True vapor pressure
True vapor pressure is a common measure of the volatility of petroleum distillate fuels. It is defined as the
equilibrium partial pressure exerted by a volatile organic liquid as a function of temperature as determined by the test method ASTM D 2879.
The true vapor pressure at 100 °F differs slightly from the Reid vapor pressure , as it excludes dissolved fixed gases such as air. Conversions between the two can be found
