How To Avoid Poor Interpretation Of Test Results
1. Train your maintenance professional
Too often in oil analysis, the failure of a program can be attributed to the lack of interpretation of the conditions report and an inappropriate response to the results. When this happens, valuable information is lost. The reason for this can largely be attributed to the lack of training of your maintenance professionals. Without a solid understanding of the purpose of oil analysis and the ability to interpret test results, they can not be expected to carry out this duty. Maintenance professionals should receive training and education in oil analysis. In fact, training and education should occur at several different levels and with everyone who contributes to machine reliability, from management all the way to craftsmen.
2. Choose the right lab
Your lab should also be adept at interpreting results. Many labs advertise that their analysts have degrees, but when it comes to analyzing test results experience in the field is paramount. Make sure the analysts’ education is relevant and note the experience of the technical people in the lab as well.
3. Improper test package selection
Oil analysis test packages should be designed specifically for each piece of equipment. Generally, when a sample is analyzed by an oil analysis laboratory, the basic testing for each piece of equipment is applied. However, there are many more tests available that should be considered, particularly when an abnormal operation is observed or suspected. Unfortunately, correct test selection is something that you will likely need to drive yourself rather than relying on your oil analysis lab. You should make yourself familiar with all of the tests available so you know what to ask for and when to ask for it. You should also make an effort to develop a relationship with someone at your oil analysis lab who you can call and discuss results with and possible alternate testing.
4. Weak alarming methodologies
Hard alarms are pre-set either by the machine owner or by the lab at the request of the machine owner. If the alarm limit (marginal or critical) is reached at any time during the life of the machine, then an alarm is triggered. It should be realized that trending is one of the most useful tools in oil analysis. It is normally not the number of wear particles generated in a machine over time but the rate, as well as the rate of change of the particles generated. Hard alarms certainly have their place. One place I like hard alarms is on water count. Another would be demulsibility. One should always check with the lab or ASTM standards to see where these alarms should be set. This is another reason that hard alarms should only be set by a qualified person that understands the consequences of using such an alarming procedure.
Linear regression is normally the smart choice for alarming particle count, wear metals, contaminants, etc. This methodology looks at past history of the equipment being tested and then determines where the next wear point should be. If the trend is off by more than two data points then an alarm is triggered. By using linear regression, abnormal wear in the machine is readily evident. By catching the machine at the proper time in the wear cycle, corrective action can be taken. Lube changes, dehydration, filter changes, can be used to prolong the life of the equipment. This is what oil analysis> is all about. Primarily, extending the life expectancy of the equipment, and secondarily extending the life of the lubricant. Reduced maintenance would be the third consideration.
5. Lack of training at the plant to interpret
Training personnel is extremely vital to the success of a program. Having someone in the organization that can pick up a report and interpret it in the context of the environment is absolutely essential. This is a skill that can easily be developed with a minimal investment in training and certification.
6. Lack of Analytical Ferrography
Analytical Ferrography is a valuable test for determining severity of machine wear and should be part of any test package on an as-needed basis. A trained analyst visually determines the type and severity of wear deposited onto a substrate by using a high magnification microscope. The particles are readily identified and classified according to size, shape, and metallurgy. The test is expensive to run and shouldn’t be considered on every sample, but is mandatory any time you see an abnormal machine condition.
About TestOil
With more than 30 years of experience in the oil analysis industry, TestOil focuses exclusively on assisting industrial facilities with reducing maintenance costs and avoiding unexpected downtime through oil analysis program implementation. As industry experts in diagnosing oil-related issues in equipment such as turbines, hydraulics, gearboxes, pumps, compressors and diesel generators, TestOil provides customers with a guarantee of same-day turnaround on all routine testing. With in-house certified training professionals, TestOil offers lubrication and oil analysis training, private onsite training, certification training and exams, and educational webinars. For more information on partnering with TestOil on oil analysis programs or training opportunities visit www.testoil.com. Contact us: 216-251-2510; sales@testoil.com.
