolt Torque Values for class 1500 spiral wound gaskets 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 1500 Bolt Torque
(ft-lb)
Bolt Torque
(N-m)
No. of
Bolts
Bolt
Size
(in)
Min Max Min Max
1/2 4 3/4 17 52 23.0 70.5
3/4 4 3/4 28 83 38.0 112.5
1 4 7/8 43 130 58.3 176.3
1-1/4 4 7/8 71 214 96.3 290.1
1-1/2 4 1 111 332 150.5 450.1
2 8 7/8 70 211 94.9 286.1
2-1/2 8 1 94 283 127.4 383.7
3 8 1-1/8 155 466 210.2 631.8
4 8 1-1/4 242 725 328.1 983.0
5 8 1-1/2 375 1124 508.4 1523.9
6 12 1-3/8 304 911 412.2 1235.2
8 12 1-5/8 424 1272 574.9 1724.6
10 12 1-7/8 583 1750 790.4 2372.7

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.

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