How far must urinal partitions extend from the wall surface at each side of the urinal?

The requirement for urinal partitions to extend from the wall surface at each side of the urinal is set to ensure privacy and comfort for users. The correct distance of 18 inches provides a balance between functionality and the use of space in restrooms. This distance allows for sufficient screening from adjacent areas while not taking up excessive room in potentially confined restroom environments.

In the context of public health and safety, this dimension is crucial for preventing splashing, thus maintaining cleanliness. Additionally, it aids in compliance with accessibility standards, ensuring that all users can comfortably access the facilities.

While other options represent larger distances, these would unnecessarily occupy more space and are not required by code, thus highlighting the importance of adhering to specified standards for the proper installation of plumbing fixtures.