NGVConnection Newsletter - June 2012

Vehicle Maintenance/Repair Facilities:  Using Administrative
Procedures as an Interim Measure

By Annalloyd Thomason, Vice President/General Manager, NGVi

NGVi frequently receives distress calls from clients who are involved in maintaining or repairing natural gas vehicles because they have just been made aware of the need to modify their facilities to accommodate the lighter-than-air fuel, but need to service and maintain vehicles now.  The calls usually go something like this.

NGVi: Good morning and thank you for calling NGVi.  How can we help you?

Client: Hello, my name is John Doe.  I work for XYZ Company and we are beginning to (sell/service/operate) natural gas vehicles.  I just learned that there are modifications that need to be made to our maintenance and repair facility to accommodate CNG.  Can you give me a list of these?

NGVi: We’ll be happy to help.  The modifications that need to be made will depend on the specific design and construction of your individual facility, and may involve the heating, lighting, ventilation systems, building structure, pits, drains, and other components. 


Client: Wow.  I had no idea.  It sounds like these modifications could take some time to implement.

NGVi: Yes, they can.  Generally, the process starts with a facilities evaluation where NGVi sends a trained staff member to your location to audit the entire facility and provide a report of the modifications required for your operation.  After the evaluation, we provide a comprehensive report of all the modifications required for your specific facility.

Client: That sounds great.  The problem is that we’ve already begun to (sell/service/operate) natural gas vehicles and I need to be able to service and maintain my vehicles even before the modifications are determined or completed.  What can I do in the short run to ensure the safety of my technicians?

Fortunately, there are administrative procedures that can be implemented before facilities modifications are performed that can allow technicians and other employees to safely bring a CNG-powered vehicle inside an unmodified vehicle maintenance or repair facility.  A critical pre-requisite to establishing and implementing administrative procedures, however, is training.

All vehicle technicians and repair personnel should be trained regarding the properties and characteristics of natural gas, possible fuel system leak scenarios, proper leak check procedures, safe fuel handling practices, and safe vehicle repair procedures.  This is the most important step in ensuring safety.

In addition to training, administrative procedures for parking a CNG powered vehicle inside any existing unmodified maintenance and repair facility include the following. 


  • A CNG powered vehicle can be parked inside an existing facility during normal operating hours while vehicle maintenance and repair personnel are inside.  At least 50% of the maintenance and repair facility roll-up doors must be raised a minimum of 12 inches, exhaust ventilation fans must be turned on and should provide a minimum of five air changes per hour. All existing open flame space heaters or space heaters with a skin temperature exceeding 750o F must be disconnected from the electrical and natural gas/propane/other energy supply.
  • To help mitigate the possibility of a CNG fuel system leak, a complete fuel system leak check must be performed before the CNG powered vehicle is parked inside the facility.
  • Once a CNG powered vehicle is inside the facility, all CNG fuel cylinder storage valves must be closed. 
  • In the highly unlikely event of a natural gas leak from any portion of the vehicle fuel system, the odorant in the natural gas should be easily detectable, well below the flammability limit of the fuel, by one or more vehicle technicians.
  • In the event of a CNG fuel system leak, the technician must turn off all electrical power to and within the vehicle maintenance and repair facility. This action will eliminate all ignition sources. 
  • At the end of normal operating hours of the existing maintenance and repair facility, the CNG powered vehicle must be removed from the building and parked outside beyond the bay door. The bay door must be closed.
  • The modified operating procedures discussed here must be communicated to each vehicle maintenance and repair technician, and management audit procedures for conformance must be implemented.

While these procedures allow for vehicle maintenance and even repair of the non-CNG fuel system components of a natural gas powered vehicle, there are restrictions.  It should be noted that none of the actions described above allow:

  • Any CNG powered vehicle to be parked overnight within the existing unmodified vehicle maintenance or repair facility unattended;
  • Any part of the CNG fuel system (defined as all components from the fuel receptacle to and including the fuel injectors) installed on the vehicle to be repaired while inside the maintenance and repair facility because there are not adequate safety systems installed within the existing facility;
  • Any LNG powered vehicle to be parked, maintained, or repaired inside the unmodified facility because LNG is an un-odorized fuel and LNG fuel tanks will vent a small portion of the gas build up inside the tank without warning.

Of course, in the long-term, existing vehicle maintenance and repair facilities must be modified to accommodate maintenance of CNG or LNG fuel systems.  However, these interim administrative procedures can help keep the operation safely running until the modifications are complete.

For more information about NGVi’s Vehicle Maintenance and Repair Facility Evaluation services, contact us at or 800-510-6484.

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Enhancing Technician Safety When Working on CNG Cylinder Solenoid Valves

By NGVi Staff

During April, 2012, Wesley Little, a CNG business owner and technician in Broken Arrow, Oklahoma, was killed while working on what he thought was an empty CNG cylinder. There was no explosion or fire, but the force of the pressure released from the cylinder was enough to throw him approximately 25 feet through the air, according to Fox23 News, causing massive fatal internal injuries.

According to the police investigation, Mr. Little was trying to remove the electric solenoid valve from a CNG cylinder that he thought had been properly vented. He began to unscrew the valve while standing over the edge of the truck, with the valve pointed toward his chest. As soon as he broke the seal, the pressure release shot the valve directly toward his chest, resulting in the fatal injury.

This deeply unfortunate situation should cause fleet managers and vehicle technicians to re-examine standards and specialized safety practices for performing work on CNG powered vehicles. Technicians must follow appropriate safety procedures at all times – even when performing routine maintenance. Making assumptions about pressurized components will eventually lead to accidents.

There are two types of valves normally used on CNG cylinders:  mechanical and electro-mechanical.  With a mechanical valve, the vehicle technician has the ability to manually operate the valve, enhancing the certainty of whether it is open or closed.

Electro-mechanical valves utilize an electric solenoid  that, when energized or de-energized, either opens or closes a valve orifice. Some view the use of electric solenoid valves as a safety enhancement for NGVs because they are designed to close when the ignition of the vehicle is in the off position. In fact, ANSI/IAS NGV 3.1 test procedures require that they fail in the closed position. In reality, however, valve closing during failure does not always happen. When an electro-mechanical valve failure occurs, or if for any reason the valve needs to be removed from the cylinder, the technician must use a mechanical override procedure to open the valve in order to defuel the cylinder.

The concern here is the technician’s ability to discern whether or not the CNG cylinder and high-pressure system have been properly defueled and depressurized. Work of any kind on pressurized components and fittings can be inherently dangerous. When disconnecting a component that may contain pressure, the technician has no readily available external method of determining the integrity of the component, whether there is any degradation of the metal, whether the threads are intact, etc. As the technician starts to apply torque to loosen the component, its structural integrity is stressed and the component can fail without warning.

The only reliable way to ensure that a CNG cylinder equipped with an electric solenoid valve has been defueled, and therefore depressurized, is to carefully follow the service procedures from the manufacturer of the specific valve involved. This information can be difficult to locate, and trying to figure it out without the manufacturer’s instructions can result in severe injury or fatality.

When service or repair of solenoid valves on CNG cylinders is required, there are some very important safety guidelines that must be followed.

  • Always follow the manufacturer’s instructions while defueling cylinders with internal electric solenoid valves, and never attempt to remove a valve without doing so.
  • When installing new solenoid valves or making retrofits, always follow the manufacturer’s installation guidelines for torque, sealant, mounting, etc.
  • Use only the approved solenoid valve specified by the manufacturer of the cylinder. Remember, the cylinder certification process was conducted with a specific model valve. If a different valve is used, the cylinder/valve assembly will not meet ANSI/NGV2 requirements. The cylinder manufacturer is the only authority that can specify approved valves.
  • Be aware of the age and condition of all automatic valves in the CNG vehicle—especially for solenoid valves 15 years or older.
  • Examine the valve, as well as the threaded interface between the valve and the tank. Solenoid valves have fine pilot orifices that can be plugged with debris or ice.
  • Special tools will be necessary for safe defueling or venting of solenoid valve-equipped cylinders.
  • Remain cautious throughout the entire process and treat each cylinder as if it is fully pressurized.
  • Physically position your body away from the direction of travel of a possible component failure.

Ensuring the proper functioning of CNG fuel systems is an important part of fleet safety. Following manufacturer guidelines and industry best practices at all times will help fleet operators avoid accidents. Relying solely on past experience in working on vehicles is not adequate to prepare technicians to safely open or remove a solenoid valve, and training in recommended procedures is essential.


NGV maintenance technicians should be properly trained to visually inspect the entire CNG fuel system, including the cylinders and all pressurized components. This training should cover the design and failure modes of CNG fuel system components, and especially those on the high-pressure side of the regulator.  NGVi’s two-day CNG Fuel System Inspector Training, taught by CSA and ASE certified instructors, covers detailed discussion of the fuel lines, regulators, coalescing filters, receptacles, mechanical and solenoid valves, pressure relief devices as well as defueling procedures.


For more information about CNG Fuel System Inspector Safety training, visit our website at or contact us at 800-510-6484.




Providing Everyone the Opportunity to Learn

By Paul Pate, Training Manager, NGVi

Have you ever experienced a training course that was so engaging it left you wanting more? What about one that was, for lack of a better word…boring? Most students, at one time or another, have experienced both of these scenarios. What makes one training class so enjoyable and another so painful to sit through? NGVi designs and delivers training classes in a way that addresses this issue directly, by keeping classes dynamic via quality instructional design.

To deliver a dynamic course, instructors must reach and connect with every student, regardless of a student’s mental awareness upon walking into the classroom.  To accomplish this goal, the relevance of the content to the students' needs must be established before the instructor can determine how to motivate his or her students. At this point, students will learn either because of, or in spite of, the teacher.

So how does an instructor connect with and motivate students? The most effective way is by determining the primary learning style of each student and presenting material in the appropriate manner(s). If an instructor presents a topic in a style that the student understands, the student is more likely to be motivated to learn the material. Conversely, when the teaching style doesn’t match the learning style, students are likely to be bored, not pay attention, be unable to understand the subject matter at a deep enough level, and become discouraged. 

The key to teaching, motivating, and connecting with a student in their learning style is to understand the differences and the “tells” for each type. There are three primary learning styles: audible, kinesthetic and visual.

Audible – This type of student learns mostly through listening, hearing an instructor speak, or reading aloud. They typically sit where they can easily hear, but don’t need to be in the front of a class. When they become disinterested, the audible learner tends to talk to himself/ herself or others.

Kinesthetic – This type of student learns by doing, touching, and disassembly/reassembly. The kinesthetic learner is uncomfortable when confined to a seat in a class or a static environment and feels the need to move around and have frequent hands-on activities. This student can typically recall what was done, but not what was said. When distracted, they may engage in activities such as taking something apart (i.e. the pen lying on their desk) or finding something to do with their hands.

Visual – The visual learner is extremely organized and often sits toward the front of the class with training materials laid out in order as they take extensive notes.  They might close their eyes when attempting to understand a concept so they can visualize it. The visual learner appreciates visual aids, such as cut-away drawings, charts and graphs. They do not typically enjoy noisy classrooms or distracting environments.

How does NGVi keep its classes effective and dynamic? First, the instructors are aware of the indicators of student learning styles, and matches presentation techniques to those styles. Secondly, courses are pre-designed to have components of each learning style built in.

Some examples of the methods used to meet the needs of every type of student in NGVi training courses include:

Auditory – Extensive questioning in each course encourages conversation and feedback, rather than just presenting the material one-sided. “Stand and deliver” is an outdated, ineffective educational method and is avoided whenever possible. Interactive classrooms are strongly preferred, as auditory learners thrive in an environment of conversation. Additionally, a focused classroom environment is important to these learners, so outside noise distractions are reduced as much as possible.

Kinesthetic - The majority of NGVi's students are kinesthetic and NGVi creates learning opportunities tailored to these students' needs. One example of a kinesthetic learning environment is the cylinder inspection workshop that is embedded in each CNG Fuel System Inspector Training (FSI) course provided by NGVi.  Every student inspects a cylinder for damage and uses the manufacturer’s guidelines to determine the action required, based on the damage they find. The student physically measures and assesses each of the multiple damage areas on a cylinder, and results are discussed as a group (to help the audible learners). All of this occurs under the guidance of experienced instructors. NGVi has found this method to significantly improve the level of understanding for each student.

Visual – For visual learners, NGVi offers engaging classroom visual presentations by importing fresh and relevant photos, using advanced presentation software technique, and preparing professional quality written course materials in order to avoid the infamous “death by Power Point.” Additionally, directly tied to our CNG cylinder inspection exercise is an activity that requires students to locate technical information and make determinations as to the course of action based on the specifications. Visual learners thrive during this exercise.

All learning activities happen in both individual and group settings in order to meet the needs of each auditory, kinesthetic and visual learner. Students gain experience looking up specifications and procedures based on the vehicle’s manufacturer guidelines—the very task they will be required to do upon completing the course.  

NGVi recognizes the importance of every learning style and takes the educational design of its training very seriously in order to cater to each type of learner—auditory, visual, and kinesthetic. NGVi’s training is more than just a certificate of completion handed to each student as they walk out the door, because it offers life-long educational benefits for a safe and successful career in the natural gas vehicle and automotive industries. 

Natural Gas Clear Leader at 2012 Waste Expo
By Kasia McBride, Marketing Manager, NGVi

Nearly 11,000 participants from 64 countries and 500 exhibitors representing the refuse industry gathered in May for the 2012 Waste Expo, a trade show for waste management and recycling professionals. Held at the Las Vegas Convention Center, the event was well-received by those in attendance.  NGVi’s booth was nestled inside the NGV Pavilion, organized by NGVAmerica, which included 14 participating companies from the NGV industry. We had a great opportunity to talk with many clients and industry partners about their CNG or LNG program plans and needs.

Waste Collection is the fastest growing market for natural gas as a transportation fuel in the United States. The economic, environmental, and engine performance benefits afforded by the fuel, as well as the unique operating characteristics of refuse trucks, create a perfect combination that attracts many refuse companies. According to the report “Strategic Analysis of the North American Class 6-8 Natural Gas Truck Market,” recently published by Frost & Sullivan, the number of medium- and heavy-duty natural gas-powered trucks will grow from 1,950 units today to more than 29,483 units in 2017.

This growth trend was clearly noticeable at the Waste Expo this year. NGVi found that natural gas as a transportation fuel has become a serious talking point for many participating companies, and natural gas powered trucks dominated the show. Nearly 21 natural gas refuse trucks, were displayed by a wide array of truck manufacturers including McNeilus, Peterbilt, Heil Environmental, Navistar, Curotto-Can, Mack Trucks, Mercedes-Benz, and Freightliner.

McNeilus, which reported that 50 percent of their product mix is CNG, brought five CNG-powered trucks to the show. Peterbilt displayed three natural gas refuse trucks, one of which was LNG. Mack Trucks showcased natural gas-powered MACK® TerraPro™ models – two Cabover and one Low Entry, and Freightliner brought its 114SD CNG-powered truck with a McNeilus 25-yard rear loader body. Navistar Inc. displayed its International LoadStar--the natural gas version of which is planned for early 2013. Presenting four CNG-powered trucks, Heil Environmental predicted that their sales of CNG products will increase from 30 percent now to 60 percent in two years.

Vocational Energy introduced its Portable Fuel System (PFS), a portable CNG fueling station mounted on a standard commercial roll-off truck, which allows fleets to operate CNG vehicles to fuel at their locations of choice, rather than driving their trucks to a public station across town.

Finally, a large number of waste companies proudly displayed natural gas trucks that they already operate. These companies included Waste Management, Choice Environmental, Veolia Environmental Services, Casella Waste Systems, Republic Services, and Waste PR.


After attending the show, it can be concluded that the role of natural gas among refuse company fleets is unquestionably growing. Certainly the many benefits of natural gas, along with unique operational characteristics of these high-mileage refuse vehicles make this fuel a very desirable option for waste companies. The growing array of technologies and natural gas truck choices presented at the Waste Expo, as well as an obvious interest in natural gas among refuse companies was very exciting. More importantly, it clearly indicated that CNG is quickly becoming the fuel choice for this industry.

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 2012)


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

Did You Know?  

Vehicle fuel storage cylinders for CNG, manufactured to NHTSA Federal Motor Vehicle Safety Standard (FMVSS) 304 and American National Standard Institute (ANSI) NGV 2, have a useful life of 15, 20 or 25 years from the date of manufacture, depending upon the manufacturer’s specifications. Once the cylinder reaches the end of its useful life as stated on the cylinder label, or if a cylinder is damaged, it must be defueled and disposed of in accordance with the cylinder manufacturers’ guidelines or CGA guidance documents.

NGVs & CNG in the News

NGVi Sponsors

Alternative Fuel Tour Comes to Tallahassee

Shell to Invest $300 Million on LNG Refueling Station Network


OCC Approves Rebates for CNG Vehicle
Tulsa World


Alberta Looks at Expanding Natural Gas Use

California Grant Funds Targeted Primarily at CNG Stations, Biofuel Development
NGT News

Maloney Pushing Natural Gas Fleet
Parkersburg News and Sentinel

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NGVi Partners in Comprehensive U.S. - Canadian NGV
Market Analysis

Upcoming Training from NGVi

TIAX LLC, on behalf of America’s Natural Gas Alliance (ANGA), recently released the report U.S. and Canadian Natural Gas Vehicle Market Analysis: Compressed Natural Gas Infrastructure.

The primary objective of this report was to identify the most productive and effective resources for increasing the use of natural gas vehicles (NGVs).

NGVi served as the lead contributor and subcontractor on the new release, which is the first segment of a multi-faceted natural gas vehicle market analysis.

To view the full study, go to


NGV Driver & Technician Safety Training
September 19, 2012, Dallas, TX

CNG Fuel System Inspector Training
September 20-21, 2012, Dallas, TX

Click here to Register

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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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