Adopting Reliability Strategies

Daniel Penn - Article

The Case for Adopting Reliability Strategies for Achieving Equipment Maintenance Excellence

by Steve Mueller, Director of Operations

History Lesson

The strategic options available to maintenance managers for improving equipment effectiveness and reliability have expanded from the purely reactive Repair on Failure in the early part of the century, through Preventive Maintenance (PM) in the 1950’s and Predictive Maintenance (PdM) in the 1970’s, to fully proactive Reliability Centered Maintenance (RCM) and Total Preventive Maintenance (TPM) along with other conceptual advances in reliability engineering in recent decades. Maintenance managers now have tools and strategies at their disposal to keep pace with the parallel strategic leaps made on the production side of the house such as just-in-time (JIT), total quality management (TQM) and other strategies for continuous improvement.

What was the impetus for the strategic leap to RCM and related practices? RCM has its roots in the airline industry in the 1960s. It arose in response to a combination of rapidly rising maintenance costs, poor availability and the recognition that traditional time-based PM tactics had little effect on the overall effectiveness of complex equipment (unless it failed frequently) and that the effectiveness of many types of equipment did not respond to any form of scheduled maintenance.

The solution was the development of a strategy for improving reliability that recognized 1) maintenance is a key function in helping a company achieve its goals, not just a necessary evil, and 2) reliability increases when maintenance is approached from a multidisciplinary perspective that integrates maintenance, production, materials and engineering in the creation of a comprehensive, logical strategy that reduces redundancy, institutes condition-based rather than time-based tactics, and accepts operate-to-failure where appropriate. The key is to recognize which tactic is most likely to improve reliability for which piece of equipment.


Current RCM processes, such as Daniel Penn Associate’s (DPA) Reliability Risk Analysis (RRA) or FMECA (Failure Modes, Effects and Criticality Analysis) address the issue through a structured process applied to each selected asset to answer such basic questions as:

What is likely to fail?

  • How will it fail?
  • Why will it fail?
  • What should be done to either prevent the failure or respond if failure cannot be prevented?
  • This process can also address the costs and consequences of failure as well as the savings that will accrue from executing the resulting recommended maintenance tactics.

The RRA technical strategy is concerned with the technical aspects of maintenance and specifies how technical knowledge and experience are used to:

  • Identify the best proactive strategies to maintenance, repair, service, and replacement involving all maintainable items
  • Implement the chosen maintenance approaches

A key objective of the technical strategy is to minimize emergency or breakdown maintenance. This is achieved only through the reliability attained in the equipment and the ability to restore it to a state in which it can perform its required function. The RRA process is designed to identify a high percentage of the most significant and costly failures. RRA is focused on identifying maintenance tasks aimed at the prevention or early detection and mitigation of repeat equipment failures to close the gap in your reliability effort. Some tasks may also aid in detecting and preventing unanticipated first time component failures.

RRA allows a plant maintenance organization to focus resources on the important systems to support plant safety and production functions. This focus provides the greatest impact on the plant’s maintenance costs, productivity and quality. The benefits of a reliability-centered approach to equipment maintenance include:

  • Higher plant availability (uptime)
  • Reduced scheduled maintenance
  • Elimination of chronic failures
  • Improved Safety
  • Improved and consistent product quality
  • Increased life for expensive equipment
  • Improved administration of contract maintenance
  • Compliance with regulatory requirements (eg. FDA)
  • Less disruption of production due to unplanned downtime


There is every reason to believe the improvement trend in equipment diagnostic tools for conditioned-based maintenance (CBM) and computerized maintenance management systems (CMMS) will continue. Companies will be more and more dependent on the ability of maintenance to deliver equipment effectiveness (OEE) and consistent product quality. Maintenance managers have more options than ever before to help their companies achieve their goals.

DPA recognizes the crucial role of reliability-centered maintenance in helping maintenance managers fulfill their role in reducing cost and improving reliability. To help you recognize some of your own opportunities for eliminating cost and improving reliability, we offer some general maintenance best practice benchmarks* (all of which affect or are affected by reliability). How does your organization compare?

  • 100% of the required reliability level is reached 100% of the time.
  • 100% of a maintenance person’s time is covered by a work order.
  • OEE exceeds 65%.
  • 90% of work orders are generated by preventive maintenance inspections.
  • 90% compliance of planned/scheduled work.
  • 65:35 Planned to Unplanned hours ratio
  • Spare parts stockouts are rare (less than one per month).
  • Overtime is less than 2% of total maintenance time.
  • Supervision:Craft:Support – 1:15:2
  • Maintenance costs are within 2% of budget.
  • Maintenance Cost/Equipment Replacement Value is a common overall measure. 1 to 2.5% is World-class.

A comparison to these metrics will suggest your organization’s opportunities for improvement. Closing the gap between where your organization is today and where you need to be tomorrow based on this comparison is not an easy journey and a subject for another article. Any questions or comments, write me at