we have tower in 60 m height ,after hydrotest in horizontally position in the workshop we want to move the tower into the site for installation for this purpose we want to cut the tower from the point 30 m and now we have tower with two pieces. after shipment to the site we add the 20 cm plate and weld it between the two pieces so i want to know am i allowed to hydrotest the tower again?

What you are going to do is a field assembly of the vessel. If the tower was constructed to ASME Code you need to be U-Stamp holder and comply with U-2(h) requirements. By following you Quality Manual procedures including AI involvement you will create a solid plan of actions before doing any physical work. That includes calculations to consider the test loadings per UG-22(j).

Thanks,

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AI-OR-US

Hi, khv
This is a corrected answer.
Case 1.
You have completed shop fabrication of that 60m tower per Section VIII Div. 1 including a Code stamping and a Manufacturer's Data Report. In this case, cutting the vessel into two parts with subsequent welding is an alteration of the existiong vessel. ASME Code is no longer mandatory as a set of construction rules. You need to follow local Jurisdiction codes and standards which, however may reference ASME Code as a technical standard. For example, in the most states of USA, you would need to have R-Stamp to do alteration and follow NBIC Code with reference to ASME Code as a technical standard. Subject to acceptance of the local Jurisdicion and the Owner/User, when doing alteration you may substitute hydrotest with NDE.

Case 2.
You built two vessel parts with partial Code stamping of each part and partial Data Reports. You may continue a field assembly per U-2(f) with subsequent final examination, testing, inspection and Code stamping of assembled vessel.

Case 3. You did not Code stamp the tower and still are in a process of construction. This process is addressed in your drawings and calculations and you have all hold points established by AI including a field activity. In this case You may continue a field assembly per U-2(f) with subsequent final examination, testing, inspection and Code stamping of the tower, including a hydrotest.

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AI-OR-US

Great answer, AIORUS. Interesting thing is that in Case2 the final work can be subcontracted to other company (if khv doesn't have field assembly in his certification scope) at a lowest cost.

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Konrad Anikiel