Predictive Maintenance (PdM)

Predictive Maintenance (PdM) is a Maintenance Strategy where Condition Monitoring (CM) techniques and tasks are applied to help determine the condition of in-service equipment in order to determine and plan when maintenance intervention should be performed. This approach promises cost savings over routine or time-based Preventive Maintenance (PM), because tasks are performed only when warranted and scheduled.

The main benefit of PdM is to allow convenient scheduling of corrective maintenance, and to prevent unexpected equipment failures. The key is “the right information in the right time”. By knowing which equipment needs maintenance, maintenance schedules can be optimised and intervention work can be better planned (spare parts, people, etc.). “Unplanned shutdowns” are transformed to shorter and fewer “planned shutdowns”, thus increasing plant availability. Other potential advantages of PdM include extended equipment lifetime, increased plant safety, fewer incidents with negative impact on the environment, and personnel, and optimisation of spare parts handling and system reliability.

PdM evaluates the condition of equipment by performing periodic or continuous (online) CM. The ultimate goal of PdM is to perform scheduled maintenance intervention when the maintenance activity is most cost-effective and prior to the equipment performance falling below a pre-defined threshold. The Maintenance Strategy review will determine the suitability of PdM, the correct CM technique and the right frequency of CM data collection.

Most PdM inspections are performed while equipment is in service, which minimises disruption of normal system operations whilst having little or no impact on asset availability. Adoption of PdM can result in substantial cost savings and higher system reliability.

Taking the PM and Run To Failure (RTF) example to the next stage:

An individual bought an incandescent light bulb. The manufacturing company mentioned that the life span of the bulb is 3 years. The individual has the opportunity to observe the bulb operation daily. After two years, the bulb starts flickering. The individual predicts at that time that the bulb is going to fail very soon and decides to change it for a new one. This is PdM and this time note that both PM and RTF strategies would have allowed the bulb to fail.