Exam Class B Practice Exam Questions And

Gas Fitter Natural Gas & Propane Licensing Exam Class B Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary component of natural gas supplied to consumers?
• Butane
• Propane
• Methane
• Ethane

Rationale: Methane makes up approximately 90% or more of typical

natural gas supplies.

• Propane is stored and transported in what state?
• Vapor state only
• Solid state
• Liquid under pressure
• Free gas in cylinders 1 / 3

Rationale: Propane is liquefied under pressure for efficient storage

and transportation.

• Which standard typically governs gas appliances installation?

A. ANSI Z41

B. OSHA 29 CFR 1910

C. CSA B149.1

D. NFPA 30

Rationale: CSA B149.1 is the primary natural gas and propane

installation code in Canada.

• Which gas is heavier than air?
• Natural gas
• Propane
• Hydrogen
• Nitrogen

Rationale: Propane’s higher density causes it to accumulate near

floors.

5. The primary purpose of a gas regulator is:

• Filtering
• Metering gas usage
• Reducing and controlling gas pressure
• Controlling combustion air

Rationale: Regulators drop and stabilize pressure delivered to

appliances. 2 / 3

6. The flame of a properly adjusted natural gas burner should be:

• Yellow with long tips
• Blue and stable
• Mostly red
• Orange and lifting

Rationale: A clean blue flame ensures efficient, complete

combustion.

• Which tool detects gas leaks using bubbling action?
• Combustion analyzer
• Multimeter
• Leak detection solution
• Manometer

Rationale: Soap-type leak solutions create visible bubbles at leak

points.

• What is the odorant added to natural gas for detection?
• Acetone
• Mercaptan
• Sulfuric acid
• Naphthalene

Rationale: Mercaptan produces the characteristic rotten-egg smell

for safety.

9. The minimum slope required on horizontal gas piping for drainage is:

• Level
• / 3