ONTARIO GAS TECHNICIAN 1 (G1) CERTIFICATION EXAM ACTUAL EXAM –QUESTIONS AND CORRECT ANSWERS (VERIFIED ANSWERS)
PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF.
_Core Domains:
Technical Standards and Safety Act and Applicable Regulations (TSSA)
CSA B149.1 Natural Gas and Propane Installation Code
CSA B149.2 Propane Storage and Handling Code
Large Commercial and Industrial Gas Appliance Controls and Safety Systems
Flame Safeguard Controls and Programming Sequences
Industrial Combustion Air and Venting Design
Gas Pressure Regulation and Metering Stations (Over 400 psig)
Flame Detection Systems and Trial for Ignition Parameters
Valve Proving Systems and Automatic Shut-off Valve Trains
Commissioning, Troubleshooting, and Decommissioning Procedures_
Introduction
The Ontario Gas Technician 1 (G1) Certification Exam assessment is designed to verify the advanced technical, legal, and safety competencies
required of a fully certified G1 technician operating within Ontario. This comprehensive exam targets the critical knowledge needed to install, service,
and maintain high-input gas-fired equipment exceeding 400,000 BTUh without supervision. The evaluation incorporates both multiple-choice
theoretical items and detailed, scenario-based problems reflecting real-world industrial installations. Candidates are assessed on their capacity to
navigate complex regulatory frameworks, interpret industrial code requirements, configure flame safeguard program sequences, and apply rigorous
troubleshooting logic under pressure. Mastery of these fields ensures public safety and industrial operational excellence.
Section One: Questions 1–100
What is the minimum clearance required from the discharge of a relief valve on a pressure-regulating station to an building opening that is lower than
the discharge?
A. 3 feet
B. 5 feet
,C. 10 feet
D. 15 feet
🟢 C. 10 feet
🔴 RATIONALE: According to CSA B149.1, the minimum clearance required from the discharge of a relief valve to any opening into a building that is
lower than the discharge point is 10 feet (3 meters) to prevent vented gas from migrating into the structure.
Which regulation under the Technical Standards and Safety Act, 2000, governs the licensing and certification of Gas Technicians in Ontario?
A. O. Reg. 211/01
B. O. Reg. 212/01
C. O. Reg. 213/01
D. O. Reg. 215/01
🟢 D. O. Reg. 215/01
🔴 RATIONALE: Ontario Regulation 215/01 (Fuel Industry Certificates) specifically mandates the certification, training, and scope of practice
requirements for gas technicians and operators under the TSSA.
An industrial boiler with an input of 5,000,000 BTUh requires a dynamic gas pressure test. What is the minimum required size of the test tapping on
the main gas valve train?
A. 1/4 inch NPT
B. 3/8 inch NPT
C. 1/2 inch NPT
D. 3/4 inch NPT
🟢 A. 1/4 inch NPT
🔴 RATIONALE: Standard industrial valve trains built to CSA B149.3 require a minimum 1/4 inch NPT test tapping upstream and downstream of
major pressure regulating and safety shut-off components to allow for accurate pressure verification.
During the pre-purge cycle of a programming flame safeguard control on a 12,000,000 BTUh burner, how many air changes of the combustion
chamber and flue passages are legally required?
A. 2 air changes
B. 4 air changes
C. 6 air changes
D. 8 air changes
🟢 B. 4 air changes
🔴 RATIONALE: For large commercial and industrial burners, standard codes and flame safeguard rules require a minimum of 4 complete air
changes of the combustion space during the pre-purge period to ensure any residual combustibles are cleared before ignition.
A flame scanner utilizing a lead sulfide (PbS) cell is sensitive to which specific wavelength spectrum of a flame?
,A. Ultraviolet light
B. Infrared radiation
C. Visible green light
D. X-ray radiation
🟢 B. Infrared radiation
🔴 RATIONALE: Lead sulfide cells are photoconductive detectors designed to react primarily to infrared radiation (heat), making them capable of
detecting the presence of industrial oil and gas flames by monitoring flame flicker.
When configuring a pilot valve train for a burner with an input rating of 3,500,000 BTUh, what is the maximum allowable timed trial for ignition (TFI)
for the pilot flame?
A. 5 seconds
B. 10 seconds
C. 15 seconds
D. 30 seconds
🟢 B. 10 seconds
🔴 RATIONALE: For burner inputs of this scale, industrial standards limit the pilot trial for ignition to a maximum of 10 seconds to minimize the
volume of unburned fuel entering the combustion chamber if ignition fails.
What is the maximum permitted setting of a high-gas-pressure switch installed on a commercial boiler valve train rated for 800,000 BTUh?
A. 110% of the normal operating pressure
B. 125% of the normal operating pressure
C. 150% of the normal operating pressure
D. 200% of the normal operating pressure
🟢 B. 125% of the normal operating pressure
🔴 RATIONALE: Safety regulations dictate that high-gas-pressure switches must be calibrated to trip and lock out at no more than 125% of the
normal operating gas manifold pressure to protect downstream components and maintain stable combustion.
A G1 technician discovers a severe safety hazard on a 2,500,000 BTUh makeup air unit where the heat exchanger has completely collapsed. What
action must be taken immediately under O. Reg. 212/01?
A. Advise the owner and return within 30 days to check if it has been repaired.
B. Shut off the gas supply, lock out the equipment, and notify the TSSA and the fuel distributor immediately.
C. Tag the appliance with a 14-day notice and allow it to operate with reduced input.
D. Report the hazard to the building owner and let them decide whether to shut it down.
🟢 B. Shut off the gas supply, lock out the equipment, and notify the TSSA and the fuel distributor immediately.
🔴 RATIONALE: Under Ontario fuel regulations, an immediate hazard requires the technician to isolate the gas supply, tag the equipment, lock it
out, and give immediate notice to both the user and the fuel distributor/TSSA.
, Which type of flame detection system operates on the principle that a flame can conduct electricity and rectify an alternating current into a direct
current signal?
A. Cadmium sulfide cell
B. Ultraviolet scanner
C. Flame ionization rod
D. Thermocouple loop
🟢 C. Flame ionization rod
🔴 RATIONALE: A flame rod relies on flame rectification, where the ions within the flame conduct an AC voltage between the rod and the grounded
burner head, allowing current to flow more easily in one direction, producing a measurable DC signal.
What is the minimum required distance between a standard schedule 40 gas pipe line and an underground electrical conduit, according to Ontario
utility guidelines and CSA B149.1?
A. 6 inches
B. 12 inches
C. 24 inches
D. 36 inches
🟢 B. 12 inches
🔴 RATIONALE: When installing underground gas piping parallel to or crossing other utility conduits such as electrical lines, a minimum clearance of
12 inches (300 mm) of well-tamped earth must be maintained.
A heavy industrial process burner uses a secondary air damper to control excess air. If the oxygen reading in the flue gas drops to 0.5% while carbon
monoxide spikes to 800 ppm, what is the most logical condition?
A. Excessive high gas pressure
B. High excess air condition
C. Sub-stoichiometric combustion
D. Faulty draft hood installation
🟢 C. Sub-stoichiometric combustion
🔴 RATIONALE: A sharp drop in oxygen combined with a major increase in carbon monoxide signifies insufficient combustion air, meaning the
mixture is running rich or sub-stoichiometric, leading to incomplete combustion.
What is the required color coding for a dedicated propane vapor line operating inside an industrial facility at pressures exceeding 5 psig?
A. Yellow with black lettering
B. Green with white lettering
C. Red with white lettering
D. Orange with black lettering
PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF.
_Core Domains:
Technical Standards and Safety Act and Applicable Regulations (TSSA)
CSA B149.1 Natural Gas and Propane Installation Code
CSA B149.2 Propane Storage and Handling Code
Large Commercial and Industrial Gas Appliance Controls and Safety Systems
Flame Safeguard Controls and Programming Sequences
Industrial Combustion Air and Venting Design
Gas Pressure Regulation and Metering Stations (Over 400 psig)
Flame Detection Systems and Trial for Ignition Parameters
Valve Proving Systems and Automatic Shut-off Valve Trains
Commissioning, Troubleshooting, and Decommissioning Procedures_
Introduction
The Ontario Gas Technician 1 (G1) Certification Exam assessment is designed to verify the advanced technical, legal, and safety competencies
required of a fully certified G1 technician operating within Ontario. This comprehensive exam targets the critical knowledge needed to install, service,
and maintain high-input gas-fired equipment exceeding 400,000 BTUh without supervision. The evaluation incorporates both multiple-choice
theoretical items and detailed, scenario-based problems reflecting real-world industrial installations. Candidates are assessed on their capacity to
navigate complex regulatory frameworks, interpret industrial code requirements, configure flame safeguard program sequences, and apply rigorous
troubleshooting logic under pressure. Mastery of these fields ensures public safety and industrial operational excellence.
Section One: Questions 1–100
What is the minimum clearance required from the discharge of a relief valve on a pressure-regulating station to an building opening that is lower than
the discharge?
A. 3 feet
B. 5 feet
,C. 10 feet
D. 15 feet
🟢 C. 10 feet
🔴 RATIONALE: According to CSA B149.1, the minimum clearance required from the discharge of a relief valve to any opening into a building that is
lower than the discharge point is 10 feet (3 meters) to prevent vented gas from migrating into the structure.
Which regulation under the Technical Standards and Safety Act, 2000, governs the licensing and certification of Gas Technicians in Ontario?
A. O. Reg. 211/01
B. O. Reg. 212/01
C. O. Reg. 213/01
D. O. Reg. 215/01
🟢 D. O. Reg. 215/01
🔴 RATIONALE: Ontario Regulation 215/01 (Fuel Industry Certificates) specifically mandates the certification, training, and scope of practice
requirements for gas technicians and operators under the TSSA.
An industrial boiler with an input of 5,000,000 BTUh requires a dynamic gas pressure test. What is the minimum required size of the test tapping on
the main gas valve train?
A. 1/4 inch NPT
B. 3/8 inch NPT
C. 1/2 inch NPT
D. 3/4 inch NPT
🟢 A. 1/4 inch NPT
🔴 RATIONALE: Standard industrial valve trains built to CSA B149.3 require a minimum 1/4 inch NPT test tapping upstream and downstream of
major pressure regulating and safety shut-off components to allow for accurate pressure verification.
During the pre-purge cycle of a programming flame safeguard control on a 12,000,000 BTUh burner, how many air changes of the combustion
chamber and flue passages are legally required?
A. 2 air changes
B. 4 air changes
C. 6 air changes
D. 8 air changes
🟢 B. 4 air changes
🔴 RATIONALE: For large commercial and industrial burners, standard codes and flame safeguard rules require a minimum of 4 complete air
changes of the combustion space during the pre-purge period to ensure any residual combustibles are cleared before ignition.
A flame scanner utilizing a lead sulfide (PbS) cell is sensitive to which specific wavelength spectrum of a flame?
,A. Ultraviolet light
B. Infrared radiation
C. Visible green light
D. X-ray radiation
🟢 B. Infrared radiation
🔴 RATIONALE: Lead sulfide cells are photoconductive detectors designed to react primarily to infrared radiation (heat), making them capable of
detecting the presence of industrial oil and gas flames by monitoring flame flicker.
When configuring a pilot valve train for a burner with an input rating of 3,500,000 BTUh, what is the maximum allowable timed trial for ignition (TFI)
for the pilot flame?
A. 5 seconds
B. 10 seconds
C. 15 seconds
D. 30 seconds
🟢 B. 10 seconds
🔴 RATIONALE: For burner inputs of this scale, industrial standards limit the pilot trial for ignition to a maximum of 10 seconds to minimize the
volume of unburned fuel entering the combustion chamber if ignition fails.
What is the maximum permitted setting of a high-gas-pressure switch installed on a commercial boiler valve train rated for 800,000 BTUh?
A. 110% of the normal operating pressure
B. 125% of the normal operating pressure
C. 150% of the normal operating pressure
D. 200% of the normal operating pressure
🟢 B. 125% of the normal operating pressure
🔴 RATIONALE: Safety regulations dictate that high-gas-pressure switches must be calibrated to trip and lock out at no more than 125% of the
normal operating gas manifold pressure to protect downstream components and maintain stable combustion.
A G1 technician discovers a severe safety hazard on a 2,500,000 BTUh makeup air unit where the heat exchanger has completely collapsed. What
action must be taken immediately under O. Reg. 212/01?
A. Advise the owner and return within 30 days to check if it has been repaired.
B. Shut off the gas supply, lock out the equipment, and notify the TSSA and the fuel distributor immediately.
C. Tag the appliance with a 14-day notice and allow it to operate with reduced input.
D. Report the hazard to the building owner and let them decide whether to shut it down.
🟢 B. Shut off the gas supply, lock out the equipment, and notify the TSSA and the fuel distributor immediately.
🔴 RATIONALE: Under Ontario fuel regulations, an immediate hazard requires the technician to isolate the gas supply, tag the equipment, lock it
out, and give immediate notice to both the user and the fuel distributor/TSSA.
, Which type of flame detection system operates on the principle that a flame can conduct electricity and rectify an alternating current into a direct
current signal?
A. Cadmium sulfide cell
B. Ultraviolet scanner
C. Flame ionization rod
D. Thermocouple loop
🟢 C. Flame ionization rod
🔴 RATIONALE: A flame rod relies on flame rectification, where the ions within the flame conduct an AC voltage between the rod and the grounded
burner head, allowing current to flow more easily in one direction, producing a measurable DC signal.
What is the minimum required distance between a standard schedule 40 gas pipe line and an underground electrical conduit, according to Ontario
utility guidelines and CSA B149.1?
A. 6 inches
B. 12 inches
C. 24 inches
D. 36 inches
🟢 B. 12 inches
🔴 RATIONALE: When installing underground gas piping parallel to or crossing other utility conduits such as electrical lines, a minimum clearance of
12 inches (300 mm) of well-tamped earth must be maintained.
A heavy industrial process burner uses a secondary air damper to control excess air. If the oxygen reading in the flue gas drops to 0.5% while carbon
monoxide spikes to 800 ppm, what is the most logical condition?
A. Excessive high gas pressure
B. High excess air condition
C. Sub-stoichiometric combustion
D. Faulty draft hood installation
🟢 C. Sub-stoichiometric combustion
🔴 RATIONALE: A sharp drop in oxygen combined with a major increase in carbon monoxide signifies insufficient combustion air, meaning the
mixture is running rich or sub-stoichiometric, leading to incomplete combustion.
What is the required color coding for a dedicated propane vapor line operating inside an industrial facility at pressures exceeding 5 psig?
A. Yellow with black lettering
B. Green with white lettering
C. Red with white lettering
D. Orange with black lettering
