ASME BPVC tolerances

[Silvio Zanni]

Dears, i need informations about heat exchanger tubesheet flatness tolerance (requirement). It is a vertical heat exchanger, Ø 8000mm.

 

[SnTMan]

Silvio Zanni, I am not aware of any flatness tolerance as such on the tubefield portion of the tubesheet. Flatness of this portion is affected by such things as tube pitch / pattern, tubesheet - tube joint preparation, PWHT and so forth. Flatness of gasket surfaces would be governed by standards such as TEMA or API 660. ASME Code does not generally address fabrication tolerances.

How un-flat are you, and at what stage of fabrication?

Regards,

Mike

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

 

[TGS4]

Check with your customer. More than likely there is some overriding process requirement.

 

[Silvio Zanni]

TEMA code is not applicable because the tubesheet in question has a Ø 8000mm. We found a difference of flatness of 66.0 mm in the heat exchanger assembly, after the tubes positioning. Which I believe to be exaggerated, but I did not find references to linear tolerances for tubesheets.
My supplier claims to be normal...

 

[Silvio Zanni]

Ops! Tanks Mike and TGS4

 

[SnTMan]

So, guessing here, but your tubesheet was reasonably flat before welding a w/ corner joint to the shell. If so and the tubesheet was not fixtured somehow, 66 mm out-of-flat would seem reasonable on 8000 mm diameter.

Regards,

Mike

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

 

[Silvio Zanni]

Mike, grateful for your help!

Regards,

Silvio