Question of the Day - #107 Bedrooms don’t matter?

[RDavidson]

I have a house built in 2015. The basement is unfinished. I want to finish the basement. I’m wondering about energy code and ventilation requirements. 1322.0100, subpart 3, addresses additions, alterations, and repairs to existing buildings, building systems, or portions of buildings. I don’t see any exceptions to the ventilation requirements. I am adding two bedrooms in this basement. I am looking at the mechanical ventilation requirements in Energy Code section R403.5 to determine the amount of ventilation I need based on the number of bedrooms. But then I come to R403.5.1 that says alterations are exempt from complying with this section? So I don’t have to be concerned about ventilation. But if I had finished the space when the home was built I would have needed to account for them. Is that strange or what?

But, what if I construct an addition to the same house and add two bedrooms? Now I have to expand my mechanical system in order to accommodate the bedrooms. Is that strange or what?