What is preventive maintenance?Get your free guide to preventive maintenance
Preventive maintenance (or preventative maintenance) is maintenance that is regularly and routinely performed on physical assets to reduce the chances of equipment failure and unplanned machine downtime that can be very costly for maintenance teams and facility managers. Effective preventive maintenance is planned and scheduled based on real-time data insights, often using software like a CMMS. A preventive maintenance task is performed while the equipment is still working to prevent unexpected breakdowns. A preventive maintenance strategy is a commonly used approach that falls between reactive maintenance (or run-to-failure) and predictive maintenance.
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Why is preventive maintenance important?
Preventive maintenance is important because it lays the foundation for successful facility management. Preventive maintenance keeps equipment and assets running efficiently, maintains a high safety level for your employees, and helps you avoid large and costly repairs down the road. Overall, a properly functioning preventive maintenance program ensures operational disruptions are kept to a minimum.
Why do you need a preventive maintenance schedule?
A preventive maintenance schedule helps you organize and prioritize your maintenance tasks (like creating a work order) so that a maintenance technician can create the best working condition and life span for the equipment. By conducting regular preventive maintenance, you can ensure your equipment continues to operate efficiently and safely.
Maintaining a preventive maintenance schedule can be very complex when dealing with lots of equipment, so maintenance personnel often use preventive maintenance software to organize their preventive maintenance tasks.
Types of preventive maintenance
There are three main types of preventive maintenance: Time, usage, and condition-based triggers. A variation of these types of preventive maintenance should ideally be scheduled and performed on all equipment items to prevent unplanned failure. Manufacturers often provide recommendations on how best to maintain equipment. Along with real-time data insights, your maintenance team can schedule preventive maintenance using the appropriate type of preventive maintenance. Below are examples of each type of preventive maintenance.
Time-based preventive maintenance
A time-based approach schedules a preventive maintenance task using a set time interval, such as every 10 days. Other examples include triggering preventive maintenance (like a regular inspection of critical equipment) on the first day of every month or once in a three-month period.
Usage-based preventive maintenance
Usage-based preventive maintenance triggers a maintenance action when asset usage hits a certain benchmark. This can include after a certain number of kilometers, hours, or production cycles. An example of this trigger is routine maintenance being scheduled on a motor vehicle every 10,000km.
Condition-based preventive maintenance
Condition-based maintenance is a form of proactive maintenance. It's a maintenance strategy that monitors the actual condition of an asset to determine what maintenance task needs to be done. Condition-based maintenance dictates that maintenance should only be performed when certain indicators show signs of decreasing performance or upcoming failure. For example, preventive maintenance will be scheduled when vibration on a certain component reaches a certain threshold, indicating that it should be replaced or lubricated.
When should I use preventive maintenance?
The exact timing of when you should use preventive maintenance will vary depending on the equipment and the operation it is performing. You can follow the manufacturer guidelines to help determine preventive maintenance schedules and inspection so that assets do not run to failure. Creating a preventive maintenance schedule will help ensure proactive maintenance rather than resorting to costly reactive maintenance if the equipment starts to fail unexpectedly.
Suitable preventive maintenance applications
Assets suitable for preventive maintenance include those that:
- Have failure modes that can be prevented (and not increased) with regular maintenance
- Have a likelihood of failure that increases with time or use
- Are critical to production, operations, or health and safety
Unsuitable preventive maintenance applications
Assets that are unsuitable for preventive maintenance include those that:
- Have random failures that are unrelated to maintenance (such as circuit boards)
- Do not serve a critical function
- Require costly repairs that are more expensive than running it to failure
Preventive maintenance examples
Common examples of preventive maintenance tasks are the regular cleaning, lubrication, replacing of parts, and equipment repairs. Preventive maintenance scheduling requirements differ depending on the equipment being maintained.
Specific examples of preventive maintenance within a manufacturing facility include ensuring equipment in the production line is working efficiently. Other examples include checking that your HVAC, heating, ventilation, or air conditioning systems are inspected, cleaned, and repaired if necessary, and your water, sanitation, and electrical systems are functioning properly within safety and compliance levels.
Advantages of preventive maintenance
There are two main advantages of using preventive maintenance as your main maintenance strategy: Being able to plan maintenance tasks and not requiring condition-based monitoring.
A preventive maintenance program allows you to plan maintenance tasks that reduce your costs and increase your productivity in the long term. Facility managers are able to prevent incipient failures (equipment imperfections that can cause degradation or catastrophic failure if corrective action is not taken).
Unplanned and reactive maintenance has many overhead costs that can be avoided during the planning process. The cost of unplanned maintenance includes lost production, higher costs for parts and shipping, and time lost responding to emergencies and diagnosing faults while equipment is not working. Unplanned maintenance typically costs three to nine times more than planned maintenance.
When you have a maintenance plan, it's easy to reduce the maintenance cost of your program. Equipment can be shut down to coincide with production downtime. Before the shutdown, any required spare parts, supplies, and personnel can be gathered to minimize the time taken for a repair. These proactive maintenance measures decrease the total cost of maintenance activities. Safety is also improved because equipment breaks down less often than in less complex strategies.
Additionally, a preventive maintenance program does not require condition-based monitoring. This eliminates the need (and cost) to conduct and interpret condition monitoring data and act on the results of that interpretation. It also eliminates the need to own and use condition monitoring equipment.
Disadvantages of preventive maintenance
The disadvantages of preventive maintenance are that, unlike reactive maintenance, preventive maintenance requires maintenance planning, and you run the risk of conducting preventive maintenance too frequently.
Preventive maintenance planning requires an investment in time and resources that aren’t required with less complex maintenance strategies. Maintenance may occur too often with a preventive maintenance program. Unless, and until the maintenance frequencies are optimized for minimum maintenance, too much or too little preventive maintenance will occur.
Additionally, the frequency of preventive maintenance might be too high. Fortunately, the frequency can be lowered without sacrificing reliability when condition monitoring and data analysis are used. The decrease in maintenance frequency is offset by the additional costs associated with conducting condition monitoring.