Can any body advice if ASME B 16.5 Flanges be machined for modifying the bore diameter and to change the gasket finish surface ?

If allowed can supplier machine and give letter of confirmaty or can vessel manufacturer get it machined ?

If it can be machined then can i get code backup or code case for the same.

Thanks
Prashant

Pprane,

Of course a B16.5 flange can be machined. But it will not be a standard flange afterwards, and the rating, as certified by the flange manufacturer is no longer applicable.

I strongly suggest to remove the conformity stamping "B16" and the rating class.

If this flange is used in a vessel, it is the vesel Mfr responsible for the machining, or the subcontracting, and he shall have an Apendix 2 calculation for that flange on file. The material remains SA-105, or whatever it was before, but the allowable pressure will be different.

DK

DK
Thanks for your reply.

For more clarity to understand.

1. B16.5 does not mention about bore diameter requirement of weld neck flange.
2. B16.5 is silent on the machining of flanges.

I do accept if i change dimensions other than the bore diameter of weld neck flange i have to comply with requirement of Appendix 2 in design. Since B16.5 is silent about bore diameter when i modify bore diameter i am actually not making any changes on the B16.5 standard requirement.

Regards,

Not true

Not true

It is easier to gain knowledge, when you start listening rather than manifesting.

_________________
Konrad Anikiel

pprane,
As Akonrad has stated - not true.
Look at B16.5 Clause 6.1 for Wall thickness (machine the bore and you are changing the wall thickness)
B16.5 Clause 6.3 & 6.4 Facings for what you can and cannot do to a flange face,
Regards,
BB