CO Journeyman Plumber Exam
Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant
Download Pdf.
1. Which component of a plumbing drainage system is primarily
responsible for protecting the water trap seal from siphonage and
backpressure by allowing air to enter or leave the drainage piping
system?
A. Cleanout
B. Vent system
C. Water hammer arrestor
D. Pressure-reducing valve
The vent system equalizes pressure within the drainage piping and
protects trap seals from siphonage, backpressure, and other pressure
disturbances.
2. In a typical sanitary drainage system, what is the primary purpose of
a P-trap installed beneath a plumbing fixture?
A. To increase drainage velocity
B. To prevent pipe corrosion
C. To maintain a water seal that prevents sewer gases from entering the
,building
D. To prevent water hammer
A P-trap retains a quantity of water after the fixture drains, creating a
barrier against sewer gases and odors entering occupied spaces.
3. When sizing a building sanitary drainage system, which
measurement is commonly used to represent the probable
discharge demand of plumbing fixtures?
A. Gallons per minute
B. Pounds per square inch
C. Drainage fixture units
D. Cubic feet per minute
Drainage fixture units, or DFUs, provide a standardized method for
assigning probable drainage loads to plumbing fixtures and appliances.
4. What is the primary function of a building sewer?
A. To distribute potable water throughout a building
B. To collect stormwater from the roof
C. To carry sanitary drainage from the building to the public sewer or
private sewage disposal system
D. To supply water to fire sprinklers
The building sewer conveys sanitary wastewater from the building
drainage system to the point of disposal or connection with the public
sewer.
, 5. Which fitting is generally preferred when changing the direction of
horizontal drainage flow because it provides a smoother transition
than a standard sanitary tee?
A. Straight coupling
B. Wye fitting
C. Reducing bushing
D. Cap
A wye provides a gradual directional change and is well suited for
horizontal drainage connections because it promotes smoother flow.
6. What is the principal reason plumbing codes limit the developed
length between a fixture trap and its vent connection?
A. To reduce water pressure
B. To increase fixture capacity
C. To protect the trap seal from excessive pressure fluctuations and
siphonage
D. To prevent thermal expansion
Excessive trap-arm length can allow pressure changes and excessive
drainage flow to disturb or siphon the trap seal.
7. A plumbing vent terminates through a roof primarily to accomplish
which function?
A. Increase potable-water pressure
B. Discharge sewer gases and provide atmospheric pressure to the
drainage system
, C. Remove sediment from the building sewer
D. Increase hot-water temperature
A vent terminal communicates with the atmosphere, allowing the
drainage system to breathe while providing a safe path for sewer gases
to disperse above the building.
8. Which condition is most likely to cause a trap to lose its water seal
because of negative pressure in the drainage system?
A. Backpressure
B. Thermal expansion
C. Siphonage
D. Corrosion
Siphonage occurs when negative pressure draws water out of a trap,
potentially allowing sewer gases to pass into the building.
9. What is the primary purpose of a cleanout in a sanitary drainage
system?
A. To increase water pressure
B. To regulate water temperature
C. To provide access for inspection and removal of obstructions
D. To prevent cross-connection
Cleanouts provide accessible openings through which drainage piping
can be inspected, rodded, or otherwise cleared of blockages.
Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant
Download Pdf.
1. Which component of a plumbing drainage system is primarily
responsible for protecting the water trap seal from siphonage and
backpressure by allowing air to enter or leave the drainage piping
system?
A. Cleanout
B. Vent system
C. Water hammer arrestor
D. Pressure-reducing valve
The vent system equalizes pressure within the drainage piping and
protects trap seals from siphonage, backpressure, and other pressure
disturbances.
2. In a typical sanitary drainage system, what is the primary purpose of
a P-trap installed beneath a plumbing fixture?
A. To increase drainage velocity
B. To prevent pipe corrosion
C. To maintain a water seal that prevents sewer gases from entering the
,building
D. To prevent water hammer
A P-trap retains a quantity of water after the fixture drains, creating a
barrier against sewer gases and odors entering occupied spaces.
3. When sizing a building sanitary drainage system, which
measurement is commonly used to represent the probable
discharge demand of plumbing fixtures?
A. Gallons per minute
B. Pounds per square inch
C. Drainage fixture units
D. Cubic feet per minute
Drainage fixture units, or DFUs, provide a standardized method for
assigning probable drainage loads to plumbing fixtures and appliances.
4. What is the primary function of a building sewer?
A. To distribute potable water throughout a building
B. To collect stormwater from the roof
C. To carry sanitary drainage from the building to the public sewer or
private sewage disposal system
D. To supply water to fire sprinklers
The building sewer conveys sanitary wastewater from the building
drainage system to the point of disposal or connection with the public
sewer.
, 5. Which fitting is generally preferred when changing the direction of
horizontal drainage flow because it provides a smoother transition
than a standard sanitary tee?
A. Straight coupling
B. Wye fitting
C. Reducing bushing
D. Cap
A wye provides a gradual directional change and is well suited for
horizontal drainage connections because it promotes smoother flow.
6. What is the principal reason plumbing codes limit the developed
length between a fixture trap and its vent connection?
A. To reduce water pressure
B. To increase fixture capacity
C. To protect the trap seal from excessive pressure fluctuations and
siphonage
D. To prevent thermal expansion
Excessive trap-arm length can allow pressure changes and excessive
drainage flow to disturb or siphon the trap seal.
7. A plumbing vent terminates through a roof primarily to accomplish
which function?
A. Increase potable-water pressure
B. Discharge sewer gases and provide atmospheric pressure to the
drainage system
, C. Remove sediment from the building sewer
D. Increase hot-water temperature
A vent terminal communicates with the atmosphere, allowing the
drainage system to breathe while providing a safe path for sewer gases
to disperse above the building.
8. Which condition is most likely to cause a trap to lose its water seal
because of negative pressure in the drainage system?
A. Backpressure
B. Thermal expansion
C. Siphonage
D. Corrosion
Siphonage occurs when negative pressure draws water out of a trap,
potentially allowing sewer gases to pass into the building.
9. What is the primary purpose of a cleanout in a sanitary drainage
system?
A. To increase water pressure
B. To regulate water temperature
C. To provide access for inspection and removal of obstructions
D. To prevent cross-connection
Cleanouts provide accessible openings through which drainage piping
can be inspected, rodded, or otherwise cleared of blockages.
