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Exclusion From the Scope of ASME BPVC VIII-1 - water-based solution

RistEcho

Chemical
Apr 10, 2025
1
Dear all,

I'm designing a finned tube exchanger (think a shell tube exchanger with extruded fins on tubes) as a condenser. Gas at approximately atmospheric pressure flows on the shell side, while an ethylene glycol-based (in water) solution runs on tube side at up to 50 psig (from pump) at low temperature to cool and condense the gas.

Question - would this exchanger considered a pressure vessel based on ASME Section VIII and need a U stamp?

The introduction part of the code says that among those excluded is the following:
ASME BPVC VIII-1 Edition 2015 U-1 (c) (2) (-f) said:
a vessel for containing water under pressure, including those containing air the compression of which serves only as a cushion, when none of the following limitations are exceeded:
(-1) a design pressure of 300 psi (2 MPa);
(-2) a design temperature of 210°F (99°C);

The tube side contains a water-based solution (ethylene glycol), is nonflammable, and has a high boiling point, but I don't know if ASME Code Committee sees it this way.

Thank you everyone for your expertise.
 
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RistEcho,
Cannot comment on whether it falls within the scope of ASME VIII but if it does:
Whether or not it requires U stamp will be based on the Owner and the jurisdiction.
Hope that helps,
Cheers,
Shane
 
Since the pressure is 50 psig>15 psig, the HEX should fall within the scope of Sec VIII-1. Refer TEMA Clause RCB 1.13, where this requirement is mentioned.

The subclause you mentioned refers to accumulators, which are excluded if they are within limits. However, if within limits, they can be U-stamped, provided applicable code rules are followed.
 

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