What is the purpose of a circuit vent in plumbing?

The purpose of a circuit vent in plumbing primarily revolves around providing air for a battery of fixtures. This type of venting system is typically utilized in installations where multiple drainage fixtures are interconnected, such as in a bathroom with closely placed sinks, toilets, and showers. By allowing air to enter the drainage system, circuit vents help to maintain proper atmospheric pressure and facilitate the smooth flow of wastewater.

This air supply plays a crucial role in preventing the formation of negative pressure that can hinder drainage, which could lead to issues like slow draining or backups. Additionally, this system ensures that the traps in the fixtures remain filled with water, effectively blocking sewer gases from entering the living spaces. By supporting multiple fixtures with a single venting system, circuit vents optimize efficiency in plumbing design while ensuring proper ventilation for the entire assembly of fixtures.