Reliability is more valuable when you understand its connection to maintenance

The concept will provide more value if you know how it relates to maintenance.

By Ricky Smith, CMRP

Reliability is an important focal point for many companies. It’s a source of competitive advantage for visionary, capital-intensive companies. It’s the theme for maintenance departments improving their bottom-line impact. To some, it identifies the right work, and is synonymous with reliability centered maintenance (RCM). So, let’s define reliability and discuss critical issues that help achieve it.

Many of the first books written about reliability focused on RCM. But, that isn’t reliability; it’s a proactive methodology for identifying the right work to be done to maintain an asset’s desired performance. In its most effective and most widely accepted form, RCM II, it consists of seven structured and rigorous steps for building a maintenance program for a specific asset. When companies first try to improve reliability, they label the undertaking RCM, but it’s really a reliability improvement initiative.

Understanding the term reliability and how it differs from maintenance is critical to the success of any capital-intensive organization. Reliability is the ability of an object to perform a required function under a stated set of conditions for a stated period of time. Maintenance is the act of maintaining, keeping in an existing state, restoring to like-new condition or keeping from failing.

With these definitions, the differences start to become clear. A reliability culture needs new thinking. Rather than asking how to restore the capability of a failed asset efficiently and effectively, you really only need to ask what can be done proactively to ensure the asset meets the business needs of the overall operation.

A cultural challenge in this transition is the belief that we should strive to maximize equipment availability. But, if you manage in terms of equipment and plant performance, you’ll realize that ensuring 100% availability often results in performing too much maintenance. By defining an asset’s reliability requirements in the context of supporting the underlying business need, you’ll inevitably find that you need a new maintenance program.

When I was in maintenance management, I focused on keeping the equipment available. I realize now that many times, we applied more energy to complete PMs than we spent defining the asset’s exact reliability needs. In today’s world, we can’t afford that kind of thinking and, for the majority of assets, we don’t need 100% availability. The question then becomes, will defining appropriate reliability goals reduce the cost of maintenance? The answer is yes -- provided you follow three steps.

1. Perform a risk prioritization analysis. This helps to focus and get results quickly. Asset risk prioritization ranks your assets according to management’s business goals for the company. This process ensures that you understand which assets provide the largest impact to your operation.

This process makes sense considering that 20% of your assets typically consume 80% of your maintenance resources. The challenge is determining which assets are in the 20%. It’s only through asset prioritization that you’ll understand which assets are critical, based on consequence and risk of failure, measured by effect on the business.

2. Work one asset at a time. Start with assets that have the biggest effect. Identify the asset’s functions, its performance standards (what we expect an asset to do in its present operating context), the functional failures (the inability of the asset to do what its users want it to do) and what failure modes cause the functional failures.

3. Identify proactive tasks that detect or prevent functional failure. Proactive tasks identify the reliability status of an asset, which initiates an activity to restore the asset’s reliability before a functional failure occurs. Remember that a failure is defined as the inability of an asset to do what its users want it to do. Some proactive tasks include:

  • Condition-based monitoring. This can be performed with remote devices, hand-held devices, or through visual means.
  • Predictive maintenance. This includes vibration monitoring, ultrasonic monitoring, infrared monitoring and others.
  • Age-related PMs. Yes, these do have their place, but only after your reliability assessment identifies the need. Only 20% of most preventive maintenance programs is effective. Using condition-based monitoring and predictive maintenance technology provides the best method for identifying an asset’s reliability status.

Remember, reliability is key to the success of any operation and maintaining that reliability is paramount. To do this, start by understanding reliability and maintenance, and how they’re interrelated.

You can contact Contributing Editor Ricky Smith, CMRP, at

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