Hazards differing degrees

Chemical plant equipment—including tanks, pressure vessels, piping, rotating equipment, vent systems, and safety instrumentation—should be identified and categorized into different degrees of hazard potential. Classification systems could be simple or very complex. A complex system could be a matrix of increasing severity ratings on one axis and the... 

SAFETY PROFILE A very dangerous fire and explosion hazard when exposed to heat, flame, shock, or oxidizers. It is a powerful high explosive. Nitrostarch is not a definite compound, but a mixture of various nitric acid esters of starch with different degrees of nitration. When heated to decomposition it emits toxic fumes of NOx. See also NITRO COMPOUNDS. 

Alternative process chemistries will likely pose different hazards and different degrees of hazard. The comparison of alternatives will inevitably lead to tradeoffs. The chosen candidate, although not devoid of hazards altogether, will likely be the one with the least risk. There is at present no universally accepted tool to judge among alternatives (see discussion in Sections 2.4 and 2.5). Edwards et al. 

It is naive to think that all HIT systems, in aU care settings, influence clinical care to the same extent. The reality is that there is a broad spectrum ranging from those systems which hardly touch clinical business processes to those on which clinicians utterly rely. Similarly, the same system implemented in different settings may influence care to different degrees. Even when one studies individual users there will typically be variability in the significance that a system plays in their day-to-day delivery of care. Whilst one cannot separately evaluate a hazard for each individual... 

Areas with different degrees of risk are determined according to the multivariate hierarchical evaluation on the risk of rock burst in working face. The method focuses on specific conditions and has a dynamic and integrated feature. Since some of the indexes depend on experience, it belongs to semi-quantitative evaluation method that can more accurately determine the risk of hazardous area. 

An awareness of the differing degrees of hazard to people will enable appropriate control measures to be developed and implemented. 

The Code of Practice on Pressure Systems considers that competence should be related to the size, complexity and hazard associated with the plant concerned and suggests different degrees of qualification for minor, intermediate and major pressure systems. The largest employers of competent persons, the engineer-surveyors, are the specialist engineering... 

Accident proneness can, therefore, not be expected to be a static function which remains unchanged throughout very long periods of time. There are different degrees and kinds of accident proneness depending on the type and degree of hazards to be coped with in various tasks and environments. However, the fact that accident proneness can be conceived in such a flexible manner does not mean that it cannot be studied and predicted by scientific means. 

If possible, there should be measurement of the toxic effect in order quantitatively to relate the observations made to the degree of exposure (exposure dose). Ideally, there is a need to determine quantitatively the toxic response to several differing exposure doses, in order to determine the relationship, if any, between exposure dose and the nature and magnitude of any effect. Such dose—response relationship studies are of considerable value in determining whether an effect is causally related to the exposure material, in assessing the possible practical (in-use) relevance of the exposure conditions, and to allow the most reasonable estimates of hazard. 

The PM and SS should be aware that no single eombination of PPE ean guard against all hazards beeause every worksite is different and the degree of hazards (known or unknown) may vary day by day. The PPE ensemble probably will be required to ehange as work eontinues. 

Tlie reader should also note that tlie risk to people can be defined in terms of injury or fatality. The use of injuries as a basis of risk evaluation may be less disturbing tlian tlie use of fatalities. However, tliis introduces problems associated with degree of injury and comparability between different types of injuries. Further complications am arise in a risk assessment when dealing witli multiple hazards. For example, how are second-degree bums, fragment injuries, and injuries due to toxic gas e.xposure combined Even where only one type of effect (e.g., tlueshold to.xic exposure) is being evaluated, different durations of e.xposure can markedly affect tlie severity of injury. 

The degree of confidence in the final estimation of risk depends on variability, uncertainty, and assumptions identified in all previous steps. The nature of the information available for risk characterization and the associated uncertainties can vary widely, and no single approach is suitable for all hazard and exposure scenarios. In cases in which risk characterization is concluded before human exposure occurs, for example, with food additives that require prior approval, both hazard identification and hazard characterization are largely dependent on animal experiments. And exposure is a theoretical estimate based on predicted uses or residue levels. In contrast, in cases of prior human exposure, hazard identification and hazard characterization may be based on studies in humans and exposure assessment can be based on real-life, actual intake measurements. The influence of estimates and assumptions can be evaluated by using sensitivity and uncertainty analyses. - Risk assessment procedures differ in a range of possible options from relatively unso-... 

In Part Two will be found a presentation of NFPA reactivity codes (when these are different from 0). The table below gives twenty substances which have the different NFPA degrees. These will later be used as examples when comparing the different types of classification of instability hazard. 

Also indices such as the Dow Fire and Explosion Hazard Index and the Mond Index have been suggested to measure the degree of inherent SHE of a process. Rushton et al. (1994) pointed out that these indices can be used for the assessment of existing plants or at the detailed design stages. They require detailed plant specifications such as the plot plan, equipment sizes, material inventories and flows. Checklists, interaction matrices, Hazop and other hazard identification tools are also usable for the evaluation, because all hazards must be identified and their potential consequences must be understood. E.g. Hazop can be used in different stages of process design but in restricted mode. A complete Hazop-study requires final process plans with flow sheets and PIDs. 

The chemical substances in the process are all flammable and /or toxic in varying degrees. The process streams pose different hazards according to the type and quantity of chemicals present. The capacity of process is 100000 t/a acetic acid. 

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