ASTM D2533 Test Method for Vapor-Liquid Ratio of Spark-Ignition Engine Fuels
1. Scope
1.1 This test method covers a procedure for measuring the volume of vapor formed at atmospheric pressure from a given volume of gasoline. The ratio of these volumes is expressed as the vapor-liquid (V/L) ratio of the gasoline at the temperature of the test.

1.2 Dry glycerol can be used as the containing liquid for nonoxygenated fuels.

1.3 Mercury can be used as the containing liquid with both oxygenated and nonoxygenated fuels. Because oxygenates in fuels may be partially soluble in glycerol, gasoline-oxygenate blends must be tested using mercury as the containing fluid.

NOTE 1 - Test Method D4815 can be used to determine the presence of oxygenates in fuels.

1.4 The values stated in both inch-pound and SI units are to be regarded separately as the standard. The units given in parentheses are for information only.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 7 and Note 11.

2. Referenced Documents
2.1 ASTM Standards:
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4815 Test Method for Determination of MTBE, ETBE, TAME, DIPE, tertiary-Amyl Alcohol and C1 to C4 Alcohols in Gasoline by Gas Chromatography
D5188 Test Method for Vapor-Liquid Ratio Temperature Determination of Fuels (Evacuated Chamber Method)
E 1 Specification for ASTM Thermometers

3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 T (V/L = 20), n - the equilibrium temperature at which the partial pressure of a sample under test conditions is equal to 101.3 kPa (14.69 psia) and the vapor-liquid ratio is 20.

3.1.2 vapor-liquid ratio of a fuel, n - the ratio, at a specified temperature and pressure, of the volume of vapor in equilibrium with liquid to the volume of liquid sample charged, at 0°C (32°F).

NOTE 2 - This ratio differs from the absolute vapor-liquid ratio because corrections are not made for (1) liquid sample expansion with increasing temperature, (2) decrease in liquid sample volume by vaporization, and (3) dissolved air in the liquid sample.