Practice Test Geeks(CNG) Compressed Natural Gas Practice Test
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Facility and Ventilation Requirements 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 Facility and Ventilation Requirements flashcards as text

  1. What minimum separation distance is typically required between a CNG dispensing unit and the nearest building opening such as a window or door?

    Answer: 10 feet

    NFPA 52 requires CNG dispensers to be located at least 10 feet from building openings to prevent gas from entering the structure.

  2. In a CNG facility, what must automatically activate when a gas detector reaches 25% of the lower explosive limit (LEL)?

    Answer: An audible and visual alarm

    At 25% LEL, gas detection systems must trigger audible and visual alarms to alert personnel before concentrations reach dangerous levels.

  3. Which of the following facility configurations requires the highest level of ventilation per NFPA 52?

    Answer: Fully enclosed CNG vehicle storage and maintenance building

    Fully enclosed buildings trap gas most readily and therefore require the most stringent mechanical ventilation to maintain safe atmospheric conditions.

  4. What action must occur automatically when a gas detector in a CNG facility reaches 50% of the lower explosive limit?

    Answer: Emergency shutoff of gas supply to the facility

    At 50% LEL, NFPA 52 requires automatic emergency shutoff of the gas supply to prevent further accumulation and potential ignition.

  5. CNG storage cylinders located inside a building must be stored in an area that meets which ventilation requirement?

    Answer: Ventilated to the outside at both high and low points

    Storage areas for CNG cylinders must be ventilated at both high and low points to address any leakage regardless of whether the gas rises or condenses with heavier air components.

  6. What is the purpose of classifying areas around CNG dispensers as hazardous locations?

    Answer: To mandate special electrical equipment that won't ignite released gas

    Hazardous location classification ensures all electrical devices in the area are rated to prevent sparks that could ignite any CNG release.

  7. How far must the exhaust ventilation outlet of a CNG compressor enclosure be located from any ignition source?

    Answer: 10 feet

    Ventilation exhaust outlets must discharge at least 10 feet from any ignition source to prevent expelled gas from igniting near the building.