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Advanced Maintenance Strategies
by Kevan Slater, Trico Corporation 

For decades, industries have primarily relied on Preventive Maintenance (PM), which is time-based maintenance, and Corrective Maintenance (CM), which is merely fix it when it breaks. To remain competitive within the increasing global competition, companies targeted maintenance budgets to help the bottom line (profits). As a consequence of the reduced budgets, fewer maintenance resources remained available to complete the basic equipment care tasks resulting in increased equipment failures and the accompanying increased operating costs. Conversely, maintenance managers have always argued that to increase the level of availability and reliability of the equipment, more expenditure needs to be committed to the maintenance budget to perform the critical CM and PM activities.

This traditional maintenance view of balancing maintenance costs with equipment availability and reliability still remains a business strategy for many companies. With the on-set of substantial equipment availability requirements and rising costs, some management teams have realized that this strategy will not produce a cost effective solution.  In order to meet the competitive challenges in the manufacturing industry, a definite shift from historical maintenance practices to an advanced maintenance strategy is required. This desired maintenance program must be aimed to reduce maintenance costs while increasing the availability and reliability of our aging equipment.

The evolution to move an organization to an advanced strategy requires a systematic review and dedication to answer the following basic questions:

• How are the specific maintenance tasks accomplished?
  • Examination of the work process from work initiation, to parts scheduling, to work completion and ending with work closeout.
• Who will perform the maintenance tasks?
  • For any maintenance approach to be successful it requires a well-trained work force. Moving from a reactive (fixing what is broke) to a planned (preventing it from breaking) mindset requires fundamental change in work culture (management and staff), training requirements, and people skills for success.
• What advanced tools are to be used to perform maintenance and diagnostics tasks?  
  • There have been significant advancements in the technologies that can help an organization meet its goal of keeping the plant commercially available; and, for the most part, the plants require the latest tools.
• How will the organization learn from the experiences?
  • All past and future events (failures) must be reviewed by operations, maintenance, engineering and management to reduce or eliminate future maintenance work.

Understanding your organization and the following terms will assist in determining a maintenance strategy that could be implemented to meet your company’s requirements: 

• Equipment Criticality Ranking (ECR)

This strategy determines a numerical ranking of the plant assets (systems and equipment) according to their value to commercial availability, safety, environmental, cost and efficiency.

• Reliability Centered Maintenance (RCM)

This conceptual exercise identifies the most effective and applicable maintenance tasks for each piece of equipment. A full classical RCM study involves an exhaustive investigation of all failure modes and their effects. This approach, however, has now been streamlined by some organizations by investigating the common known failure modes and the analysis of the resultant effects, as well as the determination of effective and applicable maintenance tasks to address those modes.

• Corrective/Reactive Maintenance (CM)

Although it is critical to move beyond the reliance on Corrective Maintenance (i.e.…fire fighting, breakdown maintenance), there still exists a place for this strategy in the overall maintenance plan. Certain systems and assets simply lack the criticality to justify Preventive, Predictive, or Proactive action. The ECR approach helps to identify when this is the case, which prevents valuable resources to be used on these lower priority assets.

• Preventive Maintenance (PM)

Performing a task on a time or interval basis in an effort to avoid catastrophic failure is referred to as Preventive Maintenance. This strategy offers the efficiency of performing maintenance tasks on a planned rather than reactive basis, thus avoiding the losses associated with unplanned downtime. However, the penalty of PM is that many times maintenance is performed that is unnecessary and costly.

• Predictive Maintenance (PdM)

PdM relies on employing technologies to understand the current condition of equipment so that only the required maintenance is performed, and PdM tasks are performed on a planned basis. (vibration, oil analysis, infrared thermography, acoustics, etc.)

• Proactive Maintenance (PaM)

Any asset, whether being maintained using PM, PdM, or Reactive Maintenance, that continues to demonstrate unacceptable reliability should be considered a candidate for a PaM investigation. PaM is a study that determines the root cause of the problem. Chronic problems warrant the application of advanced technologies, additional resources, and time to fix the problem or reduce the occurrence.  These problems could be the result of poor design, maintenance, or operating procedures.

The emphasis on Predictive Maintenance (PdM) technologies has increased in recent years, at least in part due to advances in PdM technology. As well we must recognize the need to have a well-orchestrated blend of Predictive (PdM), Preventive (PM), Proactive (PaM), and Corrective maintenance (CM) strategies to improve plant reliability in a cost-effective manner. PdM focuses on the critical equipment of the plant. Critical in this case is defined as equipment that, if it fails to operate the unit will suffer a loss of production, or a failure results in a safety, environmental or a costly repair. Therefore, when implementing a PdM Program it is important to have a process that helps select the plant critical equipment. The ECR process ranks the plant systems, and then it ranks the equipment in each system. The initial PdM effort should focus on those highest ranked critical equipment that will remain manageable, and as the program matures it can be expanded.

Predictive Maintenance (PdM) is both a strategy and a process. It is a strategy designed to determine maintenance based on the condition of the equipment and then to plan work far enough into the future so that it minimizes the effect on production and commercial availability. Since PdM assists in determining the equipment condition, this approach also helps protect the equipment from failure. The approach of determining equipment condition and scheduling the work makes PdM a process. For PdM to be successfully implemented at a plant, it requires that it fits into and becomes a part of the work process. It cannot stand on its own as a separate or extra task, but must be fully integrated and be part of the work culture.

Proactive maintenance on the other hand is a process of learning from past maintenance problems in order to reduce future maintenance work and improve equipment reliability. Root cause analysis is a formal method to determine the most basic reason for a problem and recommend effective corrective actions. Root cause analysis is a natural part of the proactive maintenance process. PaM is a daily process that compliments the maintenance work process, and the predictive maintenance process. Three major steps in proactive maintenance are: review, analysis, and follow-up. The analysis step may or may not include formal root cause analysis.

Implementing any advanced maintenance strategy that focuses on how an organization identifies and accomplishes work while continuously learning from these activities is an effective way to achieve lower operating cost and higher equipment reliability. The process begins by introducing the concepts of an ideal maintenance program throughout the whole organization followed by an assessment of the existing maintenance process. Understanding the gaps, a development plan is created and executed to implement the required changes ensuring that all elements of the desired maintenance program are put into effect. Finally, an audit should be performed to evaluate how effective the program has been executed.