Rationale

This proposed revision to ASTM C618 maintains the requirement to determine replicate fineness values in accordance with ASTM C311, but clarifies that the average fineness value shall be report only. The intent is to preserve the statistical integrity of the test method by requiring multiple determinations, while simplifying reporting to reflect the practical use of the data in uniformity and compliance assessments. By specifying the average as report only, the revision eliminates the potential for misinterpretation of minor variation between replicates—variation that is expected within the precision of the test method. This change aligns the reporting format with the performance-focused objectives of the standard.