What should occur when interior drainage piping reaches a length of 100 feet?

When interior drainage piping reaches a length of 100 feet, providing a vent to atmosphere is essential to ensure proper drainage function and to maintain the necessary air pressure in the drainage system. This distance is significant because as the drainage system operates, venting allows air to enter the pipes, preventing the formation of negative pressure, which can hinder the flow of wastewater and lead to issues such as backups or slow drainage.

Venting also helps to alleviate odors from the drainage system and prevent siphoning of water seals in traps, which is critical for maintaining a sanitary environment. In plumbing design, proper venting and management of air pressure in piping systems are necessary for efficient function and compliance with plumbing codes.

While installing a cleanout, rerouting the pipe, or increasing the diameter may be considerations in certain contexts, they are not directly mandated when the length of piping reaches 100 feet. The specific requirement for venting at this length is a fundamental aspect of plumbing design standards regarding drainage systems.