Standard Test Method for Determination of Vapor Pressure (VPX) of Petroleum Products, Hydrocarbons, and Hydrocarbon-Oxygenate Mixtures (Triple Expansion Method).
Get more information about the standard at ASTM D6378-22.
ASTM D6378 is a standard test method for determining the vapor pressure of volatile, liquid petroleum products, hydrocarbons, and hydrocarbon-oxygenate mixtures, including ethanol blends up to 85% by volume. This method employs automated vapor pressure instruments to measure the vapor pressure exerted in a vacuum by these substances. Accurate vapor pressure measurements are crucial for ensuring the safe handling, storage, and transportation of volatile fuels and for compliance with environmental regulations.
Details
The ASTM D6378 test method is suitable for samples with boiling points above 0 °C (32 °F) that exert a vapor pressure between 7 kPa and 150 kPa (1.0 psi and 21 psi) at 37.8 °C (100 °F) with a vapor-to-liquid (V/L) ratio of 4:1. The procedure involves introducing a chilled, air-saturated sample into a temperature-controlled chamber of an automated vapor pressure instrument. The sample is then subjected to a vacuum, allowing it to expand to the desired V/L ratio. The instrument measures the resulting pressure, which corresponds to the vapor pressure of the sample.
This method also applies to aviation turbine fuels with boiling points above 0 °C that exert vapor pressures between 0 kPa and 110 kPa (0 psi and 15.5 psi) at a V/L ratio of 4:1, within a temperature range of 25 °C to 100 °C (77 °F to 212 °F). The vapor pressure determined at a V/L ratio of 4:1 (VP4) for gasoline and gasoline-oxygenate blends at 37.8 °C can be correlated to the dry vapor pressure equivalent (DVPE) value determined by ASTM D5191.
Industries and Applications
ASTM D6378 is significant in various industries and applications, including:
- Petroleum Industry: Refineries and fuel distributors utilize this method to assess the vapor pressure of gasoline, ethanol blends, and other volatile fuels, ensuring product quality and compliance with regulatory standards
- Environmental Agencies: Regulatory bodies employ this test method to monitor and control the vapor pressure of fuels, aiding in the enforcement of environmental regulations aimed at reducing volatile organic compound emissions
- Automotive Industry: Engine manufacturers and researchers use this method to evaluate fuel volatility characteristics, ensuring compatibility with engine performance requirements and emission standards