Abstract: Fresh air is circulated to rooms of a highrise building during an emergency, such as a fire, from a source of compressed air located outside the building. Air is passed through insulated pipes to breathing units located in the rooms. Each breathing unit contains a plurality of extendable masks for placing over the user's nose and mouth, precluding inhalation of smoke and fumes in the room. A preferred valving arrangement permits fresh air to be drawn from the pressurized air source or from outside the building immediately adjacent the room.