U-Stamping / Documentation for "Replacement-in-Kind" 1

[thermmech]

I am now outside of North America and am trying to sort out PV safety / integrity policies within my new company which is an owner-operator.

We are replacing lots of S&T bundles which were mostly designed and fabricated in the mid '90s. Local fabricators are coming back to us asking whether they need to provide U-stamp. My understanding is that in order to provide a U-stamp, one has to make sure that the design is in compliance with the LATEST ASME. Therefore, no U-stamp can be provided if the unit fabricated is not as per latest ASME.

In Alberta every unit that is replaced either entirely or partially has to comply with the latest ASME Ed/Add in order for manufacturer to provide U-stamp and relevant documentation (PV travel sheet, etc).

To clarify further:
My question is not related to repair and alteration, but rather to what happens when the owner wants to order a new S&T tube bundle because the old one corroded? If the bundle was designed and manufactured in early '90s, tubesheet design was likely based on TEMA rules, and not ASME.

My recollection when dealing with AIA in Canada was that you had to check with them first to get an approval to build it according to the original drawings, i.e. you had to run a mechanical design check and show them it is safe to reuse the old design. As we all know, UHX sometimes requires thinner and sometimes thicker tubesheets. So, old design could be deemed unsafe, and new design would have to be fabricated. This means modification of tubeside piping, replacement of bolting on girth flanges, etc.

What is your take on when it is OK to just provide replacement-in-kind? Is it always up to the AIA in a particular jurisdiction to decide?

Please provide me with some feedback. Thanks,
Sean

 

[CodeRef]

That is a good question....Lets walk through the Code requirements.
The ASME Code is specific only to new construction and does not address repairs to existing ASME Stamped items. Repairs to existing ASME stamped items are addressed by the Jurisdictional authority in place where the pressure retaining item is installed. The Jurisdictional authority could be an AIA, or it may not, in either case the Jurisdictional authority will have the final word and not the AIA.
Typically for North America the NBIC governs in many cases along with special conditions established by the Jurisdiction.
As for ASME Parts, Data Reports for those parts of an ASME Section VIII pressure vessel which are furnished by a parts Manufacturer to the user of an existing Code vessel as replacement or repair parts shall be executed on Form U-2 or U-2A by the parts Manufacturer and his Inspector. A copy of the parts Manufacturer’s Partial Data Report shall be furnished to the user or his designated agent. The parts Manufacturer shall indicate under “Remarks” the extent he has performed any or all of the design functions. When the parts Manufacturer performs only a portion of the design, he shall state which portions of the design he performed.

So, the question is, who is taking responsibility for the design of a replacement tube bundle if the ASME Part manufacturer is not? The answer is, the original manufacturer through the owner/user specifying the original design criteria in the request for a new tube bundle. Personally, I would want to get the Jurisdiction of installations approval for this type of repair/replacement. This is typically handled in North America by bringing in the R-Stamp holder to review and accept the replacement. Note: This is why I require all tube bundle replacements to be handled with an R-Stamp.
If the jurisdiction does not provide direction in written legislation addressing this, then I would make a call to the person in charge and get clarification.

Of course this is only my opinion and I am sure there are many who may have a differing opinion. The one that matters is the Jurisdiction of installation and that is where I would go for the final rule.



FAQ731-376

 

[CodeRef]

In addition, I think that the concerns that ABSA has with tubular heat exchangers are for heat exchangers designed and fabricated to Part UHX after the mandatory date of January 2004 ...."in view of the numerous revisions to Part UHX since its introduction in 2003".... and not particularly for those prior to 2003

Here is the information bulletin link:

http://www.absa.ca/IBIndex/IB08-001.pdf

As before, just my opinion...

FAQ731-376

 

[thermmech]

Thanks for your replies. Just to clarify, I am not working in Alberta any more... thus I am unsure of jurisdictional requirements here, and no-one around seems to be able to help me.

I found this "white paper" by Compress authors and here's the excerpt (

http://www.codeware.com/support/papers/UHXWhitePaper.pdf):

For replacement heat exchanger bundles in-kind, it is a common and acceptable practice for an owner to ship a drawing of a tube bundle to fabricator with no consideration at all given to whether design calculations are required or not. The fabricator builds the bundle to the current code rules, and, if needed, applies a Part Stamp and sends it back to the owner who fills out the necessary post construction paper work to the satisfaction of the jurisdiction. (The Part Stamp holder is not required by Section VIII to certify any design.)
This does not violate any ASME requirements and is, in fact, what the NBIC suggests be done. Since a U Stamp is not normally required for replacement heat exchanger bundles, Section VIII does not prohibit “fabrication to the drawing” because design calculations are required by Section VIII for Parts or materials. For Section VIII construction, the design responsibility belongs to the U Stamp Certificate holder; however, for a post construction replacement bundle, there is not necessarily a U Stamp Certificate holder involved.

 

[GenB]

"The fabricator builds the bundle to the current code rules, and, if needed,
applies a Part Stamp"
If the item is stamped, the fabricator IS responsible for the engineering design per Code.

"(The Part Stamp holder is not required by Section VIII to certify any design)"
Right: if the part is not stamped, any non-code shop can make it.

The National Board has no-control and does not get involved in replacement parts specially those which welding is not involved.
It is up to the Jurisdictions to rule, control and police the practice.
If the Jurisdiction requires R stamp, then isthe owner's responsibility to get the required ASME stamped aprt.
If weldng is not involved, The jurisdiction may allow the owner to use own drawings and the an R stamp holder to install it.
Some Jurisdictions will allow the owner's maintenance people (not R stamp holder) to install the prt legally.
OWNER USER: they have the sky clear, their Inspector calls the shots as long as the QC is under control using the above requirements.
w/or w/o the R stamp holder

 

[thermmech]

Thanks for your replies!

 

[rneill]

My understanding is that the Authority in Alberta (ABSA) permits designs based on either ASME UHX or the TEMA rules but you must pick one set of criteria and then be consistent. Strictly speaking, a U stamp is not legally required in Alberta. A "CRN" is required on the design and then an "A" stamp is required for the fabrication.

ABSA provides the "CRN" on the design and if I'm correct would provide this certification on the basis of either ASME or TEMA, and then will provide the "A" stamp so long as the fabrication is in accordance with the registered design. You would not be able to "U" stamp unless the design met the current ASME UHX requirements.

This bulletin may be superceded but it is still on the ABSA Website and I believe it is still valid as there is no indication it has been rescinded or superceded.

http://www.absa.ca/IBindex/IB03-010.pdf

 

[metengr]

I really don't see a problem here. In our company we have heat exchangers that have been retubed with no welding. In our RFQ for manufacturing a new bundle we provide a copy of the original ASME data report and drawings that the fabricator will use to reverse engineer a replacement bundle. In most cases, the design has not changed especially if the bundle has been in service for 30 years.

The fabricator has an ASME Stamp and when the replacement bundle is sent to use with a new data report, we have an R-Stamp holder install it under their QC program.

 

[metengr]

Also, I forgot to mention that in the 2007 Edition of the NBIC, Part 3, 2008 addendum we included a statement that for replacement parts that were fabricated and stamped to a different edition of the part being replaced, there is a cautionary statement to seek advice to make sure that this is still a repair and not an alteration, and it is at least as safe in design as the oriignal part.

Basically, for reverse engineering this would be a repair under the NBIC and as I stated before, this is relatively straight forward. Using later editions of ASME Code is absolutely acceptable. However, if the later editions require changes that results in modifications that fall under alteration, the scope of work could change from repair to alteration (not a big deal but must be accounted for).

 

[rneill]

I think metengr has laid out a good process to follow for a bundle replacement and I guess I was really clarifying more the process to be used for a new design in Alberta.

The main point I was trying to get across was that TEMA rules are still acceptable in Alberta and that older designs based on TEMA do not necessarily have to be reworked to ASME, even for new units.

Thanks

 

[thermmech]

Thanks for your replies.

I would like to add that at this point in time, ABSA doesn't allow tubesheet designs based on TEMA alone; all ASME requirements have to be met, but not TEMA. The end user always has an option to specify that the more onerous of ASME / TEMA should govern the design.

As for the ABSA bulletin, it states that as of 2004 ASME Code stamped equipment (which is a requirement in Alberta to get the CRN) shall be designed to ASME as a minimum, as Code Case 2429 will have expired by 2005.

Thanks to meteng for his comments:
When doing reverse engineering and bundle design check according to the latest edition, the process is clear (it will either be a repair or alteration depending on whether the bundle passes the check). I guess what I'm struggling with is how would manufacturer provide an ASME Code Stamp to an old Code Edition (30 years old one)? They probably do not have those old Code Editions at hand.

 

[metengr]

thermmech;

I guess what I'm struggling with is how would manufacturer provide an ASME Code Stamp to an old Code Edition (30 years old one)?

The Certificate holder does not need to stamp the part using code rules from 30 years ago. The most likely scenario is that an ASME Certificate holder would design the replacement part using current code rules and if it results in an in-kind replacement, the design is as safe as it was 30 years ago.

Where I could see a potential issue is an allowable stress value that has been revised to allow for thinner wall replacement parts using the same material, as from original design. In this case, the current design is still as safe as it was from 30 years ago. However, you now have a potential change in dimensions, etc that could result in an alteration of the pressure retaining item under NIBC rules.

For parts this is not a huge problem, you just need to plan ahead.

 

[thermmech]

Thank you all!