For a 6-inch diameter vent measuring 20 feet vertically, the maximum horizontal length of a 6-inch single-wall connector is 15 feet.

• A. 15 feet
• B. 20 feet
• C. 10 feet
• D. 25 feet

Answer: (A)

Understanding how far a vent connector can run horizontally based on its diameter and vertical rise is key here. For a 6-inch diameter vent using a single-wall connector, the code provides a maximum horizontal run when the vertical rise is 20 feet. In this scenario, that limit is 15 feet. This restriction helps maintain proper draft and reduce problems like backdraft, excessive resistance, or condensate buildup in the horizontal portion. If more than 15 feet of horizontal run is needed, you’d typically adjust the approach—use a larger diameter, a double-wall connector, or a different routing method—to meet code requirements.