Practice Test Geeks(CNG) Compressed Natural Gas Practice Test
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Cylinder Inspection and Regulations 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 Cylinder Inspection and Regulations flashcards as text

  1. According to CNG cylinder inspection standards, which condition requires immediate removal from service?

    Answer: A visible crack, burn mark, or bulge anywhere on the cylinder

    Cracks, burn marks, or bulges indicate structural compromise and require immediate cylinder removal from service.

  2. Which standard specifically governs the design, testing, and labeling of compressed natural gas vehicle fuel containers in the US?

    Answer: ANSI/NGV-2

    ANSI/NGV-2 is the American National Standard specifically for CNG vehicle fuel containers, covering design, manufacture, and testing.

  3. A Type 4 CNG cylinder is best described as having which construction?

    Answer: Plastic (non-metallic) liner fully wrapped with carbon fiber or fiberglass composite

    Type 4 cylinders use a non-metallic plastic liner (typically HDPE) fully overwrapped with composite fiber material, making them the lightest cylinder type.

  4. What is the standard maximum service life of a DOT-specification CNG vehicle cylinder from its manufacture date?

    Answer: 20 years

    Most DOT-approved CNG cylinders carry a 20-year maximum service life from the stamped manufacture date, after which they must be replaced.

  5. What is the primary purpose of hydrostatic pressure testing performed on CNG cylinders?

    Answer: To verify the cylinder can withstand test pressures significantly above service pressure

    Hydrostatic testing subjects the cylinder to pressures well above service pressure (typically 5/3 of service pressure) to verify structural integrity and detect permanent deformation.

  6. Which of the following is NOT required to be permanently marked on a DOT-specification CNG cylinder?

    Answer: The owner's contact information and vehicle identification number

    DOT required markings include serial number, service pressure, and manufacture date, but owner contact information is not mandated on the cylinder itself.

  7. What is the maximum permissible depth of an isolated gouge on a Type 1 (all-steel) CNG cylinder wall?

    Answer: 10% of measured wall thickness

    Gouges exceeding 10% of the cylinder wall thickness on Type 1 steel cylinders require rejection, as deeper material loss compromises pressure-bearing capacity.