(55c) Process Industry Tool for Operator Action Analysis

Human error has been proved to have bigger contribution in causing accidents in process industry during the latest time. Nevertheless, too few efforts have been done to discover the underlying causes of such errors. This is primary due to the fact that people are overestimating human being's capability in interacting with machines and the lack of systematic analysis methods. The widely implemented safety analysis methods do not take HF into account as one of their main focuses. On the other hand, the existing HF methods are insufficient to be implemented in process industry. This leads to a call for a systematic and comprehensible HF assessment method. Since the attempts to lessen the probable consequences of human error and to minimize risks must be started in the earliest design phase [1], such method should also be applicable during design of a process plant.

A new developed computer program PITOPA (Process Industry Tool for Operator Action Analysis) facilitates the performance of an overall HF analysis on existing plants. By exploiting the available plant documents such as P&IDs, process flow diagrams, working instructions and safety reports, an operator action analysis [2] can be carried out more systematically and effortlessly. With this tool, possible operator workload as well as consequences of incorrect or omitted operator actions can be evaluated in both normal and abnormal operating conditions. Moreover, the most influencing factors on human performance during each task can be determined and the results are presented in the form of diagrams, graphs and tables in a comprehensible way. A catalogue of improvement suggestions in addition to these results can help the industry revealing the key problems and finding solutions accordingly, so that the configuration and construction of a safer operation will be achievable. Investigations carried out in various process plants have proved the efficacy of the method in existing plants, as well as the applicability of the computer program assisting it. An extended applicability of PITOPA is required in order to implement it during design phase.

Human factors consideration must be included in every single phase of plant design. Each component of a system must be formed in a way that suits human beings and therefore, a design needs to pay more attention to their requirements. HF design activities should be done iteratively during design process until an adequate human-friendly system configuration is achieved, preceding the commissioning and start-up.

This paper describes systematic approaches to incorporate human factors into process plant design. An introduction of PITOPA as a reliable tool for HF assessment purpose is explained and an enhancement of it for an application in plant design into PITOPADesign, is conceptualized. This new approach provides a clear and systematic way in considering HF early in plant design in order to improve plant safety and to reduce the number of accidents caused by human error. Incorporating HF into design of a process plant will minimize the likelihood of further modifications during operation. Consequently, realizing a safer operation can be achieved with minor cost implications.