Based on the Red Seal Gasfitter Class B exam blueprint: gas piping and tubing, venting and air supply, controls and electrical, appliances and conversions, testing and commissioning, service and repair
Practice on the go and jump straight back to where you left off.
About the certification
The official Red Seal trade name is Gasfitter – Class B. A Class B gasfitter installs, converts, tests and services gas piping and gas-fired appliances up to 400,000 Btuh, such as furnaces, boilers, water heaters and residential or light-commercial equipment. Class A has no input limit. Passing the interprovincial Red Seal exam, with the provincial requirements, earns the Red Seal endorsement.
Exam details as of October 2026, from the Red Seal Gasfitter – Class B exam information page and the Red Seal Exam Preparation Guide.
| Exam detail | Value |
|---|---|
| Questions | 100, multiple choice (four options) |
| Blocks | 7 (A to G) |
| Pass mark | 70% |
| Writing time | 4 hours |
| Code book | Supplied at the exam; SkilledTradesBC lists the B149.1 Natural Gas and Propane Installation Code as the code book provided |
| Question types | Procedural and application 50-60%, recall 25-35%, critical thinking 10-20% |
ExamHub's free Gasfitter Class B practice quiz has 158 original questions weighted to the exam blocks, with an explanation and a source for every answer. The CSA B149.1 code is a paid standard, so each question cites the public document that quotes the clause: the Red Seal standard, regulator bulletins from Alberta, British Columbia and Ontario, open trade textbooks and manufacturer instructions. Questions that rest on one province's rules say so. See how ExamHub checks its questions.
Studying for the Ontario licence instead? Try the TSSA G3 Gas Technician practice test. Gas work also overlaps with the 306A Plumber and 307A Steamfitter trades.
What's covered
Categories follow the 7 Red Seal exam blocks, weighted like the real exam.
| Block / topic | Exam Q | Bank Q |
|---|---|---|
| Common Occupational Skills | 7 | 11 |
| Fuel Piping and Tubing | 14 | 23 |
| Venting, Air Supply and Draft Control | 15 | 28 |
| Controls and Electrical Systems | 15 | 24 |
| Appliances, Conversions and Fuel Storage | 15 | 25 |
| Testing and Commissioning | 16 | 24 |
| Maintenance, Repair and Decommissioning | 18 | 23 |
Try a few
Five sample questions from the question bank, with the answer and explanation.
Why: Near or above the lower explosive limit, the make-safe steps are to evacuate the building, do not cross-ventilate (it could carry an explosive mixture to an ignition source), shut the riser or cylinder valve only if it is on the way out, and phone from a safe distance. The gasfitter must not go back in to reach a valve.
Why: A jointing sealant is applied to the male threads of a metal pipe. Tape is stretched and applied in a clockwise direction with a 50% overlap, leaving the first two starter threads bare so that loose tape cannot enter the pipe. The sealant must be certified to CAN/ULC-S642.
Why: Gas flow is 200,000 / 1,000 = 200 cfh, so combustion air is 2,000 cfh and 50% excess air is 1,000 cfh. With a draft control device, dilution air usually equals the combustion air plus the excess air: 2,000 + 1,000 = 3,000 cfh.
Why: Gas flow is 3,600 x 2 / 50 = 144 cfh. Input is cfh x heating value: 144 x 1,000 = 144,000 Btuh. Forgetting the dial size gives 72 cfh, or 72,000 Btuh.
Why: When all appliances shut off, the pressure rises slightly before the regulator achieves positive lock-up, then stops rising. Appliance inlet pressure must stay below 14 in. w.c. or the internal gas valve will be damaged. A pressure that keeps creeping up means the regulator is not closing tightly.
FAQ
The Red Seal Gasfitter Class B exam has 100 multiple-choice questions. ExamHub's bank has 158 questions, and Test Mode draws a 100-question timed simulation.
The Red Seal exam preparation guide states a pass mark of 70% and a writing time of four hours. ExamHub's Test Mode uses the same 70% and up to 4 hours.
Seven blocks: common occupational skills (7 questions), fuel piping and tubing (14), venting and air supply (15), controls and electrical systems (15), appliances, conversions and fuel storage (15), testing and commissioning (16) and service: maintenance, repair and decommissioning (18).
No. CSA B149.1 is a paid standard, so ExamHub does not reproduce it. Each question is original and cites the Red Seal standard or a public document that quotes the clause, such as a regulator bulletin, an open trade textbook or a manufacturer's instructions.
No. These are original practice questions written from the Red Seal standard and free public sources. They are not copies of exam questions.
Class B covers gas lines and gas-fired appliances up to 400,000 Btuh. Class A has no input limit and includes appliances and equipment above 400,000 Btuh, such as boilers, burners, makeup air units and process burners. Sources: the Red Seal Gasfitter overview pages and the SkilledTradesBC Gasfitter Class A program profile.
You do not bring your own material. The Red Seal preparation guide says candidates are supplied with exam materials such as a math formulas sheet, an acronym list, code book information, a pencil and eraser, and a calculator if needed. SkilledTradesBC lists the B149.1 Natural Gas and Propane Installation Code as the code book provided.