There is much debate in the industry and within code committees about the reuse of sprinklers. A recent article on the NFPA website provides clear guidance about past and current code requirements for sprinkler reuse. They nailed it! Provided below is the article in its entirety (emphasis – mine).
NFPA 13R Sprinkler Systems – Are You Double-Dipping?
For residential occupancies, a 13R sprinkler system is permitted by the building codes for many applications, and a 13R system offers numerous economic advantages for the building owner. Most notably, with a 13R system, attics and concealed spaces do not have to be protected with sprinklers.
But, be careful! Although the building codes permit a 13R system for residential occupancies, a 13R system is not permitted when a 13 system is used by the Architect for tradeoffs to other code requirements.