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1. © 2012 Allied Reliability, Inc. 1
Oil Analysis Integrated with Other Condition Monitoring Strategies
By Angie Meinsma, Oil Analysis & Lubrication Technician, Allied Reliability
It is often said that oil is the “lifeblood” of machines and equipment. Taking oil samples from rotating equipment for condition monitoring is like taking blood samples from a human. Analysts look for abnormalities within the fluid. The goal is to find faults, treat the condition, and extend the life expectancy.
When used properly, fluid analysis becomes a valuable diagnostic tool that can reduce maintenance costs, increase productivity, and boost company profits. When used in conjunction with other diagnostic technologies such as vibration analysis and thermography, well- executed fluid analysis strategies can detect a variety of equipment problems before they become failures and give users the valuable time necessary to make decisive, well-informed maintenance decisions. Time has allowed most people and organizations to see the value of integrating the condition monitoring resources for root cause management; they team up to provide control over the root causes of machine failure. Vibration analysis detects abnormal running conditions, such as unbalance, misalignment, and looseness, while oil analysis detects overall lubricant quality and contamination.
The three major reasons for lubricant failure are:
• Contamination – Component life is dependent on the cleanliness of the lubricating fluid. The cleanliness of any lubricant is dependent on oil handling practices, top up procedures, and the quality of both air breather and oil filtration.
• Oil Degradation, specifically oxidation – Oxidation occurs when atmospheric oxygen combines with hydrocarbon molecules and undergoes a chemical change. This chemical change results in the catastrophic and permanent change to a different chemical makeup for the oil molecule. The rate at which the oil molecules react with the oxygen depends on a number of factors, but the most prevalent are temperature and/or additive depletion.
• Additive Depletion – Additives are consumed or chemically depleted while performing their function. After being totally consumed, the additive can no longer provide the special property it

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performs for the base oil. The lubricant’s performance then suffers, and again the oil must be changed. Each one of these additives has a finite life, and when they reach the end of that life, you can forget about any advantage they helped provide. Some machines rely heavily on this advantage, and when it goes, so does the life expectancy of the machine.
These three factors are why we change oil. No matter what you do, eventually you will have to change it. However, the cleaner, cooler, and drier it is kept, the longer you will be able to go between those changes.
In order to establish appropriate maintenance strategies for your equipment, it is necessary to first understand the failure modes that are inherent in the parts and components that make up your asset base. Once the failure modes are identified, the proper condition monitoring and preventive maintenance tasks can be put in place to identify the warning signs of those failure modes or defects, keeping in mind that the earlier we identify an issue, the better. Unfortunately it is not uncommon for lubrication to be overlooked during the maintenance strategy design session. This is often due to the fact that lubrication is rarely thought of as an integral “part” that comprises your asset. The reality of the situation is that it is in fact a vital part and lubrication failure holds the same consequences as a bearing or coupling failure. Ultimately, the asset fails to perform according to it’s designed function. As with all failure modes, certain condition monitoring technologies are better suited to identify certain failures. This is why lubrication analysis is an integral piece of your maintenance and reliability initiatives.
When condition monitoring technologies are used in conjunction with lubrication analysis, the findings and recommendations are typically far superior. This approach ensures comprehensive coverage consistent with the the likely failure modes of your critical equipment and allows the earliest detection capabilities possible, which foster root cause issue identification. This approach affords ample time to plan, schedule, and perform recommended corrective actions and provides the highest possible return on your maintenance investments.