Oil Contamination Detection

The buildup of contaminants in your oil is inevitable, as air compressor systems not only ingest large quantities of contaminants, they also create contaminants as byproducts of chemical reactions in the compressed air system, as well as through mechanical wear of internal components.  To keep your compressor from wearing and failing prematurely, you must change your oil before its useful life is spent.  This can only be accomplished by monitoring your oil through routine oil analysis.

Common Oil Analysis Tests

There are many tests and measurements associated with oil analysis, which can vary somewhat depending on the laboratory and the type of oil being tested.  Some tests though are almost universally performed, and they can provide a baseline and an ongoing method to determine your compressor oil condition.

The most common and informative test is the TAN or Total Acid Number Test.  This will indicate the amount of acids in the oil, which deplete the oil of its additives and hasten the oils degradation.  Additionally, the PH of the oil is usually tested, which will give also give and indication of the buildup of acids. Other common tests check viscosity, specific gravity, foaming characteristics and various measures of contaminants including metals and water. 

Laboratories that perform oil analysis will provide you with an oil analysis report, that should be charted to aid in scheduling oil changeovers, and indicating wear in the compressor.  Oil analysis can often provide early warning prior to failure, through the presence of wear metals, and can indicate of coolers and oil systems need cleaned by indicating oil varnish.  Preventative maintenance should include oil analysis.