100+ Free TSSA Gas Technician 3 (G3) Practice Questions

Prepare for the TSSA Gas Technician 3 (G.3) Certificate of Qualification — Ontario exam with instant access — no signup required.

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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) Exam

The Ontario TSSA Gas Technician 3 (G.3) certificate is the entry-level Fuels credential authorizing supervised work on natural gas and propane appliances and equipment within the scope of the supervising G.1 or G.2 certificate holder. Accredited training covers CSA Gas Trade modules 1–9 (~180 hours). The written exam is multiple choice, Fuels pass mark 75%, with up to 3.5 hours allowed. Candidates study CSA B149.1/B149.2 plus safety, tools, fuel-gas properties, codes, basic electricity, manuals/drawings, customer relations, introductory piping/tubing, and introductory gas appliances.

Assessment

Multiple-choice written Fuels exam covering regulatory sector knowledge plus G.3 technical content (CSA Gas Trade modules 1–9 and CSA B149.1/B149.2). Open-book with permitted unmarked Act, regulations, Code Adoption Documents, and B149 codes. Practical evaluation is completed through the accredited training program (or assessment pathway).

Time Limit

Up to 3.5 hours (210 minutes)

Passing Score

75%

Exam Fee

CAD $89 Other Examination / CAD $255.50 Challenge Examination (Natural Gas & Hydrogen Fee Schedule, effective May 1, 2026). Biennial certificate CAD $136. Confirm current schedule; provider admin/invigilation fees may apply. (Technical Standards and Safety Authority (TSSA))

TSSA Gas Technician 3 (G3) Exam Content Outline

10%

Safety & Workplace Practices

Module 1 PPE, hazards, fire/explosion prevention, and safe fuel-gas work practices

Tools, Fasteners & Testing Instruments

Module 2 tools, fasteners, gauges, and leak-detection instruments

12%

Fuel Gas Properties & Characteristics

Module 3 NG/propane properties, combustion, and safe handling

15%

Codes, Acts & Regulations

Module 4 TSS Act, O. Reg. 215/01, B149.1/B149.2, CAD, and G.3 scope

10%

Introduction to Electricity

Module 5 electrical basics for gas appliances and controls

Manuals, Specifications & Drawings

Module 6 nameplates, manuals, and installation drawings

Customer Relations

Module 7 communication, documentation, and professional conduct

18%

Introduction to Piping & Tubing Systems

Module 8 materials, joints, drip legs, testing, and shut-offs

17%

Introduction to Gas Appliances

Module 9 appliance types, approval, clearances, ignition, and venting awareness

How to Pass the TSSA Gas Technician 3 (G3) Exam

What You Need to Know

Passing score: 75%
Assessment: Multiple-choice written Fuels exam covering regulatory sector knowledge plus G.3 technical content (CSA Gas Trade modules 1–9 and CSA B149.1/B149.2). Open-book with permitted unmarked Act, regulations, Code Adoption Documents, and B149 codes. Practical evaluation is completed through the accredited training program (or assessment pathway).
Time limit: Up to 3.5 hours (210 minutes)
Exam fee: CAD $89 Other Examination / CAD $255.50 Challenge Examination (Natural Gas & Hydrogen Fee Schedule, effective May 1, 2026). Biennial certificate CAD $136. Confirm current schedule; provider admin/invigilation fees may apply.

Keys to Passing

Work through all 100 available questions
Review every answer and explanation
Track weak areas and revisit them
Use our AI tutor for tough concepts

TSSA Gas Technician 3 (G3) Study Tips from Top Performers

1Tab CSA B149.1 for piping, clearances, venting, and combustion-air clauses — G3 is heavily code-navigation, not pure memorization

2Memorize gas properties: natural gas SG ~0.6 (rises); propane SG ~1.52 (settles low); know typical residential manifold pressure ranges for NG vs LP

3Drill module 8 drip-leg/dirt-pocket rules, shut-off locations, and leak-test concepts before exam day

4Know G.3 scope cold: supervised work only — unsupervised residential/light-commercial work requires G.2

5Practice flame-supervision basics: thermocouple millivolts and what a standing pilot proves vs modern ignition

6Complete all 100 practice questions, then rework every miss with the AI tutor under timed conditions

Frequently Asked Questions

What score do I need to pass the TSSA G3 exam?

Fuels Safety examinations require 75% to pass, per the TSSA Certification Examination Preparation Guide. Unsuccessful candidates receive a mastery report and may re-write after 30 days for Fuels exams.

How many questions are on the TSSA G3 written exam?

TSSA does not publish a fixed G3 question count. Fuels written exams typically range from 50 to 165 multiple-choice items depending on certificate type, with up to 3.5 hours allowed.

What is the G3 certificate scope in Ontario?

Gas Technician 3 (G.3) is the entry-level certificate. A G.3 holder may work on gas-fired appliances and equipment only under the supervision of a G.1 or G.2 certificate holder and within that supervisor’s scope.

What do I study for the G3 exam?

Accredited G.3 training covers CSA Gas Trade modules 1 through 9 (~180 hours) plus CSA B149.1 (Natural Gas and Propane Installation Code), CSA B149.2 (Propane Storage and Handling Code), the Technical Standards and Safety Act, and applicable Fuels regulations and Code Adoption Documents.

Can I bring code books into the TSSA G3 exam?

Yes. For Gas Technician 2/3 exams, TSSA permits unmarked Technical Standards and Safety Act materials, Fuels regulations and Code Adoption Documents, CSA B149.1, CSA B149.2, and optionally B149.2S1. Page/section dividers and highlighting of text are allowed; other notes or electronics are not.

How much does the TSSA G3 exam cost?

Per the TSSA Natural Gas & Hydrogen Fee Schedule effective May 1, 2026, Other Examination is CAD $89 and Challenge Examination is CAD $255.50 (biennial certificate initial/renewal CAD $136). Confirm the current schedule, and expect possible training-provider administration or invigilation fees if the exam is hosted at a college.