CSLB C-36 Plumbing ContractorRough-in PlumbingMedium
A plumbing contractor is installing a new drain, waste, and vent (DWV) system for a commercial kitchen. The contractor needs to connect a 4-inch horizontal drain pipe to a new 4-inch vertical stack. What is the maximum permissible angle for this connection relative to the vertical stack?
- A90 degrees
- B22.5 degrees
- C60 degrees
- D45 degrees
Show answer & explanationAnswer & explanation
Correct answer: D. 45 degrees
Connections of horizontal drainage pipes to vertical stacks must be made at an angle no greater than 45 degrees from the vertical to ensure proper flow and prevent blockages.
Why the other options are wrong
- A. A 90-degree connection directly into a vertical stack from a horizontal drain is prohibited as it causes immediate turbulence and poor drainage.
- B. This angle is too shallow for a horizontal to vertical connection and is typically used for changes in direction in horizontal runs.
- C. This angle is too steep and would impede proper drainage, potentially causing stoppages.
Horizontal to Vertical Drain Connection Angle
The maximum angle at which a horizontal drainage pipe can connect to a vertical stack to ensure proper waste flow.
- Ensures effective drainage
- Prevents turbulence and blockages
- Typically 45 degrees or less from the vertical
Memory trick: Smooth flow ensures no clog, like water down a slide, not a cliff.