Maintenance strategy

Maintenance strategy is often explained as a decision rule that has to determine the order of necessary actions which should be performed in order to keep the system which we are using in the company working properly. It provides information about scheduling and it can be assigned to as many tasks (for example project manager's tasks) as needed. Maintenance strategies are meant to improve quality and productivity while reducing costs of operations.

Common maintenance strategies

Maintenance strategies fall into one of three types: corrective (reactive), predictive and preventive.

Most common maintenance strategies are: run to breakdown, time-based maintenance and condition based maintenance.

• Run to breakdown maintenance (RTB, also called run to failure or failure ending maintenance) - allowing operations to run until they fail. Maintenance work is only performed after failure has taken place. This strategy is often implemented when breakdown has minor impact and/or is easy to repair.
• Time-based Maintenance (TBM) - scheduling work to reduce failure chances. This strategy is useful when operation has to run continuously and error-prone in given periods of time and maintenance may be undertaken in idle time. Other important factor in choosing PM strategy may be low maintenance cost compared to failure impact.
• Condition-based maintenance (CBM) - monitoring characteristics of operation to plan maintenance when failure is imminent. CBM can be used in operations where breakdown can be predicted and it's cost is high. The latter might be true in cases where failure would mean disruption to critical operation or when maintenance itself is expensive.

System or operation might use few maintenance strategies at the same time. A car mixes all three approaches. Replacing light bulbs usually happens when they fail (RTB), engine oil should be changed regularly (PM) while many components might have an indicator when they start to exhibit unusual behavior (CBM).

Choosing maintenance strategy

When choosing maintenance strategies, different factors must be considered. All maintenance strategies must have defined parameters to allow continuity of operations and risk management. Economical factors in choosing maintenance planning are crucial. This should especially include costs of both repair and downtime in case of failure. Evaluating consequences (economical, environmental, safety, etc.) of failure is useful in answering how important it is to prevent failure from happening. Knowing probability of failure is useful to adjust maintenance schedule. Time-related parameters help to define maintenance strategy. Time horizon might be distance in future to maintenance or intervals between consecutive tasks. Shift factor is allowed deviation from time horizon.

Risk-based maintenance

One of the most important tools in maintenance planning is risk-based maintenance (RBM). It is methodology which tries to minimize effort and cost of maintenance while choosing effective strategy. Risk is calculated as a product of probability and consequence of failure. Any given area of operation is rated by its risk factor. Then all values are juxtaposed and priotizations might be assessed. This tool is very useful for preventive maintenance planning. There are many variants of RBM. Risk-based methodology, while simple in concept, requires in-depth risk analysis and different techniques might used to perform it. It must be noted that risk values are always subjective and prioritizations based on this approach are debatable.

Examples of Maintenance strategy

• Preventive Maintenance: Preventive maintenance is a strategy that involves regularly scheduled inspections, tests, servicing, and replacements of necessary components and parts, before they actually fail or malfunction. This helps to avoid unplanned downtime and equipment failure.
• Predictive Maintenance: Predictive maintenance is a strategy that uses sensors and other diagnostic technologies to monitor the performance of equipment and anticipate potential problems. It allows for proactive maintenance, which can help to reduce the costs associated with unplanned downtime.
• Condition-Based Maintenance: Condition-based maintenance is a strategy that focuses on the actual condition of the equipment, rather than on a predetermined schedule. It can be used in conjunction with predictive maintenance to help identify potential problems with equipment before they become serious.
• Reliability-Centered Maintenance: Reliability-centered maintenance is a strategy that focuses on maximizing the reliability and availability of equipment. This strategy involves analyzing the criticality of components, determining the right maintenance strategy for each component, and allocating maintenance resources accordingly.

Advantages of Maintenance strategy

• Maintenance strategies help to reduce costs of operations by allowing the company to identify and prioritize necessary repairs and maintenance tasks.
• It also provides an easy-to-follow framework for efficient management of resources and personnel.
• Maintenance strategies ensure that all required maintenance tasks are completed in a timely manner, reducing the risk of operational failure or downtime.
• They provide a systematic approach to preventative maintenance, reducing the cost of repairs and increasing the lifespan of equipment.
• They also help to maintain the quality of equipment and services, ensuring that the company remains compliant with industry standards.
• Maintenance strategies can also help to identify potential problems before they become too costly or damaging to the business.

Limitations of Maintenance strategy

• Maintenance strategies can be difficult to implement and maintain, as they require specialized knowledge and skills.
• Maintenance strategies are often costly and require significant resources to implement and maintain.
• Maintenance strategies may not be able to keep up with changes in technology or customer needs over time, leading to obsolescence.
• Maintenance strategies are often limited in scope, meaning they may not address all aspects of a system or process.
• Maintenance strategies may be inflexible, meaning they may not be able to adjust to changing conditions or requirements.
• Maintenance strategies may not be suitable for all types of systems or processes, meaning that different strategies may need to be developed for different types of systems or processes.

Other approaches related to Maintenance strategy

In addition to Maintenance strategy, there are several other approaches related to maintenance management:

• Failure-based maintenance: This approach focuses on minimizing the effects of failure and identifying potential threats to the system before they occur. It includes preventive maintenance, predictive maintenance and corrective maintenance.
• Condition-based maintenance: This approach focuses on monitoring the condition of the system and replacing or repairing components when necessary. This method relies on condition monitoring techniques such as vibration analysis, temperature monitoring and infrared imaging.
• Reliability-centered maintenance: This approach focuses on improving the reliability of the system by identifying and eliminating sources of failure. It includes root cause analysis, failure modes and effects analysis and system modeling.
• Scheduled-based maintenance: This approach focuses on scheduling maintenance activities based on predetermined criteria such as time, usage or environmental conditions.

Overall, Maintenance strategy is an important approach for maintenance management that focuses on determining the necessary actions for keeping the system working properly, improving quality and productivity, and reducing operational costs. Other approaches such as failure-based, condition-based, reliability-centered and scheduled-based maintenance are also important for maintaining the system in a safe and efficient manner.

Maintenance strategy — recommended articles

Failure Mode and Effects Analysis — Overall equipment effectiveness — Quality loss function — PFMEA — Line balancing — Zero defects — Types of control system — Visual inspection — System safety

References

• Aghezzafa, E.H., Jamalib M.A., Ait-Kadi D. (2007), An integrated production and preventive maintenance planning model, "European Journal of Operational Research", vol. 181
• Ahmad, R., Kamaruddin, S. (2012) An overview of time-based and condition-based maintenance in industrial application, "Computers & Industrial Engineering", volume 63
• Arunraj, N.S., Maiti, J. (2007), Risk-based maintenance—Techniques and applications , "Journal of Hazardous Materials", vol. 142
• Bagleea, D., Jantunen, E. (2014), Can Equipment Failure Modes Support the Use of a Condition Based Maintenance Strategy?, "Procedia CIRP", vol 22
• Bechtel, J., Ganesan, S., Prajapati, A. (2012) Condition based maintenance: a survey, "Journal of Quality in Maintenance Engineering"
• Kelly, A. (2000), Maintenance Strategy: Business-centred Maintenance, Butterworth-Heinemann, University of Surrey, Guildford, UK
• Khan, F. I., Haddara, M. H. (2003), Risk-based maintenance (RBM): a quantitative approach for maintenance/inspection scheduling and planning, "Journal of Loss Prevention in the Process Industries", vol. 16
• Najim K., Ikonen E., A. K. Daoud (2006), Stochastic Processes: Estimation, Optimization & Analysis, "Automatica", vol 42
• Slack, N., Chambers S., Johnston R. (2007), Operations Management 5th edition, Prentice Hall, Harlow, UK
• Swanson, L. (2001), Linking maintenance strategies to performance, "Int. J. Production Economics", vol. 70

Author: Karolina Próchniak