If you’re looking at the title of this blog and don’t recognize the terms we’re using, don’t just click the big X and move along. Here at The Snell Group, we strive to deliver knowledge products that fall all along the spectrum of understanding, not just of the technology of IR Thermography, but of Reliability Centered Maintenance (RCM) as well. We understand full well that many practitioners of IR Thermography are maintenance workers who are in different places in their overall journey toward understanding RCM, so even if you’re a neophyte to Reliability, hopefully, you’ll find value in some of these slightly more advanced topics.
Having said that, let’s roughly define “Failure Modes Mapping”. Failure Modes Mapping is simply the assignment of failure modes to components of assets to identify which PdM technologies should be applied to that component as part of an overall maintenance strategy. A failure mode is further defined as an existing condition that will ultimately lead to functional failure of an asset. One of my very favorite things (I’m laying on the sarcasm pretty thick here) is when I use the term “failure” in the presence of a maintenance person who is unfamiliar with RCM. “What do you mean ‘failure’? The dang thing is workin’” is a common response. The correct term for use in a situation like this is actually “failure mode”. Here’s a good example. A motor has a misaligned bearing, the motor may run like that for a good while, so it’s functioning. However, a failure mode exists; the misalignment. Eventually, this failure mode will result in what should be precisely described as a “functional failure”, which is when the asset (the motor) fails to perform its function. You know, the dang thing ain’t workin’ no more. Allow me to explain what is meant by functional failure. Let’s imagine that you have a pump that is designed to move 500GPM of product with an allowable variance of +/- 5%. If the flow rate drops below 475GPM, or rises above 525GPM, or flow stops entirely, functional failure has occurred. The pump is not functioning as designed. Total failure of an asset would obviously also constitute a functional failure.
So, in Failure Modes Mapping, identifying the failure modes and the component to which it occurs is very important in developing your overall maintenance strategy. In the above example, we would want to assign “misalignment” as a potential failure mode for assets of this type (the exact size and type of motor) so that decisions about which technologies to apply to the motor can be made. Here’s where we dig into the overall topic, component identification.
If you’re a millwright who has been trained in thermography and you’re assigned mechanical routes to inspect, you’re likely to encounter components that are easy for you to recognize. If you are tasked with electrical inspections, you may have trouble with this task. The opposite is often true as well; electricians inspecting mechanical systems may also have some trouble identifying some components. In past years this wasn’t as widespread a problem as it is today. More and more we see multidiscipline maintenance professionals; folks who are responsible for a wide array of systems and assets. In general, I like this approach, but one downside is the learning curve associated with mastery of all the components you’re likely to encounter. Here’s where component recognition can fall through the cracks.
A hydraulic system has a number of components, and if you’re not a specialist you may not know them all on sight. Likewise, with electrical system assets, a combination starter is a relatively small asset but has several components associated with it. When discovering failures modes with IR Thermography it is essential to correctly identify these components in the inspection report. Whether a particular facility is actually utilizing Failure Modes Mapping or not, they in all likelihood will someday. The trend away from reactive maintenance strategies to Condition Monitoring/Precision is growing. Failure Modes Mapping and Failure Mode and Effect Analysis are among the foundational elements in starting down this path. Doing your part as the technology provider helps to have this data available when it’s needed.
So be precise in your analysis. If you’re unsure what the correct nomenclature for a component might be, don’t be afraid to ask. You’ll learn as you go, we all do that. This is among the finer points of what we do as RCM pros. Do it right; you’ll be glad you did. And if you struggle with this, please don’t hesitate to contact The Snell Group as we have several consulting options available to you to help.