ASTM D4055 Standard Test Method for Pentane Insolubles by Membrane Filtration
4. Summary of Test Method
4.1 A sample of new or used lubricating oil is mixed with pentane in a volumetric flask. The oil solution is filtered through an 0.8-µm membrane filter. The flask, funnel, and filter are washed with additional pentane to effect a complete transfer of particulates onto the filter. The filter and its particulates are dried and weighed to give the pentane insolubles.
5. Significance and Use
5.1 Pentane insolubles above 0.8 µm in size may lead to increased wear. This increased wear can lead to premature equipment failure in critical applications.
