SoCalGas - Safety and cylinder inspection
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Safety and cylinder inspection

According to the Clean Vehicle Education Foundation's report, Natural Gas Vehicles (NGVs) have a favorable safety record comparable to almost any traditional or alternative fuel vehicle available today. More than thirty years of experience and millions of problem-free-driven miles support that natural gas is an extremely safe fuel for vehicles.

Natural gas vehicles offer significant safety advantages over many of its fuel competitors in the market. The physical properties of natural gas make Compressed Natural Gas (CNG) as safe as gasoline or diesel fuels. Natural gas is not toxic to touch. Natural gas also has a very narrow concentration range for combustion, which reduces the possibility of accidental combustion. It is lighter than air and will rise and dissipate into the air if released. The odorant added to natural gas makes it easier to detect its presence. CNG does not form combustible pools on the ground, as other fuels might.

Natural gas storage cylinders

The cylinders that hold the compressed natural gas are significantly stronger than gasoline tanks. They can withstand impact and bonfire testing, and meet or exceed U.S. Department of Transportation safety standards. More information is available on the use, care and maintenance of composite cylinders. * The Clean Vehicle Education Foundation has also published safety bulletins related to specific issues, including certain CNG cylinders exposed to acid as well as pressure relief devices (pdf). *

Cylinder inspection: 36 months or 36,000 miles

CNG cylinders have a limited lifespan of generally 15 to 20 years. They also need to be inspected periodically. The current standard for this interval is every 36 months or 36,000 miles, whichever comes first or after any vehicle accident or fire. Please consult the manufacturer of your vehicle to find the specific interval for your cylinder. The Clean Vehicle Education Foundation has published more details on inspection in its Compressed Natural Gas (CNG) Container Visual Inspection Advisory (pdf).

Become a certified fuel system inspector1

CSA America is "a leading standards developer for gas-fired product and alternative energy standards and a solutions-oriented organization serving businesses, trade associations, governments, and industries in the U.S. and the global marketplace. They are accredited by the American National Standards Institute (ANSI) * under the Committee, Canvass and Organizational Methods of standards development."

Per CSA America, "the CNG Fuel System Inspector Certification program * replaces the CNG Cylinder Inspector Certification. This improved, expanded program offers inspectors the highest level of certification to include the inspection of containers, valves, pressure relief devices (including vent system) and other fuel system components of compressed natural gas powered vehicles. The certification complies with the International Organization for Standardization (ISO) 17024 standard for personnel certification programs. CSA America is an ANSI Accredited Certifier Accreditation #0779."

The National Alternative Fuels Training Consortium (NAFTC) offers a variety of courses related to alternate fuel vehicles, * including CNG fuel system inspection.

Contact Us

For more information, please contact us at 1-800-GAS-2000 or

*By clicking the link, you will leave and transfer directly to the website of a third party provider which is not part of the Southern California Gas Company. The Terms and Conditions and Privacy Policy on that website will apply.

1Provided for informational purposes only. Neither Southern California Gas Company nor the CPUC recommend or endorse the products or services of any third party listed herein, or represent that the particular products or services are fit for any particular purpose or use. By publishing this list, neither Southern California Gas Company nor the CPUC is acting in an advisory capacity, or assumes responsibility for any use of the list by customers. Although commercially reasonable efforts are used in posting this list, no representation is made that it is complete or free from error. Related information is posted at

Updated 1/2013

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