New Mexico (LP-9) Station for
Dispensing LP-Gas Practice Exam |
Questions and Answers | 2026 Update |
100% Correct
1. Before refilling a customer's portable cylinder, the primary check for container
requalification is to examine the:
A. Water capacity stamp.
B. Manufacturer's nameplate.
C. Date of manufacture or last requalification.
D. Type of service valve.
Answer: C
Rationale: The date of manufacture or the last requalification date is the critical piece of
information to determine if the cylinder is still within its legal retest interval (typically 5
or 12 years). This is a core safety check.
2. The maximum permitted fill level for a propane container is:
A. 100% of its water capacity.
B. 95% of its water capacity.
C. 80% of its water capacity.
D. It varies based on cylinder size.
Answer: C
Rationale: By law, propane containers must never be filled beyond 80% of their water
capacity. This 20% vapor space (ullage) is essential to allow for liquid expansion with
temperature increases and prevent dangerous over-pressurization.
3. The purpose of the bleeder valve on a fixed liquid level gauge is to:
A. Relieve excess pressure from the container.
B. Signal when the container is 80% full.
C. Sample the vapor quality inside the tank.
D. Check for the presence of odorant.
Answer: B
,Rationale: The fixed liquid level gauge (or "spit valve") is opened during filling. Liquid,
followed by a white vapor spray, is released. The moment vapor is discharged indicates
the liquid level has reached the fixed dip tube, signaling the 80% fill level has been
achieved.
4. When dispensing into a motor fuel container on a vehicle, the transfer hose
must be:
A. Made of stainless steel.
B. Listed for LP-Gas service and have a rated working pressure of at least:
C. A minimum of 25 feet in length.
D. Orange in color.
Answer: B
Rationale: NFPA 58 requires that transfer hoses be listed for LP-Gas service and have a
working pressure rating of at least 350 psig for ASME containers and 250 psig for DOT
cylinders to ensure integrity under service conditions.
5. A required emergency shut-off device for an LP-gas dispensing station is the:
A. Fusible plug on the storage tank.
B. Emergency shear valve at the base of the pump.
C. Pressure relief valve on the storage container.
D. Vapor return check valve.
Answer: B
Rationale: An emergency shear valve or an excess flow valve is required at the base of
the pump or at the storage tank liquid outlet. This device is designed to close
automatically if the pump or piping is ruptured, limiting the release of liquid product.
6. The primary reason a cylinder must be removed from service if it has excessive
rust or pitting is:
A. It may be difficult to paint.
B. It affects the cylinder's tare weight.
C. It can compromise the structural integrity of the cylinder wall.
D. It may clog the service valve.
Answer: C
Rationale: Excessive rust, gouges, or pitting reduce the wall thickness of the cylinder,
compromising its ability to safely contain pressure. This poses a significant risk of failure
and is grounds for condemnation.
7. If a propane leak is suspected at the pump during a transfer, the first action
should be to:
A. Notify the fire department.
B. Stop the transfer, shut off the source, and secure the area.
,C. Attempt to locate the leak with a leak detector.
D. Vent the vapor to a safe location.
Answer: B
Rationale: Immediate action to stop the flow of product and isolate the source is
paramount to prevent a leak from escalating into a fire or explosion hazard. Securing
the area ensures safety before further investigation.
8. A cylinder with a three-digit service valve (e.g., "635") is equipped with a:
A. Pressure relief valve.
B. Fixed liquid level gauge.
C. Excess flow valve.
D. Vapor return valve.
Answer: C
Rationale: A three-digit service valve (like QCC or Type 1 ACME) indicates a connection
designed for vapor service on motor fuel and other applications. It incorporates an
internal excess flow valve that closes if the hose is disconnected during flow.
9. The primary hazard associated with propane is that it is:
A. Toxic when inhaled.
B. Heavier than air and flammable.
C. Lighter than air and explosive.
D. Corrosive to skin.
Answer: B
Rationale: Propane vapor is heavier than air and will flow to low spots and accumulate.
When mixed with air in the correct concentration (2.15%-9.6%), it is highly flammable.
This combination of being a heavy, accumulating fuel gas defines its primary hazard.
10. The required distance between an LP-gas dispenser and the nearest public
building (e.g., a store) is:
A. 10 feet.
B. 25 feet.
C. 50 feet.
D. 100 feet.
Answer: A
Rationale: NFPA 58 specifies a minimum distance of 10 feet from any part of a
dispenser to the nearest important building on the same property or a line of adjoining
property that can be built upon. This provides a safety buffer.
11. The primary purpose of a hydrostatic relief valve on a liquid line is to:
A. Relieve vapor pressure in the tank.
B. Protect against liquid expansion from heat exposure.
, C. Act as a backflow preventer.
D. Regulate dispenser pressure.
Answer: B
Rationale: Hydrostatic relief valves are installed in sections of liquid piping that can be
isolated (between shut-off valves). If trapped liquid is heated, it expands dramatically;
this valve relieves the resulting over-pressure to prevent pipe rupture.
12. A cylinder is considered "overfilled" when:
A. It weighs more than its marked tare weight.
B. The liquid level exceeds 80% of the container's water capacity at 60°F.
C. The pressure gauge reads over 250 psig.
D. The bleeder valve releases liquid only.
Answer: B
Rationale: Overfilling is strictly defined by the liquid volume, not weight or pressure.
The 80% fill rule (based on water capacity at 60°F) is the legal maximum to ensure safe
vapor space.
13. Before connecting to fill an RV motor fuel container, the operator should
ensure the:
A. RV's engine is warmed up.
B. RV's electricity is connected to shore power.
C. The vehicle's ignition is OFF.
D. The vehicle is parked uphill.
Answer: C
Rationale: The vehicle's ignition must be OFF to eliminate potential sources of ignition
(sparks from electrical systems, switches, etc.) during the refueling operation. This is a
fundamental safety rule.
14. The component on a dispenser that automatically stops the flow if the
connection is improperly disconnected is the:
A. Pressure relief valve.
B. Breakaway coupling.
C. Vapor check valve.
D. Fusible link.
Answer: B
Rationale: A breakaway coupling is designed to separate at a predetermined force (e.g.,
if a vehicle drives off with the hose still connected). It self-seals on both sides of the
break to prevent uncontrolled release of propane.
15. The correct personal protective equipment (PPE) for dispensing LP-gas
typically includes:
Dispensing LP-Gas Practice Exam |
Questions and Answers | 2026 Update |
100% Correct
1. Before refilling a customer's portable cylinder, the primary check for container
requalification is to examine the:
A. Water capacity stamp.
B. Manufacturer's nameplate.
C. Date of manufacture or last requalification.
D. Type of service valve.
Answer: C
Rationale: The date of manufacture or the last requalification date is the critical piece of
information to determine if the cylinder is still within its legal retest interval (typically 5
or 12 years). This is a core safety check.
2. The maximum permitted fill level for a propane container is:
A. 100% of its water capacity.
B. 95% of its water capacity.
C. 80% of its water capacity.
D. It varies based on cylinder size.
Answer: C
Rationale: By law, propane containers must never be filled beyond 80% of their water
capacity. This 20% vapor space (ullage) is essential to allow for liquid expansion with
temperature increases and prevent dangerous over-pressurization.
3. The purpose of the bleeder valve on a fixed liquid level gauge is to:
A. Relieve excess pressure from the container.
B. Signal when the container is 80% full.
C. Sample the vapor quality inside the tank.
D. Check for the presence of odorant.
Answer: B
,Rationale: The fixed liquid level gauge (or "spit valve") is opened during filling. Liquid,
followed by a white vapor spray, is released. The moment vapor is discharged indicates
the liquid level has reached the fixed dip tube, signaling the 80% fill level has been
achieved.
4. When dispensing into a motor fuel container on a vehicle, the transfer hose
must be:
A. Made of stainless steel.
B. Listed for LP-Gas service and have a rated working pressure of at least:
C. A minimum of 25 feet in length.
D. Orange in color.
Answer: B
Rationale: NFPA 58 requires that transfer hoses be listed for LP-Gas service and have a
working pressure rating of at least 350 psig for ASME containers and 250 psig for DOT
cylinders to ensure integrity under service conditions.
5. A required emergency shut-off device for an LP-gas dispensing station is the:
A. Fusible plug on the storage tank.
B. Emergency shear valve at the base of the pump.
C. Pressure relief valve on the storage container.
D. Vapor return check valve.
Answer: B
Rationale: An emergency shear valve or an excess flow valve is required at the base of
the pump or at the storage tank liquid outlet. This device is designed to close
automatically if the pump or piping is ruptured, limiting the release of liquid product.
6. The primary reason a cylinder must be removed from service if it has excessive
rust or pitting is:
A. It may be difficult to paint.
B. It affects the cylinder's tare weight.
C. It can compromise the structural integrity of the cylinder wall.
D. It may clog the service valve.
Answer: C
Rationale: Excessive rust, gouges, or pitting reduce the wall thickness of the cylinder,
compromising its ability to safely contain pressure. This poses a significant risk of failure
and is grounds for condemnation.
7. If a propane leak is suspected at the pump during a transfer, the first action
should be to:
A. Notify the fire department.
B. Stop the transfer, shut off the source, and secure the area.
,C. Attempt to locate the leak with a leak detector.
D. Vent the vapor to a safe location.
Answer: B
Rationale: Immediate action to stop the flow of product and isolate the source is
paramount to prevent a leak from escalating into a fire or explosion hazard. Securing
the area ensures safety before further investigation.
8. A cylinder with a three-digit service valve (e.g., "635") is equipped with a:
A. Pressure relief valve.
B. Fixed liquid level gauge.
C. Excess flow valve.
D. Vapor return valve.
Answer: C
Rationale: A three-digit service valve (like QCC or Type 1 ACME) indicates a connection
designed for vapor service on motor fuel and other applications. It incorporates an
internal excess flow valve that closes if the hose is disconnected during flow.
9. The primary hazard associated with propane is that it is:
A. Toxic when inhaled.
B. Heavier than air and flammable.
C. Lighter than air and explosive.
D. Corrosive to skin.
Answer: B
Rationale: Propane vapor is heavier than air and will flow to low spots and accumulate.
When mixed with air in the correct concentration (2.15%-9.6%), it is highly flammable.
This combination of being a heavy, accumulating fuel gas defines its primary hazard.
10. The required distance between an LP-gas dispenser and the nearest public
building (e.g., a store) is:
A. 10 feet.
B. 25 feet.
C. 50 feet.
D. 100 feet.
Answer: A
Rationale: NFPA 58 specifies a minimum distance of 10 feet from any part of a
dispenser to the nearest important building on the same property or a line of adjoining
property that can be built upon. This provides a safety buffer.
11. The primary purpose of a hydrostatic relief valve on a liquid line is to:
A. Relieve vapor pressure in the tank.
B. Protect against liquid expansion from heat exposure.
, C. Act as a backflow preventer.
D. Regulate dispenser pressure.
Answer: B
Rationale: Hydrostatic relief valves are installed in sections of liquid piping that can be
isolated (between shut-off valves). If trapped liquid is heated, it expands dramatically;
this valve relieves the resulting over-pressure to prevent pipe rupture.
12. A cylinder is considered "overfilled" when:
A. It weighs more than its marked tare weight.
B. The liquid level exceeds 80% of the container's water capacity at 60°F.
C. The pressure gauge reads over 250 psig.
D. The bleeder valve releases liquid only.
Answer: B
Rationale: Overfilling is strictly defined by the liquid volume, not weight or pressure.
The 80% fill rule (based on water capacity at 60°F) is the legal maximum to ensure safe
vapor space.
13. Before connecting to fill an RV motor fuel container, the operator should
ensure the:
A. RV's engine is warmed up.
B. RV's electricity is connected to shore power.
C. The vehicle's ignition is OFF.
D. The vehicle is parked uphill.
Answer: C
Rationale: The vehicle's ignition must be OFF to eliminate potential sources of ignition
(sparks from electrical systems, switches, etc.) during the refueling operation. This is a
fundamental safety rule.
14. The component on a dispenser that automatically stops the flow if the
connection is improperly disconnected is the:
A. Pressure relief valve.
B. Breakaway coupling.
C. Vapor check valve.
D. Fusible link.
Answer: B
Rationale: A breakaway coupling is designed to separate at a predetermined force (e.g.,
if a vehicle drives off with the hose still connected). It self-seals on both sides of the
break to prevent uncontrolled release of propane.
15. The correct personal protective equipment (PPE) for dispensing LP-gas
typically includes:
