ASTM D4860 Free Water and Particulate Contamination in Mid-Distillate Fuels
ASTM D4860 Standard Test Method for Free Water and Particulate Contamination in Mid-Distillate Fuels (Clear and Bright Numerical Rating)
12. Report
12.1 Report the results obtained in 11.1.1 regarding the appearance and presence of particulate matter and the value obtained in 11.2.7.1 as the MSEP-C&B rating.
13. Precision and Bias
13.1 Visual Examination for Free Water and Particulate Matter - It is not practical to specify the precision, and no justifiable statement can be made on the bias of the procedure in this test method since this is a pass/fail test based on a subjective visual examination.
13.2 Precision - Numerical rating of free water, as determined by statistical analysis of the test results obtained by twelve operator/instrument pairs on identical fuel samples at a common site is as follows:
13.2.1 Repeatability - The difference between successive measured MSEP-C&B ratings obtained by the same operator with the same Micro-Separometer under constant operating conditions on identical material would, in the long run and in the normal and correct operation of the test method, exceed six for only one case in twenty (Note 6).
13.2.2 Reproducibility - The difference between two single and independent measurements of MSEP-C&B ratings by different operator/instrument pairs at the same location on identical material would, in the long run and in the normal and correct operation of the test method, exceed seven for only one case in twenty (Note 6).
NOTE 6 - These results are based on a March 1989 twelve-laboratory cooperative test program using samples specifically prepared for the program. Samples were specifically prepared, since representative samples covering a wide range of level of contaminates were unobtainable from field sources. The repeatability and reproducibility values were estimated from results obtained at the same location and on two consecutive days, by different operator/instument pairs testing identical samples. Results particularly for reproducibility, obtained at different times and locations may, therefore, not be comparable according to these estimates, since they may contain errors as a result of sampling, environmental factors, and instability of the contaminates present.
13.2.2.1 In practice, two results obtained at different laboratories (locations) would be acceptable, if their difference did not exceed the published reproducibility. In the event that the difference did exceed the reproducibility, there would be no means of testing, whether the results were acceptable or not. As a practical matter, testing for free water and particulate matter is a real time test, since both contaminates can vary according to changes in the environment, particularly temperature, and time (settling effects).
13.3 Bias - The procedure in Test Method D4860 has no bias, because the value of MSEP-C&B ratings is defined only in terms of this test method.
14. Keywords
14.1 clear and bright numerical rating; free water; Micro-Separometer; mid-dillate fuels; MSEP-C&B rating; particulate contamination
