(4th FLOOR 1-HOUR CORRIDOR SYSTEM UPGRADE) A safe exiting system shall be maintained during the construction phase. Exit paths to be kept clear of debris and not used to store staging materials. This building is not sprinklered per 1973 UBC when constructed. Work includes select demolition; construction of 1-hour fire partition walls to create 1-hour corridor and separate elevator lobby from corridor; install listed & labeled, 20 minute fire rated, "S" labeled smoke-draft control, self closing with listed hardware door/frame assemblies at all openings into corridor except doors to existing stair enclosures; modify ceiling grid, mechanical, electrical, plumbing, alarm, exit signage / emergency illumination and finishes. This rated exit corridor is being installed per Sec.1015.2, exception #1 for exit separation between existing stair enclosures and to delete existing 2-hour horizontal exit installed under previous permit to provide separation. All per approved plans, notes on plans and attached plan review conditions of all plan reviewing agencies. drs