Gas or Compressed Natural Gas Exam

FDNY G22 Use of Liquefied Petroleum Gas or Compressed Natural Gas Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary component of liquefied petroleum gas (LPG)?
• Methane
• Propane
• Ethylene
• Hydrogen
• Propane

Rationale: Propane is the main component of LPG, although it can

contain small amounts of butane.

• What is the main hazard of LPG?
• Toxicity 1 / 4

• Explosiveness
• Radioactivity
• Corrosiveness
• Explosiveness

Rationale: LPG is highly flammable and can form explosive mixtures

with air.

• At what temperature does propane boil at atmospheric pressure?

A. -42°C

B. -0.5°C

C. 37°C

D. -42°F

A. -42°C

Rationale: Propane boils at approximately -42°C (-44°F) at

atmospheric pressure.

• Which of the following is a correct color code for LPG cylinders in New

York City?

• Red
• Green
• Silver
• Yellow
• Yellow

Rationale: LPG cylinders are typically painted yellow to indicate their

contents. 2 / 4

• What is the main danger of a compressed natural gas (CNG) leak?
• Fire and explosion
• Frostbite
• Radiation
• Electrical shock
• Fire and explosion

Rationale: CNG is primarily methane, which is highly flammable and

can ignite easily in air.

• What type of valve is commonly used on LPG cylinders?
• Globe valve
• Safety relief valve
• Ball valve
• Needle valve
• Safety relief valve

Rationale: Safety relief valves prevent overpressure in LPG cylinders.

• How should LPG cylinders be stored?
• Lying down horizontally
• In a cool, well-ventilated area upright
• In direct sunlight
• Inside a basement
• In a cool, well-ventilated area upright

Rationale: Upright storage prevents liquid leakage and proper

operation of safety valves. 3 / 4

• What is the lower explosive limit (LEL) of propane?
• 2%
• 4%

C. 10%

D. 20%

• 4%

Rationale: The LEL is the lowest concentration of gas in air that can

ignite; propane’s LEL is 4%.

• What is the upper explosive limit (UEL) of propane?

A. 10%

B. 12.5%

C. 15%

D. 20%

B. 12.5%

Rationale: The UEL is the maximum concentration of gas in air that

can ignite; propane’s UEL is 12.5%.

• What is the proper action if a small LPG leak is detected?
• Ignore it
• Ventilate the area and shut off the source
• Use a flame to check the leak
• Spray water directly on the leak
• Ventilate the area and shut off the source
• / 4