Compressed Natural Gas (CNG) Fuel Systems

FMVSS 304 requires that Compressed Natural Gas (CNG) vehicular fuel containers include the following on the label: "This container should be visually inspected after a motor vehicle accident or fire and at least every 36 months or 36,000 miles, whichever comes first, for damage and deterioration." Industry standard ANSI NGV 2 includes similar inspection requirements. The natural gas vehicle industry has in place a cylinder and fuel system inspection procedure (CGA C-6.4) and an inspector certification program. Since inspection is only required by law in California, there is a safety need to be sure the periodic inspection is performed. The attached inspection procedure, developed by the ANSI NGV 2 Technical Advisory Group, would ensure that periodic inspections are performed and documented as well as assure the safety of the remaining parts of a CNG fuel system (as the present OOSC also does). We have also submitted this proposal to AAMVA for inclusion in their state PMVI inspection handbook.

Periodic CNG cylinder and fuel system inspection is necessary to ensure vehicle safety, as recognized by the statement on the FMVSS 304 label and in the industry cylinder standard, ANSI NGV 2. Cylinder ruptures have occured on CNG vehicles in service because of lack of periodic cylinder inspection. Proper inspection might have prevented a fatal cylinder rupture on a commercial vehicle in California last year. The requirement that documentation of timely cylinder inspection be produced at CVSA inspections will ensure that commercial CNG vehicles have their CNG cylinders and fuel systems inspected as both NHTSA and the natural gas vehicle industry recommend.

On behalf of the natural gas vehicle industry, we request that the suggested wording (being emailed to Collin Mooney) be adopted or revised for use in the OOSC. We recognize that there is no direct regulatory requirement presently in the FMCSR to justify the requirement that proof of periodic cylinder and fuel system inspection be produced. Therefore, if CVSA feels that the general safety inspection requirements of section 396.3(a)(1) cannot be relied on to include this requirement, we ask you to petition FMCSA to add the specific inspection requirement on the FMVSS 304 label to 393.65 so that our request for change in the OOSC can be accommodated.