South Carolina (SC) LP Gas Dealer &
Installer Practice Exam 200 Questions |
PSI LLR Licensing Test | NFPA 58 & NFPA
54 | Propane Installer Certification Prep |
Updated | Instant Pdf Download
Domain 1: LP Gas Properties & Hazards
1. The primary reason LP-Gas containers are painted a light, reflective color
(such as silver or white) is to:
A) Make the tank visible to delivery drivers at night
B) Prevent the steel from rusting
C) Minimize internal pressure increases caused by solar radiation
D) Identify the tank as containing non-medical gas
,,,,answer,,,,: C
Rationale: Dark colors absorb heat, causing the liquid propane to expand and
vapor pressure to rise dangerously. Light colors reflect heat, keeping pressure
below the safety relief valve setting and preventing unnecessary venting.
2. True or False: Liquid propane is heavier than water.
A) True
B) False
,,,,,answer,,,,: B
Rationale: The specific gravity of liquid propane is approximately 0.5, meaning it
is about half the weight of water and will float on top if spilled.
3. Which of the following best describes the flammable range of propane when
mixed with air?
A) 1.0% to 5.0%
B) 2.15% to 9.6%
C) 5.0% to 15.0%
D) 10% to 25%
,,,,answer,,,,: B
Rationale: Propane will ignite only when it constitutes between 2.15% and 9.6%
of the air volume. Below this range, the mixture is too lean; above, it is too rich to
burn.
4. Why does propane vapor present a significant explosion hazard in
basements and crawlspaces?
A) It is lighter than air and rises
B) It is heavier than air and accumulates in low places
C) It is chemically reactive with concrete
D) It dissolves in water and creates toxic fumes
,,,,answer,,,,: B
Rationale: Because propane vapor is heavier than air (specific gravity approx. 1.5-
2.0 compared to air at 1.0), it flows downward and accumulates in low places like
basements, crawlspaces, and pits, creating a significant explosion hazard.
5. LP-Gas is non-toxic but can cause death by:
A) Poisoning the blood
B) Asphyxiation (displacing oxygen)
C) Causing immediate cardiac arrest
D) Corrosive burns
,,,,,answer,,,,: B
Rationale: Propane is an asphyxiant. In high concentrations, it displaces the
oxygen in a room, leading to suffocation without adequate ventilation.
6. What is the Standard Temperature and Pressure (STP) volume relationship
of liquid propane to vapor?
A) 1 gallon of liquid = 10 gallons of vapor
B) 1 gallon of liquid = 93 cubic feet of vapor
C) *1 gallon of liquid = 270 gallons of vapor*
D) 1 gallon of liquid = 1 gallon of vapor
,,,,answer,,,,: C
Rationale: Propane expands dramatically when it changes from a liquid to a vapor.
One gallon of liquid propane expands to approximately 270 gallons of vapor,
which is why even small liquid leaks can create large dangerous vapor clouds.
7. Which of the following are physical properties of Propane (LP-Gas) that
affect installation safety? (Select all that apply)
A) Liquid is lighter than water (Specific Gravity 0.5)
B) Vapor is heavier than air (Specific Gravity 1.5 – 2.0)
C) It is odorless in its natural state
D) It is corrosive to galvanized steel
,,,,answer,,,,: A, B, C
Rationale: Propane liquid floats on water, vapor settles in low areas, and the gas is
naturally odorless—ethyl mercaptan is added for leak detection.
8. What is the boiling point of propane at atmospheric pressure?
A) –44°F
B) 0°F
C) 32°F
D) –10°F
, ,,,,answer,,,,: A
Rationale: Propane boils at -44°F at atmospheric pressure, which is why it
vaporizes rapidly when released from a pressurized container.
9. The term "Water Capacity" (w.c.) on a tank nameplate refers to:
A) How much water is in the tank
B) The total volume of the tank in pounds of water
C) The amount of propane the tank holds in gallons
D) The maximum pressure of the tank
,,,,answer,,,,: B
Rationale: Propane tanks are rated by their total volume in pounds of water. This
is used to calculate the 80% propane filling limit (e.g., a 100 lb. water capacity
tank holds 80 lbs. of propane).
10. Which of the following is considered the primary hazard of working with
LP-Gas?
A) Corrosion of tools
B) Explosion and fire
C) Frostbite
D) Chemical burns
,,,,answer,,,,: B
Rationale: While LP-Gas can cause frostbite (due to rapid evaporation), the
primary hazard is its flammability and ability to form explosive mixtures with air,
leading to fire and explosion.
Domain 2: Container & Cylinder Requirements (Q11-Q30)
Installer Practice Exam 200 Questions |
PSI LLR Licensing Test | NFPA 58 & NFPA
54 | Propane Installer Certification Prep |
Updated | Instant Pdf Download
Domain 1: LP Gas Properties & Hazards
1. The primary reason LP-Gas containers are painted a light, reflective color
(such as silver or white) is to:
A) Make the tank visible to delivery drivers at night
B) Prevent the steel from rusting
C) Minimize internal pressure increases caused by solar radiation
D) Identify the tank as containing non-medical gas
,,,,answer,,,,: C
Rationale: Dark colors absorb heat, causing the liquid propane to expand and
vapor pressure to rise dangerously. Light colors reflect heat, keeping pressure
below the safety relief valve setting and preventing unnecessary venting.
2. True or False: Liquid propane is heavier than water.
A) True
B) False
,,,,,answer,,,,: B
Rationale: The specific gravity of liquid propane is approximately 0.5, meaning it
is about half the weight of water and will float on top if spilled.
3. Which of the following best describes the flammable range of propane when
mixed with air?
A) 1.0% to 5.0%
B) 2.15% to 9.6%
C) 5.0% to 15.0%
D) 10% to 25%
,,,,answer,,,,: B
Rationale: Propane will ignite only when it constitutes between 2.15% and 9.6%
of the air volume. Below this range, the mixture is too lean; above, it is too rich to
burn.
4. Why does propane vapor present a significant explosion hazard in
basements and crawlspaces?
A) It is lighter than air and rises
B) It is heavier than air and accumulates in low places
C) It is chemically reactive with concrete
D) It dissolves in water and creates toxic fumes
,,,,answer,,,,: B
Rationale: Because propane vapor is heavier than air (specific gravity approx. 1.5-
2.0 compared to air at 1.0), it flows downward and accumulates in low places like
basements, crawlspaces, and pits, creating a significant explosion hazard.
5. LP-Gas is non-toxic but can cause death by:
A) Poisoning the blood
B) Asphyxiation (displacing oxygen)
C) Causing immediate cardiac arrest
D) Corrosive burns
,,,,,answer,,,,: B
Rationale: Propane is an asphyxiant. In high concentrations, it displaces the
oxygen in a room, leading to suffocation without adequate ventilation.
6. What is the Standard Temperature and Pressure (STP) volume relationship
of liquid propane to vapor?
A) 1 gallon of liquid = 10 gallons of vapor
B) 1 gallon of liquid = 93 cubic feet of vapor
C) *1 gallon of liquid = 270 gallons of vapor*
D) 1 gallon of liquid = 1 gallon of vapor
,,,,answer,,,,: C
Rationale: Propane expands dramatically when it changes from a liquid to a vapor.
One gallon of liquid propane expands to approximately 270 gallons of vapor,
which is why even small liquid leaks can create large dangerous vapor clouds.
7. Which of the following are physical properties of Propane (LP-Gas) that
affect installation safety? (Select all that apply)
A) Liquid is lighter than water (Specific Gravity 0.5)
B) Vapor is heavier than air (Specific Gravity 1.5 – 2.0)
C) It is odorless in its natural state
D) It is corrosive to galvanized steel
,,,,answer,,,,: A, B, C
Rationale: Propane liquid floats on water, vapor settles in low areas, and the gas is
naturally odorless—ethyl mercaptan is added for leak detection.
8. What is the boiling point of propane at atmospheric pressure?
A) –44°F
B) 0°F
C) 32°F
D) –10°F
, ,,,,answer,,,,: A
Rationale: Propane boils at -44°F at atmospheric pressure, which is why it
vaporizes rapidly when released from a pressurized container.
9. The term "Water Capacity" (w.c.) on a tank nameplate refers to:
A) How much water is in the tank
B) The total volume of the tank in pounds of water
C) The amount of propane the tank holds in gallons
D) The maximum pressure of the tank
,,,,answer,,,,: B
Rationale: Propane tanks are rated by their total volume in pounds of water. This
is used to calculate the 80% propane filling limit (e.g., a 100 lb. water capacity
tank holds 80 lbs. of propane).
10. Which of the following is considered the primary hazard of working with
LP-Gas?
A) Corrosion of tools
B) Explosion and fire
C) Frostbite
D) Chemical burns
,,,,answer,,,,: B
Rationale: While LP-Gas can cause frostbite (due to rapid evaporation), the
primary hazard is its flammability and ability to form explosive mixtures with air,
leading to fire and explosion.
Domain 2: Container & Cylinder Requirements (Q11-Q30)
