Human reliability improving

Estimates of exposure levels posing minimal risk to humans (MRLs) have been made, where data were believed reliable, for the most sensitive noncancer end point for each exposure duration. MRLs include adjustments to reflect human variability and, where appropriate, the uncertainty of extrapolating from laboratory animal data to humans. Although methods have been established to derive these levels (Barnes et al. 1987 EPA 1989a), uncertainties are associated with the techniques. Furthermore, ATSDR acknowledges additional uncertainties inherent in the application of these procedures to derive less than lifetime MRLs. As an example, acute inhalation MRLs may not be protective for health effects that are delayed in development or are acquired following repeated acute insults, such as hypersensitivity reactions, asthma, or chronic bronchitis. As these kinds of health effects data become available and methods to assess levels of significant human exposure improve, these MRLs will be revised. 

Matching mechanical properties to human tissues Increasing reliability Improving processing methods... 

A great deal of progress has been made toward improving and evaluating the reliability of hardware systems however, the place where systems most frequently fail is in the interface of humans with the system. Human reliability is generally much lower and more difficult to control than hardware reliability. 

Barry Kirwan works for Eurocontrol in France. His principal responsibility is miming the European Air Traffic Management Safety Culture Programme, which involves surveys for around 30 European States, helping them evaluate and improve their safety culture. He also chairs a Eurocontrol-FAA group on safety research and periodically works on human factors and human reliability assessment issues with the nuclear power indrrstry in the USA and UK. 

The module is concerned with the techniques which can be applied to all main types of hazard and in particular with methods of general application for improving systems and human reliability. The module is also concerned with the ways in which changes in organisational structure and behaviour may be used to improve the control of work-based hazards. Within the module there is emphasis on the integration of safety and health with all management functions of the organisation. 

While human reliability can be improved through training, practice, increased information and good communications, there is a low probabihty of obtaining error-free performance over extended periods. Cleariy, there are areas that people excel in similarly, there are activities best suited to machines. 

Human Reliability Analysis (HRA) is used to determine the probability that a task or activity will be completed successfully within a required period of time, and that no other human action that could be detrimental to system performance will take place. HRA analysis can also help identify areas where potential improvements can be made. 

Human reliability analysis (HRA) With technological development and incorporation of redundancy it is possible to reduce equipment failure to a great extent. However, human behavior is not that predictable. So, there are chances that failure could occur because of human factors. This is a method by which probability is measured. It is also used in PFLA. This could be quantitative as well as qualitative. Although the exact value is not certain it is estimated that error committed by a human could be as high as 60—80% (even 90%). Human performance is affected by several factors, referred to as the performance shaping factor (PSF). By this method, PSF is identified and tries to improve it. In addition to PSF, normal human error probability (HEP) is also calculated on the basis of human activity. There are so many factors that affect this analysis accuracy, reproducibility, bias, etc. There have been several methods and each needs to be understood before application. An HRA event tree is often used. It may be informative to refer to Table V/1.0-1 (Chapter V). 

There may be a nnmber of individuals who could be classified as users, e.g. operators, maintenance personnel, managers etc. and the user documentation needs to be relevant and intelUgible to them all. There is a tendency among non-specialists to view computers as black boxes . This view is not conducive to making optimum use of the system facilities and is unlikely to be alleviated by an incomprehensible user manual. Any process which will deepen understanding of the system will improve safely by improving the human reliability aspect. 

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