What Is Rvp In Gasoline

Fuels with higher rvp evaporate more easily than those with lower rvp.

What is rvp in gasoline.

The pressure is exerted at a specific temperature that is 100 degrees fahrenheit. Federal law prohibits gasoline with a reid vapor pressure rvp greater than 9 0 pounds per square inch to be sold at retail stations from june 1 through september 15. Reid vapor pressure rvp is a common measure of the volatility of gasoline and other petroleum products. A particular fuel blend s rvp is based on the combined rvp of the ingredients that make up the blend.

Epa regulates the vapor pressure of gasoline sold at retail stations during the summer ozone season june 1 to september 15 to reduce evaporative emissions from gasoline that contribute to ground level ozone and diminish the effects. Reid vapor pressure is the pressure exerted by a liquid to calculate the volatile nature of gasoline. Rvp is not. Reid vapor pressure is measured in gauge pressure and is stated in psi units.

Rvp is a measure of how easily the fuel evaporates at a given temperature. The more volatile a gasoline higher rvp the easier it evaporates. Alabama rvp of 7 0 psi. Regulators worry about this evaporation because it contributes to ozone formation.

Winter blend fuel has a higher rvp because the fuel must be able to evaporate at low temperatures for the engine to operate properly especially when the engine is cold. Implementation of alabama s 7 0 psi gasoline rvp rule was suspended when epa approved alabama s request to move the rule to the contingency measure portion of the sip for the birmingham area. It is defined as the absolute vapor pressure exerted by the vapor of the liquid and any dissolved gases moisture at 37 8 c 100 f as determined by the test method astm d 323 which was first developed in 1930 and has been revised several times the latest version is astm d323 15a. It is determined by a test known as astm d 323.

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