This is a department rule in addition to the requirements in IEBC section 1012.2: Standpipe systems shall be provided in existing buildings and structures or portions of existing buildings and structures in accordance with IBC chapter 9 when existing buildings or structures that are greater than 60 feet in height are changed to include a Group R-1 or R-2 occupancy.
Wis. Admin. Code Department of Safety and Professional Services SPS 366.1012