How to ensure quality tightening of flange's bolt

1) Calculate the minimum required bolt loads (refer to ASME Sec. VIII)

2) Calculate the tightening torque

3) Ensure bolt length are 2~3 thread out of nut

4) Slightly hand tighten the flange and measure the gap (to ensure even gap and keep the reading ad initial before gasket compress)

5) Tighten the bolts with applied torque and diagonal pattern