Human Reliability Assessment

Kirwan, B.. 1992., Human Error Identification in Human Reliability Assessment, A Ergonomics, 23, pp 299-318 and pp 371-381. 

When performing human reliability assessment in CPQRA, a qualitative analysis to specify the various ways in which human error can occur in the situation of interest is necessary as the first stage of the procedure. A comprehensive and systematic method is essential for this. If, for example, an error with critical consequences for the system is not identified, then the analysis may produce a spurious impression that the level of risk is acceptably low. Errors with less serious consequences, but with greater likelihood of occurrence, may also not be considered if the modeling approach is inadequate. In the usual approach to human reliability assessment, there is little assistance for the analyst with regard to searching for potential errors. Often, only omissions of actions in proceduralized task steps are considered. 

FIGURE 5.5 Relationship of SPEAR to Human Reliability Assessment Methodology... 

Kirwan, B. (1990). Human Reliability Assessment. In J. R. Wilson E. N. Corlett (Eds.). Evaluation of Human Work, a Practical Ergonomics Methodology. Washington, DC Taylor and Francis. 

Kirwan, B. (1994), A Guide to Practical Human Reliability Assessment, Taylor Francis, Bristol, PA. 

Williams, J.C. (1985) Validation of human reliability assessment technique. Reliability Engineering, 11, 149-162. 

Firmino, P. R. A., MenSzes, R. d. C. S., Droguett, E. L. Duarte, D. C. d. L. 2006. Eliciting Engineering Judgments in Human Reliability Assessment. 52nd annual Reliability Maintainability Symposium, Newport Beach. 

Pesme, H., Le Bot, R, Meyer, P. (2007). Little stories to explain human reliability assessment A practical approach of the MERMOS method. In Joint 8th IEEE HFPP Conference on Human Factor and Power Plants and 13th HPRCTAnnual Workshop on Human Performance, Root Cause, Trending, Operating Experience, Self Assessment, August 26, 2007 - August 31, 2007 (pp. 284—287). Monterey, CA, United states Institute of Electrical and Electronics Engineers Inc. 

Hollnagel E. 2005. Human Reliability Assessment in Context. Cognitive Systems Engineering Laboratory, Department of Computer and Information Science, University of Linkoping, Sweden. 

As Chapter 17 (Kirwan and Shorrock) demonstrates, there is a huge amount that could be learnt from other safety industries and sectors. Some of the methods which have been tried and tested within the nuclear and oil and gas sectors are only just starting to be applied within healthcare (e.g. safety cases and human reliability assessment - Health Foundation 2012). Others such as the concept of safety intelhgence (discussed in Chapter 17 Fruhen et al. 2014) offer the potential for future work, particularly as it relates to senior managers within healthcare. Even a cursory glance at the accounts and recollections of well-known researchers in... 

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. 

Kirwan, B. (1999). Human reliability assessment. In J.R. Wilson and E.N. Corlett (eds), Evaluation of Human Work A Practical Ergonomics Methodology (pp. 921-68). London Taylor and Francis. 

An HEA should be undertaken using a two stage process of Human Error Identification (informed by the CTA) followed by a Human Reliability Assessment (informed by other safety analyses such as FTA etc.) which can be either qualitative or quantitative as required. Both of these activities are examined here in more detail. 

Predicting danger. Techniques for human reliability assessment... 

Kirwan, B., Human reliability assessment. In Wilson, J. R. and Corlett, N. (Eds.), Evaluating Human Work an Ergonomics Methodology, Taylor and Francis, London (1989) Royal Society, Risk Assessment a Study Croup Report, London (1983)... 

Sample times for human action in response to alarms are shown in Table B.1. These IPL time limits are based on research and are confirmed by industry experience. If the owner/operator wishes to use shorter response times or lower PFDavg values, the owner/operator is cautioned to do a detailed human reliability assessment to confirm the assumed PFDavg. The values in the table below represent the PFD of the entire IPL. They are not to be interpreted as PFDavg of the human action only. 

Human response to SIS indication or alarm with S40 minutes response time Simple well-documented action with clear and reliable indication that the action is required. Minor troubleshooting or diagnostics is allowed if needed before taking action. 1 X 10 to 1 X 10 (limited by human response) 1x10-1 or 1 X 10 to 1 X 10 (as determined by human reliability assessment)... 

From various internationally published estimates, it is found that in the world, out of the total number of plant accidental scenarios, around 60—90% are on account of human failure in different forms, and the rest are on account of technical deficiencies of equipment and control systems, or on account of other issues. Naturally, human reliability assessment or analysis claims is a major focus. In Fig. V/6.0-1A, a short... 

Various human reliability assessment techniques may be used to evaluate the effectiveness of cross-checking activities - eg THERP (Technique for Human Error Rate Prediction) and HEART (Human Error Assessment and Reduction Technique). It is important that any assessment is made by a competent human reliability specialist and that it is based on information provided by the operators who actually carry out the filling operation. 

A more detailed application of LOPA requires sufficient rather than absolute independence between protection layers or between a protection layer and an initiating event. The principles within BS EN 61511 -1 and 61511 -2 (eg clauses 9.4, 9.5 and 11.2) present the requirements on the BPCS when used as a protection layer. For example a detailed evaluation would need to be performed of the possible failure modes of each element of the protection layer - typically involving techniques such as Failure Modes and Effects /Analysis, Human Reliability /Assessment and Fault Tree /Analysis. Great care needs to be taken in using this approach to ensure that consistent assumptions about the condition of equipment or people are made throughout the analysis. 

Rail and Safety Standards Board (RSSB), Tracer for the Rail Industry Rail Specific Human Reliability Assessment Technique for Driving Tasks. 

Services, the principal Air Traffic Control organisation in the UK, managing Human Factors staff and contractors. He extended the traditional HF work in NATS to consider human error and various safety aspects of new and existing projects and systems, as well as feeding more human factors into the design of new systems. His most recent move has been to Eurocontrol, in Brussels and Paris, working on a number of projects concerned with the future automation tools aimed for 2005 onwards. He has published two textbooks (on task analysis and human reliability assessment) and various articles. 

Since PRA by that time had become established as the industry standard for how to deal with the safety and reliability of technical systems, it was also the natural starting point when the human factor needed to be addressed. Extending PRA to include human factors concerns led to the development of a number of methods for Human Reliability Assessment (HRA). At first, the... 

A THERP tree is a technique used in human reliability assessment to calculate the probability of a human error during the execution of a task. (THERP stands for Technique for Human Error Rate Prediction.) A THERP tree is basically an event tree, where the root is the initiating event and the leaves are the possible outcomes. THERP is described in a publication from 1983 (Swain, A.D. and Guttmann, H.E., Handbook of Human Reliability Analysis with Emphasis on Nuclear Power Plant Applications, NUREG/CR-1278, USNRC), and is still widely used despite its unrealistic assumptions about human performance. One important... 

The idea of contrasfing two approaches to safety was itself inspired by a similar debate that took place within the field of Human Reliability Assessment (HRA). In 1990 the Human Reliability Analysis (HRA) community was seriously shaken by a concise exposure of the lack of substance in the commonly used HRA approaches (Dougherty, E.M. Jr. (1990), Human Reliability Analysis - where shouldst thou turn Reliability Engineering and System Safety, 29, 283-99). The article made it clear that HRA needed a change, and emphasised that by making a distinction between the current approach, called first-generation HRA, and the needed replacement, called second-generation HRA. 

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