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
What is the minimum mechanical ventilation rate required for an enclosed CNG vehicle storage or repair facility?
Answer: 1.5 cfm per square foot of floor area
NFPA 52 requires a minimum of 1.5 cfm per square foot of floor area for mechanical ventilation in enclosed CNG facilities.
In a CNG facility, ventilation air inlets should be located at what height relative to the floor?
Answer: At floor level or as low as possible
Ventilation inlets should be at floor level because natural gas, though lighter than air, can accumulate in low spots when equipment is cold-starting or leaking.
Which code primarily governs CNG vehicle fueling facility design and ventilation in the United States?
Answer: NFPA 52
NFPA 52, Vehicular Gaseous Fuel Systems Code, is the primary standard governing CNG fueling and storage facilities including ventilation requirements.
A CNG compressor room classified as a hazardous location must have electrical equipment rated for which hazardous location class?
Answer: Class I, Division 2
CNG compressor rooms are typically classified as Class I, Division 2 locations where flammable gases may be present under abnormal conditions.
What is the purpose of explosion-relief panels or vents in a CNG compressor building?
Answer: To reduce overpressure in the event of an internal explosion
Explosion-relief panels are designed to fail at low pressure differentials, venting blast energy outward and protecting the building structure if a gas explosion occurs.
How should exhaust ventilation outlets be positioned in a CNG vehicle repair facility?
Answer: Near the ceiling to exhaust lighter-than-air gas that has risen
Exhaust outlets near the ceiling effectively remove natural gas that has risen due to its lower density than air, preventing dangerous accumulation.
Under NFPA 52, when is continuous gas detection monitoring required in an enclosed CNG fueling facility?
Answer: When the facility cannot provide the required ventilation rate
Continuous gas detection is required as an alternative safeguard when the required mechanical ventilation rate cannot be maintained, triggering alarms or automatic shutoffs.