A manufacturer's floor drain shall not require an individual vent if placed on a waste line within how many feet from the main waste line?

The correct reasoning behind why a manufacturer's floor drain does not require an individual vent when it is placed on a waste line within 10 feet of the main waste line is based on plumbing code regulations that aim to maintain proper drainage and prevent siphoning or backflow issues. When a floor drain is installed within this distance from the main waste line, the existing venting associated with the main line is considered sufficient to handle any potential air pressure changes during the drainage process.

This distance is significant because it allows for a shared venting system to effectively deal with the airflow and pressure differentials that occur when wastewater is discharged. The closer proximity to the main line helps ensure that the floor drain can utilize the venting created by the main waste line, reducing the need for additional, individual ventilation which could complicate the plumbing layout and increase installation costs.

Understanding these code provisions helps plumbers make informed decisions during installation to ensure compliance with regulations and the efficiency of the drainage system.