# Reliability and Risk Centered Maintenance: A Novel Method for Supporting Maintenance Management
## 2 RCM and RBM Methods as Support for Maintenance  
Maintenance management is responsible for defining its maintenance strategies following its main objectives such as ensuring the reliability of a physical asset to perform its function as required at optimum costs, considering the safety aspects and the impacts on the environment, and upholding the quality of the product or service provided by the organization [19]. However, this is far from simple and has been challenging managers as well as driving the evolution of maintenance over the years. In response, RCM and RBM were methods developed to support the thriving in maintenance management. As a process used to determine the maintenance requirements of any physical asset in its operating context [6], RCM is a traditional method that has supported maintenance planning for over 40 years. Currently, it is covered by different technical standards and guidelines [13; 20; 21; 22] that lead organizations toward success in their application as well as corroborate the importance of the methodology. Nevertheless, the RCM does not appear to have evolved significantly since its conception despite increasing maintenance challenges. To better understand the subject, a literature review was carried out in August 2023 on the Web of Science Core Collection and IEEE Xplore, two of the most relevant scientific production databases. Documents with both the terms \"RCM\" or \"Reliability-Centered Maintenance\" and \"maintenance\" in their title, abstract, or keywords were searched in the database. Furthermore, the document type and search period fields were not restricted to identifying all types of publications throughout the database coverage time. This search protocol returned a total of 1124 distinct documents, aggregated from both databases, as shown in the publication trend in Figure 1.  
The first document identified dates from 1978 and it relates to the origin of the RCM with the report developed by [PERSON] and [PERSON] commissioned by the U.S. Department of Defense [11]. Beyond the aviation sector, in the late 1980s, the first documents advocated the use of RCM for the effective determination of maintenance plans as they impact preventing unscheduled downtime is a major concern in complex facilities such as nuclear power plants [23; 24]. Although publications on the RCM began to be more present in the late 90s, followed by an increasing trend, the number of published documents is still considerably low. In addition, the literature has not shown any tendency to modify the methodology since the standards emerged in the early 2008, focusing mostly on the application of the RCM to different industry sectors through case studies [25; 26; 27; 28]. In parallel with the diffusion of RCM, the risk-based strategy through the RBM method had its first publication in the late 1990s [29; 30]. Since then, it has progressively expanded into the field of maintenance. Recently, RBM has gained greater interest and, in the last five years, has accounted for around two-thirds of the published RCM documents. This can be evidenced by the result of the literature review, which also searched for the terms \"RBM\" or \"Risk-Based Maintenance\" and \"maintenance\" in their title, abstract, or keywords on the Web of Science Core Collection and IEEE Xplore in a second search protocol in August 2023. This search protocol returned a total of 347 distinct documents, condensed from both databases, as shown in Figure 1.  
Different risk-based approaches from the 1990s already indicated a trend to use risk as a criterion to plan maintenance tasks [31]. By reducing the likelihood and/or consequence of equipment failure, maintenance acts as a risk control measure [29]. The RBM as a method  
Figure 1: The number of documents published over the years on RCM and RBM. for risk-based inspection and maintenance was proposed by [PERSON] in 2003 [PERSON] and [PERSON] in 2003 [PERSON] and [PERSON] (2003) composed of three main steps: risk estimation, risk evaluation, and maintenance planning.