So, What’s Still Wrong with Maintenance?

Maintenance is still spectacularly unsuccessful at delivering failure-free equipment—it always will be, unless you change to an equipment wellness paradigm

The role of Maintenance is to eliminate operating equipment risks. Yet, organizations using Preventive and Predictive Maintenance strategies still have equipment breakdowns. They have forced outages and stoppages. They consistently get emergency repairs.

So, what makes today’s Maintenance paradigm so unsuccessful at equipment risk elimination?

Why Maintenance Can Never Stop Plant and Equipment Failures

Every part in every machine has a degradation curve. The left-side sketch in the image below shows the degradation curve concept. The right-side sketch represents the degradation curve of selected parts from a pump set like the one pictured. The length and slope of the degradation curve depends on a component’s engineering design and how it’s cared for during its lifetime.

the component degradation model and the degradation curve concept behind the component wellness paradigm

When parts are new they provide their best service. As a part degrades its performance drops. Curves are monitored and tracked using appropriate condition monitoring methods. The ‘P’ (Potential Failure) point is the earliest that we can detect changed performance. This allows the remaining service life to be predicted so the part can be replaced or refurbished as planned maintenance before it’s unusable at the ‘F’ (Functional Failure) point.

Why breakdowns, forced stoppages, and emergency work happens to equipment, despite using the best preventive and predictive maintenance strategies is shown in the next image—their parts’ degradation curves get dramatically cut-short.

A part’s degradation curve shortens and falls as its material-of-construction is damaged by stress.

Those unintended equipment failure events—breakdowns, emergency repairs, forced stoppages—result from excessive stresses in microstructures curtailing the part’s degradation curve.

component degradation causes uncertainty and failure is probabilistic. The component wellness paradigm eliminates the chance of failure

All parts can fail, but not all parts will fail—it depends on the size of the microstructure stresses. A part’s chance of failure changes with its stresses—less stress slows the degradation rate, and the part lives for longer; higher stress lifts the degradation rate, and its life shortens.

Keeping parts microstructure at least stress to minimize the chance of failure initiation is not the focus of a preventive and predictive maintenance paradigm. In a preventive and predictive maintenance paradigm, you let parts go to the ‘P’ point, and then to the ‘F’ point. You wait for ill-health. You do repairs. You get breakdowns, forced stoppages and emergency work.

Equipment failure involves a multitude of uncertainties. High-stress situations CAN occur at several points in a part’s life cycle (formation, manufacture, assembly, installation, operation, maintenance). During its lifetime, a part CAN incur high stresses—the worst ones MAY cause microstructure damage. Once started, the damage CAN become breakdowns, stoppages, and emergency repairs, IF, the requisite cause-and-effect events occur.

The involvement of uncertainty makes failure probabilistic. The laws of probability means high stress events will always arise and then degradation curves will get cut-short. When stress changes at random, the date of failure also changes at random.

Because random failure events are unpredictable, it’s impossible for maintenance based on a failure prevention and prediction paradigm to eliminate breakdowns, stoppages, and emergency jobs—chance dictates that from time to time huge stress events happen, regardless of what maintenance strategies you use. Maintenance can never make your equipment failure-free.

New Alternative to a Maintenance Paradigm: Component Health and Wellness

First parts fail, then equipment stops—if the parts don’t fail, the equipment won’t stop. When an equipment failure happens is a matter of chance. But the stresses that damaged the microstructure of the failed component were not caused by chance.

There is an alternative to a preventive and predictive maintenance paradigm—a component health and wellness paradigm. The focus of component wellness is the lifetime wellbeing of the part’s microstructure. Throughout the life cycle, you proactively create and sustain the conditions that make parts reliable, and you eliminate the possibility of microstructure damaging stress events.

Get control of component reliability, and you get control of equipment reliability. You control parts reliability by controlling material-of-construction degradation. Utmost equipment reliability is achieved when stresses in components do least damage to parts microstructures. In a component health and wellness paradigm, microstructure stress prevention is the vital outcome you seek.

When you adopt an “equipment wellness” paradigm, you use Maintenance to keep parts at their least stress condition, and you use operational process control to minimise lifetime degradation.

For example, the equipment wellness paradigm choice for machinery is to use Precision Maintenance, because its standards and methods always guarantee reduced stress in parts.

In situations where in-service corrosion destroys a part, the wellness choice is to proactively prevent the corrosion. If you wait for the corrosion to appear and then repair it, you ensure higher operating costs. If corrosion cannot be eliminated, you provide sacrificial deterioration. As the deterioration approaches its limit, the item is replaced or refurbished on planned maintenance.

In the case where dust accumulation on electronic parts cause a short circuit, the wellness choice is to prevent all dust ingress. You don’t wait to see if dust collects and then fix a short as a breakdown.

For machines that start under high load, the wellness choice is to change the method to least stress start-up. To keep starting at high loads guarantees overload stresses and an emergency job in future.

A New Conclusion—Change to a Component Wellness Paradigm

It’s the parts that get their degradation curves unexpectedly cut-short that cause emergency repairs, forced shutdowns, and breakdowns.

Maintenance cannot deliver failure-free plant and equipment because it cannot prevent all parts life cycle failure initiation events.

To get maximum lifetime equipment reliability you need to create maximum component lifetime reliability.

You do that by extending the component degradation curve with life cycle strategies and practices that de-stress parts microstructures.

Give your parts’ microstructure a lifetime of health and wellness, and you’ll get the greatest equipment reliability for your operation.

Mike Sondalini
Lifetime Reliability Solutions

P.S. More information on the Plant Wellness Way Enterprise Asset Management methodology, which is completely based on the component wellness paradigm, is at webpage Plant Wellness Way EAM explained.