South Carolina Propane Service
Technician License Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. A common method used to detect a small leak in a propane system is
to apply:
A. A flame near the joint for visual detection
B. Soapy water solution at the connection points
C. A magnetized probe around the valve body
D. Compressed air with lubricant spray
Soapy water creates bubbles at the leak site, providing a safe,
reliable method to visually identify small leaks in propane systems.
2. The primary purpose of the relief valve on a propane cylinder is to:
A. Regulate delivery pressure to the appliance
B. Prevent vacuum conditions in the tank
C. Release excess internal pressure to prevent rupture
D. Facilitate quicker filling at the bulk plant
Relief valves prevent tank rupture by discharging vapor when
internal pressure exceeds safe limits.
3. The National Fire Protection Association (NFPA) standard that governs
the storage and handling of liquefied petroleum gases is:
A. NFPA 30
B. NFPA 58
C. NFPA 54
D. NFPA 72
, NFPA 58 is the Liquefied Petroleum Gas Code and sets minimum
safety requirements for design, installation, and operation of LP-Gas
systems.
4. Propane is heavier than air; therefore, if a leak occurs outdoors, the
gas will:
A. Rise and dissipate quickly
B. Vaporize into oxygen and nitrogen
C. Collect in low spots or depressions
D. Immediately ignite upon contact with air
Propane’s density causes it to settle in low areas, creating
accumulation hazards near the ground.
5. Before performing any welding or cutting on propane piping, the
technician must:
A. Pressurize the system with nitrogen
B. Purge the system of all flammable gas
C. Check regulator vent thermostats
D. Insulate the piping
Removing all flammable gas eliminates the risk of ignition during hot
work on the piping.
6. A double-valve protection system on a propane cylinder consists of:
A. A primary valve and an excess flow valve
B. A pressure switch and a thermal cut-off
C. A service valve and a relief valve
D. A check valve and a backflow preventer
The service valve controls gas flow, while the relief valve protects
against overpressure.
7. The maximum allowable working pressure (MAWP) for residential
propane regulators is typically set at:
A. 5 psi
B. 10 psi
C. 30 psi
D. 60 psi
Residential regulators are designed for a maximum of 10 psi to
ensure safe low-pressure distribution.
, 8. How often must a propane tank used for motor vehicle fuel be
hydrostatically tested?
A. Every year
B. Every 5 years
C. Every 10 years
D. Every 15 years
Periodic hydrostatic testing at 5-year intervals ensures the structural
integrity of vehicle fuel tanks.
9. When installing underground propane piping, the minimum required
depth of cover is:
A. 6 inches
B. 18 inches
C. 3 feet
D. 5 feet
A minimum of 18 inches prevents damage from surface activities and
frost heave while maintaining safety.
10. A regulator’s low-pressure side should be protected from
freezing by:
A. Increasing gas flow rates
B. Using a larger regulator body
C. Routing piping aboveground
D. Ensuring proper ventilation at the vent outlet
Adequate ventilation prevents moisture buildup and freezing of
regulator components.
11. The correct vapor pressure of propane at 100°F (38°C) is
approximately:
A. 25 psi
B. 50 psi
C. 100 psi
D. 150 psi
Propane’s vapor pressure rises with temperature, reaching about 100
psi at 100°F.
12. A tractor-trailer delivering propane must display placards when
the load exceeds:
A. 500 pounds
Technician License Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. A common method used to detect a small leak in a propane system is
to apply:
A. A flame near the joint for visual detection
B. Soapy water solution at the connection points
C. A magnetized probe around the valve body
D. Compressed air with lubricant spray
Soapy water creates bubbles at the leak site, providing a safe,
reliable method to visually identify small leaks in propane systems.
2. The primary purpose of the relief valve on a propane cylinder is to:
A. Regulate delivery pressure to the appliance
B. Prevent vacuum conditions in the tank
C. Release excess internal pressure to prevent rupture
D. Facilitate quicker filling at the bulk plant
Relief valves prevent tank rupture by discharging vapor when
internal pressure exceeds safe limits.
3. The National Fire Protection Association (NFPA) standard that governs
the storage and handling of liquefied petroleum gases is:
A. NFPA 30
B. NFPA 58
C. NFPA 54
D. NFPA 72
, NFPA 58 is the Liquefied Petroleum Gas Code and sets minimum
safety requirements for design, installation, and operation of LP-Gas
systems.
4. Propane is heavier than air; therefore, if a leak occurs outdoors, the
gas will:
A. Rise and dissipate quickly
B. Vaporize into oxygen and nitrogen
C. Collect in low spots or depressions
D. Immediately ignite upon contact with air
Propane’s density causes it to settle in low areas, creating
accumulation hazards near the ground.
5. Before performing any welding or cutting on propane piping, the
technician must:
A. Pressurize the system with nitrogen
B. Purge the system of all flammable gas
C. Check regulator vent thermostats
D. Insulate the piping
Removing all flammable gas eliminates the risk of ignition during hot
work on the piping.
6. A double-valve protection system on a propane cylinder consists of:
A. A primary valve and an excess flow valve
B. A pressure switch and a thermal cut-off
C. A service valve and a relief valve
D. A check valve and a backflow preventer
The service valve controls gas flow, while the relief valve protects
against overpressure.
7. The maximum allowable working pressure (MAWP) for residential
propane regulators is typically set at:
A. 5 psi
B. 10 psi
C. 30 psi
D. 60 psi
Residential regulators are designed for a maximum of 10 psi to
ensure safe low-pressure distribution.
, 8. How often must a propane tank used for motor vehicle fuel be
hydrostatically tested?
A. Every year
B. Every 5 years
C. Every 10 years
D. Every 15 years
Periodic hydrostatic testing at 5-year intervals ensures the structural
integrity of vehicle fuel tanks.
9. When installing underground propane piping, the minimum required
depth of cover is:
A. 6 inches
B. 18 inches
C. 3 feet
D. 5 feet
A minimum of 18 inches prevents damage from surface activities and
frost heave while maintaining safety.
10. A regulator’s low-pressure side should be protected from
freezing by:
A. Increasing gas flow rates
B. Using a larger regulator body
C. Routing piping aboveground
D. Ensuring proper ventilation at the vent outlet
Adequate ventilation prevents moisture buildup and freezing of
regulator components.
11. The correct vapor pressure of propane at 100°F (38°C) is
approximately:
A. 25 psi
B. 50 psi
C. 100 psi
D. 150 psi
Propane’s vapor pressure rises with temperature, reaching about 100
psi at 100°F.
12. A tractor-trailer delivering propane must display placards when
the load exceeds:
A. 500 pounds
