Reliability Centred Maintenance (RCM) analysis

Very often machinery preventive maintenance plans are far away from being cost effective at their optimum level. The main reason is that the preventive maintenance tasks are most of time based on manufacturer recommendations leading to 3 conflictual situations: 

  • On one hand, the recommendations are generally too conservative, so the tasks trend to be oversized compared to the real maintenance need.
  • On the other hand, some manufacturers, because of their lack of knowledge about the operational context, are not able to propose adequate maintenance task intervals and leave the entire responsibility to the operator to define the task interval whereas this last one has no knowledge about the equipment behavior.
  • And finally, manufacturers barely recommend predictive maintenance tasks which could contribute to a strategy that can considerably reduce maintenance costs.

Therefore, Tecnitas recommends operators to perform Reliability Centered Maintenance (RCM).

RCM  is a structured and logical decision making process which objectives are to determine the most effective pro-active maintenance tasks and frequencies to achieve the maximum inherent reliability available from a physical asset in its current operating context. The maintenance tasks can come from a number of different strategies depending upon failure modes and failure characteristics, and can be either: 

  • Predictive Maintenance ,
  • Preventive Maintenance,
  • Detective Maintenance , or
  • Corrective maintenance.

In addition, if a suitable pro-active maintenance task cannot be found, the RCM principles guide to a set of “default” actions (such as design modifications, new procedures, operational changes, product modifications, safeguard implementation…). 

For new built assets, RCM can be performed at the detailed design stage in order to assess the manufacturer recommendations and adapt the maintenance strategy to its future operational context, and also to forecast the maintenance requirements in terms of maintenance staff and spare parts. RCM at this stage can also identify the need for design modifications when preventive maintenance strategy is not effective to reduce the incident of a critical failure to an acceptable level.

For in service assets, the maintenance plan should be frequently reviewed, especially after the equipment guaranty period. The operator experience during this period is very useful to set a most appropriate maintenance strategy and task intervals taking into consideration the real equipment inherent reliability and degradation. A RCM revision is also important to be carried out because of the constant change of operational context and sometimes of some design modifications that must impact the current maintenance plan requirements and its effectiveness as well as the spare parts policy.