Fuel and Lubricant Testing


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ASTM D91 - Precipitation Number of Lubricating Oils



We perform lubricants quality testing by ASTM D91 to determine the precipitation number of steam cylinder stocks, black oils and other lubricating oils. Fully refined petroleum oils normally contain no naphtha insoluble material. Semi-refined or black oils frequently contain some naphtha insoluble material (also called asphaltenes). This test measures the amount of naphtha insoluble material in the oil. This quantity is reported as the precipitation number.

Precipitation Number by ASTM D91 determines the precipitation number of steam cylinder stocks and black oils, and can be used for other lubricating oils.

Contact us today to receive a quote for your lubricants testing.

Sample quantity required: 200 ml

For additional information on this test method or to purchase a copy of the method, please click HERE to open a new window and visit the ASTM website. Learn more about our laboratory's certifications and quality program here.