Risk Evaluation and Presentation

Once frequency and consequence estimates are generated, the risk can be evaluated in many ways. It is essential that the large number of fre-quency/consequence estimates from a QRA be integrated into a presentation format that is easy to interpret and use. The presentation format you select will depend on the purpose of the QRA and the risk measure of interest. 

Both individual and societal risks may be presented on an absolute basis compared to a specific risk target or criterion. Or, they may be presented on a relative basis to avoid arguments regarding the adequacy of the absolute numbers while preserving the salient differences between alternatives. The end results of the risk presentation may be a single number (or a range of numbers if an uncertainty analysis was performed) or one or more graphs. 

A common risk evaluation and presentation method is simply to multiply the frequency of each event by consequence of each event and then sum these products for all situations considered in the analysis. In insurance terms, this is the expected loss per year. The results of an uncertainty analysis, if performed, can be presented as a range defined by upper and lower confidence bounds that contain the best estimates. If the total risk represented by the best estimate or by the range estimate is 

While the F-N curve is a cumulative illustration, the risk profile shows the expected frequency of accidents of a particular category or level of consequence. The diagonal line is a line of constant risk defined such that the product of expected frequency and consequence is a constant at each point along the line. As the consequences of accidents go up, the expected frequency should go down in order for the risk to remain constant. As the example illustrates, if a portion of the histogram sticks its head up above the line (i.e., a particular type of accident contributes more than its fair share of the risk), then that risk is inconsistent with the risk presented by other accident types. (Note There is no requirement that you use a line of constant risk other more appropriate risk criteria for your application can be easily defined and displayed on the graph.) 

A method for graphically displaying individual risk results is use of the risk contour, or risk isopleth. If individual risk is defined as the likelihood of someone suffering a specified injury or loss, then individual risk can be calculated at particular geographic locations around the vicinity of a facility or operation. If the individual risk is calculated at many points surrounding the facility, then points of equal risk can be connected to 

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This section gives an introduction to metrics and analysis methods for risk evaluation and presents finally the decision for a risk analysis method for critical infrastructures. 

The effects are searched in order to allow the assessment of the severity. These results are documented together with the risk evaluation and, where required, with risk-reducing measures in a hazard catalog, as presented in Figure 1.1. 

More recently, activist groups and disease-based organizations have presented patients as sophisticated rational actors who can review medical information and make informed decisions for themselves. Changes in FDA regulations consequently shifted certain aspects of risk evaluation and decisionmaking control to patients and physicians. Initiatives since the peak of political attention to the AIDS crisis in the early 1990s, notably the 1992 Prescription Drug User Fee Act (PDUFA) and the 1997 FDA Modernization Act (FDAMA),... 

Sielken, R. L., Jr. (1989). Useful tools for evaluating and presenting more science in quantitative cancer risk assessment. Tox Subst J 9, 353 04. 

The F-N curve, the risk profile, and the risk contour are the three most commonly used methods of graphically presenting risk results. Normally, you will elect to use more than one of these methods when evaluating risk estimates for decision making. 

Miller, M. J. Risk Management and Reliability—An Update. Paper presented at the Conference on Fire Safety Evaluation, National Academy of Sciences, Washington, D.C., September 1978. 

Tliis cliapter is concerned willi special probability distributions and tecliniques used in calculations of reliability and risk. Tlieorems and basic concepts of probability presented in Cliapter 19 are applied to llie determination of llie reliability of complex systems in terms of tlie reliabilities of their components. Tlie relationship between reliability and failure rate is explored in detail. Special probability distributions for failure time are discussed. Tlie chapter concludes with a consideration of fault tree analysis and event tree analysis, two special teclmiques lliat figure prominently in hazard analysis and llie evaluation of risk. 

All action items are presented to management for review and evaluation, and for determination of what, if any, corrective actions should be taken to eliminate hazards or reduce risks. Because many action items may be generated during a PrHA, the team may choose to rank the items according to the probability of occurrence and/or the severity of the consequences of their corresponding accident scenarios. 

Subsequently, three methods indicating safety risks will be evaluated on these nine criteria discussed above whether indirect safety related operational deviations are used, general conclusions can be derived, detailed cause-effect relationships are available, the method is feasible, the results are reliable, only limited resources are needed, the results can be ranked, a clear link between risk reduction and operational benefit is present, and if all (root)cause areas are included. 

The quantitative dose-response assessment involves two different challenges, namely to determine the relationship between doses and the frequency of cases of cancer (i.e., potency evaluation), and to determine what statistical risk is tolerable or acceptable. This section gives a very short overview of some general aspects related to the quantitative dose-response assessment. The currently used approach by the WHO, the US-EPA, and the EU, as well as new approaches for the risk assessment of compounds that are both genotoxic and carcinogenic, are presented in Sections 6.3 and 6.4, respectively. 

It is not possible to establish the exact point in a research project when the screening tests outlined in this guide should be used. (R D safety manuals often provide additional guidance on this issue.) The persons working directly on the project are the ones who can effectively evaluate and control this need. In general, no research project should be pilot planted unless a reactive chemicals review is held. The level and depth of review will be driven by the amount of reactive chemicals potential risk present in the project or process. Higher risk projects should be reviewed sooner in their development process, some-... 

Part I gives a general introduction and presents the theoretical, methodological and experimental aspects of thermal risk assessment. The first chapter gives a general introduction on the risks linked to the industrial practice of chemical reactions. The second chapter reviews the theoretical background required for a fundamental understanding of mnaway reactions and reviews the thermodynamic and kinetic aspects of chemical reactions. An important part of Chapter 2 is dedicated to the heat balance of reactors. In Chapter 3, a systematic evaluation procedure developed for the evaluation of thermal risks is presented. Since such evaluations are based on data, Chapter 4 is devoted to the most common calorimetric methods used in safety laboratories. 

I shall present a perception of the public concerns and a little of how I evaluate and how I present the risks. I will present information on pesticide use, public concerns as they are expressed in the news, allegations of harm, toxicity of a forest pesticide—2., 4-D, human exposure to drift of this pesticide, and the margins of safety which exist when this exposure occurs. 

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