Dear All,

How can I perform the flange leakage check for class 6A flanges in C-II software ?

What important points need to be taken care while performing flanges leakage check for class 6A flanges?

Regards,
Shamalia Bhavin

Are you referring to API 6A flanges?

If so, look into API Technical Resource 6AF, 6AF1 and 6AF2 for acceptable combination of loads - tension vs bending moment vs bore pressure vs bolt makeup stress.

My opinion is the flange loading charts are not convenient for stress analysts, because in each data plot, bore pressure and bending moment are considered variables, and tension and makeup stress are held constant.

Analysts want pressure and bolt makeup to be constant, and bending moment and tension to be variables.

To that end, I replotted SES' data to give me that, and selected a "middle of the road" bending moment and tension.

I treated flange compression and tension the same out of convenience.

Should you wish, you could use the Nozzle Limit attribute to perform an automatic check.

Understand, though, that your "middle of the road" assumption may have outliers that need separate verification as they may exceed your selected tension or your selected bending moment, but perhaps not both.

Finally, be aware of the temperature limitations of API 6A (250F). Once you exceed those limitations, your recourse will likely be FEA.