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CNG Fuel System Inspector Certification

Why Certify CNG Fuel System Inspectors?

True or False?  Virtually every CNG cylinder failure that has occurred in the U.S. has been the result of undetected damage.


Fleets and dealerships performing CNG fuel system inspections carry a huge responsibility to ensure that every component of the system has been inspected, is in good repair, is installed according to code, and that the inspection results are properly documented.

Failure to fully meet that responsibility can cost lives, and organizations that want maximum assurance that CNG fuel system inspectors are 100% qualified for the job require them not only to be trained, but also CERTIFIED.

NGVi’s CNG Fuel System Inspector Certification program provides maximum risk mitigation to your organization.

NGVi offers two convenient exam modes:  online and live-proctored.  To learn more about each mode, or to register, click the link below.

Learn more about an online exam   Learn more about live proctored exam


NGVi CNG Fuel System Inspector Certification

NGVi’s CNG Fuel System Inspector Certification provides an independent assessment of the knowledge and application of skills necessary for technicians to competently conduct a CNG fuel system inspection according to all applicable codes, standards and industry best practices.

Design and Oversight

NGVi’s CNG Fuel System Inspector Certification is designed according to the requirements for a professional certification program prescribed by the National Commission for Certifying Agencies (NCCA). To ensure quality, uniformity and impartiality, the certification program is overseen by an independent Advisory Board comprised of CNG cylinder, fuel system and vehicle manufacturers, as well as end users.

Exam Content

The content of NGVi’s rigorous certification program has been identified through a job study of the tasks required to be performed by CNG Fuel System Inspectors. Content is periodically updated as needed based on additional job studies, updates to applicable codes and standards or other factors.

The exam consists of 60 questions that measure the participant’s knowledge and ability to apply skills and competencies required to perform a thorough CNG fuel system inspection on a natural gas powered vehicle according to all applicable national codes, standards and industry best practices.

Live and Online Testing

There are two modes of testing for NGVi’s CNG Fuel System Inspector Certification: (1) a live-proctored, paper exam offered at various locations throughout the country according to a published schedule; or (2) an online, electronically-proctored exam that can be scheduled individually by the participant and taken online at a time of their choosing.

Register for an online exam   Register for live proctored exam

Certification Period

NGVi’s CNG Fuel System Inspector Certification is valid for a period of five years. NGVi maintains a database of all CNG Fuel System Inspectors certified by NGVi, as well as a notification system to alert certificants when their certification is scheduled for renewal.

Training Prerequisites

NGVi conducts its CNG Fuel System Inspector Certification program independently from its training programs. While training is advisable, participation in the certification assessment is not contingent upon a participant having taken any training courses offered by NGVi or any other training provider.

Inspector Credentials

Certificants of the NGVi CNG Fuel System Inspector Certification program are designated as NGVi-Certified CNG Fuel System Inspectors. Certificants receive a certificant number, identification card and certification document.

Registration Process and Fee

Advance registration is required. For live-proctored exams, registrations will not be accepted after the registration close date listed in the schedule.

Online registration requires credit card payment and a unique email address for each exam participant.

Offline registration is only for those paying by check or government purchase order. The offline form and instructions are found on the registration page.

The fee for CNG Fuel System Inspector Certification is $295. This non-refundable fee covers the cost of the initial exam, one complimentary re-take (if necessary), management of all records, the certification document and identification card. Online registration is subject to a processing fee.

NGVi’s CNG Fuel System Inspector Certification Exam Covers
  • Background Knowledge (to include properties and characteristics of CNG, Fuel System Components, Leak Checking)
  • Preparation for Inspection
  • Required Inspection Documents
  • Inspecting Fill Receptacle, Secondary Check Valve, Defueling Valve and Defueling Receptacle
  • Inspecting Cylinder Valve and Pressure Relief Device
  • Inspecting Cylinder Shields/Covers, Mounting Brackets and Cylinders
  • Inspecting Fuel System Isolation Valve, High-Pressure Coalescing Filter,
  • Inspecting Fuel Shut-Off Solenoid, High-Pressure Fuel Gauge, Regulator
  • Verifying Installation of CNG Fuel System According to Codes
  • Determining Final Disposition
  • Completing Inspection Reports
  • Defueling, Decommissioning and Disposal of CNG Cylinders