As used in this chapter:
(a) “Existing high-rise structure” means a high-rise structure, the construction of which is commenced or completed prior to July 1, 1974.
(b) “High-rise structure” means every building of any type of construction or occupancy having floors used for human occupancy located more than 75 feet above the lowest floor level having building access, except buildings used as hospitals, as defined in Section 1250.
(c) “New high-rise structure” means a high-rise structure, the construction of which is commenced on or after July 1, 1974.