In industry, we may come across a situation where equipment is rated into A/B/C critical classes, but the findings are not systematically utilised in everyday maintenance.
What are the benefits of criticality classification, and how does it help you manage your daily maintenance effectively? How can the equipment’s criticality classes help in practice?
1. You know how to prioritize maintenance works and resource allocation
Limited resources + high workload = haste. In a hurry, criticality classes prove their strength, as you can immediately detect the most critical equipment and maintenance work, thus focus resources on them. The most critical equipment for production and safety is serviced / repaired as quickly as possible, less critical later.
2. You can define the right proactive measures
Criticality classes are formed according to information on both the causes of equipment failures and the consequences to production and safety caused by the defects. Preventive maintenance measures can be targeted at the most critical devices, avoiding excess and insufficient maintenance. You can choose the right maintenance actions and maintenance intervals to prevent faults.
Criticality classification offers great help in identifying the right condition monitoring targets and the critical signals. For example, sudden failure of a large bearing can result in months of unexpected shutdown due to the long delivery time of the spare part. Monitoring the condition of such a part is vitally important in order to get timely information about the approaching failure and have time to take action before the device malfunctions.
3. You are able to optimize spare parts stocks
When you identify the most important devices that may malfunction, you will also identify their components and the delivery times of spare parts. Identifying the most critical parts is important to know which parts should be in the spare parts warehouse – thus you can ensure the availability of spare parts.
4. You can also identify other necessary actions
Criticality classification also identifies process bottlenecks and security risks. At the same time, you will get valuable information on investment and modernization needs and the necessary redevelopment targets. From the results, you will also notice whether the maintenance or production methods need to be developed further in order to increase the reliability and usability of the device.
Typical problems are related to implementation
The biggest obstacles of criticality classification are related to its implementation and taking it into action. For example, the original Reliability-centered Maintenance (RCM) method is in many cases too heavy and time-consuming, which may also lead to a phase-out. There are also cases where a comprehensive Failure Mode and Effects Analysis has been performed, resulting only in some development targets listing rather than a true criticality classification of the equipment.
The key to criticality classification is that the criticality analysis results in a clear and reasoned breakdown of equipment criticalities and the results are put into practice.
Maintpartner manages critical ratings
We use a simulation tool based on the Failure Mode and Effects Analysis (FMEA) we have developed for criticality classification. We collect data from process experts, failure history, and process charts to identify the most common and worst defects in equipment with their effects.
The criticality of the equipment consists of the given input data in interaction of different factors:
- Usability of the device (how much time the device is available)
- Device reliability (whether device is easily broken, average failure rate)
- Does the device cause the loss of production costs when broken?
- Repair costs (repair time + spare part delivery time)
- Price of spare part
- Does the device cause environmental risk when broken?
- Does the personal safety risk arise in the event of a failure?
As a result, approximately one fifth of the equipment is determined class A devices. We present criticality classes and results for each category in tables and graphics. We are also able to fine-tune the weight of the categories with the customer's desired values.
We also provide a quick criticality classification that fully bases on plant’s failure history. It allows criticalities to be updated based on maintenance system data.
Please feel free to contact us for more information.
Juho Tuomisalo, Development Engineer, Productivity & Digital Solutions