We have a shell and tube heat exchanger at our site in Iowa in the USA that developed a hole in the endcap. The pressure of the fluid going through the tubes is rated at -2 to +2 psig while the pressure on the shell side is 65 psig. The vessel is stamped as a pressure vessel, however, if I replace the endcap, which only sees the -2 to +2 psig, do I have to have the endcap be a coded encap? I'm so confused!

You have already stated that the vessel is stamped as an ASME Vessel. Thereby, any Repairs, Alterations etc.. to the ASME stamped vessel needs to be in accordance with the requirements of the Jurisdiction where the vessel is installed. In your case the Iowa Division of Labor which regulates boilers and pressure vessels requires that alterations, retrofits, and repairs be made so that the object is as safe as the original construction. Alterations, retrofits, and repairs shall be done as though new construction and shall comply with the applicable code or codes as adopted in 875—Chapters 90 through 96. A National Board “R” form shall be filed with the division for each alteration, retrofit, or repair.

Here is the link to the Iowa Admin Code: http://www.legis.state.ia.us/Rules/Current/iac/875/87591/87591.pdf

Here is the link to the Iowa Boiler/Pressure Vessel Inspection Program: http://www.iowaworkforce.org/labor/boiler_inspection_.htm

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A question properly stated is a question half solved.

Right, it is stamped as a coded vessel and the pressure on the shell side is 60 psi. By reading the Iowa code, I found that it applies to any vessel in excess of 15 psi. However, the tubeside is only -2 to +2 psi. According to Iowa code, the tubeside should not be regulated as a pressure vessel because it is not in excess of 15 psi. Since the tubeside is the only side the endcap could possibly be exposed to, I am wondering why I need an R stamp since the Iowa code should not apply here.

aceman,
Here is where it can get tricky...... I am assuming that the vessel/Heat Exchanger has an ASME stamp for both the shellside and the tubeside. If it does not, then let me know. It will also be described as such on the ASME Data Report. You will have to discuss this issue with your Jurisdictional representative and ask him the requirements. You should also discuss this issue with your site Boiler and Machinery Insurance Inspector who writes the premiums for your sites insurance needs.

Your questions to both should be the following:

1. If the vessel (tubeside) did not require an ASME stamp upon installation, why was both the shellside and tubeside rated and stamped?

2. Because I cannot remove the ASME stamp altogether or separate the two different chambers without performing a Alteration requiring the use of the NBIC R-Stamp, what are my options?

You may find out that it would be easier maintaining the original stamping for the reasons given. But who knows?

Keep us informed.

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A question properly stated is a question half solved.

do

al

sorry about the last 2 messages. someone is having some fun with my computer! I'll ask the questions you specify. Thanks for your help and I'll keep you informed.