Ontario Gas Technician 1 (G1) Certification
Exam Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A | Instant
Download Pdf
1. Which of the following gases is commonly used in natural gas
distribution systems?
A. Propane
B. Methane
C. Oxygen
D. Carbon dioxide
Rationale: Methane is the primary component of natural gas,
making up approximately 85-95% of most natural gas supplies.
2. What is the primary purpose of a pressure regulator in a gas
system?
A. To filter impurities from the gas
B. To maintain a consistent downstream pressure
C. To measure gas flow
D. To ignite the gas safely
Rationale: A pressure regulator ensures that the downstream
pressure remains within safe operating limits regardless of supply
fluctuations.
3. What type of flame indicates a proper gas-to-air mixture on a
natural gas appliance?
A. Red flame
, B. Yellow flame
C. Blue flame with minimal yellow tips
D. Orange flame
Rationale: A blue flame indicates complete combustion, while
yellow tips may indicate incomplete combustion or insufficient
oxygen.
4. Which of the following materials is commonly used for natural gas
piping in residential installations?
A. Copper
B. Black steel
C. PVC
D. Aluminum
Rationale: Black steel is standard for natural gas piping due to its
strength and compatibility with gas.
5. What is the primary hazard associated with natural gas leaks?
A. Explosion and fire risk
B. Skin irritation
C. Eye damage
D. Hearing loss
Rationale: Natural gas is highly flammable; leaks can lead to
explosions or fires if ignited.
6. In a gas system, what does the term “BTU” measure?
A. Gas pressure
B. Gas flow rate
C. Energy content of the gas
D. Temperature of combustion
, Rationale: BTU (British Thermal Unit) measures the amount of
energy released during combustion of gas.
7. What is the minimum clearance required between a natural gas
meter and ignition sources?
A. 12 inches
B. 24 inches
C. 36 inches
D. 48 inches
Rationale: Safety standards require a minimum clearance of 36
inches to reduce the risk of fire from nearby ignition sources.
8. When testing for gas leaks, which method is commonly
recommended?
A. Using a flame
B. Soapy water solution
C. Smelling for gas only
D. Using a metal probe
Rationale: A soapy water solution will bubble at the leak site,
providing a safe and effective method of detection.
9. Which device prevents backflow of gas into the supply line?
A. Pressure regulator
B. Gas meter
C. Check valve
D. Relief valve
Rationale: A check valve allows gas to flow in only one direction,
preventing backflow.
10. What is the purpose of a vent in a gas appliance?
A. To supply gas
Exam Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A | Instant
Download Pdf
1. Which of the following gases is commonly used in natural gas
distribution systems?
A. Propane
B. Methane
C. Oxygen
D. Carbon dioxide
Rationale: Methane is the primary component of natural gas,
making up approximately 85-95% of most natural gas supplies.
2. What is the primary purpose of a pressure regulator in a gas
system?
A. To filter impurities from the gas
B. To maintain a consistent downstream pressure
C. To measure gas flow
D. To ignite the gas safely
Rationale: A pressure regulator ensures that the downstream
pressure remains within safe operating limits regardless of supply
fluctuations.
3. What type of flame indicates a proper gas-to-air mixture on a
natural gas appliance?
A. Red flame
, B. Yellow flame
C. Blue flame with minimal yellow tips
D. Orange flame
Rationale: A blue flame indicates complete combustion, while
yellow tips may indicate incomplete combustion or insufficient
oxygen.
4. Which of the following materials is commonly used for natural gas
piping in residential installations?
A. Copper
B. Black steel
C. PVC
D. Aluminum
Rationale: Black steel is standard for natural gas piping due to its
strength and compatibility with gas.
5. What is the primary hazard associated with natural gas leaks?
A. Explosion and fire risk
B. Skin irritation
C. Eye damage
D. Hearing loss
Rationale: Natural gas is highly flammable; leaks can lead to
explosions or fires if ignited.
6. In a gas system, what does the term “BTU” measure?
A. Gas pressure
B. Gas flow rate
C. Energy content of the gas
D. Temperature of combustion
, Rationale: BTU (British Thermal Unit) measures the amount of
energy released during combustion of gas.
7. What is the minimum clearance required between a natural gas
meter and ignition sources?
A. 12 inches
B. 24 inches
C. 36 inches
D. 48 inches
Rationale: Safety standards require a minimum clearance of 36
inches to reduce the risk of fire from nearby ignition sources.
8. When testing for gas leaks, which method is commonly
recommended?
A. Using a flame
B. Soapy water solution
C. Smelling for gas only
D. Using a metal probe
Rationale: A soapy water solution will bubble at the leak site,
providing a safe and effective method of detection.
9. Which device prevents backflow of gas into the supply line?
A. Pressure regulator
B. Gas meter
C. Check valve
D. Relief valve
Rationale: A check valve allows gas to flow in only one direction,
preventing backflow.
10. What is the purpose of a vent in a gas appliance?
A. To supply gas
