Attacking abnormalities head-on prevents future maintenance problems
If we do not report abnormalities early, or strive to report only those ambiguous “really important ones,” we are selling ourselves short. When we fail to report abnormalities early, we loose the ability to address them early. We must report them in an official way as soon as we see them. When I say reporting in an official way, I mean something like putting a work request into our CMMS system or using an abnormality tag that is part of our Operator Care process. This collection of official notifications represent what we know to be our backlog, and a full and rich backlog is critical to our proactive approach to maintenance.
I talk to many people who tell me, I only want people to report the “important or critical problems.” Guess what, todays unimportant problem will quickly become tomorrow’s important one. Better to have a solid reporting system, a simple method to prioritize work, so we are attacking the most important abnormalities first, as well as a robust and visual means to communicate our progress to everyone who participates in the process (managers, and technicians, operations and maintenance).
Definitions: Abnormality and Failure:
So what is the difference between an abnormality and a failure? First of all, I prefer to use the phrase “functional failure” rather than simply “failure.” I have to really concentrate and force myself to use these words, but it has an important effect on my thinking and the thinking of those around me. To me, Failure seems to be an arbitrary word open to interpretation.
The loss of a function or a functional failure, on the other hand, is quite clear because I can no longer do what I desire to do. In each case if we start with that condition that we desire, the loss of this ability or function becomes quite clear.
– If the light bulb goes out, then I can no longer read my book – loss of function.
– If the impeller wears on my pump and can no longer produce my product in the required quantity – loss of function.
– If my tire goes flat and I can no longer drive my car at full speed – loss of function.
– Abnormalities, on the other hand, are the clues that our assets provide to us that something is wrong and that we are on that
pathway to loosing our desired function.
Failures, Abnormalities and the P-F Curve Explained
The pathway to functional failure, and the abnormalities that mark this path, is best described by the P-F curve. The definition and meaning behind the P-F Curve is quite simple and powerful.
Let’s review the P-F Curve in detail:
The vertical axis represents our equipment condition while the horizontal axis represents time.
-The higher the equipment condition the better.
-The first point on the graph (upper left hand corner) is labeled “the point where the failure starts to occur.” Lets consider this point
-Example: Imagine that we forget to lubricate the bearings on an electric motor. Eventually all of the grease will evaporate
out, leaving metal to metal contact. This is point P in this example.
-The equipment (asset) starts to degrade, losing its condition slowly at first, but then increasing in speed as time continues on. As
this process continues, the equipment provides us with clues that inform us of what is happening – at first very subtle clues, but
increasing in magnitude (and our urgency I hope) as the process continue. These clues are the abnormalities we speak of.
-If we do not act proactively to the abnormalities, we will reach the point labeled “equipment fails here.” This is point F or the point
of Functional Failure.
-Because we have failed to react proactively to the abnormalities, we will now have to react to the functional failure – the choice
has been made for us!