Safety Of CNG

Natural gas is a clean, low cost, domestically available alternative fuel that can power our vehicles. The advantages to our energy independence by reducing foreign oil imports, the reduced cost compared to gasoline and less emissions have been well documented. However, there may still be a misconception about the safety of Compressed Natural Gas (CNG) compared to gasoline.

All fuel sources contain energy that is released through combustion and any fuel can be potentially dangerous if not properly handled. Throughout time we have learned to harness these fuels for heating, light and powering our vehicles.

The fact is that CNG is safer than gasoline as a vehicular fuel based upon two important facts; the physical qualities of natural gas and the structural integrity of the NGV fueling system.

Natural gas or methane is a non toxic gas that is lighter than air. This means that it will not puddle (like gasoline) or sink to the ground like propane, which is heavier than air. Instead, Natural Gas will rise and dissipate in the atmosphere.

Natural gas also has a higher ignition temperature. This means that it is much harder to ignite. The storage systems used for compressed natural gas are infinitely stronger that the gasoline tanks found on cars and trucks today.

These tanks are designed to hold natural gas at pressures up to 3,600 psi.

There are four types of tanks available, these include:

Type 1: This is an all metal – cylinder made of steel. There is no covering, other than paint, on the outside of the cylinder. This is the most common type of cylinder and least expensive. It is also the heaviest.

Type 2: This is a metal cylinder (steel or aluminum) with a partial wrapping that goes around the cylinder. The wrapping is usually made of glass, or carbon, contained in an epoxy or polyester resin. This design weighs less than the type one and costs more.

Type 3: This type of cylinder is fully wrapped with the same kind of material used for the partial wrapping of a Type 2 cylinder. This type of cylinder has a metal liner usually aluminum. They are lightweight and even more expensive than Type 1 or Type 2.

Type 4: This type of cylinder is fully wrapped with the same kind of material used for the partial wrapping of a Type 2 cylinder. This type of cylinder has a plastic liner, it is very light and the most expensive.

All CNG cylinders are constructed to withhold up to 1.25 times their operating design pressure and include valves and other safety devices to prevent leakage.