ICC LP Gas Fitter Examination Practice Questions and
Answers Complete Study Guide
Question 1: What is the primary standard governing LP gas installations in the United States?
A) NFPA 70
B) NFPA 58
C) NFPA 101
D) IRC
Correct Answer: B) NFPA 58
Rationale: NFPA 58 is the Liquefied Petroleum Gas Code, which governs LP gas storage,
handling, and installation. NFPA 70 is the National Electrical Code, NFPA 101 is the Life Safety
Code, and the IRC is the International Residential Code.
Question 2: LP gas is primarily composed of which gases?
A) Oxygen and nitrogen
B) Methane only
C) Propane and butane
D) Hydrogen sulfide
Correct Answer: C) Propane and butane
Rationale: LP gas is mainly propane and butane, or a mixture of both hydrocarbons. Methane is
the primary component of natural gas, not LP gas.
Question 3: The vapor pressure of propane increases when temperature:
A) Decreases
,B) Increases
C) Remains constant
D) Becomes zero
Correct Answer: B) Increases
Rationale: As temperature rises, propane vapor pressure increases due to increased molecular
activity. This is why LP gas containers must never be filled completely to allow for liquid
expansion.
Question 4: The minimum burial depth for underground LP gas piping is generally:
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Correct Answer: C) 18 inches
Rationale: NFPA 58 requires at least 18 inches of cover for underground piping in most
installations to protect against accidental damage from excavation and surface activities.
Question 5: A pressure regulator on an LP system is used to:
A) Increase gas flow
B) Store gas
C) Reduce and control pressure
D) Ignite gas
Correct Answer: C) Reduce and control pressure
Rationale: Regulators reduce high tank pressure to usable appliance pressure. They are critical
safety devices that maintain consistent outlet pressure regardless of inlet pressure variations or
flow demand.
,Question 6: The ignition temperature of propane is approximately:
A) 100°F
B) 600–900°F
C) 1500°F
D) 2000°F
Correct Answer: B) 600–900°F
Rationale: Propane ignites within this temperature range depending on conditions. This
relatively low ignition temperature compared to other fuels makes proper handling and leak
prevention essential.
Question 7: A first-stage regulator typically reduces pressure to:
A) Tank pressure
B) 10 psi
C) Intermediate pressure (about 10 psi or less)
D) Zero pressure
Correct Answer: C) Intermediate pressure (about 10 psi or less)
Rationale: First-stage regulators reduce high tank pressure to intermediate levels, typically
around 10 psi or less. A second-stage regulator then reduces this to the final appliance
utilization pressure.
Question 8: The main shutoff valve on an LP system is used to:
A) Increase pressure
B) Stop gas flow to the system
C) Measure gas
D) Filter impurities
Correct Answer: B) Stop gas flow to the system
, Rationale: The main shutoff valve allows complete shutdown of gas supply for safety or
maintenance. It should be readily accessible and clearly labeled for emergency use.
Question 9: Copper tubing used in LP gas systems must be:
A) Soft plastic coated
B) Type K or approved equivalent
C) Galvanized
D) Aluminum
Correct Answer: B) Type K or approved equivalent
Rationale: Type K copper tubing has the thickest wall and is approved for underground LP gas
installations. Copper tubing must be rated for fuel gas service and properly protected against
corrosion and physical damage.
Question 10: What is the primary purpose of odorizing liquefied petroleum gas (LPG)?
A) To increase the pressure of the gas
B) To enhance the nutritional value of the gas
C) To enable detection of gas leaks by smell
D) To reduce the cost of the gas product
Correct Answer: C) To enable detection of gas leaks by smell
Rationale: Odorization is a critical safety measure required by law in most jurisdictions.
Mercaptan (ethyl mercaptan) is added to odorless LPG to produce a distinctive, pungent smell
(often described as rotten eggs or sulfur). This allows consumers and service personnel to
immediately detect even small leaks that could otherwise go unnoticed, preventing explosions,
asphyxiation, and property damage.
Question 11: According to ANSI standards, what is the minimum distance a relief valve vent
must be positioned from an air intake?
A) 3 feet
Answers Complete Study Guide
Question 1: What is the primary standard governing LP gas installations in the United States?
A) NFPA 70
B) NFPA 58
C) NFPA 101
D) IRC
Correct Answer: B) NFPA 58
Rationale: NFPA 58 is the Liquefied Petroleum Gas Code, which governs LP gas storage,
handling, and installation. NFPA 70 is the National Electrical Code, NFPA 101 is the Life Safety
Code, and the IRC is the International Residential Code.
Question 2: LP gas is primarily composed of which gases?
A) Oxygen and nitrogen
B) Methane only
C) Propane and butane
D) Hydrogen sulfide
Correct Answer: C) Propane and butane
Rationale: LP gas is mainly propane and butane, or a mixture of both hydrocarbons. Methane is
the primary component of natural gas, not LP gas.
Question 3: The vapor pressure of propane increases when temperature:
A) Decreases
,B) Increases
C) Remains constant
D) Becomes zero
Correct Answer: B) Increases
Rationale: As temperature rises, propane vapor pressure increases due to increased molecular
activity. This is why LP gas containers must never be filled completely to allow for liquid
expansion.
Question 4: The minimum burial depth for underground LP gas piping is generally:
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Correct Answer: C) 18 inches
Rationale: NFPA 58 requires at least 18 inches of cover for underground piping in most
installations to protect against accidental damage from excavation and surface activities.
Question 5: A pressure regulator on an LP system is used to:
A) Increase gas flow
B) Store gas
C) Reduce and control pressure
D) Ignite gas
Correct Answer: C) Reduce and control pressure
Rationale: Regulators reduce high tank pressure to usable appliance pressure. They are critical
safety devices that maintain consistent outlet pressure regardless of inlet pressure variations or
flow demand.
,Question 6: The ignition temperature of propane is approximately:
A) 100°F
B) 600–900°F
C) 1500°F
D) 2000°F
Correct Answer: B) 600–900°F
Rationale: Propane ignites within this temperature range depending on conditions. This
relatively low ignition temperature compared to other fuels makes proper handling and leak
prevention essential.
Question 7: A first-stage regulator typically reduces pressure to:
A) Tank pressure
B) 10 psi
C) Intermediate pressure (about 10 psi or less)
D) Zero pressure
Correct Answer: C) Intermediate pressure (about 10 psi or less)
Rationale: First-stage regulators reduce high tank pressure to intermediate levels, typically
around 10 psi or less. A second-stage regulator then reduces this to the final appliance
utilization pressure.
Question 8: The main shutoff valve on an LP system is used to:
A) Increase pressure
B) Stop gas flow to the system
C) Measure gas
D) Filter impurities
Correct Answer: B) Stop gas flow to the system
, Rationale: The main shutoff valve allows complete shutdown of gas supply for safety or
maintenance. It should be readily accessible and clearly labeled for emergency use.
Question 9: Copper tubing used in LP gas systems must be:
A) Soft plastic coated
B) Type K or approved equivalent
C) Galvanized
D) Aluminum
Correct Answer: B) Type K or approved equivalent
Rationale: Type K copper tubing has the thickest wall and is approved for underground LP gas
installations. Copper tubing must be rated for fuel gas service and properly protected against
corrosion and physical damage.
Question 10: What is the primary purpose of odorizing liquefied petroleum gas (LPG)?
A) To increase the pressure of the gas
B) To enhance the nutritional value of the gas
C) To enable detection of gas leaks by smell
D) To reduce the cost of the gas product
Correct Answer: C) To enable detection of gas leaks by smell
Rationale: Odorization is a critical safety measure required by law in most jurisdictions.
Mercaptan (ethyl mercaptan) is added to odorless LPG to produce a distinctive, pungent smell
(often described as rotten eggs or sulfur). This allows consumers and service personnel to
immediately detect even small leaks that could otherwise go unnoticed, preventing explosions,
asphyxiation, and property damage.
Question 11: According to ANSI standards, what is the minimum distance a relief valve vent
must be positioned from an air intake?
A) 3 feet
