ASTM WK64393

    Revision of D2234 / D2234M - 17 Standard Practice for Collection of a Gross Sample of Coal

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    Active Standard: D2234 / D2234M - 20

    Developed by Subcommittee: D05.23 | Committee D05 | Contact Staff Manager



    WK64393


    Keywords


    Rationale

    Subcommittee D05.23 on sampling has asked the Task Group to take on the exercise of coming up with a uniform definition of the term representative sample. The term is used widely in ASTM coal standards - as well as in multiple commercial agreements and technical documents - such as the International Maritime Solid Bulk Cargo (ISMBC) Codes related to Transportable Moisture Limit (TML). An examination of current ASTM sampling documents on coal, coke and petcoke shows that there are multiple definitions of representative sample in current use. There are two definitions in the current Standard E121-15 Terminology of Coal and Coke. They are: Representative sample, n-a sample collected in such a manner that every particle in the lot to be sampled is equally represented in the gross or divided sample. And Unbiased sample (representative sample) a sample free of bias. When D121 was balloted for reapproval in 2015, there was a negative vote from C. Rose on these definitions. The objection to the first one is that the sentence is only true if you include the term every particle of equal mass in the lot.. In addition, there was the concept of substituting the word proportionally for the word equally in the definition. The objection to the second one is related to the limits of how bias is estimated. A successful bias test is one that shows no evidence of bias based on certain assumptions. But the test does not reach a conclusion that the sampling system is unbiased (or free of bias). All test results are estimates and the objection is partly based on the conclusion that there is no such thing as a sample being free of bias. The objective of this work item is to examine all various definitions of representative sample and to harmonize them into one consensus definition.

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    Work Item Status

    Date Initiated:
    07-16-2018

    Technical Contact:
    Paul Reagan

    Item:
    001

    Ballot:
    D05.23 (18-04)

    Status:
    Withdrawn From Balloting

    Item:
    004

    Ballot:
    D05 (19-06)

    Status:
    Ballot Item Approved as D2234/D2234M-2020 and Pending Publication