Sh Rahimi Kamal, J Nasl Saraji, I Mohammad Fam ,
Volume 7, Issue 4 (2-2010)
Abstract
Background and Aim: Human error often plays an important role in accident causation either through direct action or poor design . The focus of this work is was on prediction of human error probabilities during the process of emergency musters on in gas compressor stations . This paper aims to present a brief description of Human Error Probability Index (HEPI) for the on gas compressor station musters process.
Materials and Methods : Due to a lack of human error databases, and in particular human error data on gas compressor station musters, an expert judgment technique, the Success Likelihood Index Methodology (SLIM), , was adopted as a means to predict human error probabilities Two muster scenarios of varying severity (gas release, fire and explosion) were studied in detail . A total of 34 reference graphs provided data for both the weighting and rating of six performance shaping factors and the data were subsequently processed by means of SLIM to calculate the probability of success for 16 muster actions ranging from point of muster initiator to the final actions in the temporary safe refuge (TSR). The actions were categorized into 4 phases, namely, awareness, evaluation, egress, and recovery phases. The six performance shaping factors considered in this work were stress, complexity , training, experience, event factors, and atmospheric factors .
Results: Human error probabilities in the egress phase were highest, followed by those in the evaluation phase the lowest were in the awareness phase.
Conclusion: The HEPI can be applied to limit the chances of human error occurrence and mitigate the consequences of such errors through changes in training, design, safety systems, and procedures, resulting in a more error-tolerant design and operation .
M Ghasemi, G Nasl Saraji, A Zakerian, M Azhdari,
Volume 8, Issue 1 (6-2010)
Abstract
Background and Aim: Today in many work environments, such as nuclear, military and chemical industries, human errors may result in disasters. Accidents in different parts of the world bear evidence to this examples are the Chernobyl disaster (1986), the Three Mile Island accident (1974), and the Flixborough explosion (1974). Thus, identification of human error, especially in complex and intricate systems, and devising control measures are essential.
Materials and Methods: This project was a case study conducted in Zagross Methanol Company in Asalouye (South Pars), Iran. The walking-talking-through method was used to collect the required data and complete the Systematic Human Error Reductive and Predictive Approach (SHERPA) worksheets. The process experts and control room operators were interviewed and technical documents of the Company examined.
Results: Analysis of the SHERPA worksheets indicated that the majority (48.62%) of the 222 errors identified were action errors, followed by checking errors (31.97%), retrieval errors (6.75%), selection errors (0.9%), and communication errors (11.7%).
Conclusion: The results of this study show that the method can be used effectively in different industries, especially chemical industries, to identify human errors that may potentially lead to dangerous situations and accidents.
A Mazlomi, M Hamzeiyan Ziarane, A Dadkhah, M Jahangiri, M Maghsodipour, P Mohadesy, M Ghasemi ,
Volume 8, Issue 4 (2-2011)
Abstract
Background and Aim: Today in most of the work environments, such as nuclear, military and chemical industries, human error may result in catastrophic events. A common characteristic of large technological systems is that massive amounts of potentially dangerous materials are kept in one single unit controlled by control room operators. A control room is indeed the heart of a system of this type and any error in task performance by the operators may have undesirable consequences which could never be compensated. In this study we aimed to identify and assess human errors in the control room of the Aromatic Unit of Bouali-Sina Petrochemical Company, Iran using the CREAM method.
Materials and Methods: This was a cross-sectional and analytical-descriptive study carried out in the control room of the Aromatic Unit of Bouali-Sina Petrochemical Company, Iran with 39 operators. After a job analysis by the hierarchical task analysis (HTA), probable control modes and cognitive failure probability were determined for occupational tasks using the basic and the extended CREAM methodologies.
Results: Based on the results of the basic CREAM method, control modes for the tasks of action, Boardman and shift control supervisor were determined as Opportunistic Control mode, while for the task of control room head it was obtained as Tactical control mode. With regard to the error types, the following results were obtained on the basis of the extended method of CREAM: execution failure (51.70%), interpretation failure (19.55%), planning failure (14.94%), and observation failure (13.81%).
Conclusion: The basic CREAM method showed the common performance factors (CPCs) leading to reduced performance reliability to be the number of simultaneous tasks, time of day (circadian rhythm), and adequacy and quality of training and experience. These factors caused the operators to choose an opportunistic control mode. In addition, based on the extended CREAM method results, the most noticeable cognitive failure was execution failure. In addition, the most important cognitive activities related to the control process in the control room were communication, execution, diagnosis, monitoring, and planning. Based on these findings, providing instructions and guidelines for work procedures, holding training courses, shift work scheduling, optimization of the communication systems and modifications in the control software are essential to minimize human errors in the Bouali Sina Petrochemical Company control room.
