What is the maximum distance a vent can be from a fixture trap to effectively vent it?

The maximum distance a vent can be from a fixture trap is defined to ensure proper airflow and odor control within the plumbing system. When considering venting systems in plumbing, the distance helps maintain the necessary balance between the pressure throughout the drainage system and allows for the effective escape of gases. A distance of 6 feet from the fixture trap is recognized as the maximum because it best allows for the prevention of siphoning, which can occur if the trap loses its water seal.

This 6-foot rule is grounded in the principle that a shorter distance reduces the likelihood of negative pressure affecting the trap's water seal, allowing the system to function correctly without the risk of sewer gases entering the living space. A longer distance may compromise venting efficiency and increase the chances of trap siphoning, leading to potential issues with drainage performance and health risks associated with backflow of harmful gases.

The other distances, while they may align with certain factors in plumbing, do not surpass this 6-foot standard for effective venting.