South Carolina LP Gas Dealer/Installer Actual Practice
Exam: 200 Questions with Bold Answers &
Explanations | instant pdf download
Introduction
This comprehensive practice exam is designed for candidates preparing for the South
Carolina LP Gas Dealer/Installer licensing examination administered through PSI and
regulated by the SC Department of Labor, Licensing and Regulation (LLR) - Liquefied
Petroleum Gas Board .
Key Topics Covered
Propane properties and composition
Tank siting and installation distances
Piping materials and pressure testing
Regulator systems and venting
Cylinder filling and requalification
Appliance installation and combustion air
SC administrative regulations
Domain 1: Propane Properties & Basic Chemistry (Questions 1-25)
1. LP gas is primarily composed of:
A. Butane and propane
B. Methane only
C. Ethane and methane
D. Hydrogen and oxygen
Rationale: LP gas (Liquefied Petroleum Gas) is predominantly a mixture of propane
and butane. Natural gas is primarily methane.
,2. What is the boiling point of propane at atmospheric pressure?
A. –44°F
B. 0°F
C. 32°F
D. –10°F
*Rationale: Propane boils at -44°F (-42°C) at atmospheric pressure, which is why it
vaporizes immediately when released from a pressurized container. *
3. The odorant added to propane for leak detection is:
A. Sulfur dioxide
B. Ethyl mercaptan
C. Carbon monoxide
D. Methyl chloride
Rationale: Propane is naturally odorless. Ethyl mercaptan is added at a rate of
approximately 1 lb per 10,000 gallons to give propane its distinctive "rotten egg"
smell for leak detection.
4. One gallon of propane contains approximately how many BTUs?
A. 50,000 BTUs
B. 91,500 BTUs
C. 110,000 BTUs
D. 25,000 BTUs
Rationale: A gallon of propane contains approximately 91,500 BTUs (British Thermal
Units) of energy content.
5. The specific gravity of liquid propane is approximately:
A. 0.50
B. 1.00
C. 1.50
D. 2.00
Rationale: Liquid propane is about half the weight of water (specific gravity 0.50),
meaning it will float on top of water if spilled.
6. LP-gas is non-toxic but can cause death by:
A. Poisoning the blood
B. Asphyxiation (displacing oxygen)
C. Speeding up the heart rate
D. Causing blindness
Rationale: Propane is an asphyxiant; in high concentrations, it displaces oxygen in a
confined space, leading to suffocation.
,7. The vapor pressure of propane increases as:
A. Tank size increases
B. Temperature increases
C. Tank pressure decreases
D. Altitude decreases
Rationale: Propane vapor pressure is directly related to temperature—higher
temperatures create higher vapor pressure inside the container.
8. Propane gas is heavier than air. What is its approximate vapor density?
A. 0.5 (lighter than air)
B. 1.5 (heavier than air)
C. 1.0 (same as air)
D. 2.0 (much heavier than air)
*Rationale: Propane vapor is approximately 1.5 times heavier than air, causing it to settle in
low-lying areas rather than dissipating upward. *
9. Which factor affects propane vaporization rate the most?
A. Tank color
B. Ambient temperature and liquid surface area
C. Altitude only
D. Regulator type
Rationale: The rate at which liquid propane vaporizes depends primarily on ambient
temperature and the surface area of the liquid exposed to heat.
10. The term "BTU" stands for:
A. British Thermal Unit
B. Boiler Test Unit
C. Basic Temperature Unit
D. Burner Thermal Usage
Rationale: A BTU is the amount of heat required to raise the temperature of one
pound of water by one degree Fahrenheit.
11. Propane in its liquid state will expand approximately how much for every 10°F
temperature increase?
A. 0.5%
B. 1%
C. 1.5%
D. 3%
Rationale: Liquid propane expands significantly with temperature increases, which is
why containers are only filled to 80% capacity.
, 12. The primary safety concern when handling propane is:
A. Corrosion
B. Pressure and flammability
C. Noise
D. Freezing point
Rationale: Propane is both flammable and stored under pressure, creating fire and
explosion hazards if not handled properly.
13. Which gas is heavier: propane vapor or natural gas?
A. Propane vapor is heavier
B. Natural gas is heavier
C. They have the same density
D. Neither is heavier than air
Rationale: Propane vapor is 1.5 times heavier than air, while natural gas (methane) is
lighter than air and rises.
14. At what temperature does water vapor in a propane system freeze and potentially
cause regulator freeze-up?
A. 32°F
B. Below 32°F (freezing conditions)
C. 0°F
D. -44°F
Rationale: Moisture in propane systems can freeze at 32°F, blocking orifices and
causing regulator malfunction in cold weather.
15. One pound of propane contains approximately how many BTUs?
A. 10,000 BTUs
B. 21,500 BTUs
C. 50,000 BTUs
D. 91,500 BTUs
Rationale: One pound of propane contains approximately 21,500 BTUs. One gallon
weighs about 4.2 pounds.
16. Propane is stored as a liquid under pressure. At 70°F, the vapor pressure of
propane is approximately:
A. 50 psi
B. 110 psi
C. 200 psi
D. 300 psi
*Rationale: At 70°F, propane's vapor pressure is approximately 110-120 psi, which is why
containers must be rated for higher pressures. *
Exam: 200 Questions with Bold Answers &
Explanations | instant pdf download
Introduction
This comprehensive practice exam is designed for candidates preparing for the South
Carolina LP Gas Dealer/Installer licensing examination administered through PSI and
regulated by the SC Department of Labor, Licensing and Regulation (LLR) - Liquefied
Petroleum Gas Board .
Key Topics Covered
Propane properties and composition
Tank siting and installation distances
Piping materials and pressure testing
Regulator systems and venting
Cylinder filling and requalification
Appliance installation and combustion air
SC administrative regulations
Domain 1: Propane Properties & Basic Chemistry (Questions 1-25)
1. LP gas is primarily composed of:
A. Butane and propane
B. Methane only
C. Ethane and methane
D. Hydrogen and oxygen
Rationale: LP gas (Liquefied Petroleum Gas) is predominantly a mixture of propane
and butane. Natural gas is primarily methane.
,2. What is the boiling point of propane at atmospheric pressure?
A. –44°F
B. 0°F
C. 32°F
D. –10°F
*Rationale: Propane boils at -44°F (-42°C) at atmospheric pressure, which is why it
vaporizes immediately when released from a pressurized container. *
3. The odorant added to propane for leak detection is:
A. Sulfur dioxide
B. Ethyl mercaptan
C. Carbon monoxide
D. Methyl chloride
Rationale: Propane is naturally odorless. Ethyl mercaptan is added at a rate of
approximately 1 lb per 10,000 gallons to give propane its distinctive "rotten egg"
smell for leak detection.
4. One gallon of propane contains approximately how many BTUs?
A. 50,000 BTUs
B. 91,500 BTUs
C. 110,000 BTUs
D. 25,000 BTUs
Rationale: A gallon of propane contains approximately 91,500 BTUs (British Thermal
Units) of energy content.
5. The specific gravity of liquid propane is approximately:
A. 0.50
B. 1.00
C. 1.50
D. 2.00
Rationale: Liquid propane is about half the weight of water (specific gravity 0.50),
meaning it will float on top of water if spilled.
6. LP-gas is non-toxic but can cause death by:
A. Poisoning the blood
B. Asphyxiation (displacing oxygen)
C. Speeding up the heart rate
D. Causing blindness
Rationale: Propane is an asphyxiant; in high concentrations, it displaces oxygen in a
confined space, leading to suffocation.
,7. The vapor pressure of propane increases as:
A. Tank size increases
B. Temperature increases
C. Tank pressure decreases
D. Altitude decreases
Rationale: Propane vapor pressure is directly related to temperature—higher
temperatures create higher vapor pressure inside the container.
8. Propane gas is heavier than air. What is its approximate vapor density?
A. 0.5 (lighter than air)
B. 1.5 (heavier than air)
C. 1.0 (same as air)
D. 2.0 (much heavier than air)
*Rationale: Propane vapor is approximately 1.5 times heavier than air, causing it to settle in
low-lying areas rather than dissipating upward. *
9. Which factor affects propane vaporization rate the most?
A. Tank color
B. Ambient temperature and liquid surface area
C. Altitude only
D. Regulator type
Rationale: The rate at which liquid propane vaporizes depends primarily on ambient
temperature and the surface area of the liquid exposed to heat.
10. The term "BTU" stands for:
A. British Thermal Unit
B. Boiler Test Unit
C. Basic Temperature Unit
D. Burner Thermal Usage
Rationale: A BTU is the amount of heat required to raise the temperature of one
pound of water by one degree Fahrenheit.
11. Propane in its liquid state will expand approximately how much for every 10°F
temperature increase?
A. 0.5%
B. 1%
C. 1.5%
D. 3%
Rationale: Liquid propane expands significantly with temperature increases, which is
why containers are only filled to 80% capacity.
, 12. The primary safety concern when handling propane is:
A. Corrosion
B. Pressure and flammability
C. Noise
D. Freezing point
Rationale: Propane is both flammable and stored under pressure, creating fire and
explosion hazards if not handled properly.
13. Which gas is heavier: propane vapor or natural gas?
A. Propane vapor is heavier
B. Natural gas is heavier
C. They have the same density
D. Neither is heavier than air
Rationale: Propane vapor is 1.5 times heavier than air, while natural gas (methane) is
lighter than air and rises.
14. At what temperature does water vapor in a propane system freeze and potentially
cause regulator freeze-up?
A. 32°F
B. Below 32°F (freezing conditions)
C. 0°F
D. -44°F
Rationale: Moisture in propane systems can freeze at 32°F, blocking orifices and
causing regulator malfunction in cold weather.
15. One pound of propane contains approximately how many BTUs?
A. 10,000 BTUs
B. 21,500 BTUs
C. 50,000 BTUs
D. 91,500 BTUs
Rationale: One pound of propane contains approximately 21,500 BTUs. One gallon
weighs about 4.2 pounds.
16. Propane is stored as a liquid under pressure. At 70°F, the vapor pressure of
propane is approximately:
A. 50 psi
B. 110 psi
C. 200 psi
D. 300 psi
*Rationale: At 70°F, propane's vapor pressure is approximately 110-120 psi, which is why
containers must be rated for higher pressures. *
