1. Prevent Air Lock: The U-trap is designed to hold a certain amount of water to act as a seal, preventing sewer gases and odors from escaping into the room. However, if the U-trap dries out, due to evaporation or other reasons, it can create an "air lock," blocking the flow of water and preventing the sink or drain from functioning properly. The air vent allows air to enter the U-trap, breaking the air lock and allowing water to flow freely.
2. Facilitate Drainage: In some cases, the plumbing system may not have enough slope or gravity to ensure proper drainage. The air vent helps to create negative pressure in the drain line, which assists in pulling the water down the drain and preventing blockages or slow draining.
3. Reduce Odors: The air vent provides a pathway for sewer gases and odors to escape from the plumbing system, ensuring better indoor air quality and preventing unpleasant smells in the room.
4. Comply with Plumbing Codes: In many regions and countries, plumbing codes require the installation of air vents in certain parts of the plumbing system, including U-trap lines, to ensure proper drainage and ventilation.
5. Prevent Siphonage: When water flows quickly down a drain, it can create a suction effect that can draw water out of other fixtures connected to the same drain line, such as sinks or toilets. The air vent breaks this siphonage effect, preventing the loss of water from other fixtures.
