Practice Test Geeks(CNG) Compressed Natural Gas Practice Test
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Properties and Safety Flashcards

7 cards from real CNG practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Properties and Safety flashcards as text

  1. What is the primary component of compressed natural gas (CNG)?

    Answer: Methane

    CNG is composed primarily of methane (CH4), typically making up 90% or more of its composition.

  2. CNG is stored in vehicle cylinders at approximately what pressure?

    Answer: 3,600 psi

    CNG is typically stored in high-pressure cylinders at around 3,600 psi (248 bar) in vehicles.

  3. What color are CNG fuel lines typically required to be for identification purposes?

    Answer: Orange

    CNG fuel lines are typically color-coded orange to distinguish them from other vehicle fluid lines.

  4. Which property makes CNG safer than gasoline in terms of spill behavior?

    Answer: It dissipates into the atmosphere rather than pooling

    Being lighter than air, CNG disperses upward and dissipates into the atmosphere rather than pooling on the ground like liquid fuels.

  5. What is the Lower Flammability Limit (LFL) of methane in air?

    Answer: 5%

    Methane's Lower Flammability Limit is approximately 5% by volume in air, below which ignition cannot occur.

  6. Which type of CNG cylinder is made entirely of metal with no composite wrapping?

    Answer: Type 1

    Type 1 cylinders are all-metal (typically steel or aluminum) with no composite overwrap, and are the heaviest type.

  7. A CNG cylinder must be removed from service when it reaches what condition?

    Answer: When it exceeds its requalification date or shows structural damage

    CNG cylinders must be removed from service when they exceed the manufacturer's requalification date or show signs of structural damage, bulging, or deep corrosion.