ASME Flange modification 2

[phfau]

I am under the opion that by reducing the hub lenght of a 600# flange it does not change the rating as long as the min thickness `C` is kept Quoted from a ASME site "Question Does ASME B16.5-1996 have a required tolerance for a lapped ,slip-on,or socket welding flange for the overall lenght through hub?
Answer "no"
My problem is trying to convince an engineer that by welding a flange that has had the hub machine off and welded to a flexible hose that any loading generated by the system is absord by the flexible and the sole purpose of the flange is to act as a seal.
Has anyone been in this situation and how was the problem resolved

 

[Duwe6]

Get a different engineer. Your reasoning is correct, and with the use of a flex hose *very* conservative. If ASME allows it [which it does], injecting personal opinion is exceptionally unprofessional, and very poor engineering practice.

In all ASME items, there are more-than-adequate safety factors. The Code was developed based on both sound engineering, and literally billions of hours of operating experience.

Engineering calculations only try to duplicate reality; actual experience and destructive testing is needed to validate the initial calc's. By compairing the results of experience & testing with the calc's, the formulaes were adjusted and finalized. All that was done, verified multiple times, peer-reviewed, and accepted prior to your current engineer being born.

 

[SnTMan]

It is not unusual for a person to hold the opinion that when modifiying a standard flange it is no longer "standard" and that published temp / pressure ratings are no longer valid. And from designing any number of Appendix 2 flanges I can tell you that hub dimensions do have an effect on the ring thickness.

Regards,

Mike

 

[phfau]

Sound like you guys know this engineer,thanks heaps