ASME VIII-2 & AD Merkblatt : Choice of Code for Heat Exchanger Ordering

[Awais Arshad]

Hi all and Happy New Year,

Though design philosophies of Codes (especially for Tubesheets in case of HE Design) differ and cannot be cross-compared, given an option to select AD Merkblatt and ASME VIII-2, I seek suggestions on the selection for an exchanger to designed, manufactured and inspected for Ammonia service (DP=267 bar; MDMT=-33dC)

In a bid to enhance efficiency of plant, we (from client side) are ordering an exchanger similar to the one installed in one our other plants. The old exchanger was designed on AD Merkblatt. We initially kept the room open to the vendor for both the AD & ASME VIII-2, but he has asked for a specific Code to follow; this makes me mindful of the change in fabrication and inspection requirements (alongside Design aspect), that follow with a change in Code.

You are requested to enumerate the challenges (which I find the most appropriate word owing to lesser cross-command of the two Codes) that I may face while selecting either of the Codes. Among others, the ones I can think of while selecting ASME VIII-2 is a full-blown User Design Specification (UDS) and stringent RT requirements. AD Merkblatt, on the other hand, is not supported by Codeware Compress so technical review of the Design might not be possible from our end.

Thank you.

Regards,
Awais

 

[FacEngrPE]

See thread1203-352508 for a prior discussion on this question.
Usually the OP's question is answered by the rules of the Authority Having Jurisdiction boiler and pressure vessel regulations.

 

[XL83NL]

Though that’s a very informative discussion posted by FacEngrPE, it only answers part of the question I think. What you’re asking is a list of differences between the 2.
I think we have had the same exact question about just over a year ago. The listing of differences is large but will highly depend on the initial sizing, spec and details of the equipment. What works best for you is also dependent on things like your company (a.o. engineering and workshop capabilities) , local market labour rates, and is best answered by yourself.

Huub
- You never get what you expect, you only get what you inspect.