ASTM D5305 Test Method for Determination of Ethyl Mercaptan in LP-Gas Vapor
11. Report
11.1 Report the observed tube reading and corrected concentration of ethyl mercaptan in parts per million by volume (ppmv) to the nearest 0.5 ppmv.
12. Precision and Bias
12.1 Precision:
12.1.1 The precision of this test method as determined by statistical analysis of interlaboratory test results is as follows:
12.1.1.1 Repeatability - The difference between successive 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 following values only in one case in twenty: from 5 to 20 ppmv, the larger of 1 ppm or +/- 15 % of the mean of the two results; above 20 ppmv, +/- 20 % of the mean of the two results.
12.1.1.2 Reproducibility - The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material, would, in the normal and correct operation of the test method, exceed the following value only in one case in twenty: the larger of 1.5 ppmv or +/- 20 % of the mean of the two results.
NOTE 3 - The preceding repeatability and reproducibility were obtained from statistical analysis of results submitted by twelve testers who cooperatively tested five samples of propane with ethyl mercaptan concentrations ranging from 3.3 to 32 ppmv in the vapor phase.
12.2 Bias - Within the precision limits defined in 12.1.1.1 and 12.1.1.2, this test method has no bias.
13. Keywords
13.1 ethyl mercaptan; liquefied petroleum gases; odorant-stain tube
