The Annals of occupational hygiene
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This paper describes a study that was carried out at work sites in the primary nickel production industry to investigate the difference between inhalable and 'total' aerosol exposures by using the mannequin sampling method, and to compare the results with those from an earlier study where actual workers' personal exposures were assessed in the same way. Experiments were carried out at 21 work sites located in mining, milling, smelting, and refining works of two primary nickel production companies. During sampling, mannequins were used to simulate the physical presence of workers and the 'exposures' of these were obtained for strategic positions at selected work sites. ⋯ The consistency of the (inhalable/'total') ratios between mannequin and actual personal sampling strongly suggests that the characteristics of the aerosol sampled by the two methods, most notably the particle size distribution, were the same. This in turn suggests that mannequin sampling can be useful in occupational hygiene for determining such properties of personal workers' exposures. It certainly provides a useful and cost effective method for determining factors at work sites in individual industry settings by which to examine the impact of changing exposure assessment from one based on 'total' aerosol to the recommended new approach based on inhalable aerosol.
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The performance of a fume cupboard is determined by a complex interaction of factors which are time consuming and expensive to determine. This paper describes a simple and practical means of ranking, and assessing fume cupboard installations that can help to discharge managerial responsibility for a 'safe' environment. The method also gives an economically viable and technically defensible system for assessing fume cupboard performance as part of upgrading exercises or performance audits. ⋯ The method has been used to carry out a condition and performance survey of 199 fume cupboards, both aerodynamic and box-type designs, in an academic institution. The results of this survey are presented which not only highlight performance characteristics but also provide insights into user attitudes and knowledge of fume cupboard operation and performance. It is suggested that surveys such as this could be helpful in training programmes for laboratory workers to enable them to optimise the use of fume cupboards.
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Respirator fit testing is necessary before entering hazardous working environments to ensure that the respirator, when worn, satisfies a minimum fit and that the wearer knows when the respirator fits properly. In the many countries that do not have fit testing or total inward leakage regulations (including Korea), however, many workers wearing respirators may be potentially exposed to hazardous environments. It is necessary to suggest a useful tool to provide an alternative for fit testing in these countries. ⋯ The Series 7500 Medium is more limited in providing adequate fit for females at specific facial dimensions than for males. For adequate fitting performance, the SK-6 is not preferentially recommended for Korean male and female workers due to low GMFFs and pass proportions. The result of this study indicates that after more accurate studies are performed, facial size categories, on the basis of facial dimensions, could be a useful tool to assist in the selection of adequately fitting respirators for workers in the countries having no fit testing requirements.
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A commercially available computational fluid dynamic (CFD) software program, specific for HVAC systems, was used to study the performance of an aerodynamic fume cupboard. The numerical results showed good qualitative agreement with physical measurements giving confidence in the CFD model to simulate and predict overall fume cupboard performance. However, there were some quantitative differences specifically around 'aerodynamic' features that could not be accurately simulated by the software code. ⋯ The computer model was used to simulate the gas tracer containment test method described in BS 7258 (1994) [Laboratory Fume Cupboards], and had a much greater sensitivity than the recommended physical measuring instruments. The results given in this paper demonstrate the potential for using a commercially available software package for the optimisation of fume cupboard design and testing. It also indicates the economy of using CFD compared with building a prototype and testing a model.