ASTM D86 for distillation of petroleum products
ASTM D86 for distillation of petroleum products at atmospheric pressure
13. Precision and Bias
13.1 Precision - The precision of this test method, as determined by the statistical examination of the interlaboratory test results, is as follows:

NOTE 25 - The precision and bias have been derived according to the group number in the following fashion. Group 1, 2, and 3 samples are labeled as NOT4, and Group 4 samples are labeled GRP4.

NOTE 26 - The precision was derived from data produced by automated D 86 apparatus. Typical examples of precision for manual apparatus can be calculated from the information contained in Annex A4 (see A4.9).

13.1.1 Repeatability - The difference between successive test results, obtained by the same operator using the same apparatus under constant operating conditions on identical test material, would in the long run, in the normal and correct operation of this test method, exceed the following only in one case in twenty.

NOT4: Refer to Annex A1 for tables of calculated repeatability.
IBP: r = 0.0295(E + 51.19)valid range: 20 – 70°C
E10: r = 1.33valid range: 35 – 95°C
E50: r = 0.74valid range: 65 – 220°C
E90: r = 0.00755(E + 59.77)valid range: 110 – 245°C
FBP: r = 3.33valid range: 135 – 260°C
GRP4: Refer to Annex A1 for tables of calculated repeatability.
IBP: r = 0.018Tvalid range: 145 – 220°C
T10: r = 0.0094Tvalid range: 160 – 265°C
T50: r = 0.94valid range: 170 – 295°C
T90: r = 0.0041Tvalid range: 180 – 340°C
FBP: r = 2.2valid range: 195 – 365°C

where:
E = evaporated temperature within valid range prescribed,
and
T = recovered temperature within valid range prescribed.

NOTE 27 - For naphthas, solvents and other similar materials where percent recovered are reported and the percent loss is typically less than one percent, the percent recovered temperatures can be considered identical to the percent evaporated temperatures and precision can be calculated as shown for NOT4.

13.1.2 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 normal and correct operation of this test method, exceed the following only in one case in twenty.

NOT4: Refer to Annex A1 for tables of calculated reproducibility.
IBP: R = 0.0595(E + 51.19)valid range: 20 – 70°C
E10: R = 3.20valid range: 35 – 95°C
E50: R = 1.88valid range: 65 – 220°C
E90: R = 0.019(E + 59.77)valid range: 110 – 245°C
FBP: R = 6.78valid range: 135 – 260°C
GRP4: Refer to Annex A1 for tables of calculated reproducibility.
IBP: R = 0.055Tvalid range: 145 – 220°C
T10: R = 0.022Tvalid range: 160 – 265°C
T50: R = 2.97valid range: 170 – 295°C
T90: R = 0.015Tvalid range: 180 – 340°C
FBP: R = 7.1valid range: 195 – 365°C

where:
E = evaporated temperature within valid range prescribed,
and
T = recovered temperature within valid range prescribed.

NOTE 28 - For naphthas, solvents and other similar materials where percent recovered are reported and the percent loss is typically less than one percent, the percent recovered temperatures can be considered identical to the percent evaporated temperatures and precision can be calculated as shown for NOT4.

13.2 The precision statements were derived according to Practice D 6300 from a 2005 interlaboratory cooperative test program.7 Sixteen laboratories participated and analyzed thirty three sample sets comprised of; specification grade gasolines, some containing up to 10 % ethanol, specification grade diesel, with a B5 and B20 biodiesel, specification grade heating oil, aviation turbine fuels, aviation gasolines, marine fuels, mineral spirits and toluene. The temperature range covered was 23 to 365°C. Information on the type of samples and their average boiling points are in the research report.

NOTE 29 - The precision was not determined for one sample of gasoline with high vapor pressure which exhibited high loss, and one sample of aviation turbine fuel doped with gasoline, which is atypical.

13.3 Bias:
13.3.1 Bias - Since there is no accepted reference material suitable for determining the bias for the procedure in these test methods, bias has not been determined.

13.3.2 Relative Bias between Manual and Automated Apparatus - An interlaboratory study5 conducted in 2003 using manual and automated apparatus has concluded that there is no statistical evidence to suggest that there is a bias between manual and automated results.

14. Keywords
14.1 batch distillation; distillates; distillation; laboratory distillation; petroleum products