CNG Facility and Ventilation Requirements 2

Question 1

What is the minimum mechanical ventilation rate required for an enclosed CNG vehicle storage or repair facility?

Accepted Answer

1.5 cfm per square foot of floor area

Answer

NFPA 52 requires a minimum of 1.5 cfm per square foot of floor area for mechanical ventilation in enclosed CNG facilities.

Question 2

In a CNG facility, ventilation air inlets should be located at what height relative to the floor?

Accepted Answer

At floor level or as low as possible

Answer

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.

Question 3

Which code primarily governs CNG vehicle fueling facility design and ventilation in the United States?

Accepted Answer

NFPA 52

Answer

NFPA 52, Vehicular Gaseous Fuel Systems Code, is the primary standard governing CNG fueling and storage facilities including ventilation requirements.

Question 4

A CNG compressor room classified as a hazardous location must have electrical equipment rated for which hazardous location class?

Accepted Answer

Class I, Division 2

Answer

CNG compressor rooms are typically classified as Class I, Division 2 locations where flammable gases may be present under abnormal conditions.

Question 5

What is the purpose of explosion-relief panels or vents in a CNG compressor building?

Accepted Answer

To reduce overpressure in the event of an internal explosion

Answer

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.

(CNG) Compressed Natural Gas Practice Test

(CNG) Compressed Natural Gas Practice Test

CNG Facility and Ventilation Requirements 2