ASTM International Standard Practice for Calculation of Permanent Shear Stability Index ASTM D6022-26

1.1 This practice specifies the procedure for the calculation of Permanent Shear Stability Index (PSSI) of an additive using viscosities before and after a shearing procedure. 1.2 PSSI is calculated for a single blend component and can then be used to estimate the effects of that component on finished lubricant blends. 1.3 This practice is applicable to many products and may use data from many different test methods. The calculation is presented in its most general form in order not to restrict its use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.