Maintenance cost optimization in condition based maintenance: a case study for critical facilities

The increasing availability required to industrial plants and the limited budget often existing to assure it, require a careful formulation of maintenance optimization models. This need is primary for process plants, for which minimization of stops and maximization of their availability, are essential for ensuring targeted production and, therefore, profitability. In this context, the choice of the maintenance strategy is hence fundamental, depending on the system features and then on the effectiveness of the strategy. To evaluate the maintenance activities expected costs, it is necessary to implement appropriate technical and economic models, in order to represent the different types of maintenance types adopted. The aim of this study is to evaluate the technical and economic feasibility of condition based maintenance techniques for a service facility of a process plants. For this aim, the study was done for a HVAC system of a pharmaceutical laboratory. Three different kinds of maintenance strategies (corrective, time based and condition based) were considered, referring to three important equipment of the laboratory. For each system, the evaluation of the average cost of each maintenance strategy was done, so as to identify the most affordable one. Finally, we considered the cost-effectiveness of the implementation of a reliability continuous monitoring system, through the installation of an up-todate supervision structure. The paper offers an example of an economic model for the maintenance of a HVAC service system, presenting an original evaluation of continuous monitoring economics. Moreover, in this study, the newest monitoring technologies were considered, up to date and improved from the latest studies. This paper is directed to facility service and process plant managers. Keyword-CBM, HVAC system, maintenance optimization models.