June 29, 2012

What is My Condemning Limit on This Test Result?
by David Doyle,CLS, OMA I & II
Vice President & Operations Manager

This question is asked quite regularly but many times the answer is not that simple. Flagging a test result whether for a warning or condemning notification generally requires assessment of multiple factors associated with the sample that was tested.

Generally it’s not feasible to provide a list of absolute wear limits on sample test results since there is so much that goes into evaluating the wear pattern of different types of equipment or equipment applications. Having an absolute wear metal limit (such as iron levels in a gearbox) is just a starting point. Different makes and models for similar types of equipment can have unique wear metal limits, but this is also affected by work environment and the age of the lubricant in service.

Many times our diagnosticians will not wait for a single test result to reach a condemning limit before indicating a problem on a test report. An accelerated increase or rate of change from the previous sample for the time on the oil can raise a warning flag. There are also situations where a combination of test results are heading in a detrimental direction, yet no single test result has reached a condemning limit on its own.  Generally the diagnosticians try to look at a combination of parameters, both related to the oil and equipment information, as well as a matrix of test results. This is where the diagnosticians applies their extensive training and experience in making a judgment on your equipment, and not just go by a list of absolute upper and lower limits for each test parameter.  When reviewing the subtleties of the data on an in-service lubricant test report, having complete information provided when the sample is submitted allows for a more complete analysis of the equipment.  If the diagnostician can notify a customer of an impending problem as soon as possible before it becomes apparent to the equipment operator and maintenance personnel then the service is doing what it is intended to do.

Overall test reports and specific test results are categorized by our diagnosticians into four categories. Normal, Caution, Abnormal and Severe. When a condition level above normal is noted on a test report, it is indicative of the need for action or awareness. A Caution condition is meant to note a situation that the client should be aware of. No action is required but the situation should be monitored. Abnormal indicates a condition where a decision needs to be made whether the person(s) responsible for the equipment can live with the situation or not. If corrective action appears to be required then the scope of the problem should allow maintenance or changes to occur in a timely fashion that is least disruptive to schedules and workflow. A Severe condition indicates that immediate corrective action is required in order to prevent further damage or impending equipment failure and work interruption.

As always, comparing information provided on a report with the lab or one of our diagnosticians can in many instance increase the value of the data reported and any corrective action that may be necessary.


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