precautions while using cng

To vent the fuel that remains after the engine stalls or if the engine cannot be run to consume the fuel, the CNG can be vented safely into the atmosphere. Special precautions are necessary to safely vent the CNG without causing a fire. NFPA 52 Vehicular Gaseous Fuel Systems Code, the International Fire Code and some state and local regulations require that any venting system be approved by the Authority Having Jurisdiction AHJ, generally the fire marshal. Always use a vent system approved by the AHJ. If the vehicle is equipped with a special connection to transfer fuel out, it can be connected to the approved vent system and emptied as in the direct defueling example, making sure that the solenoid valves open.

If the cylinders are equipped with manual valves, these should be carefully cracked open after the piping is disconnected. If no significant pressure is present, the valve can then be fully opened, assuring that the cylinder is empty except for a small amount of gas at atmospheric pressure.

Always use approved CNG kit And cylinder. It is dangerous and illegal to use substandard cylinder and fittings. Do not install LPG, Propane or any other cylinder in place of a CNG cylinder. It is unsafe and unlawful. It is advisable to have insurance coverage of the CNG kit along with the vehicle accessories. Always, park the vehicle at least 6 meters away from sources of ignition fire. Always refer to the CNG kit suppliers manual for operating instructions and do not do trouble shooting yourself, other than that recommended by the manufacturer. Be aware of the location and operation of cylinder valve, master shut off valve and burst disc in the CNG system. Ask your mechanic to identify these parts for you. It would be helpful for emergency handling of any CNG leak.

Make sure that clamps are tight and cylinder fixed properly and safely.
Confirm that cylinder valve is safe and valve wheel is in place.
Ensure that gas tubing is intact and supported properly.
Check for gas leakage from the kit by using soap solution.

Check out of the vehicle.
Do not start the vehicle. Push vehicles to a place out side the station in open Air.
Stop all activities in the vicinity, which can provide source of ignition, e.g. smoking, use of mobile phone etc.
Close down the cylinder valve master shut off valve in the CNG system to control the leakage.
Call CNG kit retrofitter to repair the same.

Evacuate the vehicle and surrounding place.
Take help of fire fighting experts.
Extinguish the fire with water fire extinguishers.
If feasible, close down the cylinder valve master shut off valve in the CNG system to control the gas leakage.

Endorsement of CNG or bi fuel mode in Registration Certificate.
Annual checking of the CNG Kit and maintaining the certificate.
Hydro testing of the cylinder, once in 5 years, as per Gas cylinder rules.
Certificate of CNG Kit, Fitness and hydro test to be possessed by the driver all the time. Maintain cylinders in good condition.
No repair to be done on cylinder and valves. No oil, Grease or lubricant to be used for cylinder. Dont change the color of the cylinder.
If safety disc has burst, replace it with genuine one. Do not allow make shift arrangements.
Do not allow cylinder for heat treatment. In case vehicle is undergoing repairs involving welding or heat application to any part within 1.5 m of the cylinder,the cylinder should be flush out with inert gas.

CNG has the narrowest flammability range, leading to slim chances of catching fire in the event of a leakage. Simplified, it means that the combustible mixture of natural gas and air does not ignite if the mixture is leaner than 5Percent or richer than 15Percent of the air fuel ratio required for ignition. Thus, this limited inflammability range makes CNG one of the safest fuels in the world. Being lighter than air, in case of a leak, CNG just rises and disperses into thin air. The CNG conversion kit is definitely safe, with the cylinders specially manufactured for use in vehicles being cast from a single piece of special steel alloy without any welded joints.

Ministry of Petroleum and Natural Gas may be asked to review the layout of the dispensing stations to ensure easy approachability to dispensers and protection of the installed pumps.
Standardise all vehicle refuelling receptacles or nozzles on the NGV 1 standard to reduce filling time, minimise safety risk posed by leakage of gas due to O ring failure, and allow more efficient use of existing compression capacity.

Ministry of Petroleum and Natural Gas may be asked to lay down the specifications of pipeline gas. The gas composition as indicated by methane content and the Wobbe index indicator to measure the effect of changes in gas composition on air fuel ratio and engine combustion should be laid down.