ASTM D3601 Standard Test Method for Foam In Aqueous Media (Bottle Test)
8. Calculation and Report
8.1 Calculate maximum foam height, Fm, as follows:
Fm = M - I
where:
I = initial height (7.6), and
M = maximum total height at zero time (7.9).
8.2 Time to Defoam to 10 mm (7.10) - Record the time to defoam to 10 mm of net foam to the nearest 0.5 min if foam subsides to this point within the 5-min test time. Otherwise, record "5 +".
8.3 Calculate residual foam after 5 min, Fr, as follows:
Fr = R - I
where:
R = residual total height to nearest 1 mm after 5 min (7.11).
NOTE 9 - A suitable report form is described in Fig. 2.
9. Precision and Bias
9.1 The precision of the test method as determined by the statistical examination of interlaboratory test results is as follows:
9.1.1 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, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty:
Maximum foam - 7.0 mm
9.1.2 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, exceed the following values only in one case in twenty:
Maximum foam - 72 % relative
9.2 Since there is no accepted reference material suitable for determining the bias for the procedure in this test method, no statement on bias is being made.
NOTE 10 - Residual foam and defoam time values are not suitable for statistical evaluation due to the large number of "zeros", "<0.5 min" and "5 + min" included in the data.
NOTE 11 - Referee Work - No more than three replicate tests will normally be required.
10. Keywords
10.1 aqueous media; bottle test; foam; low shear; water based metalworking coolant
