The following modifications to the minimum fire-resistance rating of the building elements in Table 601 shall be as follows:
1. High rise buildings 420 feet (128 000 mm) or greater in building height shall be constructed of Type IA construction.
2. For high rise buildings not greater than 420 feet (128 000 mm) in building height, and constructed to meet the fire-resistance rating requirements of Type IB or IIA construction, the required fire-resistance rating of columns supporting floors shall be constructed to meet Type IA construction.
1. High rise buildings 420 feet (128 000 mm) or greater in building height shall be constructed of Type IA construction.
2. For high rise buildings not greater than 420 feet (128 000 mm) in building height, and constructed to meet the fire-resistance rating requirements of Type IB or IIA construction, the required fire-resistance rating of columns supporting floors shall be constructed to meet Type IA construction.