High frequency welded finned tubes acc. to ASME I

[frauw]

Dear all,

because we are an european manufacturer and normally we fabricate boilers acc. to PED, I need some assistance:

We plan to suborder high frequency welded finned tubes (for evaporator and economizer) for boilers acc. to ASME Section I, S-Stamp.

Now we are discussing about the order text.

Can we order the high frequency welded finned tubes with S-Part acc. to current ASME Code, Section I? Or isn't it possible to order with S-part but only with an inspection certificate?

With this S-Part can we be sure that the manufactuer of the finned tubes has to comply with all the requirements of the current Code?
Or do we have to consider some other special requirement acc. to Section I?

Thank you in advance

Best regards

 

[frauw]

Hi again,
unfortunately it seems, that nobody has an answer for me.
So I will ask in another way:

Do the high frequency welded finned tubes fall under ASME Section I, PG-11, Miscellaneous Pressure Parts?

So, for them inspection by an Authorized Inspector, and Partial Data Reports are not required?

Thank you in advance.

Best regards

 

[metengr]

Do the high frequency welded finned tubes fall under ASME Section I, PG-11, Miscellaneous Pressure Parts?

No, PG-11 does not apply. Welded fin tubes must be ordered as pressure parts with a partial data report. In other words, as long as there are no butt welds (pressure bundary welds) in the tubing, they can be ordered as pressure parts with no S-Stamp, hydrostatic test or AI involvement because they are not fabricated parts from welding. See PG-112.2.4.

 

[frauw]

Thank you for your answer.
But the high frequency welded finnes on the tubes are not pressure retaining welding seams, only attachment welds on the pressure-retaining tubes. Does this make any difference? And does it make some difference if filler metals are used or not?

 

[metengr]

If the finned tubes are for a new boiler, the pressure part can be supplied with only a partial data report by an S-Stamp organization or the S-Stamp holder is willing to take responsibility and this is in their Quality Manual. If this is a replacement pressure part, either an inspection certificate or partial data report are only required.

The welded fins are no different than waterwall panels with welded membranes that are fabricated by an S-Stamp shop. As long as no butt welds are in the tubes the panels are considered to be pressure parts with no welding, therefore, no stamping is required nor a hydrostatic test.

 

[frauw]

Thank you again, know some things are more clear.
But one thing isn't clear yet:

"Quote: As long as no butt welds are in the tubes the panels are considered to be pressure parts with no welding, therefore, no stamping is required nor a hydrostatic test. "

Do the attachment welds on the tubes fall under butt welds? Because for me the attachment welds are filled welds and no butt welds - or has ASME another interpretation of butt welds?

 

[metengr]

Do the attachment welds on the tubes fall under butt welds?

No, the nonpressure part to pressure part welds are fillet welds regardless if filler metal is used. The previous example I provided is one I use when we purchase boiler waterwall tube panels from suppliers. The membrane that is fillet welded along the sides of each tube to make a gas tight panel is not considered a pressure part butt weld - it is a non-pressure part to pressure part fillet weld.