300-question practice set is compiled from verified
student study guides, third-party exam-preparation
materials, and the official Railroad Commission of Texas
LP-Gas Examination Study Guides.
Section 1: LP-Gas Fundamentals (Questions 1–50)
Question 1: What is the primary purpose of the Texas RRC Engine Fuel examination?
A) To authorize filling LP-gas motor fuel containers
B) To qualify an individual to install LP-gas motor or mobile fuel containers, cylinders, and
systems and replace container valves on motorized vehicles
C) To certify individuals to operate LP-gas transports
D) To license LP-gas retail dealers
Answer: B
*Rationale:* The Engine Fuel examination specifically qualifies individuals to install LP-gas
motor or mobile fuel containers, cylinders, and LP-gas systems and replace container valves on
motorized vehicles, including trailers, catering trucks, mobile kitchens, tar kettles, and similar
vehicles.
Question 2: Which activity is NOT authorized by the Engine Fuel certification?
A) Installing LP-gas motor fuel containers
B) Replacing container valves
C) Filling LP-gas motor or mobile fuel containers
D) Installing LP-gas systems on non-road vehicles
Answer: C
*Rationale:* The Engine Fuel examination does not authorize an individual to fill LP-gas motor
or mobile fuel containers.
Question 3: Which NFPA code specifically governs the safe handling and storage of liquefied
petroleum gas (LP-Gas)?
A) NFPA 30
B) NFPA 58
C) NFPA 70E
D) NFPA 13
Answer: B
*Rationale:* NFPA 58, the Liquefied Petroleum Gas Code, provides the comprehensive safety
requirements for LP-Gas installation, storage, and use.
,Question 4: A Category L license permits an individual to:
A) Install residential natural-gas piping only
B) Service, repair, and install LP-Gas equipment and containers
C) Manufacture LP-Gas cylinders
D) Conduct electrical work on LP-Gas appliances
Answer: B
*Rationale:* The Category L license authorizes holders to work on LP-Gas systems, including
installation, maintenance, and repair of equipment and containers.
Question 5: The expansion ratio of liquid propane to vapor at 21 °C (70 °F) is approximately:
A) 1:30
B) 1:150
C) 1:270
D) 1:500
Answer: C
*Rationale:* Propane expands roughly 270 times when it vaporizes at ambient temperature, a
critical factor in container sizing and pressure calculations.
Question 6: Which chemical is most commonly used as an odorant for propane?
A) Ammonia
B) Ethyl mercaptan
C) Hydrogen sulfide
D) Chlorine
Answer: B
*Rationale:* Ethyl mercaptan (also called ethanethiol) imparts a strong "rotten-egg" odor to
otherwise odorless propane, aiding leak detection.
Question 7: The Lower Explosive Limit (LEL) for propane in air is about:
A) 0.5 % volume
B) 2.1 % volume
C) 10 % volume
D) 15 % volume
Answer: B
*Rationale:* The LEL for propane in air is approximately 2.1% by volume.
Question 8: What is the primary hazard associated with LP-gas?
A) It is toxic and causes poisoning
B) It is flammable and can ignite or explode
C) It is corrosive and damages equipment
D) It is radioactive
,Answer: B
*Rationale:* LP-gas is highly flammable. Fuel-gas work requires immediate control of ignition,
pressure, and release hazards before troubleshooting continues.
Question 9: LP-gas is stored as a liquid under pressure. What happens when pressure is
released?
A) It remains a liquid
B) It expands into a vapor that is heavier than air
C) It expands into a vapor that is lighter than air
D) It solidifies
Answer: B
*Rationale:* When LP-gas pressure is released, the liquid vaporizes and the vapor is heavier
than air, which means it will settle in low areas such as basements, pits, or ground level.
Question 10: What is the correct air-to-fuel ratio for complete combustion of LP-gas?
A) 5:1
B) 10:1
C) 15.5:1
D) 25:1
Answer: C
*Rationale:* The ideal air-to-fuel ratio for LP-gas is approximately 15.5:1 for complete
combustion.
Question 11: Which document provides the official study guide for the Texas LP-Gas
examinations?
A) NFPA 70
B) TEXAS LP-GAS EXAMINATION STUDY GUIDE
C) ASME Section VIII
D) DOT 49 CFR
Answer: B
*Rationale:* The Railroad Commission of Texas publishes the TEXAS LP-GAS EXAMINATION
STUDY GUIDE for all employee-level LP-gas qualifying examinations.
Question 12: What are the three books referenced for LP-gas examination preparation in
Texas?
A) LP-Gas Safety Rules (Texas RRC), NFPA 58, and NFPA 54
B) ASME, OSHA, and EPA regulations
C) DOT, FAA, and FRA regulations
D) Texas Statutes, Federal Register, and Local Codes
, Answer: A
*Rationale:* The examination tests knowledge found in LP-Gas Safety Rules (Texas Railroad
Commission), NFPA 58 Liquefied Petroleum Gas Code, and other applicable standards.
Question 13: What is the minimum passing grade for LP-gas examinations in Texas?
A) 60 percent
B) 70 percent
C) 75 percent
D) 80 percent
Answer: C
*Rationale:* The minimum passing grade is 75 percent on all LP-gas examinations.
Question 14: Where may an individual take the LP-gas qualifying examination without
pre-registering?
A) Any RRC field office
B) Austin at the AFS Training Center
C) Any community college
D) Only online
Answer: B
*Rationale:* Individuals may take any LP-gas qualifying examination in Austin without
pre-registering at the AFS Training Center on any business day from 8:00 a.m. to 12:00 noon.
Question 15: Which agency has primary oversight of LP-gas safety compliance in Texas?
A) EPA only
B) Texas Department of Transportation
C) Texas Railroad Commission
D) Federal Energy Regulatory Commission only
Answer: C
*Rationale:* The Texas Railroad Commission has primary oversight of oil and gas safety
compliance, including LP-gas.
Question 16: What is the primary responsibility of the Railroad Commission of Texas regarding
LP-gas operations?
A) Setting prices for LP-gas
B) Regulating the safe installation, transport, and service of LP-gas
C) Marketing LP-gas to consumers
D) Manufacturing LP-gas equipment
Answer: B
*Rationale:* The RRC is responsible for regulating LP-gas operations to ensure public safety
through installation, transport, and service standards.
student study guides, third-party exam-preparation
materials, and the official Railroad Commission of Texas
LP-Gas Examination Study Guides.
Section 1: LP-Gas Fundamentals (Questions 1–50)
Question 1: What is the primary purpose of the Texas RRC Engine Fuel examination?
A) To authorize filling LP-gas motor fuel containers
B) To qualify an individual to install LP-gas motor or mobile fuel containers, cylinders, and
systems and replace container valves on motorized vehicles
C) To certify individuals to operate LP-gas transports
D) To license LP-gas retail dealers
Answer: B
*Rationale:* The Engine Fuel examination specifically qualifies individuals to install LP-gas
motor or mobile fuel containers, cylinders, and LP-gas systems and replace container valves on
motorized vehicles, including trailers, catering trucks, mobile kitchens, tar kettles, and similar
vehicles.
Question 2: Which activity is NOT authorized by the Engine Fuel certification?
A) Installing LP-gas motor fuel containers
B) Replacing container valves
C) Filling LP-gas motor or mobile fuel containers
D) Installing LP-gas systems on non-road vehicles
Answer: C
*Rationale:* The Engine Fuel examination does not authorize an individual to fill LP-gas motor
or mobile fuel containers.
Question 3: Which NFPA code specifically governs the safe handling and storage of liquefied
petroleum gas (LP-Gas)?
A) NFPA 30
B) NFPA 58
C) NFPA 70E
D) NFPA 13
Answer: B
*Rationale:* NFPA 58, the Liquefied Petroleum Gas Code, provides the comprehensive safety
requirements for LP-Gas installation, storage, and use.
,Question 4: A Category L license permits an individual to:
A) Install residential natural-gas piping only
B) Service, repair, and install LP-Gas equipment and containers
C) Manufacture LP-Gas cylinders
D) Conduct electrical work on LP-Gas appliances
Answer: B
*Rationale:* The Category L license authorizes holders to work on LP-Gas systems, including
installation, maintenance, and repair of equipment and containers.
Question 5: The expansion ratio of liquid propane to vapor at 21 °C (70 °F) is approximately:
A) 1:30
B) 1:150
C) 1:270
D) 1:500
Answer: C
*Rationale:* Propane expands roughly 270 times when it vaporizes at ambient temperature, a
critical factor in container sizing and pressure calculations.
Question 6: Which chemical is most commonly used as an odorant for propane?
A) Ammonia
B) Ethyl mercaptan
C) Hydrogen sulfide
D) Chlorine
Answer: B
*Rationale:* Ethyl mercaptan (also called ethanethiol) imparts a strong "rotten-egg" odor to
otherwise odorless propane, aiding leak detection.
Question 7: The Lower Explosive Limit (LEL) for propane in air is about:
A) 0.5 % volume
B) 2.1 % volume
C) 10 % volume
D) 15 % volume
Answer: B
*Rationale:* The LEL for propane in air is approximately 2.1% by volume.
Question 8: What is the primary hazard associated with LP-gas?
A) It is toxic and causes poisoning
B) It is flammable and can ignite or explode
C) It is corrosive and damages equipment
D) It is radioactive
,Answer: B
*Rationale:* LP-gas is highly flammable. Fuel-gas work requires immediate control of ignition,
pressure, and release hazards before troubleshooting continues.
Question 9: LP-gas is stored as a liquid under pressure. What happens when pressure is
released?
A) It remains a liquid
B) It expands into a vapor that is heavier than air
C) It expands into a vapor that is lighter than air
D) It solidifies
Answer: B
*Rationale:* When LP-gas pressure is released, the liquid vaporizes and the vapor is heavier
than air, which means it will settle in low areas such as basements, pits, or ground level.
Question 10: What is the correct air-to-fuel ratio for complete combustion of LP-gas?
A) 5:1
B) 10:1
C) 15.5:1
D) 25:1
Answer: C
*Rationale:* The ideal air-to-fuel ratio for LP-gas is approximately 15.5:1 for complete
combustion.
Question 11: Which document provides the official study guide for the Texas LP-Gas
examinations?
A) NFPA 70
B) TEXAS LP-GAS EXAMINATION STUDY GUIDE
C) ASME Section VIII
D) DOT 49 CFR
Answer: B
*Rationale:* The Railroad Commission of Texas publishes the TEXAS LP-GAS EXAMINATION
STUDY GUIDE for all employee-level LP-gas qualifying examinations.
Question 12: What are the three books referenced for LP-gas examination preparation in
Texas?
A) LP-Gas Safety Rules (Texas RRC), NFPA 58, and NFPA 54
B) ASME, OSHA, and EPA regulations
C) DOT, FAA, and FRA regulations
D) Texas Statutes, Federal Register, and Local Codes
, Answer: A
*Rationale:* The examination tests knowledge found in LP-Gas Safety Rules (Texas Railroad
Commission), NFPA 58 Liquefied Petroleum Gas Code, and other applicable standards.
Question 13: What is the minimum passing grade for LP-gas examinations in Texas?
A) 60 percent
B) 70 percent
C) 75 percent
D) 80 percent
Answer: C
*Rationale:* The minimum passing grade is 75 percent on all LP-gas examinations.
Question 14: Where may an individual take the LP-gas qualifying examination without
pre-registering?
A) Any RRC field office
B) Austin at the AFS Training Center
C) Any community college
D) Only online
Answer: B
*Rationale:* Individuals may take any LP-gas qualifying examination in Austin without
pre-registering at the AFS Training Center on any business day from 8:00 a.m. to 12:00 noon.
Question 15: Which agency has primary oversight of LP-gas safety compliance in Texas?
A) EPA only
B) Texas Department of Transportation
C) Texas Railroad Commission
D) Federal Energy Regulatory Commission only
Answer: C
*Rationale:* The Texas Railroad Commission has primary oversight of oil and gas safety
compliance, including LP-gas.
Question 16: What is the primary responsibility of the Railroad Commission of Texas regarding
LP-gas operations?
A) Setting prices for LP-gas
B) Regulating the safe installation, transport, and service of LP-gas
C) Marketing LP-gas to consumers
D) Manufacturing LP-gas equipment
Answer: B
*Rationale:* The RRC is responsible for regulating LP-gas operations to ensure public safety
through installation, transport, and service standards.
