May 2005

Root Cause Analysis (RCA)

One of the steps in root cause analysis is to define a problem. Defining a problem can be a simple process or it can be a very complicated process depending on what process you follow. We believe it is important to keep the root cause analysis fairly simple in order for the frontline (planners, supervisors and hourly) to use the process.

Consider a problem on a centrifugal fan AC Motor. A typical problem report could state “fan XYZ motor has a problem”. Even though this type of problem reporting could be worse, for example, “fan is bad” or “funny noise from one of the fans”. “Fan XYZ Motor has a problem” it is still not a very good definition.

A better definition may be “AC Motor of fan XYZ” is hot. Can we do better with some basic Root Cause Analysis steps? Sure! Let’s ask the traditional, WHAT, WHERE, WHEN, EXTENT. The problem is:

What: AC Motor of Fan XYZ (already answered)
Where: Motor is hot close to the front (belt drive side)
When: Don’t know exactly, but 7 days ago a 138 F reading was recorded (normal)
Extent: Front of motor is running 210 F.

The above definition is usually enough to get a problem started. Is it ideal? Perhaps not, but it’s pretty good for a problem statement. This level of problem reporting for craftspeople and operators would be a huge improvement for most plants in improving day-to-day Root Cause Analysis.

If you want to take the root cause analysis process a step further, try the “what is” (done above, then state “what is not” the problem. The “is not” could look like follows:

The problem is not:

What: Any other fan motors nearby
Where: Motor is not hot in the center or at the fan side.
When: Has not been hot before 7 days ago
Extent: Not center (150F), Fan side (130F).

For more about IDCON’s Root Cause Analysis training and implementation