Automobile Desk: The reason behind the increasing popularity of CNG vehicles is their excellent mileage and economy. However, when using a CNG car, regular servicing of the vehicle or changing the engine oil is not enough. There is another very important aspect which people often do not pay attention to, and that is the safety and checking of the CNG cylinder installed in the car. The gas in CNG cylinder is filled with extreme pressure (high pressure), hence it becomes mandatory to assess its strength and condition after its continuous use for a long time. This testing process is called hydrostatic test or hydro test in technical language.
Hydro testing of CNG cylinder is mainly done to test its structural strength and safety standards. Due to years of use, the inner or outer parts of the cylinder may suffer from wear, corrosion or loss of pressure bearing capacity. During this test, the cylinder is examined with the help of water and special high pressure to ensure that there are no microscopic leaks or cracks in it. If the cylinder successfully passes this stringent test, it is declared safe for further use and its next inspection is scheduled.
As per legal and safety regulations, it is mandatory to conduct hydro test of the cylinder of every private CNG car once in every 3 years. However, for commercial vehicles this time period may be even less. The date of the last test is stamped on your car's cylinder through a metal plate or punching. Vehicle owners should keep checking this date from time to time and get re-tested before the validity expires. After the expiry of the time limit, one may have to face problems in filling gas at CNG pumps without a valid test certificate.
It is very important to note that hydro testing of CNG cylinder cannot be done in any local or unauthorized garage. For this, one should go to authorized testing centers recognized by the Government and Explosives Department (PESO). These centers have the necessary testing equipment and skilled technicians who safely remove the cylinder from the car, thoroughly inspect it and, upon passing, issue an official certificate and a new compliance plate.
Talking about the cost, the fees for hydro test of CNG cylinder may vary depending on different cities, capacity of the cylinder and testing center. On an average, this entire process costs ₹1,500 to ₹3,000. This includes charges for removing the cylinder, cleaning it, hydro testing and refitting. This is a very minor expense to avoid any unexpected danger and for the safety of the passengers in the vehicle, ignoring which can cause huge losses.
