CNG cylinder is the pressure vessel for storing compressed natural gas. Three main categories are widely used: all-steel cylinder, aluminum liner fiber wound cylinder and full carbon fiber cylinder.
All-steel cylinder: low cost, heavy weight. Common in Africa and low-budget markets. Aluminum liner fiber wound cylinder: medium weight and price, most popular choice for passenger cars. Full carbon fiber cylinder: lightest, high price, used for high-end retrofits.
All CNG cylinders have mandatory service life. Once expired, the cylinder must be scrapped, re-inspection is not allowed. The cylinder should be inspected periodically for scratches, corrosion and impact damage.