Why The Qty. of Revolving Door Wings Not 1 Or More Than 5 ?

The number of wings in revolving doors (typically 2, 3, or 4) is the optimal balance of multiple factors including traffic efficiency, space utilization, energy consumption control, and structural stability. Designs with just 1 wing or more than 4 wings like 5 wings have obvious drawbacks, and the reasons are as follows.

I. Why is a 1-wing design rarely used ?

1. Failure to form enclosed compartments and loss of core functionality. The core advantage of a revolving door lies in its "dynamic sealing": the wings divide the rotating space into several independent compartments. When people or objects pass through, the entrance and exit are never open simultaneously, which greatly reduces the exchange of hot and cold air between indoor and outdoor areas and lowers air-conditioning energy consumption.With only 1 wing, the two sides of the wing remain connected to indoor and outdoor spaces during rotation. It is equivalent to a "rotating single door", completely losing its energy-saving and sealing functions, and is even less practical than a regular swing door.

2. Structural instability and poor safety. During rotation, the force on a single wing is concentrated entirely on one side, resulting in extremely unbalanced load on the rotating shaft. This easily causes the door body to shake, increases wear and tear, and may even lead to jamming. Meanwhile, a single wing cannot form a "safety buffer zone", making pedestrians prone to collisions with the rotating wing and creating significant safety hazards.

3. Extremely low traffic efficiency. A single wing can only allow one person to pass unidirectionally at a time, and it takes a full rotation to complete one passage. Its efficiency is far lower than that of multi-wing doors, which enable "parallel passage through multiple compartments".

II. Why are designs with 5 or more wings rarely adopted?

1.Excessively small compartments and drastically reduced practicality. 

The outer diameter of revolving doors is limited (commonly 2~4 meters). The more wings a door has, the smaller the angle between adjacent wings, and the narrower the formed compartments. A 3 wing revolving door has a compartment angle of 120°, a 4 wing revolving door door 90°, while a 5-wing door only has an angle of 72°.The cramped compartments cannot accommodate multiple people, luggage, wheelchairs, or goods, which not only reduces traffic efficiency but also undermines the door's usability.

2. Complex structure, increased costs, and higher failure rates. 

More wings mean a more complex rotary drive system, load-bearing structure, and safety sensor configuration.

A greater number of wings leads to higher manufacturing and installation costs.

Sensors need to cover more narrow compartments, which increases the risk of misjudgment (like pinching people or causing jams).

Smaller gaps between wings are more likely to trap dust and debris, adding to maintenance difficulties.

3. Offsetting energy-saving advantages. 

Although more wings theoretically provide better sealing, the small compartment size forces the door to rotate more frequently (requiring frequent starts and stops) as pedestrians pass through, which instead increases motor energy consumption. Additionally, cramped spaces are prone to congestion, indirectly causing the door to remain "half-open" for extended periods and compromising its sealing performance.

Conclusion

The number of wings in a revolving door is not arbitrarily determined; it is the optimal solution balancing functional requirements and physical constraints:

1 door wing. Fails to fulfill the core sealing function, with poor structural stability and low efficiency.

2, 3 or 4 door wings. Precisely meets the traffic, energy-saving, and safety needs of different scenarios, hence becoming the mainstream design.

5+ door wings. Results in overly small compartments and complex structures, lacking practicality and economic viability.