ASTM lowers E85's minimum ethanol volume to 51 percent

By Kris Bevill | May 25, 2012

Scientific standards development body ASTM International (formerly known as the American Society for Testing and Materials) recently made significant changes to its E85 specification, lowering the approved minimum ethanol volume of the fuel to just 51 percent and renaming the specification to reflect the fact that the fuel may no longer be close to 85 percent ethanol.

In a conference call, Kristy Moore, vice president of technical services at the Renewable Fuels Association and ASTM committee member, said the sweeping changes to the standard were necessary in order to ensure that ethanol fuel blends for flex-fuel vehicles can meet seasonal vapor pressure requirements in all regions of the country. ASTM’s previous E85 specification required the fuel to contain at least 70 percent denatured ethanol by volume, 68 percent actual ethanol, and up to 83 percent actual ethanol volume. But problems regarding cold-start issues with E85 in certain areas led the committee to determine that the various vapor-pressure requirements for gasoline in certain areas, specifically in California and other states which have put in place low-vapor pressure regulations, were making it impossible for the final fuel blend to meet vapor pressure requirements in some areas. As a result, aside from occasional vehicle operator complaints, some terminals stopped carrying E85 because they could not guarantee the fuel would meet specifications. “We knew that we needed to take drastic action and make significant changes to this specification if we were going to make broad-market access for this fuel,” Moore said during the call.

The ASTM committee examined all possible options before concluding that the best remedy to the situation would be to lower the minimum volume of ethanol in the fuel blend, according to Moore, and care was taken to ensure the majority of the fuel volume would continue to be ethanol. “We believe that we have greatly improved the flexibility and ethanol content coverage for broader market place availability of these predominantly ethanol fuel blends,” she added. Fuel quality is regulated by the states and gasoline vapor pressure varies by region and season so ethanol volume in E85 blends will also vary depending on those factors.

The standard specification for E85 was previously known as Fuel Ethanol for Automotive Spark-Ignition Engines, but is now the Standard Specification for Ethanol Fuel Blends for Flexible-Fuel Automotive Spark-Ignition Engines. Moore said the name change was deemed necessary to make clear that the specification applies to fuel for flex-fuel vehicles and, because fuel ethanol is 98 percent ethanol, classifying a flex-fuel blend that could consist of just 51 percent ethanol as fuel ethanol no longer seemed accurate.