Required Bolt Area of standard flange

[mech012902]

Is there a way to calculate required bolt area of a standard flange say from ASME B16.5?
I use equations from ASME VIII-1 App 2 to calculate this but it fails. Experience prove that the bolt data from these standard is sufficient for the scope service. Please comment.

 

[codeeng]

If you're using a B16.5 standard flange (without modification) the Code allows the use of the pressure/temperatures listed in B16.5. You don't need to go to App 2. It is rare but possible for standard flanges to fail App 2. Are you using high strength bolts?

 

[TGS4]

You should also refer to ASME PCC-1.

As far as the "required" bolt area goes, the B16.5 standard specifies bolt sizes to use, and, like codeeng says, you are allowed to design to the pressures/temperatures listed in B16.5,

 

[mech012902]

codeeng:
Yes. i am using high strength bolt material A193 Gr B7.

TGS4:
What code is ASME PCC-1? Sorry for my ignorance on this material.

 

[TGS4]

http://catalog.asme.org/Codes/PrintBook/PCC1_2000_Guidelines_Pressure.cfm

 

[codeeng]

Maybe you should also tell us why you're using App 2.

 

[mech012902]

We are designing an equipment which has flange end connection. This needs to match end connection of our client. We either use standard flanges or design customise flange dimensioned to ASME B16.5 to match client end connection. There are times we can't use standard flanges because of the design geometry of our equipment.
And ASME VIII-1 App 2, gives you rules to design custom flanges.

 

[LuisLopezgil]

If you are Using standar flanges you don´t need to calculate the required bolt area, you must use the corresponding diameter and number of bolts, you can´t install other bolt number or diameter than required. It is possible that if you do ASME calculations on standard flanges the stress results are out of the permissible, but if you use the flanges inside the recommended Presure-Temperature ranges you are in the safe side and covered by norms.