What is the purpose of a common vent in plumbing?

The purpose of a common vent in plumbing is to serve as a vent for multiple fixtures. This is crucial for maintaining proper air pressure in the plumbing system, allowing sewer gases to safely escape while ensuring that wastewater can flow freely without creating a vacuum. When multiple fixtures share a common vent, the system is designed to allow air to enter the drainage pipes, which helps to prevent siphoning and encourages the smooth operation of all associated plumbing fixtures.

This arrangement is advantageous because it simplifies the plumbing layout by reducing the number of required individual vents, saving space and minimizing material costs. Utilizing a common vent effectively balances the system and helps to maintain overall plumbing efficiency, thus contributing to the functionality and health of the entire plumbing system.