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The Importance of Equipment Criticality

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The Importance of Equipment Criticality

The equipment criticality process is on how we look at the equipment in our processes and determine how critical it is to the overall process functionality and risk. There are many factors to consider when ranking a piece of equipment with a criticality assessment and many questions and considerations need to be analyzed. This process is most often completed using some form of ranking type software where the values obtained can be transferred to a CMMS system for use.

Most equipment in the process is crucial to the operation of the plant so we must make sure we use our maintenance resources effectively when performing PM’s to each unit. This is a very common misconception in many plants around the world because maintenance personnel are used ineffectively. In my early years in maintenance it was also my opinion to get someone to every plant component once per week. We inspected, performed lubrication, and used our senses to find problems. But what happens when we have more plant reactive repair problems than we have resources. Many times we skip all or most of the PM’s to fight the fires and make repairs. This usually leads to more fires and continued failures and the downhill spiral.

If you performed a survey of the different individuals at your plant location and asked the question; what is the most critical piece of equipment in the process? The answers may be consistent but may also be widely varied depending on the individual. If I ask a maintenance person, he may tell me its equipment “A” because he spends a lot of time on keeping it functioning. If I ask operations they may say its “B” because that is there main equipment type. If I ask the question to the quality department it may be something else, “C”. And so on through the safety supervisor, or the environmental personnel. We will more than likely get some different answers.

So how do we know what process or piece of equipment is most critical? We need a way to determine this, so we will use the following criteria.

What makes an asset or piece of equipment critical?

The Maintenance Viewpoint

It breaks more often than other equipment

Parts are hard to come by so we stock extra

If it breaks the process is down

It takes a special skill set to repair it

It expensive to repair

It causes damage to other equipment

The Operations Viewpoint

If it goes down everything goes down

It reduces rate of production

It results in extra labor costs

It makes a cleanup cost high or difficult

Does long term downtime lead to exponential costs

The Quality Viewpoint

It causes quality losses to the end product

It creates rework issues

It creates waste

It causes customer complaints

Possible loss of customers

Buying product in from a competitor

The Safety Viewpoint

It creates a potential for an employee injury

It creates the potential for a fire

It creates a potential for an explosion

It create a potential for an employee death

The Environmental Viewpoint

It creates a potential for a chemical air release

It creates a potential for a chemical release in runoff water

It creates a potential for waste water release

It creates the potential for employee injury

It creates the potential for community exposure

The Food Safety Viewpoint

It creates a microbiological risk

It creates an allergen risk

It creates a foreign material risk

It creates a sickness or death

Downtime creates a risk

It creates waste

By considering and rating each of the areas above on some scale an overall rating number can be assigned to each process or piece of equipment. This number is the overall criticality ranking and should be used to determine where and how to apply all your plant resources for cost effective results.

Here is a real life example from a plant I worked at last year. It was a new facility with new equipment and people. When I arrived they were having a lot of reactive maintenance issues and high downtime rate. Many of the downtimes were small, 15-30 minutes, but numerous. It kept maintenance busy correcting the issues and performing these reactive tasks.

In the process of reacting to all these issues they were missing and skipping PM’s. When they did have some time or resources to do the PM’s they just grabbed the list and started working through equipment and departments. They never made it through the entire plant from day one. So what happened were missed PM’s caused equipment to fail and more reactive work.

We worked on writing non subjective PM’s for the equipment and also performed an asset criticality process. We ranked all the equipment in the plant using the areas above. The equipment was ranked 0-1000 on a scale. We decided any equipment above 700 was considered high or “A” critical. Equipment below 300 was considered low or “C” critical. Any equipment in between was “B” critical.

Now I was able to set some rules for maintenance and work order generation.

# 1 All equipment ranked “A” critical would never be allowed to have a PM missed. Even if overtime was needed to complete the PM.

# 2 All equipment ranked “B” critical could have the PM missed but only for 1 cycle. Then it was whatever it took to get the PM’s completed.

# 3 All equipment ranked “C” critical could have the PM missed for up to 4 cycles. Then it needed to be assessed and completed.

These rules helped to make sure PM’s to critical equipment was never missed and should eliminate major downtime or other critical issues. Every PM work order had a criticality ranking attached.

When it comes to equipment criticality on any piece of equipment or process, consideration must be given to an evaluation process. Many inputs should be considered before deciding where to apply resources such as maintenance and budget limits. Another process that must use equipment criticality is the process of RCM analysis. Not using some method of evaluation may lead to a wasted the effort of an RCM analysis but not choosing the correct process. This may lead to not getting the full benefit of the RCM analysis.  It can help find another process would have given better payback for the effort.

The process can help you make decisions on:

Where to apply maintenance labor resources

Where to apply quality checks or measurements

Where to review E,H,&S issues

Where there may be food safety issues

Where to use synthetic lubes

What PM’s are performed first

Are the correct PM’s assigned

Expose environmental risks

What processes to perform RCM

Many companies sell equipment criticality software to perform this process. Make sure you get trained on how to look at all the issues so you get the best results. Many issues in a plant that are missed can cause multi million dollars loses that could have been avoided by effective use of asset/equipment criticality.

For information on equipment criticality software and training please contact or Charli or me for more information.


Terry Harris – Mr. Harris is a Certified Maintenance & Reliability Professional, certified through The Society of Maintenance & Reliability Professionals. Mr. Harris worked in the manufacturing/process industry for 26 years and perform training and consulting for 8 years. Most of his time was devoted to maintenance area efforts with most of his career being devoted to improving the reliability of his plant and other US and European locations. Mr. Harris has performed training in the US, and 12 other countries.

Mr. Harris owns Reliable Process Solutions in which he performs training in the areas of Predictive technologies, Proactive Maintenance techniques, Lubrication Excellence and many other programs. Mr. Harris has developed many Proactive maintenance programs to bring maintenance operations to a more efficient and profitable stage. Many of the training programs teach companies how to make equipment last longer.

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