2012-07-01 12:00 - Messages

Pilot task-based assessment of noise levels among firefighters

Over one million American firefighters are routinely exposed to various occupational hazards. While efforts have been made to identify and reduce some causes of injuries and illnesses among firefighters, relatively little has been done to evaluate and understand occupational noise exposures in this group. The purpose of this pilot study was to apply a task-based noise exposure assessment methodology to firefighting operations to evaluate potential noise exposure sources, and to use collected task-based noise levels to create noise exposure estimates for evaluation of risk of noise-induced hearing loss by comparison to the 8-hr and 24-hr recommended exposure limits (RELs) for noise of 85 and 80.3 dBA, respectively.

Results: Task-based noise levels were found to range from 82 to 109 dBA, with the highest levels resulting from use of saws and pneumatic chisels. Some short (e.g., 30 min) sequences of common tasks were found to result in nearly an entire allowable daily exposure. The majority of estimated 8-hr and 24-hr exposures exceeded the relevant recommended exposure limit. Predicted 24-hr exposures showed substantial imprecision in some cases, suggesting the need for increased task specificity and highlighting the variability of firefighting noise exposures.Conclusions: The results indicate potential for overexposure to noise from a variety of firefighting tasks and equipment, and suggest a need for further exposure characterization and additional hearing loss prevention efforts.Relevance to industryFirefighters may be at risk of noise-induced hearing loss, which can affect their fitness for duty and ability to respond effectively to emergencies. The results of this study suggest that additional efforts at hearing loss prevention among firefighters are warranted.

Source : Neitzel, R.L.; Hong, O.; Quinlan, P.; Hulea, R. Pilot task-based assessment of noise levels among firefighters. International Journal of Industrial Ergonomics. Available online 9 June 2012. http://dx.doi.org/10.1016/j.ergon.2012.05.004

Reducing whole-body vibration exposure in backhoe loaders by education of operators

Whole-body vibration is a health hazard for operators of construction machinery. The level of whole-body vibration exposure on the operator is governed by three different factors; performance of the suspension system of the machine, planning of the work and the skills of the operator.In this research work it is investigated whether there is a potential in bringing down the level of whole-body vibration exposure by educating operators of backhoe loaders. This is carried out by an experimental setup. Six experienced operators participated in the experiments carried out on two different sizes of backhoe loaders. Each operator had to complete three different tasks without any kind of instructions. Subsequently they got a short education on eco-driving and vibration avoidance and carried out the tasks once more. Time duration, whole-body vibration exposure and fuel consumption was registered before and after education.The result of the short education was an average reduction in the whole-body vibration exposure of 22.5%. And for all completed tasks expect one a considerably fuel saving was obtained too – up to 38%. This experiment demonstrates that education of the operator will improve the occupational health and save fuel. The results also indicate that these improvements can be obtained without reduction in productivity as the instructions become a habit for the operators. Thus it is profitable for the employer to educate the employees operating construction machinery.Relevance to industry: The findings of this work is highly relevant to the construction industry. It shows a great potential in reducing damaging vibration and at the same time reduce fuel consumption. It also emphasizes the need for better education of machine operators.

Source :  Langer, T.H.; Iversen, T.K.;  Andersen, N.K.;  Mouritsen, O.O.; Hansen, M.R. Reducing whole-body vibration exposure in backhoe loaders by education of operators. International Journal of Industrial Ergonomics, vol. 42, no 3, May 2012, p. 304–311. http://dx.doi.org/10.1016/j.ergon.2012.03.001

12e conférence internationale 'effets sur l'homme des vibrations transmises par les machines tenues ou guidées à la main'

Co-organisée par les homologues canadiens et américains de l'INRS et des universitaires, cette conférence a rassemblé à Ottawa (Canada) en juin 2011 une centaine d'experts d'Amérique, d'Asie et d'Europe. En introduction du congrès, les organisateurs ont demandé à l'INRS de faire le point sur l'évolution de la prévention des vibrations ces 40 dernières années en Europe.
La soixantaine de communications concernaient la clinique, les effets physiologiques et biodynamiques, l'épidémiologie, la métrologie des signaux vibratoires, la prévention et la législation, le transfert des connaissances aux entreprises.
La conférence s'est terminée par un atelier dédié à la révision de la pondération en fréquence des signaux d'accélération, l'objectif étant de se doter d'outils permettant une meilleure évaluation des risques et une prise en compte plus réaliste des effets physiopathologiques.

Source : http://www.hst.fr/inrs-pub/inrs01.nsf/IntranetObject-accesParReference/HST_CR%2017/$File/Visu.html

Apparent mass and head vibration transmission responses of seated body to three translational axis vibration

The apparent mass and seat-to-head vibration transmissibility response functions of the seated human body were investigated under whole-body vibration exposures to fore-aft (x), lateral (y), and vertical (z) applied individually and simultaneously. The experiments were performed with 9 adult male subjects to measure the biodynamic responses to single and uncorrelated three-axis vibration with and without hands and back supports under different magnitudes of random vibration in the 0.5–20Hz frequency range. The apparent mass and the head vibration transmission responses were derived using two different frequency response function estimators based upon the cross- and auto-spectral densities of the response and excitation signals, denoted as H1 and Hv estimators, respectively. The two methods resulted in identical single-axis responses but considerably different responses under multi-axis vibration. The responses derived from the Hv estimator revealed significant coupling effects of three-axis vibration, which could be directly related to contributions of cross-axis responses observed under single-axis vibration, particularly those attributed to sagittal plane motion of the upper body. Such coupling effect, however, was not evident in the three-axis responses derived using the commonly used H1 estimator. The results also revealed significant effects of hands and back support conditions on the coupling effects of multiple axis vibration and the measured responses. The results suggest that biodynamic responses of the seated body exposed to simultaneous three-axis vibration, commonly encountered in work vehicles, differ considerably from the widely reported responses to individual axis vibration. A better understanding of the seated human body responses to uncorrelated three-axis whole-body vibration could be developed using the power-spectral-density based Hv estimator.Relevance to industry : The seated body biodynamic responses to multi-axis whole-body vibration and knowledge of coupling in the responses are essential for developing more efficient analytical models of the seated human body for applications in vehicular seating design and dynamics, and for deriving improved frequency-weighting for exposure assessment.

Source: Mandapuram, S.; Rakheja, S.; Boileau, P.E.; Maeda, S. Apparent mass and head vibration transmission responses of seated body to three translational axis vibration. International  Journal of Industrial Ergonomics, vol. 42, no 3, May 2012, p. 268-277.  http://dx.doi.org/10.1016/j.ergon.2012.02.002

2 years after implementation of the Noise at Work Regulations for UK entertainment industry, the industry is failing to meet regulatory requirements.

From April 2008, the UK entertainment industry became regulated under the Noise at Work Regulations 2005, meaning that employers from orchestras to nightclubs are legally required to adhere to the same requirements (based on ISO 9612:2009) for controlling noise exposure for their staff. The majority of staff (70%) in all venues exceeded the daily noise exposure limit value in their working shift. Use of hearing protection was rare (<30%) and not enforced by most venues. The understanding of the hazard posed by noise was low, and implementation of the noise regulations was haphazard, with staff regularly exceeding regulatory limits. The implication is that the industry is failing to meet regulatory requirements.

Source: Barlow, C., Castilla-Sanchez, F. Occupational noise exposure and regulatory adherence in music venues in the United Kingdom. Noise and Health, 2012, vol. 14, issue, 57, p. 86-90. 



The Balancing Act: New Hearing Conservation Technology as Functional Enablers

Strike a balance between protecting workers' hearing and helping them maintain situational awareness and the ability to communicate. In this article, we will review the options hearing managers can employ to strike an appropriate balance among the challenges of achieving hearing protection, situational awareness and two-way communication.

Source : http://ehstoday.com/hearing-protection/balancing-act-new-hearing-conservation-technology-functional-enablers

Report of an International Expert Symposium on the usefulness of Otoacoustic Emissions (OAE) Testing in Occupational Health Surveillance

HSE is interested in exploring options to improve the standards of noise health surveillance to assist dutyholders in meeting the aspirations of a robust occupational health surveillance model that enables early detection of signs or symptoms of ill health and useful and timely data that can enable preventative actions in reducing irreversible noise induced hearing.

Source : http://www.hse.gov.uk/noise/OAE-expert-symposium-paper-jan-2012.pdf

Optimisation of whole body vibration analysis for suspended cabin tractor semitrailer

This work has been conducted to find out the health risk associated with suspended cabin tractor semi-trailer driving work. Suspended cabin tractor semi-trailer drivers are exposed to whole body vibration (WBV) during their work. Some drivers suffer from low back pain caused by vibration. The practical significance of applying suspended cabin type of tractor semi-trailer was tested at different road conditions, different speeds as well as different load conditions for comfortable driver seat interface (x, y, z axes) and the ride comfort parameters have been prioritised using Taguchi's L27 orthogonal array. Genetic algorithm (GA) is used to optimise the whole body vibration of suspended cabin tractor semi-trailer drivers. The practical significance of applying GA to whole body vibration of suspended cabin tractor semi-trailer has been validated by means of computing the deviation between predicted and experimentally obtained vibration different measurement conditions.

Source : P. Velmurugan, L.A. Kumaraswamidhas, K. Sankaranarayanasamy. International Journal of Vehicle Noise and Vibration 2012 - Vol. 8, No.2  pp. 152 - 165.

Hearing, sound fatigue and annoyance highly affected employees at the preschools.

Hearing impairments and tinnitus are being reported in an increasing extent from employees in the preschool. The investigation included 101 employees at 17 preschools in Umeå County, Sweden. Individual noise recordings and stationary recordings in dining rooms and play halls were conducted at two departments per preschool. The effects of noise exposures were carried out through audiometric screenings and by use of questionnaires. The average individual noise exposure was close to 71 dB (A), with individual differences but small differences between the preschools. The noise levels in the dining room and playing halls were about 64 dB (A), with small differences between the investigated types of rooms and preschools. The hearing loss of the employees was significantly higher for the frequencies tested when compared with an unexposed control group in Sweden. Symptoms of tinnitus were reported among about 31% of the employees. Annoyance was rated as somewhat to very annoying. The voices of the children were the most annoying noise source. The dB (A) level and fluctuation of the noise exposure were significantly correlated to the number of children per department. The preschool sound environment is complex and our findings indicate that the sound environment is hazardous regarding auditory disorders. The fluctuation of the noise is of special interest for further research.

Source : Sjödin F, Kjellberg A, Knutsson A, Landström U, Lindberg L. Noise exposure and auditory effects on preschool personnel. Noise Health 2012;14:72-82.

Available from: http://www.noiseandhealth.org/text.asp?2012/14/57/72/95135

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