# Reliability and Risk Centered Maintenance: A Novel Method for Supporting Maintenance Management
## 3 The Proposed RRCM Method
### Maintenance Plan Definition and Implementation
In this policy, maintenance tasks are scheduled and performed only when there are signs of degradation that indicate the future occurrence of the failure mode;
* Scheduled restoration or replacement: it recommends preventive maintenance as it comprises a set of pre-scheduled periodic maintenance tasks of replacement or restoration of the item, regardless of its condition, to avoid the occurrence of the failure mode;
* Combination of tasks: it recommends a combination of on-condition and scheduled restoration or replacement tasks;
* Failure finding: it recommends a set of periodic maintenance tasks that seek to verify the occurrence of a hidden failure mode, i.e., a failure mode not perceptible to the system operators;
* No scheduled task; run to failure: it recommends that maintenance tasks only intervene in the physical asset when the failure mode occurs, i.e., when the item does not perform at least one of its functions;
* No scheduled task; redesign may be desirable: it includes a consideration to be made by the maintenance team about a possible update or modification in the physical asset. It is a one-time task to allow other types of policies to be used or to reduce the risk associated with the occurrence of the failure mode;
* Redesign is mandatory: it indicates that none of the previous failure management policies can effectively reduce the risk associated with the failure mode, requiring, therefore, that an asset redesign is carried out to make the risk acceptable according to organizational objectives. To determine the appropriate failure management policy for each of the failure modes, five decision diagrams are used to support the decision-making based on their corresponding FMRL as input, as presented in Figures 3-7. For instance, if a given failure mode was classified as a very high FMRL in step 6, the questions presented in Figure 3 shall be properly answered to determine which of the possible seven failure management policies is the most appropriate. Figure 3: Diagram for determining failure management policy for a very high FMRL. Figure 4: Diagram for determining failure management policy for a high FMRL. Figure 5: Diagram for determining failure management policy for a medium FMRL. It is worth noting that in the previous decision diagrams, the on-condition tasks, scheduled restoration or replacement, and failure-finding policies are always confronted as to their applicability, technical feasibility, and effectiveness. For that, Figure 8 provides support to properly interpret these three criteria according to each policy. This represents an advancement of the proposed method when compared to traditional RCM standards that lack further discussion and guidance on these criteria, which can lead to dubious interpretations and implementation barriers. Once the fault management policies have been determined, step 8 requires the determination of the maintenance tasks corresponding to them. These tasks will integrate the maintenance plans that may also include the necessary manpower, spare parts, and tools, the associated costs, and their periodicity. The derived maintenance plans shall then be validated through a management review, in step 9, which will verify if they meet the cost and labor requirements, and if it has the potential to address the risks associated with the failure modes analyzed. Once approved, the maintenance plans can be implemented as in step 10. However, if they are not approved, step 7 shall be revisited to make adjustments to the previously determined plans based on the feedback provided by management. Figure 6: Diagram for determining failure management policy for a low FMRL. Figure 7: Diagram for determining failure management policy for a very low FMRL.