CNG cylinders typically consist of 12.5-18mm thick aluminum or steel. CNG tanks average 80 kg
Although CNG tanks are lighter than other technologies, they are very expensive and not widely used commercially. Regular calibration of natural gas tanks must be done. Natural gas can be filled to a pressure of 216 bars. This gas provides safety well beyond the international norms. The tanks are designed to withstand 450 bar pressure and are calibrated for 300bar pressure. Every 5 years, tanks should be tested. The tank should be labeled. The tank can be relabelled and used for an additional 5 years if there are no problems.
There are 4 types CNG cylinders.
1. All metal tubes made of carbon and mild steel
2. Top-wound tube with an aluminum or steel metal jacket and a hoop wrapped filament image matrix
3. A milk-wrapped tube, with a steel or aluminium metal jacket and a fully wound filament matrix.
4. Similar to the 3rd type, but with a completely composite jacket and a fully-wound filament overwrapped in a picture matrix.
