Does this Shell and Tube fall under Section VIII Div 1?

[MechBRR]

While reviewing existing equipment we came across a type of heat exchanger in use that may or may not fall under Section VIII Div 1. It is a single pass carbon tube cartride with a water cooled steel shell. The process (tube) side carries product at 1/2 to 2 psig and the shell side carries cooling water at ~80 psig.

Under scope (U-1) of Section VIII Div 1 "..the following classes of vessels are not included in the scope of this Division...U-1(c)(2)(f)a vessel containing water under pressure..when none of the folling limitations are exceeded: (1)design pressure of 300 psi (2)a design temp of 210 degrees F." Further, U-1(c)(2)(h)(1)"vessels having an internal pressure not exceeding 15 psi". The shell side falls under the first case and the tube side falls under the second case. However, U-1(c)(2)(h)(2) states, "combination units having an internal or external pressure in each chamber not exceeding 15 psi and dP on the common elements not exceeding 15 psi."

Does anyone have any knowledge of how these heat exchangers should be classified? The shell is about 8 inches in diameter and about 10 feet long. Thanks!

 

[CodeRef]

First check to see if the scope of this vessel does not fall under any other administrative or federal Codes.

Then read the rules of the jurisdiction governing installation of this vessel.

What is the "cross section", or "width" between the tube cartridge and water cooled shell?

Look at ASME VIII-1, para. U-1(c)(2)(i), if applicable.

 

[MechBRR]

Thanks, Jackal, for the quick reply. The ID of the shell is over 6", but I will need to check distance between the outer tube and the shell. Does the fact that the tube bank occupies the internal space of the shell allow another dimension other than the ID of the shell to be considered under part (i)?

 

[CodeRef]

Thats a good question and not a clear answer is given in the Code (in my opinion). I would find out the cross section and submit this question to ASME for interpretation.
I think the "cross section" or "width" is intended to refer to other than circular vessels, however, I know of half pipe jacketed tanks where the jacket diagonal cross section was less than 6" and above 15 psi which were considered exempt from stamping requirements.
See the following Interpretation:
Interpretation: VIII-1-01-15
Subject: Section VIII, Division 1 (1998 Edition, 1999 Addenda); U-1(c)(2)(h) and (i)
DateIssued: January 3, 2001

 

[unclesyd]

Why wouldn't this assembly be called a jacketed pipe?

The following assemblies are called jacketed pipe.

We have 8" Sch 80 pipe with 5" Sch 160 operating at 1500 lbs @ 600F in the core and 12 psig at 610F on the jacket side.
We also have a lot of powder coolers with very similar to that in OP.

 

[CodeRef]

Uncle,
Thats a good question too! I am sure there are alot of opinions floating around about this.
See the following link for how the Europeans (PED) classify heat exchangers.

http://ec.europa.eu/enterprise/pressure_equipment/ped/guidelines/guideline2-4_en.html

Note that near the end, the PED defines a halfpipe coil (jacket) as a vessel.

I would not want to make this call, whatever the decision, it is important that it is understood by all involved.