Identification and Analysis of Human Errors in the Maintenance Activities of Molecular Sieve Replacement in the Dehydration Unit of Gas Refineries Using Predictive Human Error Analysis Method

Abstract

Background and Objective:Incidental events due to human error in the maintenance activities of molecular sieve replacement in the dehydration unit of gas refineries indicate the inadequate effectiveness of the techniques available to identify human errors. This study aimed to identify and analyze human errors in this maintenance activity using the predictive human error analysis (PHEA) technique and provide appropriate control strategies to prevent or reduce the consequences of identified errors. Materials and Methods: In this study, all activities and tasks performed to achieve the main goals were identified using hierarchical task analysis (HTA) technique. Subsequently, possible types of human errors in each phase of the above processes were predicted and identified using the PHEA method and a series of guidance keywords.After determining the consequences of each error, appropriate control methods were also provided. Results: Out of 11 operations and 111 sub task occupations analyzed in the PHEA worksheets, a total of 337 errors were identified, of which 246, 13, 28, 33, and 17cases were regarded as action, checking, retrieval, information transfering and planning errors, respectively. The most significant identified errors were forgetting the task, doing the task incorrectly, incompletely, at the wrong time, making the right decision on the wrong option, and doing the task more or less than necessary. Conclusion: According to the obtained results, it can be concluded that functional errors were the most prevalent type of errors. Theses results emphasize the necessity of using control strategies in terms of adequate and effective training for personnel, the preparation and modification of instructions, the monitoring of implementation of work and hardware changes.