The revolving door consists of 3 or 4 wings. The wings rotate outward from the central axis. The revolving door is of cylindrical structure and the wings are spaced in such a way that the door is never open. Main advantages of revolving door: it allows large numbers of people to pass in and out easily and quickly, it prevents for indoor pollution and regulates temperature. It also increases space and efficiency of space usage. Boon Edam first introduced us revolving door over 100 years ago.