Recommended minimum Bolt Torque Values for class 300 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 300 Bolt Torque
(ft-lb)
Bolt Torque
(N-m)
No. of
Bolts
Bolt
Size
(in)
Min Max Min Max
26 28 1-5/8 766 2297 1038.6 3114.3
28 28 1-5/8 820 2457 1111.8 3331.2
30 28 1-3/4 950 2850 1288.0 3864.1
32 28 1-7/8 1089 3266 1476.5 4428.1
34 28 1-7/8 1152 3455 1561.9 4684.4
36 32 2 1138 3413 1542.9 4627.4
38 32 1-1/2 650 1897 881.3 2572.0
40 32 1-5/8 927 2457 1256.8 3331.2
42 32 1-5/8 972 2457 1317.9 3331.2
44 32 1-3/4 1173 3117 1590.4 4226.1
46 28 1-7/8 1495 3887 2026.9 5270.1
48 32 1-7/8 1370 3887 1857.5 5270.1
50 32 2 1532 4595 2077.1 6230.0
52 32 2 1590 4771 2155.8 6468.6
54 28 2-1/4 2130 6390 2887.9 8663.7
56 28 2-1/4 2206 6617 2990.9 8971.4
58 32 2-1/4 2005 6014 2718.4 8153.9
60 32 2-1/4 2071 6213 2807.9 8423.7

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.