Human Factors Safety Analysis

DOE Order 5480.23, Nuclear Safety Analysis Reports (DOE 1994a), Paragraph 8b(3)(n), as amplified by Attachment 1, Paragraph 4f(3)(d)14, of the order (Topic 14) requires a systematic inquiry into or evaluation of human factors for the facility. DOE Memorandum, Safety Analysis Report Guidance - Human Factors, DOE/DP-625 (DOE 1992), indicates that the use of the Human Factors Safety Analysis checklist will satisfy the requirements of DOE Order 5480.23 concerning human factors for existing facilities. 

As stated in DOE-STD-3009-94, in order to meet the human-factors safety requirements of DOE Order 5480.23, a systematic inquiry into human factors must be performed. An effective method for accomplishing this for existing facilities is through the application of the Human Factors Safety Analysis checklists found in reference DOE 1992. 

The process for the specification of human subsystem safety requirements is no different to software or hardware although it is ai uably considerably harder due to the difficulties associated with the immense scope and variety of issues affecting the reliable performance of human tasks. This paper has examined issues relating to the consideration of human subsystem safety and has outlined the scope and activities necessary for a comprehensive human factors safety analysis. A pragmatic method was introduced that advocates the application of focused Human Factors techniques to the assurance of safety for human subsystems. 

The primary system safety tools being used are hazard analysis and fault tree analysis. However, the transit industry could very much benefit from more human factors safety analysis. Though the industry has used it before, it has never been applied to the same level of detail as it has in the commercial nuclear power industry or civil aviation. Even though quantitative human factors safety analysis is still controversial, it could prove useful in the transit industry. Some countries, such as Erance, have already started to look more deeply into this. 

The objective of human factors safety analysis is to identify and correct human error situations that could lead to significant hazards. The analysis can be either qualitative or quantitative, depending on the level of detail desired and what the consequences are of a person making a mistake. The steps of a human factors safety analysis are as follows ... 

Brief Example of Human Factors Safety Analysis ... 

You will need to understand which particular events led to the event scenario. For example, it is important to identify the sequence of events or failures that could lead to a loss of in-flight aircraft control. Or, for example, the event could be that a blocked valve causes system overpressure. If humans are in the process, then some sort of human factors safety analysis will help find human error causes. 

HAZOP and wAat-iJ/safety checklists, two of the most common safety methods in the chemical industry, are explained. Sample process problems, which engineers face every day at work, are shown. Other safety tools, such as fault tree analysis, failure modes and effects analysis, human factors safety analysis, and software safety, are explained. Examples of the use of these tools are also presented. 

The design review, a formal and documented review of a system design, is conducted by a committee of senior company personnel who are experienced in various pertinent aspects of product design, reliability, manufacturing, materials, stress analysis, human factors, safety, logistics, maintenance, and so on. Tlie design review extends over aU phases of product development, fiom conception to production. In each phase, previous work is u( ted, and the review is based on current information. 

Search of Google and (review summaries) in December 2011, limited to eight journals Human factors, Safety Science, Ergonomics, Accident analysis and Prevention, Journal of Safety research. Journal of Risk research. International Journal Quality in Health Care, British Medical Journal Quahty and Safety. 

B. J. M. Ale, The Implementation of an External Safety Policy in the Netherlands, International Conference on Elazard Identification and Risk Analysis, Human factors and Human Reliability in Process Safety, January 15-17, 1992, Orlando, PL, 173-183, American Institute of Chemical Engineers, New York, NY, 1992. 

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... 

Banks, W., Wells, J. E. (1992). A Probabilistic Risk Assessment Using Human Reliability Analysis Methods. In Proceedings of the International Conference on Hazard Identification and Risk Analysis, Human Factors, and Human Reliability in Process Safety. New York American Institute of Chemical Engineers, CCPS. 

Opschoor, G., R. O. M. van Loo, and H. J. Pasman. "Methods for Calculation of Damage Resulting From Physical Effects of the Accidental Release of Dangerous Materials." International Conference on Hazard Identification, Risk Analysis, Human Factors and Human Rehabihty in Process Safety, January 15-17, 1992. 

See also Benchmark Dose Chemical-Specific Adjustment Factor (CSAF) Environmental Protection Agency, US International Programme on Chemical Safety Risk Assessment, Human Health Uncertainty Analysis. 

International Conference on Hazard Identification and Risk Analysis, Human Factors and Human Reliability in Process Safety... 

Topics Include methods lor calculating damage resulting from the physical effects of accidental releases, using risk assessment Information to specify safety control systems, fault tree analysis, hazards of trace substances, warehouse fires, human exposure to process systems, and solutions to human factor problems. 

The human factors literature is rich in task analysis techniques for situations and jobs requiring rule-based behavior (e.g., Kirwan and Ainsworth 1992). Some of these techniques can also be used for the analysis of cognitive tasks where weU-practiced work methods must be adapted to task variations and new circumstances. This can be achieved provided that task analysis goes beyond the recommended work methods and explores task variations that can cause failures of human performance. Hierarchical task analysis (Shepherd 1989), for instance, can be used to describe how operators set goals and plan their activities in terms of work methods, antecedent conditions, and expected feedback. When the analysis is expanded to cover not only normal situations but also task variations or changes in circumstances, it would be possible to record possible ways in which humans may fail and how they could recover from errors. Table 2 shows an analysis of a process control task where operators start up an oil refinery furnace. This is a safety-critical task because many safety systems are on manual mode, radio communications between control room and on-site personnel are intensive, side effects are not visible (e.g., accumulation of fuel in the fire box), and errors can lead to furnace explosions. 

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