Asset Criticality Ranking

A database of accurately ranked assets is the foundation of any preventive, predictive, or condition-based Asset Management Program.

Without proper asset criticality ranking, all other programs based on this data will potentially fail. Before starting the ranking process, it is important to complete certain prerequisites, discussed in this blog post.

First, ask yourself these questions: Is my asset catalog up to date? How can ranking information be used for other processes? Understanding how to leverage asset ranking across other areas is a powerful tool to gain buy-in from your organization and to get the most out of this exercise.

The numerical “criticality value” assigned to each asset can be used to prioritize the following, depending on what drives your needs:

  • A repair backlog for planning
  • A ready backlog for scheduling
  • Where to focus Bill of Material (BOM) optimization
  • A spare parts plan
  • Assets to receive scheduled maintenance, both preventive- and condition-based

Criticality Analysis is part of an overall reliability improvement process, called Asset Health Assurance (AHA). A graphical representation of the AHA process is shown below.

Asset Health Assurance (AHA) Process
Asset Catalog

The first step is to verify and update your site’s asset list, or catalog. Investing the time to do this ensures sufficient data is available to support subsequent reliability processes, and for purchasing replacement parts. Once the asset catalog is corrected, you can begin the actual ranking process to determine asset importance—assets whose failure more immediately and/or more severely impacts the desired state. “Criticality” is the name for this combination of importance plus failure rate.

Asset Hierarchy
The next step is to ensure your asset hierarchy is compliant with ISO 14224, as shown in the pyramid diagram below. An asset hierarchy with the appropriate parent-child relationships enables a criticality assessment of each component’s effect on its assigned system or functional location.
Asset hierarchy diagram
An asset hierarchy provides the following benefits:
  • Enables better drill-down, roll-up of costs — to charge the right resources to the right equipment; makes it easier to correct the Notification/Work Order functional location, and reduces functional location clutter.
  • Enhances reliability continuous improvements efforts — improves information gathering speed, done in a fraction of the time, and to greater depth/granularity. For example: with Equipment Class or Smart Names, you can compare/track equipment level reliability by type (e.g. BH-30 Spindle life all machines), as well as a particular machine.
  • Enhances planner efficiency — allows cleaner BOMs for job planning, fast BOM updating, and assures Project Management (PM) and Corrective Job plans are all related to the parent functional location, rather than multiple functional locations spread horizontally.

Successful asset ranking requires a team of people from various areas of your plant environment. Below is a high-level process flow depicting criticality ranking steps performed by this team, followed by more detailed descriptions.

Criticality Ranking process flow
Step 1: Project Governance

When defining roles and responsibilities of your criticality team, reach beyond the maintenance organization alone. Commonly, craftsmen, operators, maintenance supervisors, and operation supervisors are included, along with other stakeholders—representing safety, environmental, purchasing, maintenance, repair, and materials operations.

The following roles and responsibilities support the asset criticality process:

  • Executive Sponsor — controls all resources necessary to the project; provides an organization charter to the sites, takes actions to align competing initiatives, removes obstacles, and provides realignment of organizational constraints to reinforce new behaviors.
  • Executive Steering Committee — comprised of the owners of the functions that support the new process; monitors implementation progress and value return, removes obstacles, sets priorities, and mitigates or eliminates risks factors.
  • Site Manager — normally the site sponsor, or the owner of all resources at the site level necessary for successful implementation; monitors implementation and value return, sets priorities by aligning competing initiatives, and removes obstacles.
  • Leadership Team — usually comprised of direct reports to the site manager/sponsor, as they typically are the department heads who own a specific functional responsibility at the site; aligns their part of the organization; and demonstrates active leadership presence.
  • Project Manager (Facilitator) — implements the project at the site; provides project management (time, cost, and quality) and ensures change management actions occur, i.e. workforce engagement, effective communication, and systems that reinforce correct behaviors.
  • Change Management Team — a working group chartered by the site sponsor and leadership team, and charged with tactical actions needed to drive change; supports the leadership team and manages risk, communication, site employee engagement, and change management plans.
  • Workstream Champion — advocates for a particular workstream (team), defends decisions made by the team, and actively supports the overall project improvement process; includes evaluating team dynamics and member participation to provide feedback and direction, as necessary, to improve efficiency, ensuring on-time completion of the implementation plan.
Step 2: Load Site Asset List into Facilitation Tool

Take the completed asset list, including asset hierarchy, and put this information into your site’s preferred format. Common formats include a text document, spreadsheet, or database program. This is the list of equipment used for the criticality analysis.

Step 3: Form Site Criticality Analysis Team

Assembling a criticality assessment team is vital to accurate equipment ranking and, therefore, should include experienced department representatives, who have knowledge in the areas to be assessed. They should be able to speak for the department when answering assessment questions. It will be a challenge to get the time from the most experienced people, but it is their knowledge that will yield the desired results.

Step 4: Conduct Basic Criticality Awareness Training

The project manager conducts an awareness session of the criticality analysis process. This includes information on the process, itself, resources required, customization, what to expect, intended output, and opportunities to incorporate the results into other workstreams. He/she communicates in a coordinated manner across all levels of the organization to promote awareness, understanding, acceptance, commitment, and advocacy. The engagement curve below illustrates how commitment is developed through the execution of the strategies outlined in each stage.

Engagement curve
Step 5: Develop Site-Specific Assessment Criteria

Decide the level at which the criticality analysis will be performed—system, equipment, or failure mode. Then, develop your assessment criteria by asking certain questions under main category groupings. To ensure your entire organization’s needs are met, include categories such as safety, environmental, maintenance, operations, purchasing, and customer/facility impact.

System criticality is often performed at plants that have not conducted a criticality assessment, or may have one that is outdated. Going through a system-level criticality assessment helps you identify which systems are most critical to the process or facility. It can be a great starting point because: 1) the number of systems is less than the number of pieces of equipment, and 2) the team can begin to form and gain knowledge of the facilitated process.

However, system-level criticality is not sufficient for making machine-level decisions for resource allocation. The asset-level criticality assessment provides the granularity required to compare almost any asset to the
next, yielding a clearer path as to where resources should be allocated.

Another level of refinement should be applied to the most critical assets, ideally the top 5-20%. Because of their importance and their failure rate, these assets pose the greatest risk to the plant if they fail. So, the next crucial area of focus needs to be at the failure-mode level. This is also known as the Failure Mode, Effects, and Criticality Assessment (FMECA). Reviewing the specifics of how a given machine fails will lead to better understanding of which maintenance techniques are needed to eliminate, or at least prevent, the failure from occurring. The FMECA is an essential part of developing an effective and efficient Equipment Maintenance Plan (EMP).

Step 6: Begin Criticality Facilitation

An often-overlooked member of the criticality team is the facilitator, who assists the team in understanding the common objective of the criticality process and enables them to reach consensus, while remaining neutral. A seasoned facilitator uses an adaptive leadership style to guide the team through inevitable conflicts. This “referee” should also challenge team members when questions are not consistently evaluated from one piece of equipment to the next.

The first step is to document the assumptions for the analysis. An assumption is used as a frame of reference and a source of consistency during the analysis. Start with a few easy ones to get the group moving in the right direction. Then, begin the equipment analysis process, reminding team members to focus on the question being asked, and provide their input as to the best answer to select. The goal is to randomly select approximately 100 machines to rank, so an initial quality assurance check can be done.

One example would be to gain consensus that the most reasonable work case scenario will be used. The point of the analysis is not to select the catastrophic failures that may only occur once in the site’s operation. If the site experienced such a failure in the past, then it is reasonable, particularly if no root cause analysis was conducted and mitigating actions implemented.

Step 7: Perform Process Quality Checks

Conduct a review of the answer distribution and overall machine ranking to verify the rationale behind a question, or group of answers, is sound. A good place to begin is with those questions where the answers are a range of values. For example, the answers to maintenance downtime may be given in a range of hours that should be checked to make sure one or two answers are not being selected routinely. In this case, pull the team together and ask for their input on refining the range of hours available for selection. These types of adjustments are common in the beginning and demonstrate to the criticality team that the process is not merely an academic exercise.

Another area to review is the ranking distribution. Evaluate the histogram to see if you notice any tendencies, high or low, in the scoring. It is possible that the initial group of equipment selected is similar in ranking, so verify this with the team. You may find it necessary to select another group of 30-40 machines to rank, and then reevaluate the distribution. The facilitator is responsible for this ongoing quality assurance process.

Step 8: Load Criticality Value into CMMS

Once ranking is completed and results approved, add the data to your organization’s Computerized Maintenance Management System (CMMS). This means migrating each machine’s criticality value from the system used to develop the score into your daily work management system to support your original intentions—to prioritize a repair backlog for planning and/or a ready backlog for scheduling, determine where to focus BOM optimization, develop a spare parts plan, or decide which assets are to receive scheduled maintenance, both preventive- and condition-based.


We have covered the key success factors to effectively and efficiently conduct an asset criticality analysis. It starts with having a governance structure in place for managing the entire project. It also requires a logical process for the analysis, carried out by an experienced team, including a knowledgeable facilitator to ensure good ROI from the effort put forth during the process. But completing the analysis is only part of the job; you must follow through with adding each machine’s rank to your CMMS. After a few weeks of incorporating criticality ranking into daily work processes, you will have a full appreciation of the value it provides.


Allied Reliability’s production and asset management experts are committed to optimizing equipment and processes. Our experts work with you for best outcomes. Understanding how critical asset failures impact the environment, production, financials, and safety enables us to deliver the right monitoring, analytics, decision making, and maintenance plans. We bring unique asset management content along with best practices, advanced tools, and proven methodologies to help customers move forward in their Digital Transformation journey to deliver enhanced performance.