Turnstiles exceeding ____ inches shall be treated as revolving doors.

• A. 35 inches
• B. 39 inches
• C. 42 inches
• D. 36 inches

Answer: (B)

The key idea is how the code distinguishes a turnstile from a revolving door based on the width of the opening. When the passage is narrow, it’s treated as a simple barrier for crowd control. Once the opening becomes wide enough, the device functions like a revolving door and must meet the stricter safety standards that apply to revolving doors. The threshold used in the code is 39 inches. If a turnstile opening exceeds 39 inches, it is classified as a revolving door, which triggers the corresponding egress and safety requirements, such as ensuring safe and unobstructed exit in emergencies and adherence to revolving door provisions. The other prescribed widths don’t meet that boundary, so they don’t trigger the revolving-door classification.