UHX-13.2 - Definition of Edge Conditions

[condesinc]

All:

For over 20 years, and as recently as several months ago, we have been getting large (16,000-27,000 ft^2) code stamped process heat exchangers for PET plants with one tubeheet integral to shell and channel, and the other tube sheet integral to shell and extended as flange.

So far, no issues have been raised as per UHX-13.2: "The two tubesheets shall have the same thickness, material, and edge conditions".

My interpretation, as well as PVElite, is that this is being violated.

Comments please!

 

[TJOrlowski]

So by that interpretation, a TEMA type AEN, or TEMA type NEM shell & tube heat exchanger is not a permissible design?

My interpretation here is that when both tubesheets have the same configuration as per fig UHX-13.1, then they must have same geometry.

The general conditions of applicability in UHX-10 refer the designer to U-2(g) when the conditions are UHX-10 are not satisfied. If all else fails, that's the answer.

-TJ Orlowski

 

[SnTMan]

condesinc, TJOrlowski I agree such designs are not within the scope of Part UHX, strictly speaking.

So what meets U-2(g) aside from FEA? Maybe the older TEMA calculations, but that depends upon acceptibility to the parties involved. Same goes for FEA.

I say again, regular readers will know I am not a big fan of Part UHX tubsheet calculations. There are far more ordinary designs excluded than included.

Regards,

Mike