Gas LNG Plants Practice Examination

FDNY C-01 Supervision of Liquefied Natural Gas (LNG) Plants Practice Examination Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

1.Which of the following best describes LNG?

• A compressed gas stored at 2,000 psi
• A cryogenic liquid stored at −40 °F
• A cryogenic liquid stored at approximately −260 °F
• A combustible solid stored at ambient temperature

LNG must be cooled to roughly −260 °F to remain in liquid form, classifying it as a cryogenic liquid.

2.

The primary hazard associated with LNG is:

• Radioactivity 1 / 4

• Flammable vapor cloud formation
• High-pressure combustion
• Toxic inhalation

When LNG vaporizes, the methane can form a flammable vapor cloud at the right concentration, posing a major ignition risk.

3.

Methane’s flammable range in air is approximately:

A. 1%–2%

B. 3%–8%

C. 5%–15%

D. 20%–40%

Methane ignites when its concentration in air is between about 5% and 15%.

4.Which agency primarily regulates cryogenic storage system design in NYC?

A. EPA

B. FDNY

C. DOT

D. OSHA

FDNY regulates storage, handling, and supervision of LNG systems within NYC.

5. 2 / 4

LNG vapor is:

• Heavier than air at all times
• Initially heavier than air when released
• Lighter than air when released and warming
• Nonflammable when warmed

Cold methane vapor stays heavier than air until it warms, making initial dispersion a ground-level hazard.

6.Which document must be readily available at an LNG plant?

• IRS filings
• Architectural drawings
• Emergency response plan
• DOT transport permits

FDNY requires operators to maintain a written emergency response plan onsite.

7.

Minimum PPE for handling LNG includes:

• Synthetic gloves and sneakers
• Cryogenic gloves and face protection
• Flame-resistant shorts
• Leather gloves only

Cryogenic materials require insulated gloves and face protection to prevent cold burns and exposure. 3 / 4

8.

A major concern with LNG spills is:

• High-temperature radiation
• Rapid vaporization and flammable cloud formation
• Pressure build-up from compression
• Toxic residue

LNG rapidly vaporizes when spilled, creating a flammable vapor cloud.

9.What is the primary component of LNG?

• Propane
• Butane
• Methane
• Ethane

LNG consists mainly of methane, typically over 90%.

10.Which type of extinguisher is appropriate for an LNG fire?

• Water mist only
• Dry chemical fire extinguisher
• Class A foam
• Halon 1211 only

Dry chemical agents are effective for flammable gas fires.

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