Introduction of the Human Factor Into the Risk Assessment Using Monte Carlo Simulation

Abstract

The frequency of occurrence of an accident scenario is one of the key aspects to take into consideration in the field of risk assessment. Aspects such as the human factor, which is a major cause of undesired events in process industries, are usually not considered explicitly in the frequency estimation, mainly due to the uncertainty generated due to the lack of knowledge and the complexity associated to it.In this work, failure frequencies are modified by including the uncertainty generated by the human factor through the Monte Carlo simulation. This technique is one of the most commonly approaches used for uncertainty assessment and it is based on probability distribution functions that represent all the variables included in the model.The Monte Carlo simulation technique has been proved be very useful in the risk assessment field. The model takes into account the uncertainty and variability generated by several variables of the human factor such as the Organizational factor (Contracting, Training, Communication and Reporting), the Job Characteristics Factor (Workload Management, Environmental Conditions, Safety Equipment) and the Personal Characteristics Factor (Skills and Knowledge, Personal Behavior).As a first attempt to test the model, it has been applied to a real case study of a chemical plant, obtaining new frequency values for a selected scenario. Since the uncertainty generated by the human factor has now been taken in to account through Monte Carlo simulation, these new values are more realistic and accurate. As a result, an improvement of the final risk assessment is achieved.