Most NGVs operate using compressed natural gas (CNG) so the fuel takes up less space. CNG is stored on board vehicles in high-pressure (3,000-3,600 psi) in tube-shaped cylinders that are attached to the rear, top or undercarriage of the vehicle.
Take a look right here at the Compressed Natural Gas Container Inspection Advisory, published Jan. 7, 2008 by the Clean Vehicle Education Foundation
The cylinders meet very rigorous safety standards. They are made of high-strength materials designed to withstand impact, puncture and, in the case of fire, their pressure relief devices (PRDs) provide a controlled venting of the gas rather than letting the pressure build up in the tank.
Storage cylinders have a usable life of 10, 15, 20 or 25 years from the date of manufacture.
CNG cylinders are categorized into the following 4 types:
| Type | Description | % load contained by metal | % load contained by composite |
|---|---|---|---|
| Type 1 (NGV2-1) | All Steel or Aluminum cylinders | 100 | n/a |
| Type 2 (NGV2-2) | Metal liner and a hoop wrapped composite | 55 | 45 |
| Type 3 (NGV2-3) | Thin metal liner and a full composite wrap | 20 | 80 |
| Type 4 (NGV2-4) | Plastic liner and a full composite wrap | n/a | 100 |
Various factors must be considered when deciding what type of cylinder to use on the vehicle:
- Weight
- Fuel capacity
- Availability of space to mount cylinders
- Cost
Type 1 is generally the heaviest going up to the Type 4 which is the lightest, and type 1 is generally the cheapest going up to the type 4 which is the most expensive. Cylinder selection is critical to ensure that the vehicle’s GVW has not been adversely affected.
For more information on cylinder selection and installation please contact us today!
The effects of severe abuse to CNG storage cylinders: