1、Best Practices Entry: Best Practice Info:a71 Committee Approval Date: 2000-03-20a71 Center Point of Contact: JSCa71 Submitted by: Wilson HarkinsSubject: Preventive Maintenance Strategies Using Reliability Centered Maintenance (RCM) Practice: Institute a Preventive Maintenance Program based upon curr
2、ent reliability-centered maintenance (RCM) techniques.Programs that Certify Usage: This practice has been used on Space Shuttle Orbiter.Center to Contact for Information: JSCImplementation Method: This Lesson Learned is based on Maintainability Technique number PM-4 from NASA Technical Memorandum 46
3、28, Recommended Techniques for Effective Maintainability.In the past, preventive maintenance was performed without any guidance or regard for safety or cost concerns, as long as systems performed their functions. The primary reason for the development of RCM was to implement a preventive maintenance
4、 strategy that could adequately address system availability and safety at the lowest possible cost. The RCM process answers and directs preventive maintenance decisions as to the what, where, and when types of questions.IntroductionIn the past, product development and manufacturing engineering domin
5、ated the technical disciplines Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-in the U.S. industrial community with operations and maintenance (O (2) a leak defined as a design basis leak (any loss beyond a certain gallon per minute value will produ
6、ce a negative effect on system function); or (3) a total loss of boundary integrity, which can be defined as a catastrophic loss of fluid and loss of function. In this example, a single function could lead to three distinct functional failures.The key to the failure identification feature is to iden
7、tify the specific failure modes in specific components that can potentially produce those unwanted functional failures.Enables Prioritization of Failure Modes. In preserving system function, RCM provides a systematic approach to deciding what priority must be assigned to budget and resource allocati
8、ons. Since functional failures and their related failure modes are as diverse as the functions and components they affect, the prioritization of failure modes is essential.Allows Preventive Maintenance Tasks To Be Judged As To Applicability and Effectiveness. The features described above help in dev
9、eloping a very specific roadmap to the where and why, of the maintenance task and the priority that should be assigned to it. Each potential task must then be judged as to (1) its applicability (i.e., will it prevent or mitigate a failure, detect the onset of a failure, or discover a hidden failure)
10、 and (2) its effectiveness (i.e., does it justify the spending of resources to do it).Generally, if more than one candidate task is judged to be applicable and effective, the least expensive task will be selected. If a task fails either the applicability or effectiveness test, a run-to failure decis
11、ion must be made.Cost-Benefit Considerations. The primary force behind the invention of RCM was the need to develop a preventive maintenance strategy that could adequately address system availability and safety without creating a totally impractical cost requirement. Figure 2 illustrates the success
12、 of keeping commercial aircraft maintenance cost per flight hour constant from the late 1960s to the early 1980s.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-refer to D descriptionD Table 1 presents another way to view the impact of RCM on the com
13、mercial aircraft world.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-refer to D descriptionD Two significant points can be observed from these data: (1) the dramatic shift in the reduction of Provided by IHSNot for ResaleNo reproduction or networki
14、ng permitted without license from IHS-,-,-costly component overhauls during the pre-1964 and post-1960/1987 periods; and (2) the constancy of the condition-directed task structure. The reduction in expensive component overhauls, brought about by run-to-failure decisions, was made possible by a desig
15、n philosophy that included double and triple structural design redundancy in the flight-critical functions. RCM was used to take advantage of these structural design features when preventive maintenance was critical and the run-to-failure decision was appropriate.The constancy of the condition-direc
16、ted task structure is attributed to the fact that the commercial aircraft industry was one of the early users of performance and diagnostic monitoring as a preventive maintenance tool. It has continued to successfully apply this practice throughout the generation of the newer jet aircraft.The result
17、s indicated in figure 2 and table 1 have led to a growing interest in other such areas as nuclear power generation and electric utility plants. The obvious reasons for this growing interest are (1) control and reduction of O&M costs and (2) increase in plant availability. All of this indicates that
18、the cost-reduction benefits of RCM that dramatically impacted commercial aviation offer similar potential dramatic payoffs in other areas in which complex plants and systems are routinely operated.ConclusionRCM is a logical approach to preventive maintenance which does not rely on any heuristic proc
19、esses. RCM helps in making direct and deliberate preventive maintenance decisions that were not previously possible. It can also be used as the methodology for defining preventive maintenance for a such new systems as the Space Station. Virtually every organization that has conducted an RCM program
20、has recognized the value of the system analysis process as a training ground for system engineers. In addition, the failure scenarios developed in RCM analyses may be used beneficially as simulator inputs to plant transient or upset conditions in order to anticipate such occurrences in the future.Re
21、ferences1. Annual Reliability and Maintainability Symposium, 1991 Proceedings.2. Matteson, Thomas D., “The Origin of Reliability-Centered Maintenance,“ Proceedings of the Sixth International Maintenance Conference, Institute of Industrial Engineers, October 1989.3. “Reliability-Centered Maintenance
22、for Aircraft Engines and Equipment,“ MIL-STD-1843, February 8, 1985.4. “RCM Cost-Benefits Evaluation,“ Electric Power Research Institute, Interim EPRI Report, January 1992.Impact of Non-Practice: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-RCM is
23、 the best approach to developing the preventive maintenance program for a new system. It provides a step-by-step approach, prioritizes preventive maintenance tasks, and optimizes the repair cost.Related Practices: N/AAdditional Info: Approval Info: a71 Approval Date: 2000-03-20a71 Approval Name: Eric Raynora71 Approval Organization: QSa71 Approval Phone Number: 202-358-4738Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
