It is not uncommon for people to use the terms Preventive Maintenance and Predictive Maintenance interchangeably. But although they are somewhat similar (i.e.: they both describe maintenance that is performed before any failures or operating problems arise), these are two different types of maintenance that you should be able to differentiate.
First of all, what is preventive maintenance?
Preventive maintenance is planned maintenance that is performed in equipment regardless of its current operating condition, with the purpose of avoiding failures and mitigating the consequences of equipment breakdowns.
It is usually determined by time (e.g.: every 6 months), events (e.g.: every 500 uses), or meter readings (e.g.: every 3,000 miles), with limits that are usually established based on statistics about the expected or average life of the equipment.
This type of maintenance has many advantages in comparison with Corrective Maintenance, which is only performed when equipment failures or breakdowns are reported. If you’d like to know more about this, check out our article about the advantages of Preventive vs. Corrective Maintenance.
The main issue with Preventive Maintenance is that, since it is not based on the actual condition of the equipment, it can result in maintenance actions, including part replacements, that are unnecessary and still cost time and money.
What about Predictive Maintenance?
It is also known as condition-based maintenance and, contrary to Preventive Maintenance, this approach is based on the actual physical or operating condition of the equipment at the time of maintenance, instead of statistics and previously defined schedules.
The idea is to predict the occurrence of a failure before it actually happens, by consistently monitoring and testing the condition and performance of the equipment in question using techniques such as vibration analysis or oil analysis. When certain unwanted conditions, such as wear, are detected, then a repair is scheduled before an actual failure happens. This way, you can guarantee that the repairs are both necessary and timely, which isn’t always the case with Preventive or Corrective Maintenance.
However, the implementation of a Predictive Maintenance strategy is usually more costly than Preventive, since there is a need to invest in specific monitoring equipment and to train personnel to use it and to interpret the data collected.
So which strategy should you use?
The best strategy is to have a maintenance program incorporating both of these types of maintenance, as appropriate for each situation. Remember that considering Corrective Maintenance is still (albeit less) necessary when adopting these strategies.
Maintenance Management Software tools, such as Infraspeak, exist precisely to help you define, perform and monitor your maintenance strategy. If you’re in doubt about investing in this kind of system, check out our article on 5 signs you should invest in a CMMS.