What is the acceptable reliability of an airplane? Would you board an aircraft if it had only a 70 percent reliability rate? How about if it were 80 or 90 percent, would that make a difference? Like most people, I would not step foot on that plane unless I knew it had a 100 percent reliability rate. I want that aircraft to have a perfect record and deliver me safely.
During a recent trip home from a consulting project, I boarded the plane and was waiting for takeoff, when the pilot announced the plane had experienced a failure. Everyone had to de-board and go to the ticket counter for rebooking to different flights.
As it turns out, the engines worked fine. The safety features on the aircraft were fine. The airplane's hull was intact. The problem: the first officer's seat in the cockpit was stuck in a position that would not allow him to adjust the seat. According to the flight crew, a pin of some sort had fallen from the seat. This simple pin caused the flight to be substantially delayed and nearly resulted in a cancellation of the flight.
The Little Things Can Be the Biggest Issues
So, how does this situation compare to plant reliability? In designing and optimizing an effective lubrication program, it is important to remember the little things. For example, items such as small centrifugal pumps and small gearboxes are often overlooked as they relate to oil analysis. It has somehow become a widely accepted fact in industry that these small components can somehow utilize a run-to-failure maintenance strategy.
Gearboxes
Using a small gearbox as an example, consider an extraction system in a plastics plant. The extractor motor, gearboxes, rotating die and hydraulic systems always seem to be high on the criticality assessment list, while the small gearbox that operates the feed auger tends to be on the opposite end.
This low assignment, coupled with the fact that these gearboxes tend to be low-sump-volume components, results in lack of attention or care. It is forgotten that this auger gearbox is part of an overall system wherein if this gearbox fails, products cannot be fed into the extractor, resulting in a shutdown of the entire line.
Centrifugal Pumps
For a second example, consider oil analysis and small overhung centrifugal pumps. These pumps are used typically with some type of redundancy. However, there are also many cases when these small pumps are considered critical and no backup is available. These are instances in which oil analysis may be warranted as a condition monitoring tool.
The Deciding Factor
While criticality is an important value to consider when optimizing an oil analysis program, always be aware of the effects that a component failure will cause. If the component is part of a larger critical system, the overall criticality of the component must be equal to the system as a whole, if the component failure will halt the entire system. While focus must be placed on utilizing the best tools for the job, sump size should not be the sole deciding factor on whether or not oil analysis is an appropriate technology to deploy.
Like the seat pin in the airplane cockpit, the smallest of details can have some of the greatest adverse effects as it relates to reliability. Leave all options on the table when deciding what to include in an oil analysis program. It is important to ensure that your actions are capable of achieving the overall reliability goals of the plant. Always consider the acceptable reliability of a component when making these decisions.
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