Journeyman Plumber ExamDrainage, Waste, and Venting (DWV) SystemsMedium
A plumber is designing the vent system for a commercial restroom. A 4-inch main vent stack is required. What is the minimum height above the roof a vent pipe termination must be located?
- A4 inches
- B6 inches
- C12 inches
- D10 inches
Show answer & explanationAnswer & explanation
Correct answer: B. 6 inches
Plumbing codes generally require vent pipe terminations to extend a minimum of 6 inches above the roof, except in specific cases like under frost closures. This ensures proper air circulation and prevents snow or debris from obstructing the opening.
Why the other options are wrong
- A. This height is typically insufficient to prevent snow or debris from blocking the vent opening.
- C. While acceptable, this is not the minimum required height.
- D. While acceptable, this is not the minimum required height.
Vent Stack Termination Height
The vent stack termination height refers to the minimum vertical distance a vent pipe must extend above the roof surface. This ensures proper operation of the DWV system and prevents issues like blockage.
- Prevents blockage from snow/ice.
- Prevents odors from entering building.
- Minimum 6 inches above roof.
- May be higher in snow regions.
Memory trick: Vents Rise Six Inches High, So Air Can Freely Fly.