Torquing

[ajcousins]

Hello. Can someone give me some guidance on when to specify torque values for heat exchanges and pressure vessels? Thanks.

 

[SnTMan]

Briefly, whenever you want the bolts tightened in a controlled manner.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[XL83NL]

Whenever there’s reason to believe that applying torque in an uncontrolled manner may lead to an unsafe situation.

Huub
- You never get what you expect, you only get what you inspect.

 

[r6155]

You must always control.
Use studs (not bolts).
For stud length greater than 5 times nominal diameter use elongation (not torque).

Regards

 

Torque is just the indirect indication of bolt tension, which is what matters. It is not the only way to tension fasteners.
Whatever you do, always control the process.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[Ehiman1]

Use ASME pcc-1 appendix J, not K

 

[GenB]

R6155, you're right. "You must always control it"
but the right bolts are allowed, studs better.

General Blr. CA,USA

 

[iangineer]

ASME PCC-1 Appendix O is what I use for determining bolt torques for flanges. You'll also want to make sure whatever load the bolts apply is ok for the flange. You typically always should provide guidance on bolt torque unless you have a sheet that shows standard bolt torques for standard flanges. Note that the lubricant used on the bolts will affect the torque required. PTFE coated bolts require much less torque for a desired bolt stress than dry bolts.

In reference to the other appendix above, I use Appendix K as long as I have nut factors for various lubricants. PTFE coated bolts tend to have a nut factor of 0.12.