What is Asset Criticality Ranking? The Complete Guide

If you are familiar with a Master Equipment List (MEL), you know that it can be extensive, sometimes including tens of thousands of functional locations. In such cases, how do you determine where to focus your maintenance efforts and resource allocation?

The ACR process addresses this by categorizing assets based on their importance to organizational operations, making it easier to prioritize maintenance and repair decisions.

A well-structured criticality ranking system provides a data-driven approach to prioritizing preventive maintenance, planning, and asset management activities. Furthermore, data collection is essential in this process, as it supports accurate asset criticality ranking and enables real-time insights for decision-making, ensuring that high priority assets receive the necessary attention and resources.

What Is Asset Criticality Ranking?

Imagine asking a boiler area manager about the most critical piece of equipment in a facility. The answer would likely be “the boiler.” But if you ask the same question to a paper machine area manager, they might say “the Fourdrinier bed” or “the couch roller.”

Both answers seem correct, but only from their respective perspectives.

At this stage, criticality is based on perception and experience, often leading to subjective decision-making.

The goal of an asset criticality assessment is to eliminate this subjectivity by applying objective, standardized criteria to evaluate and quantify asset importance, determining which assets are most significant to operations.

As part of this systematic analysis, a criticality rating is assigned to each asset, ensuring that the process is consistent and repeatable.

Once the criticality assessment is completed, assets such as the boiler and couch roller will likely rank high in the hierarchy, but their placement will be justified with clear, documented reasoning rather than personal opinions.

In essence, a criticality analysis is a structured methodology that objectively quantifies the importance of assets within an operation. This process provides a better understanding of how to prioritize and rank assets, helping maintenance teams make informed decisions.

Why Does Asset Criticality Ranking Matter?

Implementing Asset Criticality Ranking offers multiple benefits:

Identifying Critical Assets

Identifying critical assets is a foundational step in the asset criticality analysis process. Critical assets are those whose failure would have a significant impact on operations, safety, or profitability.

These assets are often characterized by either a high likelihood of failure, severe consequences if they do fail, or both. To accurately identify critical assets, organizations evaluate each asset based on specific criteria such as production impact, safety risks, and potential financial losses.

This evaluation process helps determine which assets are most essential to the organization’s success and should therefore be prioritized for maintenance efforts. By focusing on these critical assets, organizations can minimize downtime, reduce maintenance costs, and improve overall asset performance, ensuring that resources are directed where they are needed most.

Asset Criticality Criteria

When conducting a criticality analysis, assets or entire systems are evaluated based on five key criteria: Maintenance, Operation ($), Environment, Safety, and Quality. This evaluation is often criticality score based, using standardized scoring methods to prioritize assets for maintenance and investment. A management system, such as a CMMS, can be used to integrate and automate the criticality ranking process, supporting data-driven decision-making.

Each criteria includes specifics that help assess the importance of an asset within the overall process.

1. Maintenance

This category focuses on the asset’s reliability, maintainability, and the effort required to keep it operational and complete the related work order. Key criteria include:

• Failure Frequency:  How often does the asset fail, and based on failure modes, what is the impact on maintenance resources?
• Ease of Repair: The complexity and time required to restore the asset to full functionality.
• Spare Parts Availability: The lead time and cost of acquiring necessary spare parts.
• Preventive and Predictive Maintenance Needs: The level of ongoing maintenance required to prevent unexpected failures.

2. Operation ($)

This category evaluates the financial impact of asset failures and downtime. Key criteria include:

• Impact on Production Throughput: How much does the asset influence production output?
• Cost of Downtime: The financial loss incurred when the asset is non-operational.
• Energy Consumption: The efficiency of the asset and its effect on operational costs.
• Operational Dependency: How critical the asset is to other production processes and dependencies.

3. Environment

This category assesses the asset’s impact on environmental sustainability and regulatory compliance. Key criteria include:

• Environmental Risks: Potential for spills, leaks, or emissions that could harm the environment.
• Regulatory Compliance: Adherence to local and international environmental regulations.
• Waste Generation: The amount of waste or byproducts generated and their disposal impact.
• Energy Efficiency: The asset’s contribution to sustainability and carbon footprint reduction.

4. Safety

This category focuses on risks assessment to personnel and workplace safety. Key criteria include:

• Hazard Potential: The likelihood of accidents, fires, or hazardous material exposure.
• Impact on Personnel Safety: The potential consequences of asset failure on worker health and safety.
• Compliance with Safety Standards: Adherence to OSHA, ISO, or other industry-specific safety regulations.
• Emergency Preparedness: The ability to quickly respond and mitigate risks in case of failure.

5. Quality

This category ensures that asset performance aligns with product quality and customer satisfaction. Key criteria include:

• Impact on Product Quality: How asset performance affects the consistency and standards of final products.
• Process Stability: The asset’s role in maintaining operational consistency and reducing variability.
• Defect Prevention: The asset’s ability to minimize scrap, rework, and product defects.
• Compliance with Industry Standards: Adherence to quality control and certification requirements.

By incorporating these detailed criteria into the Asset Criticality Ranking process, organizations can ensure a comprehensive, data-driven evaluation of their assets.

Calculating Criticality Score

This score is determined by evaluating each asset against specific criteria such as production impact, safety risks, and potential financial losses. Typically, a weighted formula is used to combine the likelihood of failure with the potential consequences, resulting in a numerical value that represents the asset’s criticality.

Assets with higher criticality scores are considered more important and may require more frequent or intensive maintenance strategies, while those with lower scores can be managed with less frequent interventions. By calculating and comparing criticality scores, organizations can prioritize assets based on objective data, allocate resources efficiently, and develop maintenance strategies that minimize downtime and optimize operational performance.

The Outcome of Asset Criticality Ranking

Once the scope and ranking criteria have been established, each asset is assigned a criticality score within the asset hierarchy.

Example: ACR in a Tissue Plant Converting Section

Maintaining a well-balanced ranking process is crucial to ensuring an accurate and meaningful assessment of asset criticality. This process identifies assets that are most critical for reliability centered maintenance planning. If, at the end of the evaluation, nearly half of all assets are classified as Criticality A, this may indicate that the ranking criteria are either too broad or not well-defined, leading to an overestimation of asset criticality.

Final Thoughts

Whether you’re managing large or small asset inventories, implementing an Asset Criticality Ranking (ACR) process is essential for making informed maintenance decisions. By moving away from subjective assessments and applying a structured, data-driven approach, companies can accurately determine which assets require the most attention. This ensures that maintenance efforts are aligned with operational priorities, reducing the risk of unexpected failures and optimizing resource allocation.

A well-defined ACR process helps prevent overclassification of assets and ensures that critical equipment is properly identified based on its impact on operations. Over time, this approach leads to more effective maintenance planning, reduced downtime, and improved asset reliability.

Investing in a clear and structured ACR methodology today provides long-term benefits by creating a maintenance program that is both efficient and sustainable.

Raphael Tremblay,
Spartakus Technologies
[email protected]