Hazard estimation technique

Estimates were reached by employing a hazard estimation technique. Subjects were asked to rank eight pictorials at workplaces according to the supposed accident frequency distribution. As the results showed, there was a mis-match between the hazard as perceived by the subjects and the hazards as objectively measured. Familiar work situations with high accident risks were more under-estimated than unknown situations with comparable hazard probabilities. The study is described more in detail in chapter 6. 

Hazard identification builds the foundation on which subsequent quantitative frequency and/or consequence estimates are made. Many companies have been using the hazard identification techniques listed in Figure 7 for... 

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. 

It is estimated that 43% of today s high-production-volume chemicals do not have complete toxicity data—and 7% of these chemicals have no data at all. Inherent safety implies that the process is inherently safe and that it is not kept safe with the help of several safety checks and alarms. Several available hazard analysis techniques can be used at various stages of the process development. Developing inherently safe process is more advantageous than... 

Failure Mode and Effects Analysis (FEMA)—FEMA is a tabulation of facility equipment items, their potential failure modes, and the effects of these failures on the equipment or facility. Failure mode is simply a description of what caused the equipment to fail. The effect is the incident, consequence, or system response to the failure. It is usually depicted in tabular format and expresses failures in an annual estimation. A FEMA is not useful for identifying combinations of failures that can lead to incidents. It may be used in conjunction with other hazard identification techniques such as HAZOP for special investigations such as critical or complex instrumentation systems. There is also a Failure Modes, Effects, and Criticality Analysis (FMECA), which is a variation of FMEA that includes a quantitative estimate of the significance of the consequence of a failure mode. 

Personal Factors 0 hazard perception 0 risk estimation 0 knowledge, motivation and skills Critical incident technique Risk estimation technique Questionnaire for weighing accident ... 

The Dow Fine and Explosion Index is a useful method for obtaining an estimate of the relative fine and explosion hazards associated with flammable and combustible chemicals. However, the technique is very procedure oriented, and there is the danger of the user becoming more involved with the procedure than the intent. 

Introduction Theprevious sections dealt with techniques for the identification of hazards and methods for calculating the effects of accidental releases of hazardous materials. This section addresses the methodologies available to analyze and estimate risk, which is a function of both the consequences of an incident and its frequency. The apphcation of these methodologies in most instances is not trivial. A significant allocation of resources is necessary. Therefore, a selection process or risk prioritization process is advised before considering a risk analysis study. 

Consequence Phase 3 Develop Detailed Quantitative Estimate of the impacts of the Accident Scenarios. Sometimes an accident scenario is not understood enough to make risk-based decisions without having a more quantitative estimation of the effects. Quantitative consequence analysis will vary according to the hazards of interest (e.g., toxic, flammable, or reactive materials), specific accident scenarios (e.g., releases, runaway reactions, fires, or explosions), and consequence type of interest (e.g., onsite impacts, offsite impacts, environmental releases). The general technique is to model release rates/quantities, dispersion of released materials, fires, and explosions, and then estimate the effects of these events on employees, the public, the facility, neighboring facilities, and the environment. 

The antioxidant activities of carotenoids and other phytochemicals in the human body can be measured, or at least estimated, by a variety of techniques, in vitro, in vivo or ex vivo (Krinsky, 2001). Many studies describe the use of ex vivo methods to measure the oxidisability of low-density lipoprotein (LDL) particles after dietary intervention with carotene-rich foods. However, the difficulty with this approach is that complex plant foods usually also contain other carotenoids, ascorbate, flavonoids, and other compounds that have antioxidant activity, and it is difficult to attribute the results to any particular class of compounds. One study, in which subjects were given additional fruits and vegetables, demonstrated an increase in the resistance of LDL to oxidation (Hininger et al., 1997), but two other showed no effect (Chopra et al, 1996 van het Hof et al., 1999). These differing outcomes may have been due to systematic differences in the experimental protocols or in the populations studied (Krinsky, 2001), but the results do indicate the complexity of the problem, and the hazards of generalising too readily about the putative benefits of dietary antioxidants. 

Atmospheric releases of flammable gases such as hydrogen may lead to major fires with extensive effects on the surroundings. In activities where hazards are associated with cloud fires, there is the need of societal risk assessment that involves the estimation of hazardous zones due to the resulting thermal radiation. However, till now only limited work has been done on modeling the effects of flash fires, in a way that available techniques may be judged insufficient [47],... 

It should be emphasized that the results from RSST experiments use simplified calculation methods and give estimated values for stability and vent sizing. For large scale purposes, more dedicated and accurate measuring techniques may be needed for further hazard evaluation determinations. Due to the relatively recent development of this apparatus, comparison with other stability test methods is not yet comprehensive. 

Attempts to estimate the probable hazard of handling a new compound were generally based on correlation of available test data with that of materials which had been processed successfully. Unfortunately, many of the test techniques used were designed for reproducibility of result rather than for interpretation of hazard, and they applied primarily to correlation within the industry where they were developed. 

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