CNG Fuel System Inspection Requirements
Inspection Intervals Defined by Code: 3 Years/36,000 miles/After Any Fire/After Any Accident
- Federal Motor Vehicle Safety Standards (FMVSS) Standard 304 requires that CNG cylinders be inspected every three years or 36,000 miles, whichever comes first, or after any accident or fire.
- ANSI NGV-2 also requires CNG cylinders to be visually inspected at least every three years or 36,000 miles.
- Manufacturers may have inspection intervals that are more frequent.
Four Types and Intervals for Inspections
|Inspection Type||When Performed?||Inspection Level||What is Inspected?||Who Performs?|
|Pre-Service Inspection||Prior to placing vehicle in service||Detailed Visual Inspection||Thorough inspection of all high pressure components, including cylinders||A certified or qualified CNG Fuel System Inspector|
|Driver Pre- and Post-Trip Inspection||Before and after each trip in a CNG vehicle||Cursory Visual Inspection||All visible components and cylinder shields||Driver|
|General Visual Inspection||During any preventive maintenance/service||General Visual Inspection||All visible components, with special attention to cylinder shields||Trained Vehicle Technician|
|Detailed Visual Inspection||At manufacturer’s specified intervals, or 3 years/36,000 miles (whichever comes first); after any fire or accident||Detailed Visual Inspection||Thorough inspection of all high-pressure components, including cylinders||A certified or qualified CNG Fuel System Inspector|
What Records are Required?
For each Detailed Visual Inspection, a completed CNG Fuel System Inspection form and accompanying photos should be retained. Inspection records are not required to be submitted to any regulatory agency or manufacturer.
At the conclusion of each Detailed Visual Inspection, a “Passed” or “Failed” inspection label should be affixed to each cylinder installed on the vehicle.