CNG Fuel Safety

Any motor vehicle fuel can be dangerous if handled improperly. Fuels contain energy which must be released by burning. Gasoline is a potentially dangerous fuel, but, over time, we have learned to use it safely. The same is true of compressed natural gas (CNG). Natural gas safely generates our electricity, heats our homes and cooks our meals. But, like gasoline, CNG must be understood and respected to be used safely as a fuel.

CNG has safety advantages compared to gasoline and diesel: it is non-toxic, and has no potential for ground or water contamination in the event of a fuel release. An odorant is added to provide a distinctive and intentionally disagreeable smell which is easy to recognize. The odor is detectable at one-fifth of the gas’ lower flammability limit.

CNG, unlike gasoline, dissipates into the atmosphere in the event of an accident. Gasoline pools on the ground creating a fire hazard.

The fuel storage cylinders used in NGVs are much thicker and stronger than gasoline fuel tanks. The cylinders are constructed of metal, composite materials, or a combination of the two.

NGV fuel systems are "sealed," which prevents any spills or losses to evaporation. Even if a leak were to occur in a NGV fuel system, the natural gas would dissipate up into the air because it is lighter than air.

Natural gas has a high ignition temperature of about 1,200 degrees Fahrenheit, compared with only about 600 degrees Fahrenheit for gasoline. Natural gas also has a narrow range of flammability, which means that in concentrations below about 5 percent and above about 15 percent when mixed with air, natural gas will not burn. The high ignition temperature and limited flammability range make accidental ignition or combustion of natural gas less likely.

Time has proven NGVs to be safe in actual operation. Based on a survey of 8,331 natural gas utility, school, municipal and business fleet vehicles (NGVs) that traveled 178.3 million miles:

• The NGV fleet vehicle injury rate was 37% lower than the gasoline fleet vehicle rate.
• There were no fatalities compared with 1.28 deaths per 100 million miles for gasoline fleet vehicles.
• The fleet of 8,331 NGVs was involved in seven fire incidents, only one of which was directly attributable to failure of the natural gas fuel system.

Source:  NGVAmerica