Corrective Maintenance Compared

 
 

“Corrective maintenance” is a term that has been used to define a number of processes. This has frequently caused confusion as to which maintenance types are considered to be within the category of “corrective”. Hopefully, this guide sets confusion to rest by accurately defining both what is corrective maintenance and what is not.

The Definition of “Corrective Maintenance”

Corrective maintenance is properly defined as “any maintenance performed to return equipment to a proper working order.” The failure is identified, isolated and repaired. Upon completion of the necessary corrective maintenance tasks, the equipment is once again functioning normally within the limits and tolerances established for in-service operations.

By definition, corrective maintenance requires that the equipment either has failed, or is beginning to degrade in such a way that leads to increased risk of failure in the future. Therefore, preventive maintenance, which is carried out at regularly scheduled intervals in order to prevent failure or degradation before they occur, is not considered to be a form of corrective maintenance.

However, several other types of maintenance fall under the umbrella of “corrective”. Typically, corrective maintenance can be divided into two subcategories: reactive maintenance, which occurs after the equipment has failed and no longer functions, and predictive maintenance, which occurs after degradation has begun but before the point of total failure.

Reactive Maintenance

Reactive maintenance, also known as run-to-fail maintenance, is a form of corrective maintenance in which the equipment is allowed to fail and then restored to a properly functioning state. A common example of reactive maintenance is allowing a light bulb to burn out (so that it no longer provides light, i.e. no longer functions) and then replacing it (restoring the function of providing light).

This form is maintenance is associated with high risk when compared to other strategies, because it results in periods of unplanned downtime during which the equipment is completely non-functional. Today, with so many other forms of maintenance available and more cost-effectively than ever, reactive maintenance is recommended only for equipment which does not perform a critical function. Examples of household equipment which are frequently allowed to run to failure include light bulbs, air conditioning or heating units, and vacuum cleaners.

Predictive Maintenance

In contrast to reactive maintenance, predictive maintenance is a form of corrective maintenance in which the performance of equipment is regularly monitored. This allows it to be repaired and restored once function has started to decrease but before total failure.

Predictive maintenance features a number of advantages over reactive maintenance. It is cost- and time-effective as the equipment can be restored while still running, eliminating downtime entirely. It can also be significantly less labor-intensive, if the testing and monitoring equipment operates automatically, sending real-time performance data to software or devices.

Performance data is acquired via condition monitoring, a variety of tests and devices which can be used to observe and analyze the equipment in different ways. Types of condition monitoring include ultrasonic, infrared, thermal, oil analysis and vibration monitoring. Recently, innovations in the field of vibration monitoring, specifically the development of Proaxion®’s high-tech, cost-effective TactixTM device, has lead to its emergence as the most popular and widely used form of condition monitoring.

To learn more about predictive maintenance and Proaxion’s contributions to the field, see the following articles: predictive maintenance and condition monitoring.

Immediate vs. Deferred Corrective Maintenance

Another important distinction which can be made is the difference between immediate and deferred corrective maintenance. Immediate corrective maintenance is performed as soon as the failure occurs or degradation is detected. This minimizes downtime and focuses on getting the equipment back in perfect working order as soon as possible. Reactive maintenance is usually immediate because of the cost risks associated with non-functioning equipment. Immediate corrective maintenance should always be carried out on any equipment which performs a critical function.

Deferred corrective maintenance refers to any situation in which the equipment is allowed to degrade further or remain non-functional before maintenance is carried out. Predictive maintenance is often deferred: equipment is allowed to continue functioning despite degradation until a certain minimum percentage of function is reached, after which it is restored to full working order. This is typically a more cost-effective solution, as the equipment is not maintained until it is absolutely necessary. Reactive maintenance should not be deferred unless it is a completely non-critical piece of equipment, such as the aforementioned light bulb.

Corrective maintenance is just one of the ways in which different maintenance strategies can be categorized and defined. To learn more about other ways, contact Proaxion® today or explore the many other informative articles hosted here on our site.