Asset criticality assessment: what it is and how is it managed

For a maintenance program to be truly effective, it is important to identify the risks associated with possible equipment failure modes, so as to assess which systems need to be repaired before others and to arrange various interventions in order of priority.

But how can we determine which resources are actually the most “critical” within a production system? This can be done by implementing an asset criticality assessment, that is, the analysis of asset criticality. This is a widely used methodological approach in the Facility Management sector. Its purpose is to classify a company’s assets based on the effects that a potential failure could have on processes and the overall productivity of the organization.

If you are not yet familiar with this type of analysis, below you will discover its meaning and obtain a complete overview of the methods and tools necessary to carry it out correctly.

Before showing you how to develop the criticality analysis in maintenance, I recommend trying a Facility Management software. It is a centralized and cloud-based system that allows you to keep track of every resource and activity within your facility, providing you with a reliable database on which to base any type of assessment.

The importance of criticality assessment

Implementing criticality analysis plays a fundamental role in almost all types of maintenance. The implementation of this strategy in asset maintenance helps to identify and document all possible ways in which a company’s resources can fail or experience breakdowns when it comes to tools or equipment. Furthermore, it allows for assessing the consequences that such failures may have on safety, operability, and the functioning of the production system as a whole, thus enabling greater safety and project success through a risk management plan.

The systematic assessment of criticality allows for greater confidence in achieving the organization’s final goals. Additionally, it is possible to address aspects related to the reliability and availability of equipment from an objective perspective, based on actual risk rather than simple individual perception.

Once the equipment is classified based on their criticality, it is possible to correctly assign priorities to workflows and schedule preventive maintenance or corrective maintenance actions to be undertaken. Targeted maintenance strategies are thus implemented with the aim of reducing the risks associated with potential failures related to each individual resource.

Criticality analysis: definition and basics

Criticality analysis is a structured and systematic method used in the maintenance sector. It serves to classify resources based on the operational risks associated with the probable failure modes of each piece of equipment.

Since it cannot be quantified precisely, risk, in this case, is thought of as all the possible ways in which assets can fail and the effects that a failure can have on the system and its overall functioning.

Therefore, the purpose of the analysis of risks-related criticalities is to measure the importance of certain assets relative to others. Each of them is then assigned a level of “criticality,” which is essential for establishing a priority order in planning maintenance interventions.

The results of this criticality analysis of resources will help the maintenance and reliability team focus efforts where they are most needed and thus improve the efficiency of the maintenance process.

How is criticality analysis performed?

The methods used to perform criticality analysis in maintenance are essentially two, one in-depth and the other simplified. Both approaches allow for the definition of a numerical value called RPN (Risk Priority Number) that helps classify the level of criticality of each asset.

Regardless of the method used, before proceeding with the criticality analysis, it is important to carry out some fundamental steps aimed at:

• identifying the resources that need to be included in the assessment, through the compilation of a list that should generally not exceed 20% of the total resources;
• creating a team of experts and qualified personnel to conduct the necessary investigations on the plant’s equipment;
• assessing the risks associated with potential failure events of each individual piece of equipment.

Once these steps have been developed, one can choose to follow either the in-depth or simplified method. In the first case, the RPN index is evaluated using the formula below:

RPN = Severity x Probability x Detection

This formula takes into account the likelihood of a failure occurring, how severe the effects are on the production system, and the possibility that the error will actually be detected.

For the determination of these parameters, reference scales can be set.

Starting with the first parameter, that of “severity”. The severity categories focus on different aspects related to the impact that a potential failure could have on health, safety, the environment, operability, and so on. The evaluation table can thus take the structure shown below (noting that the choice of severity level will be based on the highest impact identified):

The second parameter relates to the probability of occurrence. For its determination, we could use, for example, the following scale of values:

Finally, the detection categories refer to the likelihood of detecting a failure using the tools and controls currently available. A possible classification for this type of parameter could be as follows:

The values obtained from each table allow us to calculate the RPN index for each resource under examination using the formula illustrated previously. The RPN index corresponds to a certain risk category based on a reference scale similar to the one below:

The simplified approach, on the other hand, ignores detection requirements (which are sometimes too confusing and difficult to apply) and only uses severity and probability rates. This method involves constructing a criticality matrix corresponding to a 6×6 grid where the severity of a failure event (shown on the X-axis) is plotted against the probability of that event occurring (shown on the Y-axis), as illustrated below:

The intersection of the two parameters (severity and probability) provides the RPN index that can be used to determine the risk category of the asset.

An Exemple of critical assessment in engineering

The criticality analysis method can be applied in various sectors, from manufacturing to healthcare to engineering. In the engineering sector, particularly in welded structures, criticality analysis finds a specific use identified by the acronym ECA, which stands for Engineering Critical Assessment. This method involves evaluating the safety of a specific welded structure based on the analysis of defects.

The ECA approach is based on the knowledge of material properties and the stresses expected on the structure to determine the acceptance criteria for any defects found in the welds. The aim is to ensure that these welds will maintain the expected level of efficiency throughout the useful life of the structure.

The ECA method thus evaluates imperfections, typically arising during welding, through studies of: fracture mechanics, fatigue, stress analysis, material performance, mechanical testing, and non-destructive inspections.

It can therefore be used in various phases:

• during design, to assist in choosing the welding procedure and/or inspection techniques;
• during production, to evaluate:
  • the significance of known defects that are unacceptable for a given fabrication code;
  • the maximum size of the critical defect, the minimum fracture resistance, or the maximum operating stresses;
• during operation, to assess defects found during execution and make decisions regarding their safe retention or whether repair or replacement is necessary.

Implementing Engineering Critical Assessment in your maintenance process allows stakeholders to achieve significant cost savings and increased safety by improving awareness of the potential effects of imperfections and their acceptability, in order to define an efficient and effective preventive maintenance program that ensures the proper functioning of assets throughout their useful life.

Critical asset management: analysis and best practice

Critical Asset Management suggests 5 best practices to consider and follow, let’s look at them together:

1. definition of objectives: as the first step and thus the first best practice, we certainly find the definition of objectives. This step allows us to identify the reason for conducting the analysis based on which we will proceed to the subsequent identification of resources and their relative level of criticality;
2. identification of resources and systems: once the objective of this particular maintenance method is clear, it will be essential to list all resources, equipment, and systems that will be the focus of the evaluation;
3. data collection: this step consists of gathering all available data for each resource, equipment, or system identified in the previous step. The goal is to collect all useful information for the evaluation of assets based on the established criteria. Data collection may include previous maintenance records, manufacturer data, operational feedback, etc.;
4. risk assessment: at this point, applying one of the methods analyzed in the previous section, it is essential to extrapolate the RPN index for each identified resource. Although the methods are mathematical, their application may encounter a certain degree of difficulty mainly related to variable assessments based on the operator judging each asset;
5. annual re-evaluation: if we truly want to ensure good maintenance efficiency, we must consider repeating the criticality analysis process with a certain frequency, for example annually. Furthermore, each maintenance team should re-evaluate their analyses to ensure they align with the evolving priorities and needs of the organization.

Critical Asset Monitoring

We have seen how one of the best practices of Critical Asset Management is the identification of critical resources and the assessment of the degree of criticality associated with them. Once identified, a suitable and specific maintenance plan is clearly applied, which in the best-case scenario could also implement continuous asset monitoring.

To ensure resource monitoring, it is necessary to equip them with smart sensors that handle data collection – the settings of which obviously vary based on the asset to be monitored. The collected data – which can be thermal, vibrational, magnetic, acoustic, etc. – is securely transmitted to a platform that analyzes it, detecting any anomalies and providing automatic alerts to the maintenance team.

Implementing continuous monitoring technology allows maintenance teams to be aware of their resources, and thus to:

• reduce downtime: thanks to real-time collected data, teams can proactively address potential failures or malfunctions before they worsen;
• better information on assets: continuous monitoring provides a comprehensive inventory of assets, allowing for more efficient risk management and maintenance;
• efficient compliance with regulations: many sectors are subject to strict regulations governing the safety of critical infrastructures. Continuous monitoring offers the visibility and reporting capabilities necessary to demonstrate compliance with current regulations;
• improved response in case of incidents: in the event of safety incidents, continuous monitoring tools help teams identify the source of the problem and take appropriate actions to contain and resolve the event.

4 ways criticality analysis helps your business

Criticality analysis is often considered a crucial part of managing the resources and processes of a facility because it allows for numerous advantages, including:

• a greater focus of maintenance efforts on the elements that matter most and less time spent on activities that do not reduce risks for various equipment;
• better planning of activities in Total Productive Maintenance (TPM) or preventive maintenance processes, by assigning a higher priority to operations and interventions that need to be developed first;
• better risk management, thanks to the identification of potential failure events and the most damaging consequences for a production system, which help choose the best strategy to undertake;
• streamlining of facility management costs, with a reduction in expenses related to unnecessary activities and a significant decrease in costs due to unplanned downtime.

How a CMMS system helps in criticality analysis

Criticality analysis in maintenance relies on the collection of reliable and accurate data. These relate to the operating conditions of the equipment, so it becomes essential to use a good CMMS (Computerized Maintenance Management System).

Software specifically designed to manage maintenance activities allows, in fact, to:

• track any resource or intervention performed on the assets (maintenance log);
• monitor asset performance in real-time;
• obtain up-to-date and reliable information on equipment failure rates (MTBF, MTTF, MTTR);
• produce detailed reports that help plan maintenance activities.

Discover how easy it is to implement a criticality analysis with the help of a Facility Management software, the only system that allows you to manage all aspects related to maintenance from a single fully cloud-based centralized platform, and provides you with the information you need to assess the risk and criticality levels of your equipment.