Questions with Answers & Explanations | Study Guide for
Licensed Contractors | pdf
Question 1
Which type of pipe is commonly used for underground potable water distribution
in Wisconsin?
A. PVC
B. Ductile iron
C. HDPE (High-Density Polyethylene)
D. Copper
Answer: C
HDPE pipes are durable, flexible, and resistant to corrosion, making them ideal
for underground potable water systems.
Question 2
What is the minimum required slope for a sanitary sewer main to ensure proper
flow?
A. 0.1%
B. 0.25%
C. 0.5%
D. 1%
Answer: C
A minimum slope of 0.5% ensures self-cleansing velocity and prevents
blockages.
Question 3
Which OSHA regulation applies specifically to trenching and excavation safety?
A. 1910.120
B. 1910.134
,C. 1926 Subpart P
D. 1910.146
Answer: C
Subpart P of OSHA standards addresses trenching, shoring, and excavation
safety to prevent cave-ins.
Question 4
What is the primary purpose of a trench box?
A. To store equipment
B. To measure soil density
C. To protect workers from cave-ins
D. To divert water
Answer: C
Trench boxes provide a protective structure to prevent injury in deep
excavations.
Question 5
Which type of valve is best for controlling water flow in large-diameter utility
mains?
A. Ball valve
B. Globe valve
C. Gate valve
D. Check valve
Answer: C
Gate valves are ideal for full-flow control in large water mains.
Question 6
What is the most common method for jointing HDPE pipes in utility installations?
,A. Threaded coupling
B. Flanged connection
C. Butt fusion welding
D. Solvent cement
Answer: C
Butt fusion welding creates a seamless joint that is as strong as the pipe itself.
Question 7
Which type of backfill material should be used immediately around newly
installed water or sewer pipes?
A. Large rock
B. Native clay with debris
C. Select sand or fine granular material
D. Gravel larger than 3 inches
Answer: C
Select sand reduces pipe stress and provides proper support and compaction.
Question 8
Which tool is commonly used to verify the grade and alignment of utility pipes?
A. Tape measure
B. Laser level or transit
C. Plumb bob
D. Compass
Answer: B
Laser levels and transits provide precise elevation and alignment
measurements.
, Question 9
What is the standard color code for potable water lines in the U.S.?
A. Yellow
B. Green
C. Blue
D. Red
Answer: C
Blue identifies potable water to avoid confusion with other utilities.
Question 10
What is the typical depth for burying water mains to prevent freezing in
Wisconsin?
A. 12 inches
B. 24 inches
C. 36 inches
D. 48 inches
Answer: D
Water mains are typically buried below frost depth to prevent freezing.
Question 11
Which type of trench shoring is suitable for deep narrow excavations?
A. Sloping only
B. Benching only
C. Hydraulic or pneumatic trench shoring
D. Timber planking without support
Answer: C
Hydraulic shoring provides adjustable support for deep, narrow trenches.