Tubesheet calculation when NTIW is used (ASME interpretation)
Tubesheet calculation when NTIW is used (ASME interpretation)
(OP)
The general conditions of applicability for tubesheets of ASME Section VIII UHX-10(a) require the tubesheet be uniformly perforated over a nominally circular area.
The definition regarding "nominally circular area" has been a contentious issue on most shell and tube heat exchangers, as very few shell-and-tube layouts can be deemed to be "uniformly perforated over a nominally circular area".
Referring to ASME Interpretation VIII-1-04-61
Question: Do tubesheets for shell-and-tube heat exchangers having a no-tubes-in-window (NTIW) baffle design fall within the scope of Section VIII, Division 1 Part UHX?
Reply: No; see UHX-10(a) and U-2(g).
Since Part UHX provides no guidance for the design of tubesheets of an NTIW configuration - what is the accepted design basis used by COMPRESS?
The definition regarding "nominally circular area" has been a contentious issue on most shell and tube heat exchangers, as very few shell-and-tube layouts can be deemed to be "uniformly perforated over a nominally circular area".
Referring to ASME Interpretation VIII-1-04-61
Question: Do tubesheets for shell-and-tube heat exchangers having a no-tubes-in-window (NTIW) baffle design fall within the scope of Section VIII, Division 1 Part UHX?
Reply: No; see UHX-10(a) and U-2(g).
Since Part UHX provides no guidance for the design of tubesheets of an NTIW configuration - what is the accepted design basis used by COMPRESS?
Talk To Other Members
RE: Tubesheet calculation when NTIW is used (ASME interpretation)
U-2(g) is the way to go here. Talk with your AI - he may accept designing the tubesheet(s) in accordance with TEMA, or require you to do FEA.
ASME had a tough time of it when they were initially developing their rules for the design of tubesheets: kept telling fabricators to use TEMA when the results were unreasonable. The TEMA calculations have been consistent, and reliable.
Using the TEMA method would be my first alternative if I couldn't perform the calcs and get a reasonable output using the ASME method(s).
-TJ Orlowski
RE: Tubesheet calculation when NTIW is used (ASME interpretation)
RE: Tubesheet calculation when NTIW is used (ASME interpretation)
-TJ Orlowski