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 and standards, and industry best practices. NGVi’s CNG Fuel System Inspector Certification is administered independently from NGVi’s training programs. Certification designates that participants have sufficiently demonstrated the work-related knowledge, skills and competencies required to perform the tasks of a CNG fuel system inspector. 

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. 


The content of the 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 NGVi CNG Fuel System Inspector Certification 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.

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

Online Exam Live-Proctored Exam

Certification Period

The NGVi CNG Fuel System Inspector Certification is valid for a period of five years. NGVi will maintain a database of all CNG Fuel System Inspectors certified by NGVi, and will maintain a notification system to certificants when their certification is scheduled for renewal.

Training Prerequisites

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


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.

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

NGVi’s CNG Fuel System Inspector Certification Exam Covers

  • Background Knowledge to include CNG, Fuel System Components, Leak Checking, Temperature Compensation
  • Preparation for Inspection
  • Assemble Inspection Documents
  • Inspect Fill Receptacle, Secondary Check Valve, Defueling Valve and Defueling Receptacle
  • Inspect Cylinder Valve and Pressure Relief Device
  • Inspect Cylinder Shields/Covers, Mounting Brackets and Cylinders
  • Inspect Quarter Turn Valve, High-Pressure Coalescing Filter,
    Fuel Shut-Off Solenoid, High-Pressure Fuel Gauge
  • Inspect Regulator
  • Verifying Installation of CNG Fuel System According to Codes
  • Determining Final Disposition
  • Complete Inspection Reports
  • Defueling, Decommissioning and Disposal

Note: The 2016 version of National Fire Protection Association (NFPA) 52 Vehicular Gaseous Fuel Systems Code is in effect, and several sections of the code have been revised. These updates significantly affect the CNG fuel system inspection process. This exam includes both the 2013 and the 2016 editions of NFPA 52.

We strongly advise you to review both editions of NFPA 52 before taking the exam. Copies can be purchased from NFPA's website.

CNG Cylinder Inspection Labels

You can now order the CNG Cylinder Inspection labels online directly from our website. For more information, click here.







Upcoming Training


Level 1: NGV Essentials
and Safety Practices

August 15, 2017
Atlanta, GA

Level 2: CNG Fuel System
Inspector Training

August 16-17, 2017
Atlanta, GA

Level 1: NGV Essentials
and Safety Practices

September 12, 2017
Chicago, IL

Level 2: CNG Fuel System
Inspector Training

September 13-14, 2017
Chicago, IL

Register Now »

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About NGVi

Natural Gas Vehicle Institute is North America’s leading provider of training and consulting on natural gas as a transportation fuel.

Our services address the full range of natural gas vehicle and fueling issues, including:

Technical consulting services – Sizing and designing compressed natural gas fueling stations, vehicle assessments and technical assistance for fleets, CNG fueling station troubleshooting, natural gas vehicle maintenance facilities upgrades, liquefied natural gas fleet and fueling management.

Technical training – NGV Essentials and Safety Practices, CNG Fuel System Inspector Training, Heavy-Duty NGV Maintenance and Diagnostics Training, Light-Duty NGV Maintenance and Diagnostics Training, CNG Fueling Station Operation and Maintenance Training, CNG Fueling Station Design Training and CNG/LNG Codes and Standards Training for Fire Marshals and Code Officials.


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