CSLB C-36 Plumbing ContractorRough-in PlumbingMedium
A plumbing contractor is installing a new drain, waste, and vent (DWV) system in a multi-story commercial building. A 4-inch vertical stack is being installed. What is the maximum allowable offset angle from the vertical for this 4-inch stack without being considered a horizontal offset requiring specific sizing adjustments?
- A30 degrees
- B15 degrees
- C60 degrees
- D45 degrees
Show answer & explanationAnswer & explanation
Correct answer: D. 45 degrees
The California Plumbing Code defines a vertical pipe as one installed in a vertical position or at an angle not exceeding 45 degrees from the vertical. Any angle greater than 45 degrees from the vertical is considered a horizontal pipe and may require different sizing or venting considerations.
Why the other options are wrong
- A. 30 degrees is well within the vertical definition.
- B. 15 degrees is well within the vertical definition.
- C. 60 degrees from vertical would be considered a horizontal offset, not a vertical stack.
Vertical Pipe Definition (DWV)
A plumbing code definition for a pipe's orientation, classifying it as vertical if its angle from true vertical does not exceed a specified limit.
- Affects sizing and venting requirements.
- Distinguishes vertical stacks from horizontal branches.
- Key for proper DWV system design.
Memory trick: Angles Are Always Important.