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100+ Free TSSA Gas Technician 3 (G3) Practice Questions
TSSA Gas Technician 3 (G.3) Certificate of Qualification — Ontario practice questions are available now; exam metadata is being verified.
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2026 Statistics
Key Facts: TSSA Gas Technician 3 (G3) Exam
75%
Fuels Passing Score
TSSA Examination Prep Guide
3.5 h
Maximum Exam Time
TSSA Examination Prep Guide
1–9
G3 CSA Modules
TSSA Gas/Oil Burner Policies
180 h
Guideline Program Hours
TSSA Gas/Oil Burner Policies
$89
Other Examination Fee (CAD, May 1, 2026)
TSSA Natural Gas & Hydrogen Fee Schedule
30 days
Fuels Re-Write Wait
TSSA Examination Prep Guide
TSSA G.3 is Ontario’s entry gas technician certificate for supervised work under a G.1 or G.2 holder. Fuels written exams are multiple choice with a 75% pass mark and up to 3.5 hours; exact G3 item count is not published (Fuels range 50–165). TSSA Other Examination fee is CAD $89 effective May 1, 2026 (Natural Gas & Hydrogen Fee Schedule)—confirm the current schedule. This free bank offers 100 practice MCQs mapped to G3 modules 1–9 and CSA B149.1/B149.2.
Sample TSSA Gas Technician 3 (G3) Practice Questions
Try these sample questions to test your TSSA Gas Technician 3 (G3) exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.
1What is the primary purpose of WHMIS/GHS information on a gas technician worksite?
A.To communicate hazardous-product hazards through labels, SDS, and worker education
B.To certify Gas Technician 3 holders for unsupervised work
C.To set CSA B149.1 pipe-sizing tables
D.To schedule biennial TSSA certificate renewals
Explanation: WHMIS (aligned with GHS) communicates chemical and product hazards through supplier/workplace labels, safety data sheets (SDS), and worker education. G3 technicians routinely encounter fuels, solvents, thread sealants, and cleaners covered by WHMIS.
2Which condition is required for a fuel-gas fire or explosion to occur?
A.Fuel gas alone under any concentration
B.Fuel gas, an ignition source, and oxygen (air) in the combustible range
C.Liquid water and natural gas mixed in any ratio
D.Nitrogen blanketing of a closed room
Explanation: Combustion requires fuel, oxygen, and ignition (the fire/combustion triangle) with the fuel-air mixture inside flammable limits. Removing any side of the triangle prevents ignition.
3Before cutting or threading steel gas pipe with power tools, a technician should first:
A.Disable all building smoke detectors permanently
B.Pressurize the pipe with fuel gas to check for leaks
C.Verify PPE, secure the work piece, and confirm the tool is appropriate and in safe condition
D.Remove all eye protection to improve visibility
Explanation: Safe tool use starts with correct PPE (eye/hand protection), a secured workpiece, and a tool that is suited to the task and free of defects. Fuel gas must not be used as a test or cutting assist medium.
4If a strong fuel-gas odour is detected indoors, the safest immediate action is to:
A.Light a match to confirm the smell
B.Operate electrical switches and appliances to check power
C.Start a gasoline generator inside the room
D.Avoid creating ignition sources, ventilate if safe, evacuate as needed, and shut off gas from a safe location / call emergency responders as appropriate
Explanation: Suspected indoor gas leaks require eliminating ignition sources, protecting people, and isolating fuel from a safe point when possible. Creating sparks (switches, flames, engines) can ignite an accumulated mixture.
5Natural gas that escapes indoors tends to accumulate where first, and why?
A.Near the ceiling/high points, because natural gas is lighter than air (typical SG ≈ 0.6)
B.Near the floor, because natural gas is heavier than air
C.Only inside water pipes
D.Only outdoors regardless of release location
Explanation: Natural gas has a specific gravity less than air (commonly about 0.55–0.65), so it rises and can collect at high points. Propane is heavier than air and behaves differently.
6Propane vapour released at floor level indoors is especially hazardous because propane typically:
A.Is lighter than air and always vents itself outdoors automatically
B.Is heavier than air (SG ≈ 1.5) and can pool in low areas
C.Cannot ignite under any conditions
D.Has no odourant under Canadian distribution practice
Explanation: Propane vapour is heavier than air (specific gravity around 1.5), so it can settle and travel along floors into pits, drains, and basements, creating delayed ignition hazards.
7When working on gas equipment that could start unexpectedly, lockout/tagout practice is intended to:
A.Increase manifold pressure for a faster restart
B.Bypass all safety limits permanently
C.Prevent unexpected energization or fuel release that could injure workers
D.Replace the need for manufacturer instructions
Explanation: Lockout/tagout isolates energy sources (electrical and, where applicable, fuel) so equipment cannot start or release energy unexpectedly during service. It complements, and does not replace, manufacturer procedures and code requirements.
8Which statement about personal protective equipment (PPE) for gas piping and appliance work is correct?
A.PPE is optional if the job will take less than five minutes
B.Cotton gloves alone replace eye protection when cutting pipe
C.PPE eliminates the need for ventilation during solvent use
D.Required PPE depends on the task hazards (e.g., eye, hand, foot, hearing protection) and workplace rules
Explanation: PPE is selected for the hazards of the specific task and employer/site requirements. Short duration does not remove risk, and one PPE item does not substitute for another required control.
9A confined or poorly ventilated space containing a fuel-gas appliance is a concern primarily because:
A.Combustion products and fuel leaks can accumulate to hazardous concentrations
B.Natural gas always freezes solid in still air
C.CSA B149.1 bans all indoor appliances
D.Electricity cannot exist in confined spaces
Explanation: Limited ventilation allows fuel gases and combustion products (including CO) to build up. G3 training emphasizes recognizing atmosphere hazards and following safe entry/ventilation practices under supervision.
10Which fire-extinguisher class is generally appropriate for flammable liquid/gas fires such as those involving propane or gasoline?
A.Class A only (ordinary combustibles)
B.Class B (flammable liquids/gases) — or a multi-class extinguisher rated for B
C.Class C only for water-based cooking oils
D.Class D only for wood and paper
Explanation: Class B extinguishers are rated for flammable liquid and gas fires. Multi-purpose (e.g., ABC) units include a B rating. Water-only Class A extinguishers are inappropriate for gas/liquid fuel fires.
About the TSSA Gas Technician 3 (G3) Practice Questions
Verified exam format metadata for TSSA Gas Technician 3 (G.3) Certificate of Qualification — Ontario is pending. The practice questions above remain available while official exam length, timing, passing score, fee, and administrator details are reviewed.