ASTM D473 standard test method for sediment in crude oils and fuel oils by the extraction method
10. Report
10.1 For each sample with a calculated sediment content >0.005 % m/m as determined by Eq 1, report the sediment content of the sample, as sediment by extraction, as a percentage by mass, rounded to the nearest 0.01 % m/m following Practice E 29 rounding conventions. For each sample with a calculated sediment content not more than 0.005 % m/m as determined in Eq 1, report as, "0 % m/m". The test result shall reference Test Method D473/API MPMS Chapter 10.1 as the procedure used.
NOTE 3 - Since water and sediment values are commonly reported as volume percent, calculate the volume of the sediment as a percentage of the original sample. As a major portion of the sediment probably would be sand (silicon dioxide, which has a density of 2.32) and a small amount of other naturally occurring materials (with a relative density lower than that of sand), use an arbitrary density of 2.0 for the resulting sediment. Then, to obtain volume percent sediment, divide the mass percent sediment by 2.0 and multiply by the relative density of the crude or fuel oil.
where:
Sv = sediment content of the sample as a percentage by volume, and
S = sediment content of the sample as a percentage by mass.
10.2 Report that the sample mixing procedure was performed in accordance with the procedures specified in Practice D5854 (API Chapter 8.3). Report the temperature of the sample before and after mixing.
10.3 The test report shall also contain all details necessary for complete identification of the product tested; any deviation, by agreement or otherwise, from the procedure specified; and the date of the test.
11. Precision and Bias
11.1 Precision - The precision of the test method, as based on mass percent and as obtained by statistical examination of interlaboratory test results in the range 0 to 0.4 %, is described in 11.1.1 and 11.1.2.
11.1.1 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 in only one case in twenty:
r = 0.017 + 0.255 S
where:
r = repeatability of the test, and
S = average result, as a percentage by mass, of the values being compared.
11.1.2 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, in the normal and correct operation of the test method, exceed the following value in only one case in twenty:
R = 0.033 + 0.255 S
where:
R = reproducibility of the test, and
S = average result, as a percentage by mass, of the values being compared.
11.2 Bias - The procedure in this test method has no bias because the value of sediment can be defined only in terms of a test method.
12. Keywords
12.1 crude oil; extraction; fuel oil; sampling; sediment