Frequently Asked Questions

Find answers to commonly asked questions about Quantum products and services.

Is it safe to drive a vehicle with a high-pressure cylinder installed?

The Quantum Type 4 cylinder has been rigorously tested for impact, fire, and even gunshot resistance. Your Type 4 cylinder is, in most ways, safer than a gasoline tank in a conventional vehicle.

What should I do if I am in an accident?

If you believe there is a leak in the fuel system after an accident:

  • Verify there are no ignition sources in the area.
  • If it is safe, close the vehicle ¼ turn manual shut off valve.
  • If it is safe, close the cylinder manual shut off valve.
  • Evacuate the immediate area.

Do I need to do anything differently when driving a vehicle with a Type 4 cylinder?

The addition of a cylinder(s) may reduce the load carrying capacity of your vehicle and may affect the handling dynamics of your vehicle.

Refer to your vehicle owner’s information and any additional information provided by the fuel system installer for any guidance or precautions.

Why is the fuel level (pressure) lower a few hours after a fast fill, even if I don’t drive the vehicle?

The fuel is heated during the filling process. When the fuel is heated, the fuel pressure in the cylinder increases. As the fuel in the cylinder cools, the pressure will decrease. This is called “settling”.

Why do I occasionally smell natural gas but a leak is never found?

All Type 4 cylinders are permeable which means there is a very, very small amount of fuel that escapes through the shell of the cylinder. Occasionally this escaping fuel can accumulate in a trapped area in quantities that can sometimes be detected by smell.

How do I know if I have a leak?

Fuel leaks can be observed in a number of ways:


If a leak exists in the high pressure side of the system there may be oil residue or ice present at the point of the leak.


Depending on the size of the leak you may hear sounds ranging from a slight hissing to the sound of rushing air.


CNG has a distinctive odor. The fuel in your CNG cylinder is the same fuel and has the same odor as the gas from your natural gas stove at home.

For hydrogen cylinders the fuel is not odorized and you will not be able to detect a fuel leak by smell. Consult the vehicle’s manual for more details.

Are there any recommendations for cleaning the cylinder?

In general, it would be safe to assume that anything that you would use to wash the painted surface of your vehicle should be safe for the cylinder if used in the same concentrations. The exterior of the cylinder can be cleaned using water alone or water and a mild detergent such as Simple Green®. If a detergent is used, rinse the cylinder thoroughly with clean water.

What fuel quality should be used in my fuel cylinder?

  • Compressed Natural Gas – The CNG cylinder is designed for use only with dry compressed natural gas that meets SAE J1616 fuel quality. Do not use liquid natural gas, hydrogen, butane, LPG, or other gaseous fuels as a fuel source.
  • Hydrogen – To ensure proper vehicle operation, it is recommended that the cylinder be filled with hydrogen that meets the following specifications:
    • Industrial grade 99.95% (“Three Nine”) pure hydrogen that has been verified or certified by the supplier.
    • Less than 5 ppm carbon monoxide.
    • No sulfur, phosphates, organic compounds, or trace metals.

Where can I find fuel for my vehicle?

You can search for alternative fuel stations at the United States Department of Energy website at http://www.afdc.energy.gov/locator/stations/

Where can I get my vehicle serviced?

If repairs are necessary, we can help find a service provider near you. Contact us online or call us at 1-800-816-8691 and our technical team will be happy to assist you.

Where does natural gas come from?

Natural gas is a by-product of oil drilling and coal mining, but it can also be harvested independently from natural gas fields. It can be used as a motor fuel in two forms, Compressed Natural Gas (CNG) and Liquefied Natural Gas (LNG).

Is natural gas safe?

Natural gas itself is a safer fuel than either gasoline or diesel fuel. The Type 4 cylinder is a much stronger and damage-resistant fuel storage component than any liquid fuel container currently used in production vehicles.

How does natural gas compare to gasoline?

Natural gas is lighter than air. If a leak were to develop, the gas would rise and disperse through the atmosphere giving little chance for ignition. Compare that to gasoline and diesel fuel, both of which are dense liquids that tend to pool and are easily ignitable. When CNG is burned in the engine, it produces low emissions. This means less smog, less air pollution, and cleaner air. This makes CNG a promising motor fuel for the future.

Does natural gas have an odor?

Raw natural gas is odorless, so a distinctive odorant that smells very much like strong sulfur is added prior to distribution. This strong odor makes the presence of a leak very easy to detect. If an odor is detected, please inspect the vehicle for the source of the concern and repair as needed. When you first smell the odorant, the concentration is approximately at 1% by volume. However, the odorant does not get stronger as the concentration increases. That means if you smell the odorant, you are at least at a 1% concentration level.

Where does Hydrogen come from?

Hydrogen is the most abundant element in the universe, making up more that 90% of all matter. On Earth, it is the third most abundant element on the Earth’s surface, found in water and all organic matter.

Does hydrogen have an odor?

In its normal gaseous state, hydrogen is colorless, odorless, tasteless, and is nontoxic which makes it different from every other common fuel we use. By comparison, all petroleum fuels are asphyxiants, and are poisonous to humans. No odorant is added to Hydrogen fuel.

How does hydrogen compare to gasoline?

Hydrogen is the simplest known element, but its energy content is the highest per unit of weight of any fuel (52,000 BTUs/pound). Hydrogen is less flammable than gasoline. Hydrogen disperses quickly. Being the lightest element (fifteen times lighter than air), hydrogen rises and spreads out quickly in the atmosphere. So when a leak occurs, the hydrogen gas quickly becomes so sparse that it is difficult to ignite.

What is the impact of hydrogen on the planet?

The self-ignition temperature of hydrogen is 550 degrees Celsius. Gasoline self-ignition temperature varies from 228-501 degrees Celsius, depending on the grade. Hydrogen burns readily with oxygen, releasing considerable energy and producing only water as exhaust. When hydrogen burns in air (which is mostly nitrogen), some oxides of nitrogen (NOx, contributors to smog and acid rain) can be formed, but much fewer pollutants are formed than when normal hydrocarbon fuels such as gasoline and diesel are burned. Because no carbon is involved, using hydrogen fuel eliminates carbon monoxide and carbon dioxide, and therefore does not contribute to global warming. In fact, when a hydrogen powered engine operates, it actually cleans the ambient air, by completing combustion of the unburned hydrocarbons that surround us.