ASTM D6897 Standard Test Method for Vapor Pressure of Liquefied Petroleum Gases (LPG) (Expansion Method)
14. Report
14.1 Report the corrected total pressure as the LP-Gas vapor pressure test result and specify the test temperature and vapor to liquid ratio if not equal to 0.5:1.
VP(Tm °C) = #### kPa
where:
Tm = measuring temperature.
15. Precision and Bias
15.1 Precision - The precision of this test method as determined by the statistical examination of interlaboratory test results is as follows:
15.1.1 Repeatability - The difference between successive test results obtained by 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:
Repeatability = 7.4 kPa (1.1 psi)
NOTE 10 - The repeatability was calculated from triplicate determinations on 20 samples of propane measured under single site repeatability over the range of 300 kPa to 1463 kPa (44 psig to 212 psig) using a vapor to liquid ratio of 0.5:1, at a temperature of 37.8 °C. No trend in variance was detected over this range.
15.1.2 Reproducibility - Reproducibility has not been determined due to extreme difficulty with distribution of these sample types for an interlaboratory study.
15.2 Relative Bias to Test Method D1267 - Relative bias has not been determined.
15.3 Bias - Since there is no accepted reference material suitable for determining the bias for the procedure in this test method, bias has not been determined.
16. Keywords
16.1 expansion method; liquefied petroleum gas; vapor pressure
