The Do's And Don'ts Of Equipment Failure Analysis
Despite effective maintenance and reliability systems, in-service equipment failures still occur. While the failure may not be catastrophic or impact safety, equipment unable to perform within design specification has important cost implications for business from excessive maintenance spending and production losses.
Equipment reliability is an iterative process. When a failure occurs, an effective post-failure investigation and analysis will ensure a clear understanding of the issue, improve reliability, and prevent future loss. Yet, there are tips to observe and traps to avoid for an effective post-failure analysis.
Don't jump to conclusions
When failure occurs, it's tempting to decide the cause based on observed or historical events. While you may ultimately prove right, the trouble with having strong views is that your opinion will color the investigation. Anchoring bias is a well-understood cognitive bias that interferes with objective reasoning.
Resist speculation and focus on gathering facts and evidence that will support a compelling failure hypothesis. While you should consider the opinion of others, don't allow their views or purported expertise to derail your investigation.
Don't 'shotgun' solutions
Remember that you are there to understand why the equipment failed, not fix it. Randomly replacing parts and sub-assemblies may restore the equipment to operate and indicate which component stopped working, but it fails to explain the root cause of the failure. Returning the equipment to operation prematurely is likely to result in lost learning opportunities and continued failure. Approaching the analysis in a systematic and structured way restrains your natural impulses to repair before understanding.
Don't use less appropriate analysis techniques
There are many tools and techniques to allow the analysis of equipment failures . However, people often have a favorite method that becomes their go-to solution in every investigation. For example, 5-Whys is a common method that is easy to understand and often used; however, it may be inappropriate for complex failures. Be sure to remain abreast of the wide variety of tools and techniques available for failure analysis, including their strengths and weaknesses. Select a methodology appropriate to the context of your situation to maximize outcomes.
Do set up a team for the investigation
Serious or critical investigations require diverse skills to ensure a rigorous, wide-ranging analysis, not just the input and opinion of engineers and maintenance technicians. Ensure representation from production, quality, management, and purchasing personnel. Depending on the severity of the failure, you may also need representation from the legal department and specialist advice from metallurgists and equipment manufacturers.
Ensuring the team is well-briefed and representing a diverse skill set mitigates against jumping to conclusions and one-track thinking, providing a broader range of opinions to optimize outcomes.
Do quarantine the evidence and investigate promptly
When failure occurs, the initial response from field engineers and maintenance technicians is to return the equipment to service in the shortest possible time. Whether successful or otherwise, useful evidence can be ignored, lost, or obscured during repair attempts.
If you must restore the equipment to operation rapidly, ensure a representative from the failure analysis team is present to assist in the strip and repair process. Where possible, repair by complete replacement allows the failed item to be stripped and observed under controlled workshop conditions.
Do rigorously document everything
The documentation process should start when a failure was reported, capturing times, dates, environmental conditions, and initial impressions. Disassembly of the equipment should be slow, methodical, and captured with digital photography and clear notes. Record your and others' observations, remembering that the absence of noise, action, or a piece of equipment might be as crucial as an occurrence. Until the investigation is complete, you will not know the significance of what you document, so record everything along the way.
Do follow a structured process
An investigation can be a pressured environment, with answers urgently sought due to a need to maintain production. These pressures, coupled with an investigation team of diverse skills and personalities, can work against an effective and efficient investigation. Be sure to implement a detailed and structured failure analysis program that is promulgated and understood by all.
The Taproot methodology provides a useful six-step process to emulate. Work out what happened, before carrying out evidence gathering and diagnosis. In the third step, you will search for all the issues that led to the incident occurring, those causal factors you’ll use for analysis in the next step. Step four is the root cause analysis from the evidence gathered. Once the root cause is understood, develop the range of corrective actions in step five before repairing the equipment and implementing the corrective actions in the final step.
By using a disciplined and structured progression through the investigation process and documenting your findings as you proceed, you support a far deeper, broader, and more sophisticated analysis than might otherwise have been the case.
Equipment failure analysis provides insight into the cause of failures and supports corrective activities to prevent or anticipate future occurrences, including preventative maintenance tasks. Improving the reliability of individual components will inevitably improve the reliability of the plant while reducing costs, increasing safety, and contributing to business success.
However, the benefits of such analysis will only accrue when an investigation is carried out in a scientific and structured manner. Following simple rules and avoiding some common traps will ensure your next equipment failure analysis delivers efficient and effective results.
Author: Bryan Christiansen is the founder and CEO of Limble CMMS.
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