How should drainage systems be vented to prevent siphoning?

Venting in drainage systems is crucial to maintaining proper flow and preventing siphoning. When pipes are functioning correctly, air needs to be able to move freely in and out of the drainage system. This is where appropriate venting intervals come into play.

Venting allows atmospheric pressure to enter the drainage system, which equalizes pressure and prevents situations where fluid can be siphoned or drawn out of traps. By having vents installed at appropriate intervals, the system can effectively manage the air pressure and prevent any likelihood of siphoning occurring, which ensures that traps retain their water seal and continue to function as intended.

In contrast, improper venting methods can lead to inadequate pressure equalization, causing traps to empty and allowing sewer gases to enter the living space. Relying on only one vent may not provide sufficient air flow throughout an extensive drainage system, and declaring that no venting is needed disregards the essential role that vents play in maintaining system function and health.