Rationale

A new instrument has been developed, JF-1A-ST “Stick Conductivity”, which provides hand held measurements of electrical conductivity in aviation and distillate fuels. A Subcommittee J approved test plan (30JUL21, see attached Research Report, Section 9.0, Test Plan Approval) was used to perform a single site ILS. The ILS data analysis was conducted by ASTM Statistician Alex Lau in accordance with ASTM D6300 Precision and ASTM D6708 Equivalence and the results are provided in the attached Research Report. During the ILS study, operators at their discretion were allowed to run secondary instruments (produced by other manufacturers) on the samples after the primary ILS measurements were completed. Comparative data from these optional measures are presented in the research report, although this data is not a formal component of the ILS. Model JF-1A-ST, Stick Conductivity is manufactured by D-2 Incorporated. This is the first ballot of the changes related to ASTM D2624 to incorporate this instrument. Attached are the changes to the method and the corresponding Research Report.

D-2 Incorporated presently has a hand-held device listed in ASTM D2624, Model JF-1A-HH. In consideration of this and with advice from the D2624 Method Technical Chair (Joel Schmitigal, US Army, TARDEC, Lansing, IL) it was decided that incorporation of both units in a common table was appropriate (this approach has been followed for other suppliers listed in the Method), as it is expected that D-2 Incorporated will continue to offer both JF-1A-HH and JF-1A-ST instruments due to differences in features and use application.

As discussed in Subcommittee J during December 2021, and following the update to the Subcommittee J Operating Procedure regarding precision estimates obtained from single site laboratory studies, this ballot intends to update the precision statement according to the Subcommittee J Operating Procedures section 13.1 and 27.2. The proposed text in this ballot is a hybrid, which meets the general requirements of the Subcommittee J Operating Procedure while taking on board changes to definitions for repeatability and reproducibility which occurred while this topic was discussed over the last few years and also accounting for existing text already in the test method. ASTM methods are required to meet ASTM Form & Style, which currently does not address the specific case in which a material is not homogenous or is subject to degradation during shipping.

ASTM D2624 is another D02.J method where all precision determinations were from studies carried out at a single site. It is the intention of SC J to ballot all test methods under their jurisdiction to account for Reproducibility, Single Site. This ballot follows the format established from ballots of the reapproval of D8073, with the new wording, whilst taking into account any differences in the D2624 Method. This is the first ballot in this regard to D2624, while there have been several ballots of the reapproval of D8073 to attain the consensus wording to be used for Reproducibility, Single Site.

Other minor changes are proposed which continue the goal of this work item to improve D2624. For method consistency, the plot of r & R for the Table 1 Data will be removed, as similar plots are not given for all other tables. Each Repeatability & Reproducibility, Single Site Table data will have the equations for r & R added to the top of the table from each respective research report. Equations better allows method users to compute expected r & R for an obtained value should it lie between table values. The incorporation of formulas is more consistent with the ASTM Form & Style requirements.

The motion to ballot was approved at the December 2021 Subcommittee J virtual session.

Ballot History: This is the first time this item has been balloted.