An Improved Method of Comparing ASTM Sequence IIIE Viscosity Increase Results

A method has been developed for expressing ASTM Sequence IIIE oxidative thickening in terms of test hours to 375 percent viscosity increase (PVI), instead of by PVI at 64 hours, for use in data handling. Expressing results as hrs-to-375 provides a needed transformation for PVI, and enables clearer and more accurate tracking of PVI results. The method has been approved within ASTM for use in proposed Severity Bias Estimate and Multiple Test Acceptance Systems. Use of hrs-to-375 is expected to be required soon.