Asset criticality ranking (ACR) is a vital technique used in business and industry to identify and prioritize the most important assets for maintenance and protection. By understanding ACR, you can develop an effective asset management plan that will help ensure your organization’s continued success. This article will provide an overview of what ACR is, how to use it, and some factors to consider when ranking assets.
What is Asset Criticality Ranking?
Ranking assets based on their criticality combines three factors:
- Consequences – Failures have consequences, such as the impact on production, safety, quality, environment, and replacement or repair costs.
- Reliability – The likelihood of an asset failing and causing the above-mentioned consequences to occur.
- Detectability – How challenging it is to detect potential failure before equipment breakdown.
In addition to helping with prioritization, asset criticality ranking provides a framework to assist in making strategic business and maintenance decisions. Many organizations simply rank assets as critical, essential, or nonessential. However, asset criticality ranking establishes a numerical score based on these factors.
Asset Criticality Ranking Example
An asset with a high asset criticality ranking would be an unreliable asset with drastic consequences, and no way to detect the failure. These three factors make it a risky asset that requires more attention, prioritization, and maintenance. Alternatively, suppose the consequences of failure are very low, reliability is high, and you will be alerted when failure is imminent. An asset with these conditions poses almost no risk. Therefore, you would rank it very low on your asset criticality ranking. If your team doesn’t have the bandwidth, you could easily eliminate the preventive maintenance tasks for this asset and potentially let it run to failure.
What Decisions Does Asset Criticality Ranking Support?
ACR can assist in making important decisions. Assets with the highest scores have the greatest impact on your business if they fail, so you should pay the greatest attention to those assets. Assets with a low reliability rating will be identified by this ranking, making them viable targets for reliability enhancement projects. Furthermore, you will identify assets with a high level of criticality because their failures are not detectable. These assets are perfect candidates for condition monitoring. Finally, ACR also reveals where your criticality is high due to the severity of the consequences of failure. This alerts you of potential issues you need to address to mitigate those risks, for example, adding redundancy so production won’t be affected.
Generally, asset criticality ranking can help you with decisions for:
- Condition Monitoring
- Prioritization of Work Orders
- Risk Assessment and Mitigation
- Reliability Improvements
- Reliability-Centered Maintenance (RCM)
- Failure Mode and Effects Analysis (FMEA)
- Inventory Management
How to Determine Asset Criticality Ranking
Although some maintenance or reliability professionals try to rank each asset on their own, involving all stakeholders is necessary to ensure that you have complete and accurate information and that you have buy-in on all levels. This includes your production, operations, safety, quality, environmental, maintenance, and reliability teams. Several guidelines must be agreed upon to make this a reliable and repeatable process.
Rank Asset Reliability
Make a five-tier system based on the likelihood of a piece of equipment failing within the next year. Then, rank your assets accordingly.
Rank Failure Detectability
Record the probability, expressed as a percentage, that you will detect the onset of failure. A score of 100% would indicate that you are completely confident that you will detect conditions of failure before it occurs. A 0% rating means that there will be no detectable signs of failure.
Rank the Consequence of Failure
Here’s where things get a little tricky. For example, you could assign a score between one and five based on the consequence, with one being insignificant and five being extreme. However, you need to define the consequences of failure from several perspectives, including maintenance, production impact, safety, environmental impact, and quality or customer impact. So, you would divide those areas into five severity levels. Then, if possible, you should have each stakeholder define the consequences of failure for each asset as they see it. For example, maintenance technicians shouldn’t be ranking assets in terms of safety, production loss, or quality. They only provide their rating for maintenance consequences. This ensures that you have the most accurate data to rank your assets on.
Asset Criticality Ranking and Your CMMS
The final, and possibly most important step, is to enter your asset criticality rankings in your CMMS (Computerized Maintenance Management System). This is critical to the process because it enables you to put this data to work for you. If you invest the time and money to rank your assets, you have to make sure you actually use the rankings to get a return on your investment. Then, your ACR information can drive everyday decisions, such as developing a spare parts plan or deciding which assets should receive preventive maintenance. Additionally, performing this task is not something that you do once and forget about. Utilizing this data in your CMMS will guarantee that you reap the benefits of its insights and that rankings are updated when upgrades are performed or new assets are added.
