A maximum distance of how many feet is permitted between a 1 ½ inch fixture trap and the vent fitting?

• A. 3 feet
• B. 4 feet
• C. 5 feet
• D. 6 feet

Answer: (D)

The correct answer is based on plumbing code requirements which specify that for a 1 ½ inch fixture trap, the maximum distance allowed between the trap and the vent fitting is 6 feet. This distance is crucial to ensure proper drainage and venting of the plumbing system. If the distance exceeds 6 feet, there is a risk that the trap may become siphoned, which could lead to the release of sewer gases into the living space and compromise the overall function of the drainage system.

Vent pipes are essential for preventing negative pressure within the plumbing system during drainage and ensuring that traps remain filled with water to block odors and gases. By adhering to the 6-foot maximum distance, installers can ensure effective venting and trapping, which are vital components in maintaining the safety and integrity of residential plumbing systems.