The vent valve is a device installed to prevent negative pressure (e. g. as a result of surge pressures) in a piping system. Vent valves are also installed at the highest points in a piping, system downstream of shut-off elements or pumps, and at the highest points in domestic installation systems.

Vent valve is a safety device that discharges air at the water supply piping in order to avoid air related problems in the water piping systems.