E1921 was originally developed only with the single temperature option. That is, all specimens had to be tested at a single test temperature. Later, the multitemperature option was added which allows the user to conduct testing at different temperatures and analyze all this data together to determine To. The multitemperature option is superior because it allows consideration of larger bodies of data that have been developed over a range of temperatures. Further, the single temperature option can be derived as a special case of the multitemperature option. Both options have similar requirements but maintaining two sets of requirements has been onerous and, in some cases, caused confusion when the requirements were not identically structured. For these reasons, the E0807 subcommittee approved the task groups unanimous recommendation to eliminate the single temperature option from the standard and just support the multitemperature option. However, unique single temperature equations are still retained as a special case of the multitemperature option. The proposed changes to the standard are principally editorial in that the entire multitemperature method is now contained in the main body of the standard and references and equations related to single temperature testing has been relegated to a special case. Therefore, the redline/strikeout changes appear to be extensive but they really just reflect the extensive cutting and pasting required to implement the change. Most changes are contained in Section 10 which addresses the analysis of KJc data to determine To. However, changes to other sections that reference the single temperature test method have also been necessary. The end result of these changes is intended to streamline the standard and make it easier to understand and have a single set of requirements that are equally applicable to both multitemperature and single temperature testing.
Draft Under Development