Other Skilled Trades Pipefitting and Plumbing

Question 1

What is the minimum slope required for a residential drain pipe to ensure proper drainage per the IPC/UPC?

Accepted Answer

1/4 inch per foot

Answer

The International Plumbing Code requires a minimum slope of 1/4 inch per foot (2%) for drain lines 3 inches or less in diameter to ensure solids flow properly.

Question 2

What does the acronym PEX stand for in plumbing?

Accepted Answer

Cross-Linked Polyethylene

Answer

PEX stands for Cross-Linked Polyethylene, a flexible plastic tubing widely used in residential water supply systems for its freeze resistance and ease of installation.

Question 3

What is the purpose of a P-trap in a plumbing drain system?

Accepted Answer

To hold a water seal that prevents sewer gases from entering the building

Answer

A P-trap holds a water plug in its curved section that acts as a seal, blocking sewer gases from traveling back through the drain and into occupied spaces.

Question 4

Which pipe material requires the use of solvent cement (glue) for joining?

Accepted Answer

PVC and CPVC pipe

Answer

PVC and CPVC pipes are joined using solvent cement, which chemically welds the plastic surfaces together to form a permanent, watertight bond.

Question 5

What is the standard residential hot water temperature set point recommended by the US Department of Energy to balance scald prevention and Legionella control?

Accepted Answer

120°F

Answer

120°F is the recommended water heater set point — it prevents most scalding incidents while being hot enough to inhibit Legionella bacteria growth for most residential applications.

Other Skilled Trades Practice Test

Other Skilled Trades Practice Test

Other Skilled Trades Pipefitting and Plumbing