Plumbing Pipe Systems & Materials

Question 1

Which pipe material is most commonly used for residential water supply lines in the US?

Accepted Answer

PEX

Answer

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?

Accepted Answer

1/4 inch per foot

Answer

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?

Accepted Answer

CPVC

Answer

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?

Accepted Answer

Blue

Answer

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?

Accepted Answer

PVC

Answer

PVC pipe requires a purple or clear primer to clean and soften the surface before solvent cement is applied for a proper bond.

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