IEC reliability-based maintenance method

This article, aimed at readers with a basic knowledge of industrial maintenance, presents the principles of the methodology defined in International Electrotechnical Commission standard 60300-3-11(2009) for establishing a reliability-based maintenance (RBM) policy, noted in this article by the acronym MBF-CEI. The first section presents the origins of the approach, initially in line with the policy defined by the ATA-MSG-3 standard in the aeronautical field, and subsequently fully modified to be applicable to all sectors of the industry. The IEC's intention in this MBF standard is to provide a methodological framework, recommendations and analysis methods, while leaving potential users several alternatives without imposing formal requirements. MBF-CEI is defined "as a method for identifying and effectively selecting failure management policies to be implemented to actually and effectively achieve the required safety, availability and economically optimum operation".

The terms used in this standard will be defined in each section as required, bearing in mind that the IEC has published several standards on the terminology to be used for operational safety and on Amdec. Subsequently, the verbal forms used will be commented on to help the reader distinguish between mandatory and recommended items.

The overall procedure recommended by the IEC for establishing the MBF maintenance program comprises five stages, and is the subject of the second section.

The first stage concerns the elements that need to be gathered before undertaking the development of the MBF maintenance program: objectives sought, content of the analysis, collection of information on the system, definition of the entity's operating conditions, qualification and training of people in charge of studies and planning. An analysis plan and operating context are drawn up. The second stage is devoted to the analysis of functional failures. It calls for the collection and exploitation of experience feedback, functional decomposition methods, an inventory of the entity's functions, and the use and drafting of Amdecs (analysis of failure modes, their effects and criticality). Given that the notions of severity and criticality are important to master for the identification of dominant failure modes, evaluation methods are also detailed. The third step is dedicated to requirements for the selection of maintenance tasks. It takes into account the consequences of failures, the choice of the most appropriate and effective management policy, and the determination of the interval between tasks. References to available analytical tools for determining maintenance task intervals will also be presented, using statistical data derived from experience feedback. The fourth step outlines the procedure...