For the Gasfitter Class A Red Seal exam, know how to apply the CSA B149.1 Natural Gas and Propane Installation Code, understand combustion theory, size systems correctly, and make safe installation decisions. This guide uses the official exam breakdown. Red Seal says each exam's questions are developed to assess the activities laid out in the Red Seal Occupational Standard (red-seal.ca, checked October 2026).
Gasfitter Class A Exam Topic Breakdown
Red Seal publishes how the 100 questions are distributed across seven Major Work Activities (red-seal.ca, Gasfitter - Class A Exam Information, checked September 2026):
| Major Work Activity | Questions |
|---|---|
| A — Performs common occupational skills | 5 |
| B — Installs fuel piping and tubing systems | 9 |
| C — Installs venting and air supply systems | 13 |
| D — Installs controls and electrical systems | 19 |
| E — Installs and converts fuel systems, appliances and ancillary equipment | 13 |
| F — Tests and commissions fuel systems, appliances and ancillary equipment | 23 |
| G — Services fuel systems, appliances and ancillary equipment | 18 |
The breakdown above is for the exam based on the 2024 Red Seal Occupational Standard. SkilledTradesBC set October 26, 2026 as the start date of its interprovincial exam on this standard, which replaces the exam based on the 2014 National Occupational Analysis (checked October 2026), so confirm with your provincial or territorial apprenticeship authority which version you will write, and check red-seal.ca before you book.
Where to Focus First
On Red Seal's breakdown the three largest blocks are tests and commissions fuel systems, appliances and ancillary equipment (23 of the 100 questions), installs controls and electrical systems (19) and services fuel systems, appliances and ancillary equipment (18). Start there, and learn the principle behind each procedure rather than memorizing the steps alone.
Key Code Knowledge: CSA B149.1
Know the CSA B149.1 Natural Gas and Propane Installation Code. You don't need to memorize every table, but you need to understand the code's structure and know where to find specific requirements in the edition you will use. The 2024 Gasfitter – Class A standard names CSA B149.1 among the codes for its tasks, and SkilledTradesBC provides B149.1:20, B149.2:20 and B149.3:20 as the code books for its interprovincial exam based on the 2024 standard. Where the code applies is set by regulation: Alberta's notice says CSA B149.1:25 applies where gas is used for fuel purposes and to the installation of natural gas and propane appliances and equipment downstream of the utility installation or of a propane container's first-stage regulator. For each block of the breakdown above, find and read the parts of the code that apply to it.
Critical Formulas and Calculations
Calculations to master:
Combustion Air
Take the air-supply requirements and the calculation method from the edition of CSA B149.1 your exam uses, and practise the calculation for a space with more than one appliance.
BTU/hr to kW Conversion
1 kW = 3,412 BTU/hr — memorize this, and practise converting equipment ratings from one unit to the other.
Pressure Drop and Pipe Sizing
Be familiar with the concept of pressure drop through piping: longer runs, smaller pipe, and higher flow rates all increase pressure drop. Practise identifying a pressure drop problem and selecting the correct correction.
Heat Loss and Equipment Sizing
Know that a furnace is sized to the building's design heat loss. Oversizing causes short cycling; undersizing causes inability to maintain setpoint.
Study Strategy: 8-Week Plan
| Week | Focus | Target |
|---|---|---|
| 1–2 | Gas Properties and Supply Systems | Memorize gas properties (SG, BTU content, flammability limits), regulator types, service pressure requirements |
| 3–4 | Piping Systems and Code | Gas piping requirements in the CSA B149.1 edition your exam uses; pipe sizing methods; pressure testing requirements; materials and fittings |
| 5 | Appliances | Installation requirements for all appliance types; gas train components; pilot and ignition systems |
| 6 | Venting and Combustion Air | Category I–IV vent systems; combustion air calculations; termination requirements; masonry venting |
| 7 | Combustion Theory and Efficiency | Combustion equations; excess air; CO causes and effects; efficiency measurement; seasonal vs. AFUE ratings |
| 8 | Full Review and Mock Exams | Complete practice tests; identify weak topics; review the RSOS (or the NOA, where your exam still uses it) for anything missed; in the last 48 hours, practise finding requirements in the code quickly |
What Good Study Materials Look Like
Good Gasfitter Class A study materials are built directly from the Red Seal Occupational Standard (RSOS) and CSA B149.1. Red flags in study materials include:
- Questions that test provincial-specific requirements rather than national standards
- Outdated references to superseded code editions
- Questions focused on specific equipment brands or models rather than principles
- Answer explanations that don't cite the relevant code section
A Study Method: Topic Blocks and the Code
Work through practice questions in topic blocks, not random. When you get a question wrong, find the exact clause in CSA B149.1 that addresses it. Read the code in the context of questions you've missed, not only cover to cover.
Exam Day Tips
- Read every question completely before selecting an answer — a single qualifier word ("minimum," "maximum," "must," "should") can change the answer
- Flag and return — if you're not confident, mark it and move on. Return with fresh eyes.
- Eliminate obviously wrong answers before deciding between the remaining options
- Think code, not field habit — answer with what the code requires, not necessarily what you've always done in the field
- Change an answer only for a reason — when you find something specific in the question or the code
Practice the Gasfitter (Class A) Questions
110 free Gasfitter (Class A) practice questions covering CSA B149.1, gas supply, appliances, venting and combustion — every answer explained. Timed Mock Exam mode included.
Studying offline? The complete 110-question Gasfitter Class A bank and its revision notes come as printable PDFs — CA$19 on Ko-fi. Independent, unofficial study resource · no guarantee of results.
Start Gasfitter (Class A) Practice →Related Resources
Frequently asked questions
How many questions are on the Gasfitter Class A Red Seal exam?
The Gasfitter – Class A Red Seal exam has 100 multiple-choice questions. A minimum score of 70% (70 correct) is required to pass.
What topics are on the Gasfitter (Class A) Red Seal exam?
Red Seal's exam information page lists seven Major Work Activities for the 100-question exam based on the 2024 standard: common occupational skills (5 questions), fuel piping and tubing systems (9), venting and air supply systems (13), controls and electrical systems (19), installing and converting fuel systems, appliances and ancillary equipment (13), testing and commissioning (23), and servicing (18). SkilledTradesBC set October 26, 2026 as the start date of its interprovincial exam on that standard, which replaces the exam based on the 2014 National Occupational Analysis.
How long is the Gasfitter Class A Red Seal exam?
Red Seal's Exam Preparation Guide gives the writing time as four hours; for the 100-question Gasfitter – Class A exam that is about 2.4 minutes per question. Practise under timed conditions so you know your own pace before exam day.
Does Red Seal publish a pass rate for the Gasfitter Class A exam?
No. Red Seal does not publish a pass rate in its Gasfitter – Class A exam information or its Exam Preparation Guide; what those pages publish is the pass mark, 70%, and how the 100 questions are distributed.