An NGV stores natural gas in specially constructed cylinders on the vehicle. To ensure the continued safe operation of the vehicle, the cylinders must be periodically inspected. It is the responsibility of the owner of the cylinder to ensure that cylinders are inspected regularly.
The inspection that the cylinder requires depends upon the manufacturer's specifications. Some cylinders require a visual inspection every three or five years. Some cylinders must be removed from the vehicle and hydrostatically tested every five years.