Vapor pressure is an important physical property of volatile liquids.

The vapor pressure of gasoline and gasoline-oxygenate blends is regulated by various government agencies.

Specifications for volatile petroleum products generally include vapor pressure limits to ensure products of suitable volatility performance.

This test method is more precise than Test Method D 4953.

1.1 This test method covers the determination of the total pressure of air-containing, volatile, petroleum products. This test method is suitable for testing samples with boiling points above 0^oC (32^oF) that exert a vapor pressure between 7 and 172 kPa (1 and 25 psi) at 37.8^oC (100^oF) at a vapor-to-liquid ratio of 4:1. This test method is suitable for testing gasoline samples that contain oxygenates. No account is made of dissolved water in the sample.

1.1.1 Some gasoline-oxygenate blends may show a haze when cooled to 0 to 1^oC. If a haze is observed in , it shall be indicated in the reporting of results. The precision and bias statements for hazy samples have not been determined (see Note 8).

1.2 This test method is suitable for the calculation of a dry vapor pressure equivalent (DVPE) by means of a correlation equation (see ). The calculated DVPE very closely approximates the dry vapor pressure that would be obtained on the same material when tested in accordance with Test Method D4953.

1.3 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are provided for information only.

1.4 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 7.3 through 7.5 and 9.2.