ASTM D5190 Vapor Pressure of Petroleum Products (Automatic Method)
ASTM D5190 Standard Test Method for Vapor Pressure of Petroleum Products (Automatic Method)
14. Report
14.1 Report the corrected dry vapor pressure equivalent pressure to the nearest 0.1 kPa (0.01 psi) without reference to temperature.

14.2 If the sample was observed to be hazy in 8.5, report the test result as in 14.1, followed by the letter "H".

NOTE 8 - The precision and bias statements have not been determined for hazy samples, since these types of samples have not been evaluated as part of an interlaboratory study.

NOTE 9 - The inclusion of the letter "H" in 14.2 is intended to alert the data recipient that the sample analyzed was hazy. In the event a laboratory has a computer system that is incapable of reporting alphanumeric results according to the requirements in 14.2, it is permissible for the laboratory to report the result obtained as in 14.1, along with a statement or annotation that clearly conveys to the data recipient that the sample analyzed was hazy.

15. Precision and Bias
15.1 Precision - The precision of this test method as determined by the statistical examination of the interlaboratory test results is as follows: The following precision data were developed in a 1991 interlaboratory cooperative test program. Participants analyzed sample sets comprised of blind duplicates of 14 types of hydrocarbons and hydrocarbon-oxygenate blends. The oxygenate content (MTBE, ethanol, and methanol) ranged from 0 to 15 % by volume nominal and the vapor pressure ranged from 14 to 100 kPa (2 to 15 psi) nominal. A total of 60 laboratories participated. Some participants performed more than one test method, using separate sample sets for each. Twenty-six samples sets were tested by Test Method D4953, 13 by this test method, and 27 by Test Method D5191. In addition, six sets were tested by modified D5190 and 13 by modified Test Method D5191.
15.1.1 Repeatability - The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following value only in one case in twenty:
2.48 kPa (0.36 psi)

15.1.2 Reproducibility - The difference between two single and independent test results obtained by different operators working in different laboratories on identical test material would, in the long run, exceed the following value only in one case in twenty:
3.45 kPa (0.50 psi)

15.2 Bias - Since there is no accepted reference material suitable for determining the bias for the procedures in this test method, bias cannot be determined.
15.2.1 A statistically significant relative bias was observed in the 1991 interlaboratory cooperative test program described in 15.1 between the total pressure obtained using this test method and the dry vapor pressure obtained from using Test Method D4953, Procedure A. This bias can be corrected by applying Eq 1, as described in Section 13.

16. Keywords
16.1 automated vapor pressure measurement; dry vapor pressure; gasoline; hydrocarbon-oxygenate blends; petroleum products; vapor pressure