Vapor pressure of crude oil at various V/Ls is an important physical property for shipping and storage.

Vapor pressure of crude oil is important to crude oil producers and refiners for general handling and initial refinery treatment.

Note 1—A V/L of 0.02:1 (X = 0.02) mimics closely the situation of an oil tanker.

To prevent losses of high volatile compounds, the sample is always maintained at a pressure at least 100 kPa (14.5 psi) higher than the vapor pressure.

The vapor pressure determined by this test method at a V/L of 4:1 (VPCR₄) of crude oil at 37.8°C can be related to the vapor pressure value determined on the same material when tested by Test Method D 323 (see Appendix X1).

Chilling and air saturation of the sample prior to the vapor pressure measurement is not required.

This test method allows the determination of VPCR _x samples having pour points above 0°C.

1.1 This test method covers the use of automated vapor pressure instruments to determine the vapor pressure of crude oils at temperatures between 5 and 80C for vapor-liquid ratios from 4:1 to 0.02:1 (X = 4 to 0.02) and pressures from 7 to 500 kPa (1.0 to 70 psi).

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

1.3 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.