ASTM D91 Precipitation Number in Lubricating Oils

Precipitation number measures the amount of naphtha-insoluble particles (asphaltenes) in oils – a high precipitation number indicates a large amount of insoluble material, and a small number indicates a small amount. Precipitation numbers are normally very low in highly refined oils and higher in less refined oils. This test determines precipitation number in lubricating oils, steam cylinder stocks and black oils.

The sample is mixed with solvent and the mixture is centrifuged until a constant level of sediment is obtained. The precipitation number is reported in milliliters sediment.

Related tests offered by Petro-Lubricant Testing Laboratories:

For the amount of sediment by volume:

ASTM D2273 Trace Sediment in Lubricating Oils

For the amount of sediment by mass:

ASTM D3279 n-Heptane Insolubles

FTM 3010 (Fed-Std-791 Method 3010) Gravimetric Contamination and Ash Residue by Filtration

Price: $55.00

Sample size: 200 ml

Related tests:

• ASTM D1796 – Water and Sediment
• ASTM D2273 – Trace Sediment Contamination
• ASTM D2276 – Particulate Contamination
• ASTM D3279 – Asphaltene Content & Heptane Insolubles
• ASTM D4898 – Gravimetric Analysis by Filtration
• BT-10 – Navistar International Transportation, Oxidation & Corrosion
• ISO 4406 – Particulate Contamination, by HIAC Particle Counter, ISO Cleanliness Code