Development of Risk-Based Inspection and Maintenance procedures for an oil refinery

The management of failure analysis has a strategic importance within a refinery from the organizational, engineering and economic point of view. The determination of an algorithm, that allows a methodical and as far as possible automatic approach to management of failure data, can make substantial improvements in the organization of work and in the decision-making processes. A panel of expert, made up of academicians and refinery operators, was formed in order to develop a Risk-Based Inspection and Maintenance (RBI&M) procedure. RBI&M procedure developed comprises six modules: identification of the scope, functional analysis, risk assessment, risk evaluation, operation selection and planning, J-factor computation and operation realization. Taking into consideration historical data regarding Near Accidents, Operating Drawbacks, Occupational and Environmental Accidents occurred in refinery over the last years the panel of expert defined a risk matrix in order to evaluate the risk associated to critical events and maintenance activities. Five probability classes and five severity categories, that take into account four impact categories (Health and Safety, Environmental, Economic and Reputation), have been defined. This paper reports the application of the RBI&M method to two specific stages in the maintenance activities of the refinery, i.e. the oil refinery turnaround and work orders management. The panel of expert developed heuristic methods in order to apply RBI&M procedure to the two cases allowing the refinery to minimize the overall risk taking into consideration the limits in term of time and budget (in turnaround case) and of human resources (in the management of work orders). The results have highlighted a clear improvement in the indices which measure the quality of maintenance