This is for those of you who are overwhelmed by the complexity of such advanced tools as Reliability-Centered Maintenance (RCM), Condition-based Maintenance (CBM) and Root Cause Analysis (RCA).
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There’s a way to ease into the huge workload that some of these techniques represent, but still reap significant benefits in the process. Focus first on your critical assets to maximize the return on any effort expended, regardless of which technique you select. This is true because critical assets, if selected properly, represent the greatest opportunity for furthering an organization’s goals and objectives such as meeting customer needs, as well as mitigating risks such as ensuring regulatory compliance.
This column looks at how to determine asset criticality, and the differences in how they are handled. Additionally, various CMMS features and functions that can help you through the process will be discussed.
Determining which assets are critical can be a subjective exercise. One way of thinking about asset criticality in a somewhat more objective way is to calculate the effect of failure for each asset and determine which piece of hardware has the greatest consequences. The subjectivity of this kind of analysis lies in trying to compare the various consequences. For example, see if you can rank the relative severity of each of the following consequences:
- A minor delivery to an important customer might be a day late
- A relatively large delivery to a number of small customers might be a week late
- A person might be injured, resulting in at least one day lost time
- Minor quantities of a toxic substance might leak into the municipal wastewater system
Perhaps it might be argued that these are equal in criticality, and with unlimited dollars to spend on maintenance, ranking them is probably a non-issue. However, most companies don’t have unlimited funds or resources on hand, thus calculating asset criticality helps to prioritize the use of scarce resources. Although these four consequences can be considered somewhat critical, as opposed to catastrophic or negligible, one must judge their relative criticality on a case-by-case basis. For example, how important is the “important customer,” and how minor is the “minor delivery?” Similarly, what is a “small” customer and how important are they and their “large delivery” relative to the important customer? Finally, which has a higher priority – customer impact versus health, safety or environmental problems?
Another analysis tool for determining criticality is bottleneck analysis. This technique identifies dependencies throughout your operations. Typically, a critical path is mapped for each process flow to highlight interdependencies. Higher criticality assets are those that need to be fully operational if the operating department is to avoid a bottleneck that slows production. For example, the presses in a printing operation are critical assets. When they’re not running at full capacity, the quality, cost of goods produced and delivery schedules for the entire production line are affected.
In general, asset criticality covers a spectrum. High criticality means the effect of failure is catastrophic health, safety, environmental, customer-related or financial consequences; bottleneck analysis reveals that the process is highly dependent on this asset. Low criticality means effect of failure is low or negligible; bottleneck analysis reveals that the process isn’t particularly dependent on this asset.
Critical versus non-critical
Once you identify critical assets, treat them differently than non-critical ones. Just as you classify spare parts using the ABC or XYZ classification system to identify high-volume or high-dollar-value parts, so should you classify asset criticality. This ensures you’ll expend precious resources, time and money on the more important assets. Examples of procedures and techniques that should favor critical assets are as follows:
Scheduling for assets with a higher criticality should be given priority. Assign the better resources, sooner in the queue, and with more careful follow-up.
Repair/replace decisions depend on criticality. The greater the criticality, the easier it should be to get funding for replacing parts or the overall asset. This is because it’s generally more important to bring critical assets closer to the “as new” condition compared to non-critical assets to minimize the risk of catastrophic failure.