NGVConnection Newsletter - April 2017

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CNG Fueling Station Safety Evaluations Are Critical

By Leo Thomason, Executive Director, NGVi

CNG fueling stations are carefully engineered and designed to deliver a specific quantity of fuel over a specific time period. They are composed of dryers, compressors, high-pressure tubing, storage systems, dispensers and electronic control systems—all of which must work in conjunction with each other under a variety of sometimes severe weather and operating conditions. 

Routine maintenance is critical to keep CNG fueling stations operating at their designed performance levels. But what about safety?  How do CNG fueling station operators ensure that stations are safe? The answer lies in the routine CNG fueling station safety evaluation.

The reasons for and benefits of CNG fueling station safety evaluations would seem obvious. First, CNG fueling station operators want to ensure safety of both their employees and customers.  To ensure that safe working environment, the U.S. Occupational Safety and Health Administration, otherwise known as OSHA, requires that employers maintain a safe working environment for all employees. This OSHA requirement applies to CNG fueling stations in the same manner as it applies to manufacturing plants and office buildings.  And the only way to ensure a safe environment for employees (and customers) at a CNG fueling station is to perform a periodic safety evaluation.



Join Us for a Live One-Hour
Tech Talk Training Session

When, Why and How to Conduct
a CNG Fueling Station
Safety Evaluation

Date: Thursday, April 6, 2017
Time: 11:30 a.m. PT/2:30 p.m. ET

In this 60-minute Tech Talk, NGVi's co-founder and CNG fueling expert Leo Thomason will discuss when, why and how to conduct a CNG fueling station safety evaluation that will ensure safe fueling at your facility.

This Tech Talk will include information taken from NGVi's two-day CNG Fueling Station Operation & Maintenance Training course, which is the only formalized training available in the United States on all aspects of CNG fueling station operation and maintenance.




Secondly, CNG fueling stations store and dispense fuel at very high pressures—4,200 to 4,500 psi. These pressures require more than casual treatment of the equipment and systems that make up the station. In addition, natural gas is also flammable, so specific safety systems at the CNG station are required that should be tested periodically to ensure operability. 

Lastly, CNG fueling station safety evaluations provide an additional check on required equipment maintenance. For example, if a safety evaluation reveals worn dispenser hoses, the station operator has an opportunity to replace them before they cause a dispenser outage—or worse, a catastrophic failure that might lead to injury. In this way, a CNG fueling station evaluation gives the station operator an extra layer of assurance that the station will perform reliably day in and day out. 

I am often asked whether CNG fueling station safety evaluations are required by code, and the short answer is no, not specifically.  However, there is no way to be able to ensure safety of the CNG fueling station, or to document the safe working environment required by OSHA, without conducting periodic safety evaluations. 


Since there is no specific code governing CNG fueling station evaluations, the frequency of evaluations is left up to each station operator. However, industry best practice recommends that CNG fueling station evaluations be conducted at least every six months. 

As a side note, beginning in 2016, NFPA-52 requires that every CNG fueling station (existing or newly planned) have an active, documented maintenance plan—which should include the specifications and frequency of safety evaluations.

So what should be included in the CNG fueling station safety evaluation? In total, there are dozens of items that must be inspected to complete a through safety evaluation. The key elements of a safety evaluation involve the major safety systems designed into every CNG fueling station. These include inspection and/or testing of fueling nozzles, dispenser hoses and breakaways, quarter-turn valves on each side of dispenser, emergency shut-down devices (ESDs), pressure relief valves, fire extinguishers, safety signs, methane detection systems, grounding systems, cathodic protection, x-purged enclosures and checking for fugitive leaks. Each of these items should be inspected for damage or need for repair, and many of them must be tested and possibly calibrated to ensure operability. Others, like pressure relief valves (PRVs), must be checked to verify they have been re-certified by a U.S. Department of Transportation (USDOT) recognized certification lab within the specified time period for that component.

It is important that the technician or other person responsible for the evaluation use a form—hard copy or electronic—that is specified in the CNG fueling station maintenance plan so that all the necessary data is captured. The form should include the name of each component inspected, and should provide the ability to record any repairs that need to be made, the name or job title of the person responsible to make the repairs, and the actual date the repairs are made. This type of record keeping ensures that, in the case of any incident, there are historical records to document that the CNG fueling station operator took the necessary steps to ensure safety at the station.

It quickly becomes obvious that the technician or other person conducting the CNG fueling station safety evaluation must completely understand how the station is designed, be able to identify the components of the station and thoroughly understand their function. Otherwise, critical information may be misinterpreted, or evaluation may be omitted altogether.

Because of the safety systems required by code, CNG fueling stations can be extremely safe. However, as discussed above, CNG fueling station safety evaluations are a crucial step. They require knowledge and skill to perform, but they ultimately help meet the goal of providing CNG fueling that is not only reliable but safe. 


In April, NGVi is offering two opportunities to learn more about CNG fueling station safety evaluations. 

Join us April 6 at 11:30 a.m. for a one-hour Tech Talk titled When, Why and How to Conduct a CNG Fueling Station Safety Evaluation.

Or register for our comprehensive two-day CNG Fueling Station Operation and Maintenance Training, April 26-27 in Las Vegas, NV 

Article 2
By Annalloyd Thomason, Vice President/General Manager, NGVi


Changes to NFPA-52 Affect CNG Station Construction and Maintenance

By Leo Thomason, Executive Director, NGVi

Last April, a new version of NFPA-52 was published that affects both new and existing CNG stations. Completely rewritten, the 2016 version differs significantly from 2013 and all prior versions of NFPA-52.

While there were organizational changes to NFPA-52, and even a slight renaming of the code, this article highlights the major revisions and how they affect future station designs, as well as existing CNG stations. 

Fuel Quality Specifications Have Changed

NFPA-52 (2016) modified the requirements for CNG fuel quality, addressing both the fuel that comes to the station as well as the fuel that is dispensed into vehicles. For example, the new version of the code includes minimum hydrogen content in natural gas used as a vehicle fuel. It also specifies the water content in natural gas vehicle fuel differently than previous versions of the code. This change will affect the inlet natural gas dryer by requiring it to meet a lower temperature threshold.

A CNG Station Maintenance Plan is Now Required for All Existing and New Stations

From the standpoint of CNG fueling station maintenance, the new code requires each CNG fueling station to have an active and documented maintenance program. The plan should address every CNG fueling station component and specify the maintenance procedures and intervals required to keep the equipment safe and operable.

This NFPA-52 modification is retroactive, which means it applies to every existing station currently operating, as well as every new station to be constructed.  Regarding CNG stations maintained by a third-party, the station owner still is required to ensure this plan is in place.

Since CNG station components must be maintained in accordance with specific manufacturers’ instructions, the maintenance plan cannot be generically applied, and must be directly applicable to a specific manufacturer’s equipment.

Non-Standard Fueling Station Design

NFPA-52 (2016) now includes special requirements for what it calls an “alternate station design” for any station that deviates from what the industry considers a “typical design for 3,600 psi service.”  It requires unique site distances, operating requirements and equipment locations for these stations. 

Station Signage

NFPA-52 (2016) also makes changes to the types of signage required at CNG fueling stations.  In addition to the “flammable gas, stop motor and no smoking signs,” the new version of the code requires an additional sign to be displayed at each fast- or time-fill CNG dispenser, including one that deals with verification of the temperature compensation system.   


In addition to the requirement from the previous versions of the code, NFPA-52 (2016) now also requires the dispenser system at CNG fueling stations to detect any malfunction that fills the vehicle fuel storage cylinder in excess of its specific limits or causes the safety relief valve to open. This new  requirement is significant and may require equipment changes inside CNG dispensers.

Outdoor Storage

NFPA-52 (2016) modifies the types of high-pressure storage vessels that can be used at CNG stations to include NGV2 cylinders as long as they meet certain pressure protection requirements.

It is imperative that anyone involved with building or operating a CNG fueling station be fully familiar with the code requirements governing CNG fueling stations, including the latest version of NFPA 52.  Existing CNG station operators especially must be familiar with the codes that now apply to those stations, such as the requirement for a CNG fueling station maintenance plan.

If you'd like to learn more about the full spectrum of code requirements and how you can ensure that stations you’re involved with are in compliance, check out NGVi’s two upcoming CNG fueling station courses to be delivered in Las Vegas, NV: CNG Fueling Station Design Training, April 24-25, and CNG Fueling Station Operation and Maintenance Training, April 26-27. 

CNG Fuel Price Report
From Clean Cities Alternative Fuel Price Report published by National Renewable Energy Laboratory (NREL) for DOE's Clean Cities Program

Overall Average Fuel Prices (as of January 2017)


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


New facility to extend life of CATA buses -- The Meadville Tribune

BC Transit Completes Kamloops Transition to 100% CNG Fleet
-- NGT News

Shipley Energy opens York County's first public CNG station -- Central Penn Business Journal

Port Trucking Companies Deploy Cummins’ Ultra-Low Emissions Engine
-- Environmental Leader

Upcoming Training from NGVi

NGV Essentials and Safety Practices CNG Fuel System Inspector Training
May 9, 2017 Denver, CO
June 13, 2017 Philadelphia, PA

With a focus on safety, this one-day course teaches technicians the fundamentals of natural gas, CNG and LNG fuel systems and maintenance practices for NGVs.

May 10-11, 2017 Denver, CO
June 14-15, 2017 Philadelphia, 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.

CNG Fueling Station Design Training 

April 24-25, 2017 Spring Valley, NV

Two-day course that offers the detailed technical information needed to successfully size, design and specify a CNG fueling station.

CNG Fueling Station Operation and Maintenance Training

April 26-27, 2017 Spring Valley, NV

Two-day session that provides you with the proper techniques for operating and maintaining CNG fueling stations to help avoid oil carryover and water in the natural gas stream.

NGVi CNG Fueling Station Operation and Maintenance Training

Register Now


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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


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 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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