1.2. No Vapor Pressure waiver for E15

 

Currently, the Reid vapor pressure (RVP) limit for conventional gasoline is 9 psi (62 kPa) during summertime (“high ozone season”). Summertime is defined differently depending on the state. For details please refer to the database.

 

According to section 111(h) of the 1990 Clean Air Act Amendments, “for fuel blends containing gasoline and 10 percent denatured anhydrous ethanol, the Reid vapor pressure limitation under this subsection shall be one pound per square inch (psi) greater than the applicable Reid vapor pressure established under paragraph (1)…”. It means that E10 blends are granted a 1 psi (6.89 kPa) RVP waiver compared with no-ethanol gasoline.

 

The RVP waiver is provided because the addition of ethanol to gasoline increases vapor pressure of