What is a 'Common Vent' used for in plumbing?

A common vent is specifically designed to serve as the vent for two fixture drains. This type of vent allows for efficient air flow and helps to balance the pressure within the drainage system while preventing siphoning of the traps connected to the fixtures. By using a common vent, it reduces the number of individual vents required, making it a cost-effective and space-saving solution in plumbing design.

The configuration of a common vent typically connects two fixtures that are located close together and enables them to share the same venting system while still ensuring proper function and code compliance. This arrangement is particularly useful in residential plumbing, where multiple fixtures may be installed in close proximity, thereby simplifying the venting system and promoting better drainage performance.

The other options, while related to venting and drainage, do not accurately describe the function of a common vent in the context of plumbing systems.