ONTARIO GAS TECHNICIAN 1 (G1) CERTIFICATION EXAM 2026–2027 | COMPLETE STUDY GUIDE | VERIFIED PRACTICE QUESTIONS & CORRECT ANSWERS | LATEST UPDATED CERTIFICATION EXAM PREP

ONTARIO GAS TECHNICIAN 1 (G1)
CERTIFICATION EXAM 2026–2027 |
COMPLETE STUDY GUIDE | VERIFIED
PRACTICE QUESTIONS & CORRECT
ANSWERS | LATEST UPDATED
CERTIFICATION EXAM PREP
ONTARIO GAS TECHNICIAN 1 (G1) CERTIFICATION EXAM 2026–2027 COMPLETE
STUDY GUIDE | VERIFIED PRACTICE QUESTIONS & CORRECT ANSWERS

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• This comprehensive study guide contains 200 verified practice questions designed
to prepare candidates for the Ontario Gas Technician 1 certification exam with
detailed EXPERT RATIONALE for every answer.

• Study strategically by working through all questions, reviewing EXPERT
RATIONALE thoroughly, and identifying weak areas to focus on before attempting
the official certification exam.

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1) What is the primary purpose of a pressure regulator in a gas system?

A) To increase gas pressure to the desired appliance level

B) To filter out impurities from natural gas

C) To reduce gas pressure from the supply line to a safe, usable level

D) To control the flow rate of gas through the meter

E) To prevent backflow of gas in the system

✓ CORRECT ANSWER: C) To reduce gas pressure from the supply line to a safe,
usable level

EXPERT RATIONALE: A pressure regulator is a critical safety device that reduces
high-pressure gas from the supply line to lower, safe pressures needed by
appliances. This protects appliances and ensures safe, efficient operation. Without
proper pressure regulation, appliances could be damaged or become hazardous.

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2) According to CSA B149.1, what is the maximum allowable pressure drop for
gas piping systems?

A) 0.5 inches of water column

B) 1.0 inches of water column

C) 1.5 inches of water column

D) 2.0 inches of water column

E) 3.0 inches of water column

✓ CORRECT ANSWER: C) 1.5 inches of water column

EXPERT RATIONALE: CSA B149.1 (the Canadian Standard for gas piping
installations) specifies that the maximum pressure drop from the meter to the
appliance must not exceed 1.5 inches of water column. Exceeding this limit can
affect appliance performance and efficiency.

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3) What does BTU stand for in heating applications?

A) Basic Thermal Unit

B) British Thermal Unit

C) Boiler Temperature Unit

D) Base Thermal Utility

E) Bulk Transfer Unit

✓ CORRECT ANSWER: B) British Thermal Unit

EXPERT RATIONALE: BTU is an abbreviation for British Thermal Unit, which is the
standard unit of measurement for heat energy. One BTU is the amount of energy
required to raise one pound of water by one degree Fahrenheit. Gas technicians
must understand BTU ratings for appliances.

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4) What is the primary safety concern when working with gas lines at high
altitudes?

A) Increased gas pressure due to thin air

B) Decreased air density affects combustion efficiency

C) Gas expands and becomes more flammable

D) Copper piping becomes brittle

E) Gas has a stronger odor

✓ CORRECT ANSWER: B) Decreased air density affects combustion efficiency

EXPERT RATIONALE: At higher altitudes, air density is lower, which reduces the
amount of oxygen available for combustion. This can result in incomplete
combustion, reducing appliance efficiency and potentially creating safety hazards
like carbon monoxide production.

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5) Which of the following is the correct procedure for pressure testing a new
gas installation?

A) Use compressed air at 10 PSI for 24 hours

B) Use nitrogen gas at the operating pressure for the required time period

C) Use natural gas at normal operating pressure

D) Use pressurized water for leak detection

E) Use helium gas at atmospheric pressure

✓ CORRECT ANSWER: B) Use nitrogen gas at the operating pressure for the
required time period

EXPERT RATIONALE: Code regulations require nitrogen to be used for pressure
testing, never air or natural gas. Compressed air can create an explosive mixture,

, and natural gas is unsafe. Nitrogen is inert and safe for testing. The test pressure
must match the system's operating pressure and be held for the specified duration
(typically 10 minutes minimum).

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6) What is the flash point of natural gas in degrees Celsius?

A) -188°C

B) -150°C

C) -110°C

D) -80°C

E) 0°C

✓ CORRECT ANSWER: A) -188°C

EXPERT RATIONALE: Natural gas has an extremely low flash point of approximately
-188°C (-306°F). This means it can ignite at very low temperatures, which is why
proper handling, storage, and ventilation are absolutely critical when working with
natural gas systems.

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7) Which type of gas piping material is NOT approved for use inside residential
dwellings according to CSA B149.1?

A) Copper tubing

B) Corrugated stainless steel tubing (CSST)

C) Black iron pipe

D) Rigid steel pipe

E) Aluminum tubing

✓ CORRECT ANSWER: E) Aluminum tubing