What is the maximum distance a 2-inch fixture trap can be from the vent fitting?

The maximum distance a 2-inch fixture trap can be from the vent fitting is established as 8 feet in the International Residential Code (IRC). This distance is specified to ensure that there is sufficient venting to prevent siphoning of the trap seal, which is crucial for maintaining proper drainage and preventing sewer gases from entering living spaces.

Fixture traps must be vented properly to allow air to enter the drainage system, which equalizes pressure and facilitates smooth drainage. If the trap is located further than the specified distance from the vent fitting, it can lead to inadequate venting and potential issues like trap seal loss, resulting in the failure of the plumbing system to function effectively.

By adhering to the 8-foot maximum distance, plumbers ensure the traps remain properly vented, contributing to the overall health and safety of the plumbing system within a residential building. This regulation is well-supported by plumbing design principles aimed at efficient water flow and gas management.