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Testing Compressed Natural Gas Retail Motor-Fuel Dispensers/Arriving Prepared to Test



Richard A. Harshman


As the developing infrastructure for fueling vehicles that use compressed natural gas (CNG) as an engine fuel continues to unfold, some weights and measures jurisdictions are raising questions about the equipment needed to test the retail-motor fuel dispensers (RMFDs) that dispense CNG. The testing of CNG RMFDs necessitates some advance planning to ensure that all of the proper test equipment is available on the day that testing is to take place. There is information that officials can gather beforehand that will allow them to make a preliminary determination of whether or not the equipment made available to them for testing will be adequate and improve the likelihood that a complete test, as outlined in NIST EPO No. 28 Examination Procedure Outline for Compressed Natural Gas (CNG) Retail Motor Fuel Dispensers, can be performed on the date that testing is scheduled. This article identifies the information that needs to be known about the test equipment as well as the RMFD to be tested and explains how this information is used to make this determination.
Physical Measurement Laboratory/Office of Weights and Measures
Report Number


motor-fuel, fuel dispensers, CNG, RMFD, HB44, GGE, GLE, gasoline gallon equivalent, gasoline liter equivalent, natural gas, compressed natural gas


Harshman, R. (2014), Testing Compressed Natural Gas Retail Motor-Fuel Dispensers/Arriving Prepared to Test, Physical Measurement Laboratory/Office of Weights and Measures, [online],, (Accessed May 21, 2024)


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Created December 10, 2014, Updated February 19, 2017