G3 Study Guide 2026
Everything you need to pass the G3 exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 G3 Exam Format at a Glance
📚 G3 Topics to Study (45)
✍️ Sample G3 Questions & Answers
1. Which of the following is the primary purpose of the Technical Standards and Safety Act, 2000 (TSSA)?
The purpose of the Technical Standards and Safety Act, 2000, is to enhance public safety in Ontario by providing for the efficient and flexible administration of technical standards for various sectors, including fuels.
2. Which leak detection method is most commonly used for a quick field check of gas piping joints?
Soap bubble solution is the standard field method for locating gas leaks at joints and fittings, as bubbles form visibly where gas escapes.
3. What is the minimum burial depth for underground gas piping in Ontario?
CSA B149 requires 18 inches (450 mm) below finished grade.
4. Where are G3 certification exams administered?
Exams are administered at TSSA-approved centres throughout Ontario.
5. Gas appliances are classified into different venting categories. Which category describes a non-condensing appliance that operates with a non-positive (negative) vent pressure and uses a draft hood?
Category I appliances are natural draft or fan-assisted, operate with a negative vent static pressure (the flue gases are buoyant and not forced out under positive pressure), and their flue gases are at a temperature high enough to avoid condensation in the vent. This category includes standard-efficiency furnaces and natural draft water heaters.
6. An overpressure protection device (OPD) on a gas regulator is designed to:
OPDs protect downstream piping and appliances by closing or relieving gas flow when outlet pressure rises above a set threshold.