A new boiler idle for 2.5 years & 6 months after commissioning faces a major repair

50% of the lower division wall tubes & lower lateral wall tubes have to be cut & replaced partly (around 150 tubes)

My question is --
1. Does it required to repair under R stamp?
2. Does code specify something?

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Kareem

My answer to your question is:
ASME Code Sect.I refers to new construction only.
NBIC ("R" Stamp) provides rules for repair and alterations.

If local regulations or other requirements (e.g. insurance) mandate for certification of repairs, "R" stamp may be an answer. In almost all State of the USA this is mandatory.
Mauro