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100+ Free Red Seal Gasfitter Class B Practice Questions

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2026 Statistics

Key Facts: Red Seal Gasfitter Class B Exam

100

Practice Questions

OpenExamPrep

100

Exam Questions

Red Seal

70%

Passing Score

Red Seal

120 kW

Max Appliance Input (400,000 BTU/hr)

Red Seal Occupational Standard

CSA B149.1

Installation Code

CSA Group

~$100-170

Exam Fee (CAD, varies)

Provincial apprenticeship authorities

The Red Seal Gasfitter — Class B is the interprovincial (IP) certification for gasfitters who install and service natural gas and propane appliances and piping up to 400,000 BTU/hr (120 kW). The exam has 100 four-option multiple-choice questions, takes about four hours, and requires 70% to pass; it is administered by provincial apprenticeship authorities, with fees typically ranging from about $100 to $170 CAD. Content is grounded in the CSA B149.1 Natural Gas and Propane Installation Code and CSA B149.2, and spans codes and safety, gas properties and combustion, piping and venting, appliances such as furnaces/boilers/water heaters/fireplaces, controls and electrical, and commissioning and service. This free prep includes 100 research-based practice questions with explanations and an AI tutor.

Sample Red Seal Gasfitter Class B Practice Questions

Try these sample questions to test your Red Seal Gasfitter Class B exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which code is the primary installation standard a Class B gasfitter applies when installing natural gas and propane appliances and piping in Canada?
A.CSA B149.1 Natural Gas and Propane Installation Code
B.CSA B139 Installation Code for Oil-Burning Equipment
C.CSA B51 Boiler, Pressure Vessel and Pressure Piping Code
D.National Plumbing Code of Canada
Explanation: CSA B149.1, the Natural Gas and Propane Installation Code, is the governing installation standard for gas-fired appliances and gas piping/tubing across Canada and is adopted by reference in provincial gas safety regulations. CSA B149.2 covers propane storage and handling.
2A Class B gasfitter is authorized to install and service gas appliances up to what maximum input rating?
A.100,000 BTU/hr (30 kW)
B.400,000 BTU/hr (120 kW)
C.1,000,000 BTU/hr (300 kW)
D.Unlimited input
Explanation: The Class B gasfitter scope covers appliances with an input up to 400,000 BTU/hr (approximately 120 kW). Appliances above this rating require a Class A gasfitter. This limit defines the residential and light-commercial equipment the Class B works on.
3Which code governs the storage and handling of propane, separate from the installation code?
A.CSA B149.1
B.CSA B149.2
C.CSA B149.3
D.CSA B108
Explanation: CSA B149.2, the Propane Storage and Handling Code, covers the storage, handling, and transfer of propane including cylinders and tanks. CSA B149.1 covers appliance and piping installation for both natural gas and propane.
4Before working on a gas appliance, a gasfitter must verify that the equipment carries which of the following to confirm it is approved for use in Canada?
A.A manufacturer's warranty card
B.A certification/approval agency mark (e.g., CSA, cUL, or provincial approval)
C.A purchase receipt
D.A model number only
Explanation: CSA B149.1 requires that gas appliances and accessories be certified by an accredited agency (such as CSA or cUL) bearing a recognized certification mark, or hold a provincial field/special approval. Installing uncertified equipment is a code violation.
5What is the characteristic odorant added to natural gas and propane to aid in leak detection?
A.Chlorine
B.Mercaptan (ethyl mercaptan)
C.Ammonia
D.Carbon monoxide
Explanation: Natural gas and propane are colourless and odourless in their pure state, so an odorant such as ethyl mercaptan is added to give the distinctive 'rotten egg' smell, allowing leaks to be detected by smell. CSA codes require fuel gases to be odorized.
6The specific gravity of natural gas relative to air is approximately:
A.0.60 (lighter than air)
B.1.52 (heavier than air)
C.1.00 (same as air)
D.2.50 (much heavier than air)
Explanation: Natural gas (mostly methane) has a specific gravity of about 0.60, making it lighter than air, so a leak tends to rise and disperse upward. Propane has a specific gravity of about 1.52 and is heavier than air, so it settles in low areas.
7Approximately how much heat is released by burning one cubic foot of natural gas at standard conditions?
A.100 BTU
B.1,000 BTU
C.2,500 BTU
D.10,000 BTU
Explanation: Natural gas has a higher heating value of approximately 1,000 BTU per cubic foot. Propane is much more energy-dense at about 2,500 BTU per cubic foot, which is why propane orifices are smaller for the same input.
8The three requirements that must all be present for combustion to occur are commonly described as the fire triangle. They are:
A.Fuel, oxygen, and an ignition source (heat)
B.Fuel, water, and pressure
C.Oxygen, nitrogen, and heat
D.Fuel, carbon dioxide, and a spark
Explanation: Combustion requires fuel (gas), oxygen (from combustion air), and a source of ignition/heat at or above the ignition temperature. Removing any one element stops combustion, which is the basis of flame-supervision safety controls.
9Complete combustion of natural gas produces primarily which two harmless products?
A.Carbon monoxide and hydrogen
B.Carbon dioxide and water vapour
C.Sulphur dioxide and soot
D.Nitrogen oxides and ash
Explanation: Complete (perfect) combustion of methane produces carbon dioxide and water vapour, plus heat. The presence of carbon monoxide, soot, or aldehydes indicates incomplete combustion, usually from insufficient air or poor mixing.
10A yellow, lazy, luminous flame on an atmospheric burner most likely indicates:
A.Complete combustion with excess air
B.Incomplete combustion from a lack of primary air
C.Correct air-fuel ratio
D.Too much primary air
Explanation: A yellow, lazy flame signals incomplete combustion caused by insufficient primary air, which can produce carbon monoxide and soot. A correctly adjusted natural gas burner shows a sharp blue flame with well-defined inner cones.

About the Red Seal Gasfitter Class B Exam

The Red Seal Gasfitter Class B certification qualifies tradespeople to install, service, and maintain natural gas and propane appliances and piping up to 400,000 BTU/hr (120 kW). The interprovincial (IP) exam has 100 multiple-choice questions and requires 70% to pass, with content built on the CSA B149.1 Natural Gas and Propane Installation Code.

Assessment

100 four-option multiple-choice questions over about four hours, 70% to pass; the Gasfitter Class B Red Seal interprovincial exam is administered by provincial apprenticeship authorities. This practice bank is 100 selected-response items.

Time Limit

Approximately 4 hours

Passing Score

70%

Exam Fee

~$100-170 CAD provincial exam fee (varies by province/territory) (Employment and Social Development Canada / Red Seal Program (delivered by provincial apprenticeship authorities))

Red Seal Gasfitter Class B Exam Content Outline

16%

Safety, Codes & Regulations

CSA B149.1/B149.2, provincial gas safety regulations, WHMIS, lockout/tagout, confined space, gas-leak response, permits, red tags, and the AHJ

12%

Gas Properties & Combustion

Specific gravity, heating value, odorant, flammability limits, combustion triangle, complete vs incomplete combustion, carbon monoxide, and primary/excess air

22%

Piping & Venting

Pipe materials and sizing, pressures, drip legs, shut-off valves, CSST bonding, leak testing, vent categories, clearances, combustion air, and common venting

26%

Appliances ≤120 kW

Furnaces, boilers, water heaters, fireplaces and unit heaters up to 400,000 BTU/hr, heat exchangers, orifices, FVIR, condensate, and efficiency

12%

Controls & Electrical

Thermocouples, thermopiles, flame rectification, gas valves and regulators, 24 V controls, limit/rollout/pressure switches, ignition, and bonding

12%

Commissioning & Service

Purging, leak verification, clocking the meter, combustion analysis, manifold pressure, diagnosing spillage and short-cycling, and homeowner education

How to Pass the Red Seal Gasfitter Class B Exam

What You Need to Know

  • Passing score: 70%
  • Assessment: 100 four-option multiple-choice questions over about four hours, 70% to pass; the Gasfitter Class B Red Seal interprovincial exam is administered by provincial apprenticeship authorities. This practice bank is 100 selected-response items.
  • Time limit: Approximately 4 hours
  • Exam fee: ~$100-170 CAD provincial exam fee (varies by province/territory)

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

Red Seal Gasfitter Class B Study Tips from Top Performers

1Keep your CSA B149.1 code book at hand while studying — many exam questions test applying a clause, clearance, or table rather than recalling a fact
2Memorize core gas properties: natural gas SG ~0.6 and ~1,000 BTU/ft3, propane SG ~1.52 and ~2,500 BTU/ft3, and the flammability limits (NG ~5-15%, propane ~2.4-9.5%)
3Know the appliance vent categories: Category I uses Type B metal vent, while condensing Category IV uses listed plastic vent and produces acidic condensate
4Remember the Class B scope of 400,000 BTU/hr (120 kW) and practice input/output efficiency calculations and clocking the meter
5Drill flame-supervision controls: thermocouple (~30 mV), thermopile (~750 mV), and flame rectification (microamps) and what each proves
6Complete all 100 practice questions and review every miss with the AI tutor before sitting the exam

Frequently Asked Questions

How many questions are on the Red Seal Gasfitter Class B exam and how long is it?

The Gasfitter Class B Red Seal interprovincial exam has 100 four-option multiple-choice questions and takes about four hours. You need 70% to pass, and the content is based on the CSA B149.1 Natural Gas and Propane Installation Code.

What score do I need to pass the Gasfitter Class B exam?

You need 70% to pass the Red Seal Gasfitter Class B exam. Because it spans codes, gas properties, piping and venting, appliances, controls, and commissioning, balanced study across every area is important.

What is the difference between Gasfitter Class A and Class B?

A Class B gasfitter works on gas appliances up to 400,000 BTU/hr (120 kW), covering most residential and light-commercial equipment. A Class A gasfitter has an unlimited input scope for larger commercial and industrial equipment.

Which code does the Gasfitter Class B exam test?

The exam is built on the CSA B149.1 Natural Gas and Propane Installation Code, along with CSA B149.2 for propane storage and handling and your provincial gas safety regulation. Many questions require applying code rules to a scenario.

How much does the Gasfitter Class B exam cost?

Exam and certification fees are set by each province or territory and typically range from about $100 to $170 CAD. Check with your provincial apprenticeship authority for the exact fee and scheduling details.

Is this free Gasfitter Class B practice as good as paid prep?

Our 100 practice questions cover the same content areas as the Red Seal Occupational Standard, with a teaching explanation for every answer plus free daily AI tutor interactions. All content is free forever and updated for 2026.