Plumbing Pipe Systems & Materials 1 — Questions and Answers
Question 1: Which pipe material is most commonly used for residential water supply lines in the US?
- CPVC
- Cast iron
- PEX (Correct answer)
- Galvanized steel
Correct answer: PEX
PEX (cross-linked polyethylene) is the most widely used pipe for residential water supply due to its flexibility and ease of installation.
Question 2: What is the minimum slope required for horizontal drain pipes 3 inches or less in diameter per the IPC?
- 1/8 inch per foot
- 1/4 inch per foot (Correct answer)
- 1/2 inch per foot
- 1 inch per foot
Correct answer: 1/4 inch per foot
The IPC requires a minimum slope of 1/4 inch per foot for horizontal drain pipes 3 inches or less in diameter to ensure proper drainage.
Question 3: Which pipe is rated for both hot and cold water supply lines?
- PVC
- CPVC (Correct answer)
- ABS
- Cast iron
Correct answer: CPVC
CPVC (chlorinated polyvinyl chloride) is rated for both hot and cold water supply lines, unlike standard PVC which is only rated for cold water.
Question 4: What is the standard color code for cold water supply lines using PEX tubing?
- Green
- Yellow
- Blue (Correct answer)
- White
Correct answer: Blue
Blue PEX tubing is the standard color code for cold water supply lines, while red is used for hot water.
Question 5: Which pipe material requires primer before solvent cement is applied?
- PEX
- ABS
- PVC (Correct answer)
- Copper
Correct answer: PVC
PVC pipe requires a purple or clear primer to clean and soften the surface before solvent cement is applied for a proper bond.
Question 6: What type of fitting connects two pipes of different materials, such as copper to CPVC?
- Union fitting
- Dielectric union
- Transition fitting (Correct answer)
- Reducing coupling
Correct answer: Transition fitting
A transition fitting is specifically designed to connect pipes made of different materials, ensuring a watertight seal between dissimilar pipe types.
Plumbing Pipe Systems & Materials 1
Which pipe material is most commonly used for residential water supply lines in the US?