Knowing when a piece of equipment is going to fail (predictive maintenance) is much more difficult than making it last long (proactive maintenance). Even more complex is root cause analysis (RCA) which is performed postmortem, like an autopsy.

Still, reliability professionals are increasingly stressing the importance of performing RCAs following all failures of critical machinery. As odd as it sounds, it is more productive to study failures than successes.

After all, an apparent success may actually be a failure in disguise; more like a problem waiting to happen. Studying failures teaches us insightful lessons in developing predictive and proactive maintenance strategy.

Root cause failure analysis is a process of working backward through a sequence of events or steps that led to functional failure of the machine.

The post Root Cause Analysis for Lubrication Failures appeared first on Tesibis.

It is intuitively obvious that smart maintenance decisions require a heightened sense of both the probability and consequences of machine failure.

However, when lubricants fail, there are consequences that are, at least initially, independent of machine failure. These include the lubricant replacement cost (material, labor, flushing, etc.) and associated downtime. These costs can exist in the presence of a perfectly healthy and operating machine.

Of course, lack of timely replacement of a defective lubricant will invariably lead to dire machine failure consequences. For some machines, these cascading events can produce enormous collateral damage and financial hardship to an organization.

In the next issue, I will explain how nearly all decisions related to lubricant analysis and inspection depend on four factors: Overall Machine Criticality, Overall Lubricant Criticality, Machine Failure Modes Effects Analysis (M-FMEA) and Lubricant Failure Modes Effects Analysis (L-FMEA).

For instance, regarding inspections, these factors influence what to inspect, when to inspect and how to inspect. In relation to oil analysis, these factors affect where to sample, how often to sample, which tests to conduct, which alarms to set and the general data-interpretation strategy.

The post Don’t Forget Lubricant Criticality When Designing Oil Analysis Programs appeared first on Tesibis.

As head of Noria’s failure investigation group, I’ve led many interesting studies in search of failure root causes and remedies. These include missile system failures, highway accidents, helicopter crashes, and turbine-generator wrecks. Most of these nearly 100 investigations were substantially hampered by errors made in collecting and preserving evidence.

We know that when critical failures occur, every effort should be made to prevent repeat performances. Yet, without an intervention to remove the underlying root cause, a recurrence is almost guaranteed.

It stands to reason that maintenance organizations should consider failure investigations as seriously as they do the repair activities needed to return a machine to service. Yet all too often, once production has been restored, the urgency and memory of the failure begins to fade.

We’ve published extensively on the importance of root cause analysis (RCA) and the steps needed to carry out an RCA. This column will not address these well-documented procedures but instead focuses on the equally important task of preserving and collecting evidence.

After all, it is this evidence that serves as the essential raw material used in the RCA processes. The quality and completeness of this evidence (raw material) is arguably the central factor that determines the precision of the delivered result (the root cause and RCA end product).

Sadly, by the time I get a phone call to participate in an RCA, there is usually only a scintilla of evidence remaining. Perhaps there are a few fragments of a broken bearing or the shelled-out remains of a failed pump. In other cases, there might be photos of the crime scene taken by an alert technician. Of course, there is plenty of anecdotal evidence and personal theories from people who arrived first on the scene. But when it comes to collecting quality data and preserving physical evidence, what’s available is usually pretty skimpy.

The post Performing a Failure Scene Investigation appeared first on Tesibis.