SAE reliability-based maintenance method

This article, aimed at readers with a basic knowledge of industrial maintenance, presents the methodological content of documents drawn up by the SAE (Society of Automotive Engineers) to serve as a guide for the development and evaluation of a reliability-based maintenance (RBM) method that strictly adheres to the original principles defined by Nowlan and Heap in 1978 and noted in this article RCM-N&H According to the SAE, some methods did not respect the fundamental principles of RBM, and others proved counterproductive or even dangerous. In this article, the two documents JA 1011 and JA 1012 are analyzed and commented on. Document JA 1011 presents the minimum criteria to be met for a maintenance policy to comply with RCM-N&H Guide JA 1012 presents the methodology to be followed and the requirements needed to take advantage of RCM-N&H

The first section presents the origins of the approach, which stems from SAE's desire to make reference documents on MCR available to the various industrial sectors, by federating the efforts undertaken by several American organizations that are benchmarks in the field of MCR.

The main definitions required to define the evaluation criteria for an MCR policy are extracted and translated from documents JA 1011 and JA 1012, and form the content of the second section. Particular care has been taken to transcribe the essential information contained in these two documents as faithfully as possible. As the SAE recommends the use of seven questions to obtain the initial RCM-N&H maintenance plan, the second section will be dedicated to the five questions relating to the definitions of functions, modes, causes and consequences of failures. Given the significant differences in interpretation between the SAE definitions and those of the international standards for FMEA (Failure Mode and Effects Analysis), a comparison is provided for the reader to remove any ambiguity. Insofar as these two documents can be considered as supports for an RCM-N&H maintenance audit, the verbal forms contained in these texts are also explained. Then, the third section is devoted to the two remaining questions, the answers to which are the subject of general and specific principles for determining and selecting maintenance tasks. The general principles concern the use of conditional probability of failure curves, the notions of technically feasible, worthwhile and economically efficient tasks, the notions of obvious and hidden failures and their consequences for safety, the environment and operations. Specific principles relate to the wording and content of tasks, their selection procedure and the evolutionary program. For proactive tasks, the interpretation of the degradation curve, which monitors the behavior of the equipment between potential...