Residential Building Inspector B1Building Planning and Life SafetyEasy
A residential building inspector is reviewing plans for a new single-family dwelling. The plans indicate that the dwelling will have a common laundry area. What is the minimum required diameter for the standpipe receptor into which the clothes washer discharge hose will empty?
- A2 inches
- B3 inches
- C1 1/4 inches
- D1 1/2 inches
Show answer & explanationAnswer & explanation
Correct answer: A. 2 inches
To prevent drain overflow and ensure proper drainage, the standpipe for a clothes washer discharge hose must have a minimum diameter as specified by the plumbing codes. This minimum diameter is 2 inches.
Why the other options are wrong
- B. This diameter is larger than required, but 2 inches is the specified minimum.
- C. This diameter is too small and would likely lead to overflow during discharge.
- D. While a common drain size, 1 1/2 inches is typically not sufficient for a clothes washer standpipe.
Clothes Washer Standpipe Diameter
The minimum internal diameter of the vertical pipe (standpipe) that receives the discharge water from a clothes washer, designed to prevent overflow and ensure efficient drainage.
- Prevents flooding from washer discharge.
- Specified by plumbing codes.
- Ensures adequate flow capacity.
Memory trick: Washer 'W' for 'Wide' (2 inches).