ASTM D240 for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter
11. Report
11.1 Net heat of combustion is the quantity required in practical applications. The net heat should be reported to the nearest 0.005 MJ/kg.
NOTE 9 - Usually the gross heat of combustion is reported for fuel oils in preference to net heat of combustion to the nearest 0.005 MJ/kg.
11.2 To obtain the gross or net heat of combustion in cal (I.T.)/g or Btu/lb divide by the appropriate factor reporting to the nearest 0.5 cal/g or 1 Btu/lb.
QBtu/lb = (Q, MJ/kg)/0.002326
Qcal /g = (Q, MJ/kg)/0.0041868
12. Precision and Bias
12.1 Precision - The precision of this test method as obtained by statistical examination of interlaboratory test results is as follows:
12.1.1 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 values shown in the following table only in one case in twenty.
Repeatability: 0.13 MJ/kg
12.1.2 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 values shown in the following table only in one case in twenty.
Reproducibility: 0.40 MJ/kg
12.2 Bias - No general statement is made on bias for the standard since comparison with accepted reference materials (covering the range of values expected when the method is used) is not available.
13. Keywords
13.1 bomb calorimeter methods; gross heat of combustion; heat of combustion; heating tests; net heat of combustion
