# Reliability and Risk Centered Maintenance: A Novel Method for Supporting Maintenance Management
## 3 The Proposed RRCM Method
### Maintenance Plan Definition and Implementation  
The first RRCM process, the Maintenance Plan Definition and Implementation, comprises ten steps, as shown in Figure 2. Steps 1 to 5, briefly described below, comprise a series of activities that are also covered in a traditional RCM [13]. The first step consists of the simple selection of all items, e.g., physical assets, that will be studied and that will have their maintenance plans determined by the method individually. Due to the increasing complexity and number of items in modern engineering systems, some techniques can support this definition to be carried out in an organized and structured way, such as the Functional Tree or a Block Definition Diagram. In general, organizing assets into systems and subsystems and presenting them in a tree-like structure can help to define the items that will be analyzed. It is worth noting, therefore, that the RRCM does not require or define a specific technique for selecting items and is capable of being executed even with the one that is eventually used by any organization. The second step is the definition of the functions performed by each of the previously selected items. The functions of a given physical asset represent what its owner wants it to do, including issues of protection, control, appearance, structural integrity, and other secondary aspects. After determining the functions of an item, it is possible to define the functional failures for each function in the third step. Then, in step four, the effects that each identified functional failure can have on the system, people, and the environment need to be defined. Finally, in step five, the failure modes that can cause each listed functional failure also need to be identified. From the sixth step, the RRCM starts to distance itself from the traditional RCM. Here, the risk associated with the eventual occurrence of each failure mode shall be evaluated, which will be used in the next step to determine a recommended maintenance policy. There are several techniques used for risk assessment, which in general quantify both the severity of the impact and the probability of occurrence of the uncertain event (in this case, the failure mode) and classify it in a risk category. Such quantification and classification shall be designed following the organizational objectives and context. Although the RRCM does not require the use of a specific technique for risk classification of the failure modes, it requires that it be classified into five possible risk levels: very high, high, medium, low, and very low. By postulating that risk assessment should be limited to these five categories, the proposed method can properly prioritize failure management policies according to each Failure Mode Risk Level (FMRL) to ensure reliability while considering the costs. Once the risk level of each failure mode has been determined, the seventh step of the RRCM method determines a tailored failure management policy for each of them. Each failure management policy comprises guidelines for each type of maintenance task that can be used for failure mode control and mitigation. There are proposed seven possible failure management policies:* On-condition: it recommends the continuous monitoring of the physical asset condition, for instance through online measurements or periodic inspection routes.