I have a question regarding whether or not I can use NFPA 13R for an existing building being retrofitted into apartments. The reason I am not sure about using NFPA 13R is that, while the building is only 4 stories and less than 60' in height above grade, there is a basement which is entirely below grade, but it also has four apartment units, along with a fitness room, the occupant storage room, and the mechanical and electrical rooms. I have not found a definitive answer as to whether the 4-story requirement is just for the stories above grade, or total stories of residential occupancy. Any input would be appreciated!
Not sure which edition of NFPA 101 you are referencing but in the 2012 edition, Section 30.3.5.2 for apartment buildings states that NFPA 13R can be used in buildings four or fewer stories "above grade plane".