ASTM D287 for API gravity of crude petroleum and petroleum products
ASTM D287 standard test method for API gravity of crude petroleum and petroleum products(Hydrometer method)
10. Report
10.1 Report the corrected hydrometer reading as degrees API (°API) or as API Gravity.
11. Precision and Bias
11.1 The precision of this test method as obtained by statistical examination of interlaboratory test results is as follows:
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 0.2° API only in one case in twenty.
11.1.2 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 0.5° API only in one case in twenty.
NOTE 4 - The precision for this method was not obtained in accordance with RR:D02-1007.
NOTE 5 - This precision statement applies only to measurements made at temperatures differing from 60°F (15.56°C) by less than 18°F (10°C).
11.2 Bias - Bias for this method has not been determined.
12. Keywords
12.1 API gravity; crude petroleum; hydrometer; thermohydrometer; thermometer
