Industries have converted their fleet vehicles to run on safe, cleaner-burning Compressed Natural Gas.  Fleets owned/operated by cities, governments, school districts, refuse collection and other private operations are now running on Compressed Natural Gas (CNG).

Compressed Natural Gas vehicle cylinders must be visually inspected for external damage and deterioration at least every 36 months or 36,000 miles, after a motor vehicle accident, and or at the time of reinstallation. CSA Group's CNG Fuel System Inspector Certification was developed to meet the needs of the Compressed Natural Gas vehicle market.  CNG Fuel System Inspectors must conduct a visual inspection of CNG cylinders and fuel systems to ensure a level of safety.  Fuel System Inspectors check the cylinder’s serviceability, as well as:

  Discriminate between level 1, 2, 3  cylinder damage

  Identify the four different types of cylinders

  Accurately complete an inspection form

  Identify fuel system components

  Obtain and evaluate the vehicle history to identify possible hazards

  Follow manufacturers' recommended requirements

  Demonstrate familiarity with appropriate government and industry codes & standards

  Understand concepts and safety considerations when working with CNG

  Know when to dispose of a condemned CNG cylinder

Per DOT regulation FMVSS 304, cylinder life cannot be extended.  Expired cylinders must be removed from service.   Federal Motor Vehicle Safety Standard (FMVSS) No. 304, "Compressed Natural Gas (CNG) Fuel Container Integrity ", applies to motor vehicles designed to store CNG as motor fuel in the vehicle.  The standard was created to reduce the number of deaths and serious injuries that occur from CNG leakages during motor vehicle accidents.  It includes testing provisions which are necessary to determine whether a fuel storage system meets those performance requirements.  The test provisions include a pressure cycling test which simulates container fatigue resulting from in-use refueling, a hydrostatic burst test which determines whether or not a container meets the minimum strength requirements set forth in FMVSS No. 304, and bonfire tests which determine the resistance to rupture of a container as a result of exposure to a fire and a labeling requirement.[Ref. NFPA-52 Section 4.4]

The US standards for Compressed Natural Gas (CNG) fuel are both 3000 psi (200 bar) and 3600 psi (250 bar).  CNG cylinders, fittings, lines and hoses must be listed or approved for use as tested at the specified working pressures.  A failure or rupture of any of these fuel system components can cause an explosion of great force. Do not over pressurize 3000 psi vehicle systems by changing the fill receptacle to connect to 3600 psi dispensers. Many imported “kits” use pressure regulators and other components designed for 3000 psi (stamped “200 bar”), if so the vehicle fill receptacle must be of the 3000 psi type – even if this means somewhat reduced range on CNG and limited refueling options in the United States. [Ref. NFPA-52 Sections 4.3 / 4.11.2]