R313.1.1 Alterations and additions. When
alterations or additions requiring a permit occur, or when
one or more sleeping rooms are added or created in
existing dwellings, the entire dwelling shall be provided
with smoke detectors located as required for new
dwellings. The smoke detectors shall have a power
source in accordance with Section R313.2.
Exceptions:
1. The smoke detectors may be battery operated and are not
required to be interconnected when other remodeling
considerations do not require the removal of the
appropriate wall and ceiling coverings to facilitate
concealed interconnected wiring.
2. Alterations to the exterior surfaces of dwellings
including, but not limited to, re-roofing, re-siding,
window replacement and the construction of decks
without roofs, are exempt from the requirements of this
section.
So battery powered it is I am really starting to dislike residential.