CNG (Compressed Natural Gas) cylinders used in buses and trucks are subject to similar safety and maintenance requirements as those used in cars, but they often have larger and more robust cylinders due to the larger capacity of these vehicles. CNG cylinders for buses and trucks must undergo hydrostatic testing to assess their structural integrity. This test involves filling the cylinder with water and subjecting it to high pressure. The cylinder should be able to withstand this pressure without any issues. The frequency of hydrostatic testing is now at every 3 year as per government.
