Evaluating different maintenance management strategies

Common maintenance management strategies

Outlined below are the more widely used maintenance management strategies, as well as their pros and cons and situations when they are best applied. Typically we see plants employing either run-to-failure (only fix after a breakdown) or preventive maintenance (on a predetermined schedule). However, depending on the value of the asset or its criticality in the plant’s operations, we may see this strategy escalated to predictive or even RCM-based maintenance.

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Table of contents

• Common maintenance management strategies
• Run-to-failure (breakdown maintenance)
• Preventive (scheduled) maintenance (PM)
• Predictive maintenance (PdM)
• Reliability centred maintenance (RCM)

Run-to-failure (breakdown maintenance)

What is run-to-failure maintenance?

In run-to-failure maintenance, assets are deliberately allowed to operate until they break down, at which point maintenance is performed. No maintenance is performed before then. A plan is in place ahead of failure, so the asset can be fixed without causing production issues.

Advantages of run-to-failure maintenance

Advantages of run-to-failure maintenance include:

• Minimal time spent planning and maintaining
• The simplicity of implementation

Disadvantages of run-to-failure maintenance

Disadvantages of run-to-failure maintenance include:

• Unpredictability and inconsistency of maintenance tasks and scheduling
• Higher maintenance and inventory costs

When to use run-to-failure maintenance

Use when the total cost of repairs after breakdown is less than the cost of performing maintenance beforehand. Use for redundant, non-critical assets that pose no safety risks. Equipment is fixed until it costs less to replace it.

Requires an understanding of how an asset might break and consequences. An example is the plan for a light bulb. The bulb operates until failure and is then fixed.

Preventive (scheduled) maintenance (PM)

What is preventive maintenance?

Preventive maintenance is maintenance regularly performed on an asset to reduce the likelihood of it failing. It is performed while the asset is still working so that it doesn’t break unexpectedly. It is scheduled on a time or usage based trigger.

Advantages of preventive maintenance

Advantages of preventive maintenance include:

• Lower overhead costs, time commitments, production delays and accidents compared to unplanned maintenance
• Less expensive investments in technology, labour and data analysis compared to more complex systems

Disadvantages of preventive maintenance

Disadvantages of preventive maintenance include:

• Investing more time and resources in the planning stage compared to less complex systems
• The risk of conducting too much or too little maintenance and limiting efficiency across an operation

When to use preventive maintenance

Preventive maintenance should be used on assets that have a critical operational function, failure modes that can be prevented with regular maintenance and have a likelihood of failure that increases with time or use. An example of this strategy is scheduling maintenance for a conveyor belt on the first Monday of every month or after every 500 hours of operation.

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Predictive maintenance (PdM)

What is predictive maintenance?

Predictive maintenance aims to predict when asset failure might occur and prevents the failure by scheduling maintenance. It keeps maintenance frequency low and reliability high. Possible failure is identified with monitoring equipment linked to software or through visual inspections.

Advantages of predictive maintenance

Advantages of predictive maintenance include:

• Cost savings on labour
• Higher production rates
• More insight into the performance and potential issues of assets

Disadvantages of predictive maintenance

Disadvantages of predictive maintenance include:

• A more costly upfront investment in technology, labour and skill
• Not all assets can be cost-effectively maintained using preventive maintenance

When to use predictive maintenance

Use predictive maintenance on assets that have a critical operational function and that have failure modes that can be cost-effectively predicted with regular monitoring. An example includes being able to monitor if a conveyor belt drops below a certain speed, which will trigger a work order.

Find, analyze, and plan for failure in all your assets with this FMEA template

Reliability centred maintenance (RCM)

What is reliability centred maintenance?

Reliability centred maintenance is an in-depth, highly involved process that seeks to analyze all the possible failure modes for each piece of equipment, and customize a maintenance strategy for each individual machine.

Advantages of reliability centred maintenance

The advantages of implementing reliability centred maintenance include:

• Increased equipment availability
• Reduction in costs for maintenance and resources

Disadvantages of reliability centred maintenance

Disadvantages of reliability centred maintenance include:

• It is often considered too complex and costly for many facilities to implement with the exception of large, experienced, enterprise-level organizations

When to use reliability centred maintenance

Reliability centred maintenance should be used on critical assets with identifiable failure modes that affect system function and can be controlled. It should be used after mastering other maintenance strategies and when facilities can invest required time, money and resources to implement.