Asset Maintenance Programs

There are many benefits to equipment longevity when attention is paid to practices.  Four types of maintenance and culture tips are highlighted.

Maintenance practices vary across industry, ranging from close attention to maintenance schedules to general disregard beyond breakdown maintenance.  Improving maintenance practices translates into bottom-line benefits such as reduced wear on equipment and increased production.  However, the cultural attitude toward maintenance practices impacts how a company performs in terms of both saving money and having productive, well-maintained equipment.

Four Types of Maintenance

Four general types of maintenance have been identified: reactive, preventive, predictive and proactive.

1. Reactive maintenance.  Reactive or breakdown maintenance is repairing equipment when something breaks or when time is available.  As an example, this can mean oil changes happening well past the recommended intervals.  Reactive maintenance, or run-to-failure approaches, costs less in the short term because there is no investment in plant maintenance.  However, studies have found this approach to maintenance costs two to five times as much as proactive maintenance.  One reason for these high costs is that unplanned repairs can cost significantly more when they involve downtime, lost production, safety and environmental risks.  Complex repairs are expensive both in terms of the repair itself and in terms of missed deadlines for customer orders.  Facilities using this approach tend to have short mean time between stoppage (MTBS) metrics.  While reactive maintenance is appropriate when parts are inexpensive and simple to replace (eg., lightbulbs), a more aggressive maintenance approach can significantly improve a company’s profit and loss.
2. Preventive maintenance.  Preventive maintenance is scheduled, or interval-based, maintenance intended to lessen the likelihood of equipment failing.  While this approach is generally better than reactive maintenance, it still can cost more in the long term than other approaches that more closely assess when maintenance is actually needed.
3. Predictive maintenance.  Predictive or condition-based maintenance uses sample data to allow for coordinating maintenance programs to predict and respond to equipment failures before they occur.  The benefits of this approach include minimizing equipment downtime while also reducing maintenance costs by eliminating unnecessary scheduled maintenance.  The key is performing the right tests on the right equipment at the right time to predict when maintenance is needed.  Additionally, predictive maintenance tends to be non-invasive, allowing equipment to continue operating.  This approach requires equipment to be monitored with as little of a break in maintenance as possible.  Longer times between stoppages and improved equipment life might result in higher service costs; however, these costs are more than countered by improved productivity from well-maintained equipment.
4. Proactive maintenance.  In contrast, proactive maintenance aims to anticipate and manage equipment failures before they occur.  By determining the root causes of failures, these failures can be eliminated or managed to improve plant efficiency while eliminating unneeded service.  The optimal maintenance strategy can be identified through using sensors to collect vibrational or temperature data, which can allow for prediction of impending equipment failures so time isn’t wasted performing unnecessary service.  Proactive maintenance involves the use of processes like root cause analysis and failure mode and effect analysis (FMEA) to determine why an asset failed so that the cause might be eliminated and risk can be managed effectively.  Some aspects of predictive technologies also can be used to identify the presence of failure root causes prior to equipment damage taking place.  Properly using these technologies and taking appropriate action prior to equipment damage falls into the proactive domain.  The McKinsey Global Institute has estimated that proactive maintenance can lead to a 10% to 40% reduction in costs, up to a 50% reduction in downtime and 3% to 5% lower equipment and capital investment costs through extending machine life.  By deciding when preventive maintenance makes sense, asset life is extended, while the need for major repairs is minimized, allowing assets to work harder and boosting their contributions to earnings.  Spending money wisely on effective maintenance can pay through better running equipment that runs longer and does more work than equipment that is frequently broken.  In other words, less money spent on purchasing new parts and equipment and more time running that equipment translates to a more efficient operation with fewer operating expenses.