Compared to simple repair or restoration, corrective action involves taking the steps needed to ensure the same failure never occurs again. Generally speaking, corrective actions take the form of some kind of prevention, or possibly replacement of the failed element with one that is more robust.
To benefit from failure analysis and cause analysis in all instances where a similar fault exists, it is necessary to:
- Eliminate the physical cause in all places where it exists.
- Correct the human cause through changes to procedures or practices.
- Root out the weaknesses in the organization or systems that accept the presence of those weaknesses.
An example of a common form of corrective action might be helpful. Assume a failure occurred because a craftsperson failed to install a support in a piping system. Assume that the piping vibrations allowed by the absence of the support resulted in fatigue, the fatigue caused a crack and the crack propagated until the entire pipe was severed and a major leak caused the asset to shut down.
Failure analysis would typically identify that the piping system failed due to fatigue. Further investigation would identify that the fatigue was allowed by the absent support.
Cause analysis might show that the support was left off because the craftsperson completing the piping installation did not install the support. The craftsperson may have failed to install the support because he or she was unaware of any need for it. In turn, the craftsperson may have been unaware of the need to install a support because no drawings or instructions were provided.
While replacing the cracked pipe would restore the asset’s functionality,
it would not provide any corrective action. If the support was installed, the failure mechanism would be eliminated. Further, if steps were taken to ensure that either appropriate drawings or accurate instructions were provided in all cases, similar kinds of failures would be eliminated in a wide range of situations.
Tip from Critical Connections: Linking Failure Modes and Failure Mechanisms to Predictive and Preventive Maintenance by Daniel Daley