CNG Properties and Safety 4

Question 1

What is the approximate energy content of CNG compared to gasoline on a volume basis?

Accepted Answer

One gasoline gallon equivalent (GGE) of CNG contains about the same energy as one gallon of gasoline

Answer

One Gasoline Gallon Equivalent (GGE) of CNG is defined to contain approximately the same energy (about 114,000 BTU) as one gallon of gasoline.

Question 2

CNG cylinders must undergo periodic requalification testing. What is the standard requalification interval for most CNG cylinders?

Accepted Answer

Every 10 years or per manufacturer specification

Answer

Most CNG cylinders require requalification every 5 years or per the manufacturer's specification, and cylinders typically have a service life of 15-20 years.

Question 3

What type of ventilation is required for enclosed spaces where CNG vehicles are parked or serviced?

Accepted Answer

High-level or ceiling ventilation to prevent methane accumulation

Answer

Because methane is lighter than air and rises, ventilation for CNG vehicle areas must include high-level or ceiling-mounted exhaust to prevent dangerous gas accumulation.

Question 4

What does 'CNG equivalent' mean when comparing fuel economy ratings?

Accepted Answer

Fuel economy expressed in miles per gasoline gallon equivalent (mpgge)

Answer

CNG fuel economy is expressed in miles per gasoline gallon equivalent (mpgge) to allow standardized comparison with gasoline vehicles.

Question 5

Which NFPA standard specifically covers compressed natural gas vehicular fuel systems?

Accepted Answer

NFPA 52

Answer

NFPA 52 (Vehicular Gaseous Fuel Systems Code) covers CNG and other gaseous fuels used in vehicle fuel systems, including installation and safety requirements.

(CNG) Compressed Natural Gas Practice Test

(CNG) Compressed Natural Gas Practice Test

CNG Properties and Safety 4