Non-ASME "pressure part" welded to ASME vessel

[John21423]

Hi All,

I have a shell and tube heat exchanger where the waterbox is welded directly to the vessel tubesheet.

The waterbox is exempt from the ASME VIII rules because it contains water at 150 psi and below 210F.

I am wondering if the connection between the waterbox and tubesheet would need to conform to UG-93 rules for inspection, which is for "pressure parts welded to flat plates over 1/2" thick, or is this connection exempt because the waterbox is not code.

Thanks in advance

 

[SnTMan]

John21423, if you are referring to UG-93(d)(3), and assuming the tubesheet (the flat plate) exceeds 1/2" thickness, then I'd say the tubesheet should be inspected, as it falls within ASME rules per your description. Inspection to be performed before and after welding, per UG-93(d)(4).

I'd say the waterbox plate itself and the balance of the waterbox parts would be exempt from the balance of UG-93, assuming there are no contractual requirements to inspect. Assuming as well your AI concurs.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[GD2]

John21423,
If your joint layout is one of the Fig UW-13 (h), (i), (j) or (k), NO inspection is required by UG-93(4)(e).

From design perspective, the tubesheet will still be designed as a pressure component as the other side falls into pressure vessel definition.

You will need to however, do hydrotest on both sides as required by Sub-Section C, Part UHX, UXH-18.

GDD
Canada