ASTM D1298 for density of crude petroleum and liquid petroleum products by hydrometer method
12. Report
12.1 Report the final value as density, in kilograms per cubic metre, at the reference temperature, to the nearest 0.1 kg/m3.
12.2 Report the final value as density, in kilograms per litre or grams per millilitre at the reference temperature, to the nearest 0.0001.
12.3 Report the final value as relative density, with no dimensions, at the two reference temperatures, to the nearest 0.0001.
12.4 Report the final value as API gravity to the nearest 0.1°API.
13. Precision and Bias
13.1 Precision - The precision of the method as determined by statistical examination of interlaboratory results is as follows:
13.1.1 Repeatability - The difference between two 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 values 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 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.
13.2 Bias - Bias for this test method has not been determined. However, there should be no bias from absolute measurements, if the calibration of the hydrometer and the thermometer is traceable to International Standards, such as supplied by the National Institute of Standards and Technology.
14. Keywords
14.1 API gravity; crude petroleum; density; hydrometer; Petroleum Measurement Tables; petroleum products; relative density; specific gravity