ASME UHX - Does UHX consider tube weight and hydrotest water weight? 1

[pkyengr]

I am working on the design of a shell & tube HX with fixed tubesheets. ASME Section VIII Div1 part UHX is relevant to my design. This particular HX is a vertical unit with 40 ft. long tubes. The diameter of the vessel is nearly 9 ft. and there are over (1500) 2" diameter tubes. The tubesheets are integral with the shell.

My interpretation of the rules within UHX tells me that the design does not consider the weight of the tubes on the tubesheets. Consideration is also not given to the weight of water during a hydrostatic test (for instance a shellside hydro in the vertical position).

Does anyone have any comments to share on this subject? Do you agree with my interpretation? Does anyone have experience with designing tubesheets for these two scenarios. If I am correct, it falls into U-2(g) and I need to do calculations outside of Section VIII to check for these conditions.

Any comments are very much appreciated. Thank you.

 

[SnTMan]

pkyengr, the weight of the water is easily handled by adding hydrostatic head to your design pressures, and should be done in any case for your design, not just the UHX calculations.

Based on my (poor) understanding of Part UHX I do not believe these calculations would account for the weight of tubes as a loading on the tubesheet. UHX-10(b) states weight loadings are not condsidered. UHX-13.4(a)(3) requires consideration of pressure tests.

Perhaps you could convert this weight to an equivalent, added pressure for the UHX calculations thereby also satisfying U-2(g).

Regards,

Mike