BUILDING

PROBLEM TO BE SOLVED: To permit a door, opened toward the inside of a room, to be left opened at any time and guarantee the non-smoke property of an emergency passage by a method wherein a ventilating device is arranged in a main vent duct to generate and maintain a ventilating pressure while the value of ventilating pressure is kept so as to be higher than that of a pressure, controlling ambient outdoor air. SOLUTION: A ventilating facility 12, provided in a building 10, is divided into three up-and-down ventilating divisions 14A, 14B, 14C in the vertical direction V while respective ventilating divisions 14A, 14B, 14C are provided with ventilating main ducts 16A-16C, arranged differently. In order to function the ventilating facility 12 in good order, a pressure, controlling the inside of the building 10, and especially, a pressure P1, controlling the inside of corridors 24, is preferable to be higher than a pressure P2, controlling ambient outdoor air, by a specified pressure difference ΔP at all times. In this case, the fluctuation of the pressure difference ΔP can be allowed within a predetermined range of limit of course. The pressure difference ΔP is favorable to be about 30 Pa.