Journal of occupational and environmental hygiene
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J Occup Environ Hyg · Apr 2005
Comparative StudyThe effectiveness of hearing protection among construction workers.
Effective hearing conservation programs in the construction industry are rare. Where programs are present, they often rely on workers' use of hearing protection devices (HPDs) rather than on exposure controls to reduce noise exposure levels. Dependence on HPDs for protection from high noise is problematic, as the protection provided by the HPD depends on both the HPD's attenuation level and the time the HPD is used. ⋯ When the measured HPD attenuation levels and use time data were combined, the effective protection afforded by HPDs was less than 3 dB, a negligible amount given the high exposure levels associated with construction work. However, there was substantial variation in effective protection among the different trades assessed. These results demonstrate the need for better hearing conservation programs and expanded noise control efforts in the construction industry.
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J Occup Environ Hyg · May 2004
Effects of flange size on dividing streamlines of exterior hoods in cross drafts.
Effects of flange size on the flow patterns of an exterior circular hood subject to the influence of various uniform cross drafts were studied in an apparatus consisting of hood-model/wind-tunnel assembly. The cross draft to suction velocity ratio covered the range from 0.056 to 0.792. The flange width to hood diameter ratio spanned from 1.2 to 3.0. ⋯ Corresponding to a cross draft to suction velocity ratio, a critical flange width existed. If the flange width was smaller than the critical value, the dividing streamline would terminate at the downstream tip of the flange. The behaviors of the capture envelope and the dividing streamline of the hood in cross draft under different flange widths are presented and discussed.
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J Occup Environ Hyg · Apr 2004
Fitting characteristics of eighteen N95 filtering-facepiece respirators.
Four performance measures were used to evaluate the fitting characteristics of 18 models of N95 filtering-facepiece respirators: (1) the 5th percentile simulated workplace protection factor (SWPF) value, (2) the shift average SWPF value, (3) the h-value, and (4) the assignment error. The effect of fit-testing on the level of protection provided by the respirators was also evaluated. The respirators were tested on a panel of 25 subjects with various face sizes. ⋯ The improvement was greatest for respirator models with lower h-values. Using the concepts of shift average and assignment error to measure respirator performance yielded similar results. The highest level of protection was provided by passing a fit-test with a respirator having good fitting characteristics.
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J Occup Environ Hyg · Jan 2004
Respiratory protection against Mycobacterium tuberculosis: quantitative fit test outcomes for five type N95 filtering-facepiece respirators.
In preparing to fit test a large workforce, a respirator program manager needs to initially choose respirators that will fit the greatest proportion of employees and achieve the best fits. This article discusses our strategy in selecting respirators from an initial array of seven NIOSH-certified Type N95 filtering-facepiece devices for a respiratory protection program against Mycobacterium tuberculosis (M. tb) aerosol. The seven respirators were screened based on manufacturer-provided fit test data, comfort, and cost. ⋯ To promote the marketing of respirators that will successfully fit the highest proportion of wearers, and to increase protection for workers who might use respirators without the benefit of being fit tested, we recommend that fit testing be part of the NIOSH certification process for negative-pressure air-purifying respirators with tightly fitting facepieces. At a minimum, we recommend that respirator manufacturers generate and provide pass rate data to assist in selecting candidate respirators. In any event, program managers can initially select candidate respirators by comparing quantitative fit tests for a representative sample of their employee population.
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J Occup Environ Hyg · Jan 2004
Risk factors for work-related low back pain in registered nurses, and potential obstacles in using mechanical lifting devices.
Back pain disability is a serious and costly problem affecting the nursing profession. The purposes of this study were to determine risk factors for work-related low back pain (WRLBP) in registered nurses and to record the reported use or reasons for nonuse of mechanical lifts. Our hypothesis was that workers who attributed the cause of WRLBP to their own actions would be knowledgeable about back safety, would be more likely to use lifts, and would report less WRLBP. ⋯ Among the risk factors significantly associated with WRLBP were more years worked in nursing, frequent lifting, and low social support. Only 11% reported that they routinely used mechanical lifting devices, and the primary reason given for failure to use lifting equipment was unavailability of equipment. The reasons for the lack of use of mechanical lifts should be investigated and addressed.