Operator errors, human factors

A fundamental concept of ICAM is acceptance of the inevitabiUty of human error. Human factors research and operational experience has shown that human error is a normal characteristic of human behaviour, and although it can be reduced, it cannot be completely eliminated (Helmieich and Merritt, 2000). An organization cannot change the human condition, but they can change the conditions imder which humans work, thereby making the system more error tolerant (Reason, 2000). 

Nagel, D. (1988), Human Error in Aviation Operations, in Human Factors in Aviation, Wiener E. L. and Nagel, D. eds., London Academic Press, 263-303. 

Use an advanced control room to simplify construction, maintenance and operations. Improved human factors considerations reduce the chance of operator error during an event or accident sequence compared to the large control rooms used in currently operating plants. 

Nagel, D. 1988. Human error in aviation operations. In Human factors in aviation, ed. E. V flener and D. Nagel, 263-303. San Diego, Calif. Academic Press. 

Several nontechnical factors can significantly affect the results of a nondestmctive inspection. Many of these are classified as human factors (1,2,17). Operator experience affects the probabiUty of detection of most flaws. Typically, an inexperienced operator has more false rejects, known as Type II errors, than an experienced operator. A poor operator has few false rejects but is more likely to miss a defect in the inspection, known as a Type I error. Operator fatigue, boredom, or an unfavorable environment such as lighting, cold, or rain may further affect performance. Thus it usually is a good investment for the inspection company to assure that the operator environment is most amenable to inspection, that the equipment is suitable for the task, and that the operator is alert and well rested. 

Human errors may be dependent on the specific accident sequence displayed in the event tree, and, for that reason, may be included in the event tree. This requires the human-factors specialist to consider the context of the error in terms of stress, operator training in response to the accident, di.tgnosiic paiierns, environmental, and other performance-shaping factors. 

Williams, J. C., 1989, A Data-Based Method for Assessing and Reducing Human Error to Improve Operational Performance, Proceedings of the 1988 IEEE Fourth Conference on Human Factors and Power Plants, Monterey, CA, June 5-9, pp 436-450, IEEE. 

The application of the science of human factors to eliminating error in all aspects of process design, management, operation, and maintenance is the focus of this work. Human error has been a major cause of almost all of the catastrophic accidents that have occurred in the chemical process industries (CPI). If one adopts the broad view of human error as being the result of a mismatch between human capabilities and process demands, then clearly management s role is critical in the following areas ... 

The book begins with a discussion of the theories of error causation and then goes on to describe the various ways in which data can be collected, analyzed, and used to reduce the potential for error. Case studies are used to teach the methodology of error reduction in specific industry operations. Finally, the book concludes with a plan for a plant error reduction program and a discussion of how human factors principles impact on the process safety management system. 

The major benefits that arise from the application of human factors principles to process operations are improved safety and reduced down time. In addition, the elimination of error has substantial potential benefits for both quality and productivity. There is now a considerable interest in applying quality management approaches in the CPI. Many of the major quality experts em-... 

Human Factors Engineering/Ergonomics approach (control of error by design, audit, and feedback of operational experience) Occupational/process safety Manual/control operations Routine operation Task analysis Job design Workplace design Interface design Physical environment evaluation Workload analysis Infrequent... 

Inspection of the HRA event tree reveals that the dominant human error is Error A the operator failing to isolate the propane valves first. The other potential human errors are factors only if a propane isolation valve sticks open. Based on these qualitative results alone, a manager rrught decide to periodically train operators on the proper procedure for isolating a failed condenser and to ensure that operators are aware of the potential hazards. The manager might... 

Management must modify the culture and develop human factors awareness in the hazard identification teams so that they will be capable of identifying the potential for human error. A good practice is to involve operators in the hazard identification team. 

Fitts, P. M., Jones, R. E. (1947). Analysis of Factors Contributing to 460 "Pilot Error" Experiences in Operating Aircraft Controls. Reprinted in H. W. Sinaiko (Ed.) (1961), Selected Papers on Human Factors in the Design and Use of Control Systems. New York Dover. 

Table 3.4 presents a list of human factors that may positively or negatively influence the likelihood of operator error. This list may be used prior to, and/or during the analysis. In addition, the PrHA team may determine that human factors problems are of sufficient importance or complexity to require the assistance of a human factors specialist. 

Human Factors—Included here are human error assessment, operator/process and operator/equipment interfaces, and administrative controls versus hardware. 

Whatever method is used, there should be a clear design philosophy for the basic process control system (BPCS) employed at a facility that is consistent throughout each process and throughout the facility. Consistency in application will avoid human factor errors by operators. The philosophy should cover measurements, displays, alarms, control loops, protective systems, interlocks, special valves (e.g., PSV,... 

Finally, for a (bio)chemical sensor to effectively solve real problems it should require no immediate interpretation of its response (e.g. in order to alter some physical or physico-chemical parameter influencing its operation). In practice, this requires that the sensor be reliably used by unskilled personnel, who often work under stressing conditions, in order to avoid the human factor as a source of error in the results produced by (bio)chemical sensors. 

Human (operator) Error cannot be separated entirely from the Technical and Organisational context of task performance (see figure 2.1). At the very least one should know the importance of Human Behaviour relative to that of the Technical and Organisational factors in understanding the causes of accidents and near misses. On the basis of our own pilot CCR studies (Van der Schaaf, 1989) the following extensions arc suggested ... 

There is no method of making a plant truly inherently safe, since there is always risk when human activity is involved. But, if we carefully examine the technology available to us, we can make chemical plants inherently safer than they might be without such an examination. We can determine that a plant can be safe, but there are many factors that will determine whether a plant will be safe. CEFIC, the European Council of Chemical Manufacturers Federations (CEFIC, 1986), reports these include human factors that are so difficult to quantify that they are rarely taken into consideration. They include the human side of plant management, operation, and maintenance. Designers cannot do much about these human factors, but they can often do a lot to make the plant easy to operate, and reduce the chances of accidents that may result from human error and mechanical failure. 

ANALYSIS DOCUMENTATION. PrHA report documentation should include the PrHA worksheets, checklists, logic diagrams, human reliability analyses, and any other analysis made to better understand the scenarios. The PSM Rule requires that human factors that impact scenarios as cause or protection be expanded to analyze the basic cause of errors or response failures. For example, a cause may identify that an operator can turn the wrong valve to initiate an accident. The PSM Rule requires that basic causes also be identified. For example, valve is not labeled the operator has not been trained on the operation or the operator forgot the step. There may be more than one basic cause. (See also Section 3.2, paragraph on Human Factors.)... 

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