Journeyman Plumber ExamPlumbing Code and RegulationsHard
A plumber is installing a PVC drainage pipe in a non-combustible commercial building. According to the International Plumbing Code (IPC), what is the maximum spacing for horizontal supports for 3-inch (75 mm) diameter PVC drainage pipe?
- A2 feet (610 mm)
- B5 feet (1524 mm)
- C4 feet (1219 mm)
- D3 feet (914 mm)
Show answer & explanationAnswer & explanation
Correct answer: C. 4 feet (1219 mm)
The IPC specifies maximum support spacing for various pipe materials and sizes to prevent sagging and ensure proper drainage pitch. For 3-inch (75 mm) horizontal PVC drainage pipe, the maximum support spacing is 4 feet (1219 mm). This is crucial for maintaining the pipe's structural integrity and functionality over time.
Why the other options are wrong
- A. 2 feet is too close for a 3-inch PVC pipe; while it would provide support, it's not the maximum allowed.
- B. 5 feet would exceed the maximum allowable spacing for 3-inch PVC, leading to potential sagging and structural issues.
- D. 3 feet is less than the maximum allowed for 3-inch PVC, often associated with smaller diameters or other materials.
PVC Drainage Pipe Support Spacing
The maximum allowable distance between hangers or supports for horizontal PVC drainage piping to prevent sagging.
- Varies by pipe material and diameter.
- Ensures proper slope and prevents structural stress.
- Mandated by plumbing codes.
Memory trick: PVC three-inch, horizontal run, four feet of support, gets the job done.