Ethanol Blend Specifications

Ethanol-blended gasoline sold in the state must meet ASTM specification D4814, with the following exceptions:

  • The maximum vapor pressure of ethanol blends containing 1% or more ethanol for volatility Classes A, B, C, and D may not exceed the ASTM D4814 limit by more than 1.0 pound per square inch (psi) from September 16 through May 31;
  • The maximum vapor pressure of ethanol blends containing 1% or more ethanol for volatility Class E may not exceed the ASTM D4814 limit by more than 0.5 psi from September 16 through May 31; and
  • The maximum vapor pressure of ethanol blends containing 9% to 10% ethanol may not exceed the ASTM D4814 limit by more than 1.0 psi from June 1 through September 15.
These exceptions remain in effect until ASTM develops final vapor pressure maximums for ethanol blends. (Reference Tennessee Code 47-18-1304)