ASTM D2140 standard test method for carbon-type composition of insulating oils of petroleum origin
9. Report
9.1 Report the following information:
9.1.1 Designation of test method used (D2140),
9.1.2 Sample identification.
9.1.3 Percent of aromatic ring carbons (% CA).
9.1.4 Percent of naphthenic ring carbons (% CN), and
9.1.5 Percent of paraffinic chain carbons (% CP).
NOTE 5 - The total of 9.1.3, 9.1.4, and 9.1.5 should equal 100 %.
10. Precision and Bias
10.1 Precision - The precision of this test method has not been the subject of an interlaboratory test. This procedure involves calculations based on three experimentally observed values whose precisions are given in their respective methods. The precision of this test method (without the sulfur correction), calculated from the precisions of these values and using the equations of Section 8, is as follows:
10.1.1 Repeatability - The difference between successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test material should, in the long run, in the normal and correct operation of the test method exceed the following values only in 1 case in 20:
10.1.2 Reproducibility - The difference between two single and independent results obtained by different operators working in different laboratories on identical test material should, in the long run, exceed the following values only in 1 case in 20:
NOTE 6 - The precision of the carbon-type composition calculation varies with position on the CA–CN–CP plane of Fig. 1. Sensitivity to experimental error for the CN and CP values is greatest at high CA values. The precision values given above do not apply if routine test methods, rather than the precision methods specified, are used for determining density and refractive index.
10.2 Bias - Since there is no accepted reference material suitable for determining the bias of this test method, no statement on bias is being made. A comparison of results from this test method and a complex separation and purification procedure has been reported for petroleum fractions, with agreement between the two methods being dependent on the viscosity-gravity constant of the fraction.
11. Keywords
11.1 carbon type; composition; electrical oils; mineral oils; oils