NBIC decrease heating surface considered an alteration?

[Outtatowner]

Hello, So in the NBIC Part 3, Examples of Alterations 3.4.3 (d) states that a change in the dimensions or contour of a pressure retaining item constitutes an alteration. (e) states that In a Boiler, an increase in the heating surface or steaming capacity constitutes an alteration.
My question is; If in a fossil fuel boiler, one plugs a tube at a drum or header, and removes the now unused tubing from the boiler, is that considered an alteration? By the same logic, would shortening a loop or bend also be considered an alteration?

 

[GenB]

Yes

 

[Outtatowner]

NBIC interpretation 95-35 question 1 is: "Is the welding in of a plug to seal tubes of a boiler or pressure vessel considered a repair"
Answer: Yes
Why is this a repair and not also an alteration?

 

[metengr]

The method of tube plugging is a repair. Removing a plugged tube is not an alteration. It is outside the scope of the NBIC because it is a performance issue. De-rating, as in your case, is a Jurisdictional issue and is not addressed by the NBIC.