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Is an ASME stamp requried?

Is an ASME stamp requried?

Is an ASME stamp requried?

Hey All,

I have had a question bothering me for a while and am curious if someone in B&PV design can help me out. I want to know if you really need an ASME stamp on a plate and frame heat exchanger. And if you do, why? I work in industrial refrigeration and we use many different kinds of heat exchangers for cooling. It seems odd that a plate and frame heat exchanger must be U stamped, but a air cooling coil doesn't need to be. A plate and frame heat exchanger doesn't really seem to be a pressure vessel (at least not any more than a piece of pipe or a air cooling coil) so why should it be certified as one?

In my mind the purpose of ASME certification is to avoid the explosion of pressure vessels. When boilers and pressure vessels fail due to internal pressure they become shrapnel bombs that can cause massive damage. But an plate and frame heat exchanger? It isn't going to explode. It will just leak.

It seems stamping plate and frames may have become common practice simply because they were replacing shell and tube heat exchangers (which really are pressure vessels). Since the shell and tubes were stamped people wanted stamps on the new technology as well. Of course, you can slap a stamp on anything that meets the ASME B&PV, but that doesn't mean it is required. In fact, in my industry there used to be a trend to stamp evaporative condensers, which are basically big air coils that have water running over them. But that is no longer done because it is unnecessary. A condenser is not a pressure vessel.

If anyone can provide some insight on this I would be very grateful. Thanks!

Grace and Peace,


RE: Is an ASME stamp requried?


Read U-1 of ASME VIII-1. It defines when "U" stamp is required.

RE: Is an ASME stamp requried?

The ASME VIII scope definition includes a minimum internal diameter of 6".

U-1(c)?(i) says that vessels having an inside diameter, width, height or cross section diagonal not exceeding 6 in with no limitation on length of vessel or pressure, are exempt from the scope of ASME VIII

Unless a plate type exchanger has manifolds or bonnets exceeding 6" diameter, it would be difficult to justify a requirement for an ASME VIII U stamp.

Anything relieved below 15 psig is not a pressure vessel, irrespective of size.

Amything below 1.5 cubic feet in interior volume and less than 600 psig relief pressure is exempted from the inspection requirements of ASME VIII.

Other codes or standards may apply to things not within the scope of ASME VIII. Your particular jurisdiction may have other rules beyond ASME that will require a plate type exchanger to be designed, fabricated and certified to some other code or standard. For instance, in Ontario it would be difficult to justify the use of a plate type exchanger in pressure piping if it didn't have a Canadian Registration Number (CRN), and that would have to be obtained for the device on some basis which justifies the MAWP and MAWT ratings it is being sold with.

RE: Is an ASME stamp requried?

Section VIII Div 1 has introduced new language in the 2017 Edition of the Code for plate heat exchangers (PHE).

RE: Is an ASME stamp requried?


The ASME stamp requirement depends on a number of things like design and the jurisdiction of where the heat exchanger will be installed. I was just at the National Board of BPV in Columbus, OH and they had ASME U stamp plate heat exchangers in their training facility. I'd love to discuss this with you over the phone or email. I will try to send you a private message.


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