Apprentice Gas Fitter Licensing Exam

Apprentice Gas Fitter Licensing Exam Practice Test Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

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

Rationale: Natural gas is made up of approximately 90% methane.

• Which unit is used to measure gas pressure in low-pressure systems?

A. PSI

• kPa
• Inches of water column
• Inches of mercury 1 / 3

Rationale: Low-pressure gas is typically measured in inches of water

column (W.C.).

• What is the typical odorant added to natural gas for leak detection?
• Benzene
• Propanol
• Mercaptan
• Naphthalene

Rationale: Mercaptan provides a sulfur “rotten egg” smell for safety.

• Propane is stored in what physical state inside a tank?
• Gas only
• Liquid and vapor
• Solid
• Aerosol

Rationale: Propane is stored as a liquid under pressure with a vapor

space.

• What is the minimum height above a building opening for a vent

termination?

• 6 inches
• 12 inches
• 24 inches
• 36 inches

Rationale: Codes require 24 inches above openings to prevent flue

gas re-entry. 2 / 3

• What is the primary hazard of carbon monoxide exposure?
• Skin irritation
• Eye burning
• Lung cancer
• Oxygen replacement in the blood

Rationale: CO binds to hemoglobin and prevents oxygen delivery.

• What does a regulator do in a gas system?
• Increase flow
• Remove water from gas
• Filter impurities
• Reduce gas pressure

Rationale: A regulator ensures the appliance receives correct

pressure.

• Which piping material is commonly used for underground gas piping?
• Copper
• Steel without coating
• Polyethylene (PE)
• Brass

Rationale: PE piping is corrosion-resistant and approved for

underground.

9. Before working on a gas system, you must:

• Turn off electricity
• Shut off gas supply
• / 3