Standard Test Method for Vapor Pressure of Petroleum Products and Liquid Fuels (Mini Method).
Get more information about the standard at ASTM D5191-22.
Facts about the ASTM D5191 Standard Test Method
The ASTM D5191 test method measures the total vapor pressure of petroleum products. It is based on a known volume of chilled, air-saturated sample that is introduced into a thermostatically controlled, evacuated test chamber. Alternatively, the test chamber can have a moveable piston that expands the volume after the sample introduction – the internal volume of which is five times that of the total test specimen introduced into the chamber. The air saturation process requires complex preperations, for example a consequent shaking of the sample or a refrigerator cooling. Because of that, this test method can produce an operator bias, a fact that marks a considerable disadvantage compared to ASTM D6378. Also EN 13016 can be considered as an equivalent to this method.
At the end of a measurement, the total vapor pressure is converted to a dry vapor pressure equivalent (DVPE). Therefore the correlation equation DVPE (kPa) = (0.965 X) – 3,78 kPa is applied where X denotes the measured total vapor pressure in kPa. This test method is suitable for calculation of the DVPE of gasoline and gasoline-oxygenate blends by means of a correlation equation.