Explanation
There are different types of maintenance that organizations use to increase the uptime of their assets and utility of their facilities. Based on an organization’s budget, amount of resources, level of combined experience, and maintenance goals, one or more maintenance types are used.
Proactive types of maintenance
Preventive maintenance
Preventive maintenance is the most popular type of proactive maintenance. To start conducting preventive maintenance tasks (PMs), an organization does not need to purchase new technology if it already has a CMMS. This is not the case with predictive maintenance which requires condition monitoring sensors and new software integrations. However, with preventive maintenance, the or-ganization runs the risk of over-scheduling maintenance tasks because tasks are scheduled based on time rather than actual conditions. That said, preventive maintenance achieves 12% to 18% cost savings over reactive maintenance.
Predictive maintenance
Predictive maintenance (PdM) is what savvy maintenance teams aspire to have or are already im-plementing. The major barrier to PdM is the time it takes to implement rather than the cost of the technology itself. For instance, a vibration sensor that can identify imbalance, misalignment, and resonance issues only costs around $200. But the time it takes to install, integrate with other maintenance software, and adopt a culture around is not time that all organizations are willing to allocate. For those that do allocate the time, PdM provides an 8% to 12% cost savings over preventive maintenance.
Condition-based maintenance
Condition-based maintenance (CBM) is at the core of predictive maintenance but, on its own, does not rely on technology to determine the condition of an asset like PdM does. For instance, a manager may instruct an operator to monitor the condition of an asset and submit a work request when a specific condition is met. This approach may, or may not be, as reliable as predictive maintenance. An organization that has highly-trained operators may spot hazardous conditions better than an organization using PdM technology that doesn’t know what to look for.
Scheduled maintenance
Scheduled maintenance includes work that is scheduled on a calendar for completion. The most common type of scheduled maintenance is calendar-based preventive maintenance tasks. These are scheduled well in advance of completion. For instance, an asset with a monthly PM has twelve instances of scheduled maintenance in a given year. However, just because maintenance is scheduled does not mean it’s planned. Planned maintenance implies that a maintenance planner or other type of maintenance worker has fully planned for parts, materials, skills, and other resources to be available during the scheduled time window.
Planned maintenance
Planned maintenance is work that’s prepared for in advance of it taking place. According to an UpKeep survey, it’s also the most popular key performance indicator (KPI) to track. A high planned maintenance percentage indicates that a maintenance team will have resources available to complete work for the time/day the work is scheduled for. Having a high planned maintenance percentage also helps boost other maintenance KPIs like schedule compliance. More planned maintenance means more successful completion of scheduled maintenance.
Routine maintenance
Routine maintenance is a form of time-based maintenance and preventive maintenance, though some organizations differentiate between routine maintenance and preventive maintenance. They use the latter for smaller tasks (i.e. cleaning) performed at higher frequencies (hourly, daily) and the former for larger tasks (i.e. inspections) performed at lower frequencies (weekly, monthly, annually). Additionally, routine maintenance is performed by operators, janitors, and other staff member while preventive maintenance is performed by technicians. Non-routine maintenance includes maintenance that is performed reactively or only when needed based on an asset’s conditions.
Reactive types of maintenance
Emergency maintenance
Emergency maintenance occurs when an asset requires immediate attention in order to keep a facility operational or safe. This is the most reactive and intrusive type of maintenance as it pulls technicians away from other jobs and lowers schedule compliance. In extreme circumstances, emergency maintenance can set an organization back days depending on the scope of the repair, available parts, and the asset’s level of importance. To reduce the amount of emergency maintenance that is both unplanned and unscheduled, organizations adopt various forms of proactive maintenance.
Corrective maintenance
Corrective maintenance is inherently part of emergency maintenance because, when there is an emergency, something needs corrected or fixed. In this way, corrective maintenance is mostly reactive. However, it can also be proactive. If an asset with a condition monitoring sensor detects an issue, a workorder is created and a technician is sent to correct it. Similarly, preventive maintenance is considered corrective maintenance if there is an issue to fix. This is rare though as PMs are often conducted when an asset is in good working order.
Other types of maintenance
Deferred maintenance
Deferred maintenance includes repairs and inspections that are put into a backlog due to limited budget and resources. While deferring maintenance saves money up front, the costs of not performing important maintenance compounds at 7% annually. Rising costs come from fines resulting from missed inspections and unscheduled downtime that brings production to a standstill. By far, deferred maintenance and emergency maintenance are the least desired types of maintenance.
Total productive maintenance
Total productive maintenance (TPM) is the broadest type of maintenance that targets more than the assets that need maintained. It also aims to improve employee satisfaction and overall morale in the workplace, specifically in manufacturing plants. TPM does this by increasing overall equipment effectiveness (OEE) and the amount of planned maintenance. More planned work means more workers have the resources they need to do their job, which means higher levels of satisfaction. TPM also leverages machine operators to participate in maintenance and take ownership of their equipment.
[Reference:, Types of Maintenance - Upkeep, CIPS study guide page 158-159, LO 3, AC 3.1]
