In brief
Reliability-centred maintenance (RCM) is a method that determines the appropriate maintenance strategy for each plant function on the basis of its failure consequences.
Contents
What is Reliability-centred maintenance?
RCM was originally developed in civil aviation and later transferred to industrial plants. Instead of servicing all components at fixed intervals, RCM asks what function a plant is meant to perform, how it can fail and what consequences a failure has for safety, the environment, production and costs.
The process follows a fixed sequence of questions: functions and performance standards, functional failures, failure modes, failure effects and consequences, possible preventive tasks and default actions where no suitable preventive task exists. This results in a strategy for each failure mode, such as condition monitoring, scheduled replacement, functional testing, design modification or deliberate run-to-failure. Criteria for RCM processes are described, for example, in the SAE JA1011 standard; FMEA is methodologically closely related.
RCM provides valuable results for spare parts planning: where parts are replaced on schedule, demand is predictable; where equipment is run to failure, the part must be in stock or quickly obtainable if the consequences are critical.
In practice: maintenance and procurement
RCM analyses are particularly worthwhile for critical plants with high failure consequences. The results should be transferred directly into maintenance plans and stockholding decisions so that each strategy also has the right spare parts in stock.
Synonyms and abbreviations: RCM · reliability-centered maintenance · RCM analysis · reliability-based maintenance
Frequently asked questions
What is the difference between RCM and TPM?
RCM is an analysis method that determines the technically and economically appropriate maintenance strategy for each failure mode. TPM is a comprehensive management concept that involves operators in maintenance and aims to reduce losses throughout production. The two are not mutually exclusive: RCM can be used within a TPM programme for critical plants.
What questions does RCM ask?
RCM works with seven key questions: what are the functions of the plant, in what ways can it fail to fulfil them, what causes each functional failure, what happens when it occurs, what are its consequences, what can be done to prevent it and what should be done if no suitable preventive task is possible. The answers are documented for each failure mode.
For which plants is RCM worthwhile?
RCM is laborious and requires expertise from operations, maintenance and engineering. It is particularly worthwhile for plants whose failure affects safety, the environment or large parts of production, such as bottleneck machines, utility plants or process plants. For simple, redundant or non-critical equipment, a simplified criticality assessment is often sufficient.
What does run-to-failure mean in RCM?
Run-to-failure means deliberately operating a component until it fails, because prevention would be more expensive than the consequences of the failure. This only makes sense if the failure has no safety or environmental consequences. To keep the downtime short, the spare part and replacement procedure should nevertheless be prepared.