What is the maximum diameter of a sphere that must be prevented from passing through a swimming pool fence?

The correct response regarding the maximum diameter of a sphere that must be prevented from passing through a swimming pool fence is based on safety regulations designed to protect children from climbing or squeezing through the fence. The maximum measured diameter of a sphere that can fit through openings in pool fences is typically set at 4 inches. This standard aims to ensure that small children cannot fit through any gaps, thereby reducing the risk of accidents near the pool area.

A diameter of 4 inches is widely adopted in many building codes and safety guidelines. The rationale behind this size is that it represents a sufficient barrier against small children while still allowing for reasonable visibility and access for adults. Consequently, experiences in building safety underscore the importance of adhering to this guideline to foster a secure swimming environment.

Other specified options do not align with these safety protocols. Smaller diameters such as 2 inches and 3 inches might permit safety yet may not cover all scenarios. Meanwhile, a 5-inch diameter exceeds the established safety standard, posing potential risks that the guideline aims to mitigate.