Based on the Red Seal Gasfitter – Class A exam blueprint: flame safeguard sequencing, valve trains, interlocks, plant piping, venting and air supply, testing, commissioning and service
Practice on the go and jump straight back to where you left off.
About the certification
Gasfitter – Class A is a Red Seal trade for large commercial and industrial gas systems: appliances above 400 000 Btuh (120 kW), burner management and flame safeguard systems, plant piping, venting and air supply, and the CSA B149 codes. Licensing rules differ by province, so check with your apprenticeship or safety authority. ExamHub's questions follow the 2024 Red Seal Occupational Standard.
The Red Seal exam has 100 multiple-choice questions in 7 blocks: common skills (5 questions), piping and tubing (9), venting and air supply (13), controls and electrical (19), appliances, conversions and storage (13), testing and commissioning (23) and service (18). Between 60 and 70% of the questions test procedures and their application, 15 to 25% knowledge and recall, and 10 to 20% critical thinking. The pass mark is 70% and the writing time is four hours (exam details as of October 2026).
ExamHub's free practice quiz has 151 original questions weighted to those blocks, with an explanation and a source for every answer. The questions cover flame safeguard sequencing, valve trains, interlocks, calculations from the Red Seal formulas sheet, pressure testing and purging, and draw on public TSSA, Alberta and manufacturer documents.
Sources: Red Seal Occupational Standard 2024, the Red Seal exam-information page, the Exam Preparation Guide, TSSA code adoption documents and Alberta STANDATA bulletins. Exam details as of October 2026. See how ExamHub checks its questions.
What's covered
Categories group the seven Red Seal exam blocks, weighted like the real exam.
| Block | Exam questions | Bank questions |
|---|---|---|
| A. Common skills | 5 | 8 |
| B. Piping and tubing | 9 | 14 |
| C. Venting and air supply | 13 | 20 |
| D. Controls and electrical | 19 | 28 |
| E. Appliances and storage | 13 | 20 |
| F. Testing and commissioning | 23 | 34 |
| G. Service | 18 | 27 |
Try a few
Five sample questions from the question bank, with the answer and explanation.
Why: The pilot trial for ignition (PTFI) is the maximum time allowed to establish and detect the pilot flame. Failure within that period causes the flame safeguard system to lock out on safety, requiring a manual reset. A control never proceeds to the main valve without proven pilot flame.
Why: Gas flow is 1 500 000 / 1 000 = 1 500 ft3/h. Theoretical air at 10:1 is 15 000 ft3/h, excess air at 50% is 7 500 ft3/h, so the total is 22 500 ft3/h. Giving only the theoretical air, only the excess, or adding a dilution volume the burner does not have are the usual errors.
Why: For an engine or turbine up to 2.5 MMBtu/h, one C/I-marked safety shut-off valve or two valves are allowed (two minimum for propane). Above 2.5 and up to 5 MMBtu/h, at least two safety shut-off valves are required, each marked C/I, piped in series and wired in parallel. Proof of closure becomes mandatory above 5 MMBtu/h.
Why: The hydrostatic test pressure at every point in the system shall not be less than 1.5 times the design pressure: 1.5 x 150 = 225 psig. It is maintained at least 30 minutes or as long as needed to inspect joints, and the system is then fully drained and dried.
Why: The Red Seal formula is % CO2 = stoichiometric CO2 / (1 + excess air / 100). Rearranged, 1 + EA/100 = 11.7 / 9.0 = 1.30, so excess air is 30%. The values 77% and 23% come from dividing the wrong way round, and 130% forgets to subtract the 1.
FAQ
The Red Seal exam has 100 multiple-choice questions. ExamHub's bank has 151 questions, and Test Mode draws 100 for a 240-minute timed simulation.
According to the Red Seal Exam Preparation Guide, the pass mark is 70% and the writing time is four hours. ExamHub's Test Mode uses the same time.
Seven blocks: common skills (5 questions), piping and tubing (9), venting and air supply (13), controls and electrical (19), appliances, conversions and storage (13), testing and commissioning (23) and service (18). Commissioning and controls, including flame safeguard systems, carry the most weight.
No. The CSA B149 codes are paid documents and are not reproduced here. Each question cites the Red Seal standard and the public document (regulator bulletin, manufacturer literature, open textbook) that quotes or explains the clause. Questions that rest on an Ontario or Alberta rule say so.
No. These are original practice questions written from the Red Seal standard and free public sources. They are not copies of exam questions.