ASTM D2890 Test Method for Calculation of Liquid Heat Capacity of Petroleum Distillate Fuels
7. Report
7.1 Report the results to the nearest 0.01 Btu/lb • °F.
7.2 The heat capacity, Btu/lb • °F may be converted to the International System of Units (SI) of kilojoule per kilogram kelvin (kJ/kg • K) by multiplying the results obtained in 7.1 by the conversion factor 4.186800 and then rounding to the appropriate number of significant digits.
8. Precision and Bias
8.1 The following criteria should be used for judging the acceptability of results (95 % probability).
8.1.1 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 only in one case in twenty:
0.01 Btu/lb • °F (0.04 kJ/kg • K)
8.1.2 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 value only one case in twenty:
0.02 Btu/lb • °F (0.08 kJ/kg•K)
NOTE 3 - The preceding repeatability and reproducibility were obtained from results submitted by seven laboratories that cooperatively tested four turbine fuels with initial boiling points in the range 320 to 400°F (160 to 204°C), and end points in the range 430 to 535°F (221 to 279°C). Each laboratory determined the required distillation and gravity data in duplicate, and performed the procedures graphically once for each of the two sets of determined data for each sample. Heat capacities of the fuels were not determined during the cooperative program.
8.2 The accuracy of this test method has been reported as within 4 % for straight-run petroleum fractions and approximately 8 % for pure olefins.
8.3 Bias - Since there is no accepted reference material suitable for determining bias for this test method, no statement of bias can be made.
9. Keywords
9.1 liquid heat capacity; petroleum distillate
