AL LP Gas Fitter Contractor Exam —
Practice Exam Practice Questions And
Correct Answers (Verified Answers) Plus
Rationales 2027 Q&A | Instant
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Q1. What is the primary purpose of a pressure regulator in an LP-gas piping
system?
A. To increase gas pressure
B. To reduce and control gas pressure
C. To remove moisture from the gas
D. To measure gas volume
Answer: B. To reduce and control gas pressure
Rationale: A regulator reduces upstream LP-gas pressure to the controlled
pressure required by the downstream piping and appliances and maintains
that pressure within its operating range.
,Q2. LP gas is primarily composed of which hydrocarbons?
A. Methane and ethane
B. Propane and butane
C. Hydrogen and oxygen
D. Carbon monoxide and methane
Answer: B. Propane and butane
Rationale: LP gas commonly consists primarily of propane, butane, or
mixtures of these hydrocarbons. Commercial LP gas specifications
determine the exact composition.
Q3. Why is an odorant added to LP gas?
A. To increase its heating value
B. To prevent freezing
C. To make leaks detectable by smell
D. To lower its vapor pressure
Answer: C. To make leaks detectable by smell
,Rationale: LP gas is naturally colorless and essentially odorless, so an
odorant is added to help people detect leaks before dangerous
concentrations develop.
Q4. Which property of LP gas is especially important when evaluating a leak?
A. It is lighter than air
B. It is heavier than air
C. It is nonflammable
D. It immediately dissolves in water
Answer: B. It is heavier than air
Rationale: LP-gas vapor is generally heavier than air and can accumulate
in low areas, pits, trenches, and other enclosed spaces.
Q5. What is the most appropriate first action when a strong LP-gas odor is
detected inside a building?
A. Turn on an exhaust fan
B. Operate electrical switches to locate the leak
C. Eliminate ignition sources and evacuate the area as appropriate
D. Light a burner to determine whether gas is present
, Answer: C. Eliminate ignition sources and evacuate the area as appropriate
Rationale: Ignition sources can ignite accumulated gas. The area should be
made safe, occupants protected, and qualified personnel or emergency
services contacted as necessary.
Q6. Which fitting is commonly used to change the direction of a gas-piping
run by 90 degrees?
A. Coupling
B. Elbow
C. Union
D. Bushing
Answer: B. Elbow
Rationale: An elbow is designed to change the direction of piping, with 90-
degree elbows commonly used for perpendicular changes in direction.
Q7. What is the primary purpose of a sediment trap in an LP-gas appliance
piping system?
A. Increase gas pressure
B. Collect debris and condensate before they enter the appliance
Practice Exam Practice Questions And
Correct Answers (Verified Answers) Plus
Rationales 2027 Q&A | Instant
Download Pdf
Q1. What is the primary purpose of a pressure regulator in an LP-gas piping
system?
A. To increase gas pressure
B. To reduce and control gas pressure
C. To remove moisture from the gas
D. To measure gas volume
Answer: B. To reduce and control gas pressure
Rationale: A regulator reduces upstream LP-gas pressure to the controlled
pressure required by the downstream piping and appliances and maintains
that pressure within its operating range.
,Q2. LP gas is primarily composed of which hydrocarbons?
A. Methane and ethane
B. Propane and butane
C. Hydrogen and oxygen
D. Carbon monoxide and methane
Answer: B. Propane and butane
Rationale: LP gas commonly consists primarily of propane, butane, or
mixtures of these hydrocarbons. Commercial LP gas specifications
determine the exact composition.
Q3. Why is an odorant added to LP gas?
A. To increase its heating value
B. To prevent freezing
C. To make leaks detectable by smell
D. To lower its vapor pressure
Answer: C. To make leaks detectable by smell
,Rationale: LP gas is naturally colorless and essentially odorless, so an
odorant is added to help people detect leaks before dangerous
concentrations develop.
Q4. Which property of LP gas is especially important when evaluating a leak?
A. It is lighter than air
B. It is heavier than air
C. It is nonflammable
D. It immediately dissolves in water
Answer: B. It is heavier than air
Rationale: LP-gas vapor is generally heavier than air and can accumulate
in low areas, pits, trenches, and other enclosed spaces.
Q5. What is the most appropriate first action when a strong LP-gas odor is
detected inside a building?
A. Turn on an exhaust fan
B. Operate electrical switches to locate the leak
C. Eliminate ignition sources and evacuate the area as appropriate
D. Light a burner to determine whether gas is present
, Answer: C. Eliminate ignition sources and evacuate the area as appropriate
Rationale: Ignition sources can ignite accumulated gas. The area should be
made safe, occupants protected, and qualified personnel or emergency
services contacted as necessary.
Q6. Which fitting is commonly used to change the direction of a gas-piping
run by 90 degrees?
A. Coupling
B. Elbow
C. Union
D. Bushing
Answer: B. Elbow
Rationale: An elbow is designed to change the direction of piping, with 90-
degree elbows commonly used for perpendicular changes in direction.
Q7. What is the primary purpose of a sediment trap in an LP-gas appliance
piping system?
A. Increase gas pressure
B. Collect debris and condensate before they enter the appliance
