Large Diameter Flange design 3

[Mandeep1]

Hi colleagues,

I have some question on large diameter flange design. It is 72in (100 psi) flange operating at not very high temperature.

I started with a raised face flange.

Is there any benefit of using flat face v/s raised face v/s male-female type of flange face.

I can also try male-female type flange. But, in App. 2 calcs I probably have to take thickness from the bottom of the groove.

I saw AWWA flange standard, they are flat faced and not raised face. Is it for cost reason?

Are there are other concerns that I should consider in a large diameter flange.

Thanks,

best regards,
Mandeep Singh

 

[gr2vessels]

Mandeep1,
1. Yes, the main issue with tongue and groove is the potantial damage to the either or both the tongue and groove. Dowel pins might help. Also depends on the size of these flanges, the frequency of opening the joint, the maintenance workers hmmm, qualifications...and many many other issues, each potentially causing irreversible damage and obviously out of service condition.
2. Unequal welds are not unusual;- yes, you can increase the hub length by increasing the weld length, in accordance with the code.
Cheers,
gr2vessels

 

[SnTMan]

Gorpomon, I do not know the origin or any references for this rule of thumb, although I know of one design program that incorporates it. Other than providing a thicker flange that otherwise it is not, strictly speaking, related to rotation, which nowdays is a mandatory calculation.

Regards,

Mike