Same tube joints for top and bottom tubesheets of vertical HEX? (ASME Code)

[HungM]

Hi, All

As stated in UHX-13.5.9, we can use UW-20, UW-18(d), or Appendix A to design the tube joint. But does the Code requires the user to have the same tube joints for the tubesheets? Any restriction like as UHX-13.2 is mentioned elsewhere in the ASME Code? Considering this example of full-strength weld tube joint for top tubesheet and expanded and seal welding for bottom tubesheet.

Please have your comment

HungM

 

[SnTMan]

HungM, I am reading per 2017 Ed, but I am not aware of any rule that the tube joints be the same for both tubesheets. I'd say the calculations should be performed using the lower strength of the two.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[r6155]

Why different Tube-to-Tubesheet Joints?

Regards

 

[HungM]

Hi, All
The tube-to-tubesheet joint design considers the tube joint of lower strength (type joint f in Appendix A). But due to some practical concerns, for example, drainage, the tube joint of the top tubesheet has been modified to strength weld. My current option to persuade the local inspector to stop digging deep is to provide calculations for both of the tube joints and explain our concerns to him. But the local inspector wants to find wordings from Code to eliminate his doubt.

HungM

 

[SnTMan]

Well, I doubt he is going to find any such wording. Generally speaking if a thing is is not prohibited it is permitted.

Best of luck.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[r6155]

1) You need vent and drain
2) What is the relationship between the drain and the tube-to tubesheet joint?

Regards