Reliability Engineering Snapshot TM

Illustrated Case Studies in the Maintenance Reliability Engineering World of Failure Analysis, Predictive Maintenance, and Non Destructive Evaluation

People - Case Study No. 4: Words of Wisdom Learned the Hard Way

"Talking about something long enough will in time, regardless of its credibility, become fact"

In an industrial environment it is important to be specific when talking about what has failed. There are usually very large dollars associated with any decision made regarding the outcome to remedy the failure; and many times these decisions require precious capital and serious downtime. In the case of a leaking manway nozzle (see article "Corrosion - Case Study No. 1: Corrosion Attack of Stainless Steel Weld Metal"), the discussions about the repairs were always general, such as "repaired the top of the ... again." Nobody ever asked "Where on the top?" Pretty soon it was common belief that the entire top required replacement. This was not the case.

"Just because oil looks clear and clean, doesn't necessarily mean that it's Okay"

Many plant preventive maintenance programs rely upon the keen eye of the "Lubricator," a stalwart experienced person who uses visual inspection as the primary tool of evaluating whether the oil in a piece of machinery needs to be replaced. Consider for a fact that the human eye cannot see anything below 30 microns, and then consider that water droplets on the order of 5 microns can literally saturate an oil, not coalesce, and provide the means for an oil to turn acidic, given the right conditions (see the article in "Lubrication - Case Study No. 2: Corrosive Oil").

"Thou shalt not create stress concentrations"

Everyone involved with the design and fabrication of equipment must understand the adverse affects that sharp corners have on the long term life of a machine component. This means that adequate rounded corners should never be cut into when finishing a component (see the article in "Machine Design Case No. 140: ").

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