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
A CNG repair garage with natural ventilation (no mechanical fans) must have openings equivalent to what minimum percentage of the floor area?
Answer: 2%
NFPA 52 allows natural ventilation if the total permanent openings equal at least 2% of the floor area, distributed at both high and low levels.
What does NFPA 52 require for electrical outlets installed within the hazardous location zone of a CNG dispenser?
Answer: Explosion-proof or intrinsically safe listed equipment
Within classified hazardous zones, only explosion-proof or intrinsically safe electrical equipment may be installed to prevent ignition of any released gas.
In which scenario may the required mechanical ventilation rate for a CNG facility be reduced?
Answer: When the facility is equipped with a listed continuous gas detection system
A listed continuous gas detection system that triggers alarms and automatic shutoffs may be used as an equivalent alternative to full mechanical ventilation requirements.
What is the required minimum distance between a CNG compressor and any combustible material stored inside the same building?
Answer: 5 feet
Compressors must be separated from combustible materials by at least 5 feet or by a noncombustible partition to minimize fire spread risk.
When must CNG facility ventilation systems be interlocked with the gas supply?
Answer: When the ventilation system failure could allow dangerous gas accumulation
Ventilation and gas supply interlocks are required whenever ventilation failure would otherwise allow hazardous gas concentrations to develop undetected.
What type of floor drain is prohibited in a CNG facility classified as a hazardous location?
Answer: Drains that discharge to a sanitary sewer without a trap
Floor drains must include traps to prevent sewer gases from entering the facility, as sewer gas could create a flammable atmosphere in the hazardous zone.
Which statement correctly describes the ventilation requirement for a CNG fast-fill dispenser located under an open canopy?
Answer: No mechanical ventilation is required if the canopy has at least 25% open sides
An open canopy with at least 25% open sides is not considered an enclosed structure, so standard enclosed-facility ventilation requirements do not apply.