ASTM D2163 Standard Test Method for Determination of Hydrocarbons in Liquefied Petroleum (LP) Gases and Propane/Propene Mixtures by Gas Chromatography
12. Report
12.1 Report the concentration of each component as liquid volume percent (vol%) to the nearest 0.01%.
12.2 Individually eluted C5 olefins and hexanes-plus components may be speciated and reported separately or summed together into groups.
13. Precision and Bias
13.1 The precision of this test method is based on an interlaboratory study conducted between May 2010 and November 2012. Sixteen laboratories analyzed thirteen samples of LPG in duplicate. The composition of the LPG ranged from predominantly propane to butanes, with some samples blended to simulate out-of-specification products. Each sample was provided in two sample cylinders, with one test result generated per cylinder to minimize any loss of sample integrity.
13.1.1 Repeatability - The difference between two test results obtained by the same operator using 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 values for r in Table 4 only in one case in twenty.
13.1.2 Reproducibility - The difference between two single and independent results, obtained by different operators working in different laboratories for identical test materials would, in the long run, exceed the R values in Table 4 only in one case in twenty.
13.1.3 Bias - The bias of this test method could not be determined at the time of the interlaboratory study as no reference materials were available.
14. Keywords
14.1 floating piston cylinder; gas chromatography; gas sampling valve; liquid sampling valve; liquefied petroleum gases; LP gases; propane; propene
