Heat Exchanger design acc. to ASME Section VIII Div.1, with Tubesheet design acc. to ASME Section I

[teokal]

Hi to all!
Well I probably know the answer to this one, but I have to ask...
We are fabricating a Waste Heat Boiler (Heat Exchanger with fixed tubesheets) according to ASME VIII Div.1 Ed.2013.
It is a Stamped (U-designator) Vessel.
The calculations for the tubesheet when performed with UHX gave a tubesheet thickness of more than 100mm (4 in.), and the Client decided to use (and impose) the tubesheets calculations according to ASME Section I, Ed.2013. This gave to the tubesheet a thickness of only 30mm (1 1/4 in.).
Is this possible? Can we use another Section of the Code, like we did above, and have a U-stamped Heat Exchanger?
I looked over in VIII-div.1 and found no alternatives for the tubesheet design.
My AI is also considered, has not met such case in the past.
According to the Client, this is a globally common practice - which I have not heard about, 14 years in the business.
What is your opinion?

Only best result in absolutely necessary time

 

[SnTMan]

teokal, I'd think that one side or the other, to include the tubesheets, would have to be specified as Section 1 design & construction. Unless perhaps the tubesheet is clearly not within the scope of Part UHX, which is, after all, mandatory.

Regards,

Mike

 

[Fizza453]

You cannot go to Section I unless design or construction details are not contained in Section VIII-1. We do many times WHRB, tubesheet was designed in accordance with Section I and rest of all pressure parts in accordance with Division 1.
You know, Part UHX is not applicable if tube sheet is not perforated unfiormely. This was the case, so we had to move to Section I.

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN