Task analysis for industrial work process from aspects of human reliability and system safety

In the design, development, and manufacturing stage of industrial products, engineers usually focus on the problems caused by hardware or software, bu t pay less attention to problems caused by "human error," which may signifi cantly affect system reliability and safety. Although operating procedures are strictly followed, human error still may occur occasionally. Among the influencing factors, the inappropriate design of standard operation procedu re (SOP) or standard assembly procedure (SAP) is an important and latent re ason for unexpected results found during human operation. To reduce the err or probability and error effects of these unexpected behaviors in the indus trial work process, overall evaluation of SOP or SAP quality has become an essential task. The human error criticality analysis (HECA) method was deve loped to identify the potentially critical problems caused by human error i n the human operation system. This method performs task analysis on the bas is of operation procedure. For example, SOP, analyzes the human error proba bility (HEP) for each human operation step, and assesses its error effects to the whole system. The results of the analysis will show the interrelatio nship that exists between critical human tasks, critical human error modes, and human reliability information of the human operation system. To identi fy the robustness of the model, a case study of initiator assembly tasks wa s conducted. Results show that the HECA method is practicable in evaluating the operation procedure, and the information is valuable in identifying th e means to upgrade human reliability and system safety for human tasks.