Bolt Lubrication Lowers K Factor

Does your Owner/Operator refuse to use bolt lubrication? 

Then make sure you are using a dry Nut Factor, K in your ASME PCC-1 Appendix O calculations. This may make a significant difference in your results as small Nut Factor, K increases may drastically increase the amount of applied torque needed to meet the Selected Assembly Bolt Stress, Sbsel. 

It is not recommended to use rusty or dry bolts for bolted flange joint assemblies because the applied torque required to meet the Selected Assembly Bolt Stress, Sbsel may vary wildly from bolt to bolt. The only recourse for engineers like me is to increase the Nut Factor, K for all bolts to ensure the average applied torque is high enough to meet the Selected Assembly Bolt Stress, Sbsel. There is a much higher risk of leaky flange gaskets if the applied torque is not high enough to account for the friction force associated with dry bolts.

Many times Metalmark Engineering finds leaky flanges are due to poor assumptions made in their ASME PCC-1 Appendix O torque tables. Torque tables assuming incorrect Nut Factor, K values are a common source of flange leaks.