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Safety Guidelines for CNG Stations

  • Natural Gas is a high methane content gas mixture used as a heating fuel, motor fuel or as process feedback.
  • a. It is lighter than air and will dissipate into atmosphere.
    b. It is a colourless gas to which a foul smelling agent is added to detect leaks.
    c. Its flammable limit in air (% by volume) is from 5 – 15 %. Natural gas without sufficient air or with too much air will not burn or explode.

  • Legislative requirement is that all due precautions shall be taken and necessary techniques like gas detectors, soap test etc to be employed to determine any Natural Gas leakage and to prevent escape of Natural Gas into atmosphere.
  • In case of Natural gas leakage at CNG Station:
  • a. Eliminate all sources of ignition.
    b. Call SNGPL area office to report gas leakage if it is at SNGPL metering station. If the leakage is at downstream of metering station then get it rectified by skilled/authorized personnel.
    c. Provide maximum ventilation.

  • If any pressure relief valve is activated, it is advised to carry out emergency shutdown of the compressors and evacuate the area.
  • Area where Natural gas is being used / handled should be very well ventilated, preferably with explosion proof mechanical ventilation.
  • It is a legislative requirement that all due precautions shall be taken at all times to prevent accidents by fire and explosion.
  • No smoking and no naked light/flame shall be allowed at CNG stations.
  • In case of fire:
  • a. Stop gas flow whenever possible.
    b. Use dry chemical powder and CO2 type fire extinguishers.
    c. Use water fog for cooling the fire exposed containers, as a protective screen and to spread vapors.

  • In case of exposure / inhalation of natural gas:
  • a. Move the victim to fresh air.
    b. Shift the victim to Hospital for medical examination / treatment.

  • Before filling of CNG in the Vehicle, it is advised to ensure that:
  • a.The vehicle hand break is firmly applied.
    b. There is no naked light or flame like cigarette, lighter or match stick.
    c. All vehicle ignition electrical system and radio is switched off.
    d. Mobile phones are not in use.
    e. There is no obvious leak in the vehicles CNG equipment.

  • During filling of CNG into the vehicle it is advised:
  • a. Filling operator should not leave the vehicle.
    b. That the rate of transfer of CNG into the vehicle should be slow. This is to avoid shock loading and rapid increase in gas temperature.

  • All spark producing activities like welding, cutting etc. on the equipment or gas piping at CNG stations should be avoided. If unavoidable, these to be performed with extreme precautions to prevent formation of any explosive mixture. Government of Pakistan, Mineral Gas Safety Rules 1960 to be consulted to avoid explosions and uncontrolled fires.
  • Shut off valves, automatic valves, relief valve and its vent should be installed and maintained in accordance with Government of Pakistan, Mineral Gas Safety rules 1960.
  • It is advised to check the emergency shutdown system of compressors periodically.
  • Inflammable material like lubricants etc. required for compressor units to be stored separately. Government of Pakistan, Mineral Gas Safety rules 1960 to be consulted in this regard.
  • It is preferable to use explosion proof electrical devices including meters, bulbs, sockets, wiring and switches.
  • Maintenance of equipment at CNG stations to be carried out by authorized/skilled personnel and record of the maintenance activity to be maintained.
  • All accidents involving loss of life or serious injury to any person or severe damage to property to be immediately reported to the Company. Reporting of accidents/injuries to the Company does not replace the requirement of reporting the same to the Government agencies as described in Government of Pakistan, Mineral Gas Safety rules 1960.

Updated: 27-10-2017