While performing a lubrication assessment at a beverage manufacturer, a plant engineer approached me wanting a second opinion on an oil analysis report he just received from an outside lab. The unit in question was a compressor that had a higher contamination level than expected. I took a look at the report; the viscosity is fine, the particle count was a bit high with a fair amount of ferrous material, then what is this? DGA ASTM D-3612? I had not come across this test before so I looked it up and it was a test for dissolved gas in transformer oil. Last time I checked compressors don't have transformers in them!
When having oil analysis performed as a part of an ongoing program, it is important to have a clear understanding of what you want to accomplish and a course of action upon receiving abnormal results. The actual equipment and the surrounding environment should dictate what tests are appropriate as opposed to a ‘smorgasbord' of tests which may or may not be relevant. What we all want to accomplish is increased machine reliability through improved fluid condition and early detection of faults that otherwise would not be obvious unless it causes machine failures. Not having a course of action based from test results that are out of specifications is nothing but an exercise in futility. The specifications should be based on both the baseline testing (a reference sample of unused fluid of the same type and same batch) together with specifications for the fluid provided by the machine or component manufacturer.