Preventive maintenance - Methods and technologies

For those responsible for operating complex industrial plants, the unscheduled occurrence of equipment failure has consequences for production, the safety of goods and people, and the environment. To avoid this situation, the implementation of a preventive maintenance policy offers an effective solution for monitoring equipment degradation and taking appropriate measures to avoid the occurrence of a failure. This article presents the objectives of preventive maintenance as part of maintenance management, current standardization, methods and technologies, and how to implement maintenance programs. The first section describes the issues involved in preventive maintenance, in line with the following standards EN NF 13306 and CEI 60050-192 . The characteristic parameters of the degradation curve leading to failure are then described in detail, as they are used to establish an equipment monitoring policy. To this end, the notions of potential failure, P-F intervals and "Net P-F interval" are introduced. The second section summarizes the main definitions relating to maintenance, and explains the role of preventive maintenance. In line with current standards, tree classifications of maintenance types and activities are also provided. The third section is devoted to the techniques and technologies involved in a preventive maintenance program. Particular emphasis is placed on non-destructive testing (NDT) and its implementation in accordance with the recommendations of COFREND (Confédération française des essais non destructifs), the official French certification body. NDT is used to detect and locate surface and volumetric defects. This section provides an overview of other condition monitoring methods, such as lubricant analysis, vibration analysis and those dedicated to electrical equipment. The fourth section is devoted to preventive maintenance information processing, which is essential for failure detection, diagnosis and decision-making. In view of the growing importance of predictive preventive maintenance (called predictive maintenance by the vast majority of companies specializing in this field), the fifth section outlines the principles of this method, which aims to prognosticate the time of failure through appropriate equipment monitoring. Setting up a preventive maintenance program requires defining the nature and frequency of maintenance tasks. To clarify these elements, the sixth section proposes criteria for choosing methods and selecting intervals between tasks. It also outlines strategies for implementing preventive maintenance, in particular reliability-based maintenance (RBM). The seventh section presents recent concepts in predictive maintenance for Industry...