Gas Fitter Licensing Exam Practice Test
Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A
Instant Download Pdf
1. Which of the following is the primary purpose of a gas pressure regulator?
A. Increase gas flow
B. Maintain a constant downstream pressure
C. Filter impurities from gas
D. Convert gas from liquid to vapor
Rationale: The gas pressure regulator ensures a stable and safe gas pressure for
appliances regardless of upstream fluctuations.
2. What is the typical maximum allowable leak rate for a gas piping system
during testing?
A. 5 psi per minute
B. 2 psi per minute
C. 0 psi (no leaks allowed)
D. 1 psi per minute
Rationale: Gas systems must be leak-free to prevent dangerous gas
accumulation.
3. Which type of pipe is commonly used for natural gas distribution inside
residential buildings?
A. Copper
, B. PVC
C. Black steel
D. Galvanized steel
Rationale: Black steel is strong, durable, and resistant to gas permeation,
making it standard for gas piping.
4. When connecting a flexible gas connector to an appliance, which is
required?
A. Teflon tape on the inside threads
B. Approved fittings and proper thread sealant
C. No sealant
D. Glue for metal-to-metal connection
Rationale: Proper fittings and sealant prevent leaks and meet code
requirements.
5. What is the minimum clearance required between a gas appliance and
combustible materials?
A. 1 inch
B. As specified by manufacturer and code
C. 6 inches
D. 12 inches
Rationale: Clearance varies by appliance type; always follow manufacturer
instructions and code.
6. What is the main function of a gas shutoff valve?
A. Regulate gas pressure
B. Stop gas flow in an emergency or for maintenance
C. Filter gas impurities
D. Reduce gas temperature
Rationale: Shutoff valves provide a quick way to isolate gas supply safely.
7. For residential gas piping, which method of support is generally required?
A. Hangers every 10 feet horizontally
, B. No support needed
C. Support per code (typically every 4–6 feet for horizontal runs)
D. Wire ties
Rationale: Adequate support prevents sagging and damage to pipes.
8. What is the first step when inspecting a gas system for leaks?
A. Light a pilot
B. Open appliances
C. Perform a visual inspection and apply a leak detection method
D. Remove regulators
Rationale: Always visually check and test with approved methods (soap solution
or electronic detector) before operation.
9. Which of the following is considered a combustible gas?
A. Oxygen
B. Carbon dioxide
C. Natural gas (methane)
D. Nitrogen
Rationale: Methane is highly flammable and considered a combustible gas.
10.When testing a gas line for pressure, which instrument is appropriate?
A. Thermometer
B. Manometer or gauge
C. Multimeter
D. Anemometer
Rationale: Manometers or pressure gauges accurately measure gas pressure for
safe testing.
11.Which of the following joints is NOT acceptable for black steel gas piping?
A. Threaded joint with approved sealant
B. Welded joint
C. Flanged joint
D. Soldered copper-to-steel joint
Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A
Instant Download Pdf
1. Which of the following is the primary purpose of a gas pressure regulator?
A. Increase gas flow
B. Maintain a constant downstream pressure
C. Filter impurities from gas
D. Convert gas from liquid to vapor
Rationale: The gas pressure regulator ensures a stable and safe gas pressure for
appliances regardless of upstream fluctuations.
2. What is the typical maximum allowable leak rate for a gas piping system
during testing?
A. 5 psi per minute
B. 2 psi per minute
C. 0 psi (no leaks allowed)
D. 1 psi per minute
Rationale: Gas systems must be leak-free to prevent dangerous gas
accumulation.
3. Which type of pipe is commonly used for natural gas distribution inside
residential buildings?
A. Copper
, B. PVC
C. Black steel
D. Galvanized steel
Rationale: Black steel is strong, durable, and resistant to gas permeation,
making it standard for gas piping.
4. When connecting a flexible gas connector to an appliance, which is
required?
A. Teflon tape on the inside threads
B. Approved fittings and proper thread sealant
C. No sealant
D. Glue for metal-to-metal connection
Rationale: Proper fittings and sealant prevent leaks and meet code
requirements.
5. What is the minimum clearance required between a gas appliance and
combustible materials?
A. 1 inch
B. As specified by manufacturer and code
C. 6 inches
D. 12 inches
Rationale: Clearance varies by appliance type; always follow manufacturer
instructions and code.
6. What is the main function of a gas shutoff valve?
A. Regulate gas pressure
B. Stop gas flow in an emergency or for maintenance
C. Filter gas impurities
D. Reduce gas temperature
Rationale: Shutoff valves provide a quick way to isolate gas supply safely.
7. For residential gas piping, which method of support is generally required?
A. Hangers every 10 feet horizontally
, B. No support needed
C. Support per code (typically every 4–6 feet for horizontal runs)
D. Wire ties
Rationale: Adequate support prevents sagging and damage to pipes.
8. What is the first step when inspecting a gas system for leaks?
A. Light a pilot
B. Open appliances
C. Perform a visual inspection and apply a leak detection method
D. Remove regulators
Rationale: Always visually check and test with approved methods (soap solution
or electronic detector) before operation.
9. Which of the following is considered a combustible gas?
A. Oxygen
B. Carbon dioxide
C. Natural gas (methane)
D. Nitrogen
Rationale: Methane is highly flammable and considered a combustible gas.
10.When testing a gas line for pressure, which instrument is appropriate?
A. Thermometer
B. Manometer or gauge
C. Multimeter
D. Anemometer
Rationale: Manometers or pressure gauges accurately measure gas pressure for
safe testing.
11.Which of the following joints is NOT acceptable for black steel gas piping?
A. Threaded joint with approved sealant
B. Welded joint
C. Flanged joint
D. Soldered copper-to-steel joint
