1.1 ,This test method covers and is applicable to gasolines and gasoline-oxygenate blends with a vapor pressure range from 35 ,kPa to 100 ,kPa (5 ,psi to 15 ,psi) (see Note 2). This test method, a modification of Test Method D323 (Reid Method), provides two procedures to determine the vapor pressure (Note 1) of gasoline and gasoline-oxygenate blends.
Note 1: ,Because the external atmospheric pressure is counteracted by the atmospheric pressure initially present in the air chamber, this vapor pressure is an absolute pressure at 37.8 ,°,C (100 ,°,F) in kilopascals (pounds-force per square inch). This vapor pressure differs from the true vapor pressure of the sample due to some small vaporization of the sample and air in the confined space.