NGVConnection Newsletter - June 2014


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Understanding HPDI Natural Gas Fuel Systems

By Paul Pate, Training Manager, NGVi    


Technicians Speak Out About the Need for CNG Training

By Kasia McBride, Marketing Manager, NGVi

This year, NGVi attended the ATMC Annual Conference, the premier event for the auto and truck training industry, organized by the Automotive Training Managers Council (ATMC). ATMC, a non-profit organization, is designed to promote the advancement of training and professional development within the automotive service industry. The organization’s members are comprised of original equipment manufacturers (OEMs), aftermarket suppliers, fleets, government/utility companies, training organizations, and others.

With the goal of better understanding the training needs of its members, ATMC has been conducting benchmark surveys each year, and results are presented at the annual conference. This year there were approximately 2,200 people who completed the survey. About 60.41% of responses came from repair technicians, followed by shop managers and owners (26.91%), parts distribution representatives (5.68%), service advisors (4.64%) and collision repair technicians (2.36%). Individuals were asked to evaluate their own needs for technician training as well as share their preference regarding the training delivery methods.

Here are some results of the survey:

  • More than 25% of responders identified compressed natural gas (CNG) fuel systems as a training need.
  • Two thirds of responders have recognized deficiencies in their knowledge and skills required for their job.


  • More than 35% said that they do not have access to the training they need, and cited the following factors:

    • Availability of the right training (72.27%)
    • High cost of training (47.7%)
    • Lack of quality training (46.52%)
    • Inability to take time off from work (36.93%)
    • Excessive travel distance (33.9%)

  • Of those who participated in training over the last year, approximately 35% received instructor-led training, whether classroom or lab-based.
  • Asked about their preference regarding the delivery methods, the majority of technicians (~65%) chose instructor-led training over other methods.
  • Management level responders, however, preferred e-learning option for their technicians.

For the NGV industry, perhaps the most important finding from this report is the high percentage of technicians identifying the need for CNG training. As more NGVs are on the road, maintenance technicians who will service and repair these vehicles must be trained on how they work. Adequate technician training, sadly often overlooked by many organizations, is critical because natural gas has different chemical properties, is lighter than air, and does not behave like gasoline or diesel. 

Safety related training for gasoline and diesel is common, and technicians have learned how to maintain and repair vehicles that operate on those fuels. To safely and correctly maintain NGVs, learning about the fuel and the vehicle technology is crucial too. Servicing NGVs requires technicians to be aware of procedures and repair practices that are unique to these vehicles. Failure to understand how to diagnose technical problems with NGVs can both negatively impact the safe operation of the vehicle and increase the risk of accident both in the shop and on the road.

Another interesting finding from this report is that many organizations have difficulty in identifying the right training provider for their needs. Procuring high-quality training for technicians, controlling costs and finding time for training can be a challenge. There are many factors that need to be considered, from training organization’s credibility, experience, credentials and qualifications of the trainers, to testing methods. The most significant one, however, is the value of the training.

While fleet and dealer service managers want to make sure they get the best quality training for their education budget, they need to realize that the least expensive training does not ne
cessarily mean the most effective training. If the training provider is not knowledgeable or experienced, or does not have enough credibility, technicians who receive the training ultimately won’t have the necessary skills to handle high-pressure fuels. Not understanding how to diagnose technical problems on natural gas vehicles can cost thousands of dollars per vehicle, and inadequate safety training could cost lives.

Choosing the right training delivery method for their technicians is another challenge for fleet managers. While the majority of technicians prefer the instructor-led option, especially when it includes a hands-on portion, managers are looking into less costly options to eliminate travel costs as well as sending multiple technicians to training. For them e-learning is an attractive, cost-effective option.

Choosing between e-learning or instructor-led training is a critical step in training development planning, because management choices can greatly influence how technicians absorb the information. Technicians are historically kinesthetic learners, which means they absorb information better when given the opportunity to actually perform the skills being taught through hands-on exercises. While e-learning can be an effective way to deliver background information or test knowledge, content focused on technical skills call for instructor-led training.

For anyone involved in servicing or managing CNG or LNG vehicles and looking for the best training solution, NGVi has a proven system to assess technician training and certification needs that will help mitigate risk, ensure technician and fleet personnel safety and increase employee confidence and skills. This assessment takes about 30 minutes to complete and is free of charge.

For more information, contact NGVi at 800-510-6484 or  

Pressure Relief Devices Recalled
By Kasia McBride, Marketing Manager, NGVi

Recently, more than 67,000 pressure relief devices (PRDs) used in CNG fuel systems were recalled by Circle Seal Controls, which is a unit of CIRCOR Aerospace. The issue was reported last year by Hexagon Lincoln, after one of its customers, New Flyer, noticed a leak. This leak was traced to a PRD failure after the outside temperature dropped below -13°F. The recall, issued by the National Highway Traffic Safety Administration (NHTSA), applies to valve models 8100-11-T1T1, 8100-37-BB, 8100-44-BB, 8100-77-BB, 8100-84-BB, 8100-94-BB, and 8100-97-BB, manufactured between July 2011 and December 2013.

PRDs are mandatory safety devices located at one or both ends of CNG fuel cylinders. Their purpose is to protect the cylinder by relieving its pressure if it becomes excessive. Since pressure increases as the temperature increases, these PRDs are designed to activate at a specified temperature. They will rapidly vent fuel from the CNG cylinder before it ruptures from over-pressurization, such as in the event of a fire.

According to NHTSA, the defective valves have O-rings that could fail in cold temperatures between -10 and -5°F. Additionally, if the cylinder is fully emptied and then refilled, the O-rings may fail at temperatures of 20°F and below (this is more likely to happen in bi-fuel or dual-fuel vehicles which may run their CNG tanks empty and then switch to gasoline or diesel before refilling with CNG).

Ultimately, the O-ring failure could cause natural gas leaks from the fuel tank, which if in the presence of an ignition source, could increase the risk of fire, especially when the vehicle with the leak is parked in an enclosed environment.

The NHTSA report states that, “Circle Seal will notify the CNG tank manufacturers of the defect. Vehicle owners will likely be notified by either their vehicle manufacturer or by the supplier of the CNG kit, as applicable.”

The affected valves in dual-fuel vehicles will be replaced free of charge. Faulty valves in dedicated vehicles that were originally sold in, or are currently registered in, the cold-weather states including Alaska, Colorado, Connecticut, Idaho, Iowa, Illinois, Indiana, Massachusetts, Maine, Michigan, Minnesota, Montana, Nebraska, New Hampshire, New York, New Jersey, North Dakota, Ohio, Pennsylvania, Rhode Island, South Dakota, Utah, Vermont, Wisconsin, and Wyoming, will also be replaced. The valve replacement is expected in fall 2014.

Because ensuring the integrity of the NGV fuel system is the core of NGV safety, routine inspections of the CNG fuel system, including examining PRDs, are required at least every three years or 36,000 miles, whichever comes first. It is imperative that NGV technicians know how to check PRDs for leaks and cracks, inspect their vent side for trapped water or debris, and be able to identify defective PRDs.

NGVi strongly recommends that all CNG maintenance technicians be trained to perform these inspections and use proper procedures. NGVi’s CNG Fuel System Inspector Training helps ensure that technicians are adequately trained to knowledgeably inspect CNG fuel systems, detect and assess damage and determine necessary next steps. It prepares inspectors to recognize conditions which, if left undetected, could result in life-threatening situations.

If you would like to know more about this recall, contact the National Highway Traffic Safety Administration Vehicle Safety Hotline at 1-888-327-4236 (TTY 1-800-424-9153), or go to

For more information about NGV training, visit

CNG Fuel Price Report
From Clean Cities Alternative Fuel Price Report published by Argonne National Laboratory for DOE's Clean Cities Program

Overall Average Fuel Prices (as of April 2014)


Nationwide Average Price for Fuel This Report

Nationwide Average Price for Fuel Last Report

Change in Price This Report vs. Last Report

Units of Measurement

Gasoline (Regular)




per gallon





per gallon





per GGE

NGVs and CNG in the News

Waste Management Opens CNG Fueling Station in

Chambersburg Selects Sunoco to Run Future CNG

New Partnership on CNG

Florida School District Chooses CNG for


To read more, click here.

Upcoming Training from NGVi

Heavy-Duty NGV Maintenance and Diagnostics Training

August 12-14, 2014
San Leandro, CA

Three-day course that prepares technicians to understand the operation, maintenance, diagnosis and repair of heavy-duty natural gas vehicles.


NGV Technician and Fleet Operations Safety Training

September 9, 2014 | Clearwater, FL
September 23, 2014 |

Canonsburg, PA

One-day session that teaches you the elements involved in the safe maintenance practices, fueling procedures, and operation of NGVs.


CNG Fuel System Inspector Training

September 10-11, 2014 | Clearwater, FL
September 24-25, 2014 |

Canonsburg, PA

Two-day session that provides you with the proper techniques for inspecting CNG fuel systems, including on-board compressed natural gas fuel storage cylinders.



Click here to Register

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Upcoming Training

Level 1: NGV Essentials
and Safety Practices

August 21, 2018
Atlanta, GA

Level 2: CNG Fuel System
Inspector Training

August 22-23, 2018
Atlanta, GA

Level 1: NGV Essentials
and Safety Practices

September 11, 2018
Boothwyn, PA

Level 2: CNG Fuel System
Inspector Training

September 12-13, 2018
Boothwyn, PA

Essentials of CNG Station Planning,
Design and Construction

September 24-25, 2018
Las Vegas, NV

Essentials of CNG Station
Operation and Maintenance

September 26-27, 2018
Las Vegas, NV

Level 1: NGV Essentials
and Safety Practices

October 2, 2018
Sacramento, CA

Level 2: CNG Fuel System
Inspector Training

October 3-4, 2018
Sacramento, CA


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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 Fuel System Design and Installation Training, Essentials of CNG Station Operation and Maintenance Training, Essentials of CNG Station Planning, Design and Construction Training and CNG/LNG Codes and Standards Training for Fire Marshals and Code Officials.


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