What is preventive maintenance?
Implementing preventive maintenance is a key step toward the ideal predictive maintenance program
Preventive maintenance (sometimes called preventative maintenance) is regularly performed on a piece of equipment to reduce the likelihood of failure. Preventive maintenance ensures that anything of value to your organization receives consistent maintenance to avoid unexpected breakdowns and costly disruptions.
In the same way you would not wait until your car’s engine fails to get the oil changed, machines, equipment, buildings and anything of value to your organization need consistent maintenance to avoid breakdowns and costly disruptions.
This work is called planned or preventive maintenance. Preventive maintenance is performed while the equipment is operating normally to avoid the consequences of unexpected breakdowns, such as increased costs or downtime.
Preventive maintenance is a strategy that all companies can implement to move away from reactive maintenance modes, and to begin a reliability journey. As the best programs include a combination of maintenance approaches, implementing preventive maintenance is an important step to the ideal strategy of predictive maintenance.
Preventive maintenance vs. reactive maintenance
Though many are moving away from a reliance on run-to-failure or reactive maintenance modes, a majority of organizations still use this method today. Reactive maintenance involves repairing equipment after it has broken down to bring it back to normal operation.
On the surface it may seem less expensive to operate reactively, but planned maintenance can be much less costly, with studies observing that reactive maintenance can cost five to eight times more than preventive or predictive maintenance.
There are a variety of other costs associated with unplanned outages, such as lost production, overtime, idle equipment, expedited shipments and other “hidden” costs which can include:
- Safety issues
- Uncontrollable and unpredictable budget costs
- Shorter life expectancy for equipment
- Greater chance of inspection failure
- Increased downtime for equipment and employees
- Repeat issues and breakdowns
When preventive maintenance is scheduled, these costs can be avoided, and all parts and maintenance resources can be scheduled and accounted for to streamline the process.
Preventive vs. predictive maintenance
While preventive maintenance determines schedules based on manufacturer recommendations or the average life cycle of an asset, predictive maintenance is very different. Predictive maintenance is identified based on tracking equipment condition and scheduling maintenance from those readings.
Additionally, preventive maintenance tasks are performed during planned machine shut downs, and predictive maintenance activities are carried out during normal operation. Predictive maintenance also utilizes various advanced techniques such as infrared thermal imaging, vibration analysis and oil analysis to predict failures.
The most effective maintenance programs leverage reactive, preventive and predictive methods. This requires analyzing tasks to identify which method is best based on disruption due to equipment downtime, the P-F Interval, cost of parts, labor time and equipment history.
How does preventive maintenance work?
Preventive maintenance is a straightforward program to establish and set in motion. Maintenance is set on a schedule based on calendar dates or usage, often at the recommendation of the manufacturer. During a specified date and time, equipment is shut down, and maintenance professionals perform the outlined tasks on that piece of equipment.
Preventive maintenance can also be set up with breakdown and time-based triggers. Maintenance triggers are used to alert employees that maintenance must be performed at an operational level. Breakdown maintenance triggers occur when a piece of equipment breaks down and cannot be used until maintenance is performed. With a time trigger, maintenance is triggered whenever the calendar rolls over to a pre-specified date.
For example, most forklift manufacturers suggest performing preventive maintenance every 150 to 200 hours of operation, which can be established on a time-based trigger. Performing this maintenance can mean extending the life of assets, increasing productivity, improving overall efficiency and reducing maintenance costs.
Preventive maintenance does not require additional tools other than the manufacturer recommendations and a team willing to adopt new maintenance processes. To achieve buy in from the team, it is important to outline the benefits of a PM program, and identify the ways in which a preventive maintenance schedule will make the jobs of technicians, mechanics and engineers much easier.
With a computerized maintenance management system (CMMS), preventive maintenance is triggered for periodic inspections based on calendar intervals or usage (for air compressors and forklifts) or mileage for company vehicles. This company has increased their planned maintenance percentage from 20% to 80%, and their on-time completion rate for PMs is 85% and continues to improve.
Preventive maintenance tools
A CMMS is designed to help schedule, plan, manage and track maintenance activities. The features within a CMMS such as task generation, scheduling, inspections and data integration from tools and sensors work together to offer continuous improvement and support for an organization’s preventive maintenance program.
- Preventive maintenance task generation: Within a CMMS system, users can leverage a preventive maintenance calendar and/or meter-based PM tasks for all assets and include detailed descriptions with how-to guides and other information vital to effectively performing the work.
- Preventive maintenance task schedules: Developing an effective preventive maintenance program requires more than generating preventive maintenance tasks, and CMMS systems have the tools to make important improvements. Preventive maintenance schedules empower users to coordinate labor resources and parts needed to complete work, as well as automatically generate preventive maintenance tasks based on a daily, weekly or monthly basis, or based on usage.
- Preventive maintenance inspections: A CMMS solution can also help organizations keep up with inspections and pass compliance audits. With CMMS, users can record inspections accurately and generate corrective work orders when equipment fails inspections.
- Tools & sensors: Combined with a CMMS, condition monitoring software enables maintenance managers to remotely monitor multiple assets. It also allows for producing asset alarms and multiple data graphs per asset with correlating current, voltage, temperature, vibration and power quality monitoring.
- Data integration: Data can be integrated into CMMS functionality to enable the completion of seamless workflows on a mobile device. This allows maintenance teams to respond to fault notifications on the move and then create, access or process work orders related to the notification in real time. Planned and unplanned maintenance is better coordinated, unscheduled downtime is reduced and response times to problems or systems failure are improved.
How much can you benefit from preventive maintenance?
With an effective preventive maintenance program, organizations experience improvements in their overall business processes and costs, including increased productivity, decreased waste, improved work execution and reduced unexpected breakdowns. A preventive maintenance program (with the support of a CMMS and other tools) can help spark serious quantifiable results, such as:
- Extending the life of assets, and increasing equipment up time
- Reducing manual data entry
- Decreasing paperwork with mobile maintenance capability
- Increasing productivity and efficiency
- Improving audit compliance with extensive documentation
Advantages of preventive maintenance
Other than reactive maintenance, preventive maintenance is the simplest maintenance strategy to implement and execute, as it requires following manufacturer recommendations and developing a static maintenance schedule for critical equipment. It helps organizations avoid unplanned breakdowns, lost production as well as equipment and labor downtime. It also decreases the cost of maintenance.
Disadvantages of preventive maintenance
A common issue that organizations run into with preventive maintenance schedules is performing the inappropriate amount of maintenance on assets. Because calendar-based maintenance does not take the health of an asset into account, the frequency of maintenance work can often be too high or too low. This can be prevented by optimizing and improving preventive maintenance programs.
Does preventive maintenance make sense for your business?
World class maintenance dictates that 90% of maintenance should be planned, with an 80% planned to 20% unplanned ratio considered still beneficial compared to the typical average of 55% or less. But in some instances, it makes more sense to leverage reactive maintenance.
Both methods have a place in your maintenance plan. In some cases, it makes more sense to depend on reactive maintenance rather than following a strict preventive maintenance program. For example, changing a light bulb is cheap, easy to perform and will cause no disruption to business processes.
To determine which maintenance strategy to apply, consider these questions:
- Is the asset critical to business operations?
- Does it contribute to the safety of your product/customers/staff/etc.?
- Is business disrupted significantly if the asset unexpectedly goes down?
- Is it costly to have the asset repaired or replaced?
If you answered “yes” to any of these questions, it is important to begin developing a preventive maintenance schedule on that asset, as it will benefit you in the long run.
Tips to begin developing a preventive maintenance schedule
- Establish equipment list and determine best PM candidates: To get started, take note of all of the equipment throughout your organization to establish inventory. Within this list, you will ask yourself the above questions to help decide which pieces of equipment you will include in your future preventive maintenance plan.
- Refer to manufacturer recommendations: Take a look through manufacturer recommendations to establish an effective preventive maintenance schedule and to help figure out the necessary tasks and desired frequency of maintenance. Referring back to the original example, this could be getting an oil change for your car every 10,000 miles, or as recommended by your owner’s manual.
- Start with your heavy hitters: To effectively leverage a preventive maintenance schedule, it is important to begin with your most critical pieces of equipment one step at a time. Once you get started with those critical assets, create long term plans such as annual schedules.
- Fill in short term plans: With long term plans established, you can begin creating weekly plans for your crew. These tasks should be assigned and scheduled ahead of time, with all parts and maintenance resources accounted for.
With preventive maintenance scheduling software like CMMS, organizations have experienced benefits such as:
- Extended asset life and increased equipment uptime
- Decreased manual data entry
- Less paperwork with mobile and barcoding capability
- Consistent maintenance tasks and procedures
- Increased productivity and efficiency
- Improved audit compliance with extensive documentation
Applications of preventive maintenance
There are many applications of preventive maintenance in a wide variety of industries such as:
- Performing calendar-based maintenance on air conditioning units on a university campus
- Scheduling consistent maintenance on assets critical for production
- Meter-based PMs for maintenance of material handling equipment based on utilization
- Scheduling PM tasks in preparation for audits
