Methods of risk analysis

An important attribute of risk analysis is that it is systematic. Ideally, all possible hazards should be found and evaluated. The various risk-analysis methods apply different analytic tools and checklists to accomplish this goal. Often, they combine the use of analytic tools and checklists with brainstorming and group problem-solving techniques. There are many textbooks and standards describing various risk-analysis methods (see e.g. Suokas and Rouhiainen, 1993 Harms-Ringdahl, 1993 ISO, 1999). Table 21.1 below summarises some of the methods. 

We will here focus on four different methods Coarse or energy analysis. Job-safety analysis. Comparison analysis and CRIOP. They all involve analyses of the effects of human performance on the risk of accidents. Use of experience of earlier accidents and incidents through discussions in problem-solving groups is another common denominator. We have earlier shown how group processes support in the identification and solving of SHE-related 

Method Scope and aim Analysis object Basic characteristics Measure of risk 

Coarse/energy Overview of A geographical Checklist of Risk matrix 

Job-safety List of hazards Individual Breakdown of job Risk matrix 

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Example 11 Parameter Method of Risk Analysis Let us consider the project outlined in Table 9-5. It is estimated that the basic data represent the most likely values and that there is a 10 percent chance that As will be reduced by more than 20 percent or will be increased by more than 5 percent. In the same way the low and high levels at 10 percent probability for Ate are considered to be 5 percent below and 25 percent above the base figures respectively. The low and high values for Cpc are considered to be 5 percent below and 30 percent above the base figure, while changes in other parameters are considered to be immaterial. 

In ethical committees and public debates the emphasis is on the so-called extrinsic concerns the risks for human health, for animals and for the environment. Most methods of risk analysis look only at the consequences and the effects of genetic engineering within the framework of a utilitarian ethics (weighing costs and benefits). 

Once the NOEL and the exposure to workers are known, the margin of safety (MOS) can be calculated. It then remains to be determined whether the MOS is adequate. Obviously the acceptability of a margin will depend upon the severity and reversibility of the toxic effect. Historically, a margin of 100-fold has been accepted for many toxic effects (19). This allows for a factor of 10 for extrapolation from animals to man, and a factor of 10 to allow for differences in sensitivity from one person to another. However much larger factors (up to 5000) have been used when the effects are more severe. A more complicated procedure is utilized when the product is a proven animal carcinogen. However, any method of risk analysis requires reliable assessment of both NOEL and exposure. 

In the present chapter, we focus on the methods of risk analysis as they are performed in the chemical industry, and especially in fine chemicals and pharmaceutical industries. 

The safety case regime of the United Kingdom and Australia is lypieal of the midpoint of the dimension whereby a process (risk assessment) is specified by which the goal of risk control is to be met, and acceptable methods of risk analysis are prescribed, but it is then left to the regulated company to convince the regulator of the way it is led to control risk by that risk assessment process. Further guidance is in the form of codes which have the status of acceptable translations of the goals, but leave the choice open to the company to comply in other ways. 

The evaluation was concentrated on the release of toxic substance followed by dispersion into the atmosphere. The possibility of formation of toxic product from combustion was not considered. The limits that are used as decision criteria (which evaluate only impact ranges) - as in selective method IAEA TECDOC-727 (IAEA 1996) and in other methods of risk analysis - were not considered as well. If the limits were found in the safety documentation, the following criteria were taken into account, too ... 

According to Brito Almeida (2009) there are some limitations to traditional methods of risk analysis and risk assessment that are used for pipelines. These approaches do not consider the multiple dimensions that the impact o f accidents can cause with regard to human, financial and environmental issues. 

Monte Carlo simulation is one of the most commonly used method of analyzing parameter uncertainty in the quantitative risk analysis research (Coxl 1996, Chen Liao 2006, Sassi et al. 2007). The USEPA has put a Monte Carlo simulation method as the basic methods of risk analysis in risk... 

Each occupational accident may involve several indirect causes. Every indirect cause is indicative of a critical point. Moreover, critical points can be recognized by the methods of risk analysis. 

How to prevent the occurrence of accidental releases without first waiting for the accidents to happen Part V presents different methods of risk analysis. They are applicable already at the design stage and will help to identify the need for barriers against accidental releases. Use of risk analysis during the operations phase will speed up experience feedback and learning. 

Part V is a descriptive section. It presents different methods of risk analysis. The selected methods fall within the scope of this book, since the employee s experience of incidents and accidents is a basic data source in the analysis. 

It is the task of the hazard study team to estimate the level of risk associated with each hazard. This brings us directly back to the risk classification work we covered in Chapter 2. Recall that the quantitative method of risk analysis begins with an estimate of unprotected risk frequency and an estimate of the consequences. 

EIGURE 7. Ovei-view of risk analysis methods. 

In the minds of all authors who favour the estimation of flashpoints based on a theoretical model rather than experimental results this approach was temporary and only supposed to be used during the period used by commissions of experts to lay down a standard technique for the determination of flashpoints. As has already been seen, it is less likely that this method will be used in the near future. This is the reason why we think estimation techniques have to be part of the priority tools of risk analysis in work on chemical risk prevention. Why is such work on estimation important We will see later that flashpoint is the cruciai parameter in order to establish the ievel of fire hazard of a substance. 

From the point of view of risk analysis assessment, it might be needed both analytical methods as well as thorough toxicity assays and biological methods as it is not possible to detect all the compounds present in real samples. This is especially interesting in the case when, for example, a single sludge sample is toxic just due to a compound present at very low concentration. Combination of techniques is... 

This volume provides comprehensive information about contaminants in the food industry. The book opens with an explanation of risk analysis and analytical methods used for detecting contaminants in food products. This is followed by full details of relevant EU and USA regulations. The second part of the book provides information about specific contaminants. 

In 55% of the cases, the accidents could have been foreseen by use of risk analysis, and in 35% of the cases by thermal stability testing. Different methods of stability testing were evaluated comparatively during the investigation of a runaway exothermic reaction which occurred during the preparation of a component mixture for a sealing composition in a 1200 1 reactor only DSC was effective in identifying the cause of the hazard. 

Develop case studies to explore the application of alternative methods of uncertainty analysis to the ecological risks of pesticides... 

The workshop did not reach firm conclusions on which methods of uncertainty analysis are suitable for use in pesticide risk assessment, or when they should be used. 

In a case-control study in the north of Sweden, Hallquist et al. (1993) compared 188 men and women aged 20-70 years who had thyroid cancer with age- and sex-matched controls (two per case) selected from a register of the local population. The cases were identified retrospectively from a cancer registry and excluded a proportion of patients (19%) who had died by the time of the study. Exposure to potential risk factors, including chlorophenols, was ascertained by postal questionnaire with a supplementary telephone interview if answers were incomplete. The response rates for the cases and controls were 95% and 90%, respectively. Of the 171 cases analysed, 107 had papillary tumours. Four cases and three controls reported exposure to chlorophenols (odds ratio, 2.8 95% CI, 0.5-18). [The Working Group noted that the method of statistical analysis was not the most appropriate for individually matched data, but this is unlikely to have produced serious bias.]... 

The overall concept of all of the following tools is that of risk analysis or risk assessment. Risk analysis helps to decide whether an aspect is GMP-critical or not. The risk analysis can be performed in a formal or more informal way. Following are two popular and import types of risk analysis. Another method, the fault tree analysis (FTA), has recently been used in the area of computer validation. This method is not described here, as it is a complex form of risk analysis. 

Systematic searches for hazard, assessment of risk, and identification of possible remediation are the basic steps of risk analysis methods reviewed in this chapter. 

After an introduction that considers the place of chemical industry in society, the basic concepts related to risk analysis are presented. The second section reviews the steps of the risk analysis of chemical processes discussed. Safety data are presented in the third section and the methods of hazard identification in the section after that. The chapter closes with a section devoted to the practice of risk analysis. 

In this section, a safety dataset, resulting from over 20 years of practical experience with risk analysis of chemical processes, is presented. These data build the base of risk analysis in the fine chemicals and pharmaceutical industries, essentially in multi-purpose plants. Therefore, the dataset introduces plant considerations only at its end. This allows exchanging them without any need for recollecting the whole dataset, in cases where the process is transferred from one plant unit to another. Moreover, this dataset may be used in the frame of different risk analysis methods. 

Standards (e.g., IEC 61508), methods of risk and hazard analysis, and certification methods have evolved long before IT. Security has evolved quite recently with networked IT-systems and concerns about privacy, data integrity, authenticity and protection. Both communities have developed their own standards, methods and system views—and neither in standardization nor in application areas they cooperate well. The paper takes a holistic view of critical systems and proposes a unified approach to system dependability, integrating both safety and security, arguing that in case of massively deployed embedded systems security issues have severe safety impact and vice versa. 

The analysis of complex mixtures with unknown composition and containing many different chemicals present in environmental samples, like effluents and waste materials. In this case, identifying which chemicals are responsible for the toxicity of the mixture is the main goal, but assessment may also focus on determining the best methods of risk reduction or quantifying potential effects associated with exposure to the mixture. 

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