Preventive vs. Corrective Maintenance

What’s the Difference?

• Preventive Maintenance (PM): This type of maintenance is performed according to a scheduled routine to reduce the chance of failures. It is often time or usage-based (e.g., replacing parts after a certain number of operating hours).
• Corrective Maintenance (CM): This maintenance is performed after a failure or malfunction. It is reactive in nature and often more expensive due to possible downtime and unplanned costs.

The KPI is often expressed as a ratio, such as a percentage of total maintenance. The formula may be presented as:

Example:

If a company spends €50,000 on maintenance in a month, with €30,000 on preventive maintenance and €20,000 on corrective maintenance, the preventive vs. corrective maintenance ratio is calculated as:

• Preventive Maintenance Percentage:

• Corrective Maintenance Percentage:

This means 60% of maintenance costs were preventive, and 40% were corrective.

• Higher Preventive Maintenance Share: 
  • Reliability: A higher percentage of preventive maintenance usually leads to higher system reliability because failures are detected and addressed before they occur.
  • Lower Costs: Preventive maintenance is often less costly than corrective maintenance because unexpected failures and their associated repair costs are avoided. Furthermore, systems are more efficiently managed, resulting in less downtime.
  • Longer Lifespan: Preventive maintenance extends asset lifespan, leading to lower replacement costs in the long term.
• Higher Corrective Maintenance Share: 
  • Higher Costs: Corrective maintenance is typically more expensive due to the frequent occurrence of unexpected failures and prolonged downtime. There may also be additional costs like production or operational losses.
  • Lower Reliability: A larger share of corrective maintenance often indicates a lack of effective preventive maintenance or planning, leading to less reliable system operation.

• Maintenance Strategy Optimization: By tracking this KPI, companies can optimize their maintenance strategies. Shifting toward more preventive maintenance can reduce overall maintenance costs and improve operational efficiency.
• Cost-Effectiveness and Budget Management: Companies can try to improve the ratio by investing more in preventive maintenance, thereby reducing long-term costs.
• Better Resource Planning: A greater focus on preventive maintenance allows for better planning and distribution of maintenance tasks, reducing unexpected downtime and production interruptions.

This KPI is critical for businesses seeking a balanced and cost-efficient maintenance strategy focused on minimizing downtime and optimizing asset performance.