ASTM D2709 for water and sediment in middle distillate fuels by centrifuge
9. Report
9.1 Report the volume of the combined water and sediment read from the tube as the percentage of the total sample, since a 100-mL sample was used. Report results lower than 0.005 % as either 0 or 0.005 volume %.
10. Precision and Bias
10.1 Precision - The precision of the procedure in this test method, for measuring the volume percent amount of combined water and sediment in middle distillate fuels by centrifuge was determined by a round robin test program performed by six individuals using 13 samples at a common site.
10.1.1 Repeatability - The difference between successive measured volume percent amounts of combined water and sediment obtained by the same operator using the same centrifuge and type of pear shaped tube under constant operating conditions on identical distillate fuel samples at the same site would, in the long run and in the normal and correct operation of the test method, exceed 0.014 volume percent in one case in twenty.
10.1.2 Reproducibility - The difference between two single independent measurements of volume percent amounts of combined water and sediment obtained by different operator/centrifuge pairs using the same type of pear shaped tube on identical distillate fuel samples at the same site would, in the long run, in the normal and correct operation of the test method, exceed 0.041 volume percent in one case in twenty.
10.2 Bias - Since there is no accepted reference material suitable for determining the bias for this procedure for measuring water, the bias is not available for this test method.
11. Keywords
11.1 centrifuge; centrifuge tube; distillate fuel; water and sediment
