2011-07-01 12:00 - Messages

Safety professionals cannot simply rely on the NRR found on hearing protector labeling!

For the first time in more than 30 years, the Environmental Protection Agency is set to update its regulations concerning hearing protection devices. Although many stakeholders are pleased that EPA is attempting to update the rule, some have expressed concern that the update may not make things clearer for the end user – and that could lead to problems. Using a range of NRR numbers instead of one number could make it more complicated for safety professionals to choose the right device, he said. “There just isn't any lab-based number we can put on a product that can tell you what [hearing protection] an individual user will be achieving,” said Elliott Berger, a scientist with 3M's Occupational Health and Environmental Safety Division in Indianapolis. “Better training programs and better motivational programs are really what are needed, along with individual fit testing of actual users, regardless of what EPA puts on a package.” 

 

Source: The Environmental Protection Agency's new requirement on the labeling of hearing protection devices may be unclear. Kyle W. Morrison, senior associate editor, Safety+Health, August 2011.

 

http://www.nsc.org/safetyhealth/Pages/8.11%20Sound%20of%20confusion.aspx

A postwoman delivering mail using a low-powered motorcycle was diagnosed with bilateral Raynaud's phenomenon.

This case report presents the hypothesis that the effect of HAV may result not in a single disorder, but in multiple disorders. Although occupational epidemiological studies do not usually address comorbidity, it is not uncommon for exposure to produce multiple effects (e.g. an association between HAV and tendonitis has been reported). Comorbidity due to occupational exposure therefore needs further epidemiological investigation. For 15 years the woman had driven a two-stroke 50 cc motorcycle to deliver mail and was exposed to hand-arm vibration for 4 h/day. Before delivering the mail, she had to prepare the mailbags by herself every day. Ergonomic stress factors, as well as hand-arm vibration, are present when riding a motorcycle, like awkward postures of the wrist in combination with hand force. She also worked as a sorter for 5 years at the beginning of her working life.

Compared with men, women seem to develop injuries after a shorter period of vibration exposure. This case suggests the importance of studying gender differences in terms of dose-response to vibration exposure.

 

Source:  A case report of vibration-induced hand comorbidities in a postwoman. Stefano Mattioli , Francesca Graziosi , Roberta Bonfiglioli , Giuseppe Barbieri , Sandra Bernardelli , Luciano Acquafresca , Francesco S Violante , Andrea Farioli and Mats Hagberg; BMC Musculoskeletal Disorders 2011, 12:47doi:10.1186/1471-2474-12-47, 14 February 2011.

The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1471-2474/12/47

La modélisation par éléments finis pour l’amélioration de la conception acoustique des protecteurs auditifs.

Il s’agit d’une étude exploratoire visant à examiner le potentiel de la modélisation par éléments finis à traiter le problème de la transmission sonore à travers les protecteurs auditifs.

Dans le cas des bouchons, le modèle permet de bien représenter la physique du problème sur une grande partie de la gamme de fréquences.  Dans le cas des coquilles, le modèle fournit des tendances acceptables pour les deux types d’excitation (acoustique et mécanique), mais il existe des écarts entre la mesure et le calcul à la fois au niveau de l’amplitude et des positions fréquentielles des pics.

En conclusion, la modélisation numérique des protecteurs apparaît prometteuse. Elle permet de mieux comprendre le comportement acoustique des protecteurs et pourrait être exploitée pour expliquer les observations expérimentales, de même que pour guider les développements techniques du dispositif de mesure de la performance des protecteurs, notamment pour l’investigation de la position optimale des microphones utilisés dans le dispositif de mesure de la performance des protecteurs, en particulier des coquilles. Elle pourrait également être utilisée dans une perspective d’amélioration de la conception acoustique des protecteurs auditifs. Plusieurs pistes devraient préalablement être explorées afin de gagner en confiance dans le modèle.

 

Source : Étude de la transmission sonore à travers les protecteurs auditifs et application d’une méthode pour évaluer leur efficacité en milieu de travail - Partie 2 : étude préliminaire d’une modélisation par éléments finis. Sgard, Franck; Nélisse, Hugues; Gaudreau, Marc-André; Boutin, Jérôme; Voix, Jérémie; Laville, Frédéric. Études et recherches / Rapport  R-680, Montréal, IRSST, 2011, 115 pages.

http://www.irsst.qc.ca/-publication-irsst-etude-transmission-sonore-travers-protecteurs-auditifs-application-methode-evaluer-leur-efficacite-en-milieu-travail-partie-2-etude-preliminaire-modelisation-elements-finis-r-680.html

 

Surveys suggest that transport workers are more exposed to vibrations than the average working population.

European workers in transport over land and through pipelines seem also to be more exposed to vibrations from tools and machinery than the average working population. Several studies demonstrate the detrimental consequences of sustained sitting and being exposed to whole body vibration: exposure to vibrations may lead to back disorders. Based on the information available on heavy machines, the significance of the seat is important when steps to reduce full-body vibrations are taken. Full body vibration, for example caused by the driver’s cabin, may also affect the vision, coordination and the overall functional ability of drivers, and contribute to increased accident risk.

The report identified branches where the number of people that are exposed is rising, e.g. in airport transport and city traffic. Additionally, poorly qualified workers and heavy traffic can be seen as changes in the world of work which cause additional vibration exposure and the effect of globalization is contributing to this tendency in Europe.

 

Source: OSH in figures: Occupational safety and health in the transport sector an overview. European Agency for Safety and Health at Work; 28.03.2011

http://osha.europa.eu/en/publications/reports/transport-sector_TERO10001ENC/view

http://osha.europa.eu/en/publications/reports/transport-sector_TERO10001ENC

This report reviews the OSH risks of a wide variety of transport occupations, by analysing statistics and studies, and through selected case examples of prevention. The report has a broad scope: it covers all transport subsectors (rail, water, air and road).

 

Health and safety culture have the greatest influence in controlling noise risks: cultural changes could generate the most improvements!
What factors influence employers' decisions and practices? Three factors were found to influence noise management: (i) managers' own knowledge/awareness of noise risks and associated controls, (ii) the health and safety culture of the company and (iii) its size. Managers generally underestimated the significance of noise as an occupational health risk; a critical knowledge gap was understanding what controls exist and would work in practice. The size of the company influenced the approach taken with smaller companies showing increased likelihood of reduced quality in noise management (ie...
En centre d’appel de multiples facteurs engendrent de la fatigue, des troubles de la voix, du sommeil et du caractère ainsi que du stress.

Une enquête épidémiologique a été conduite par l'INRS dans les centres d'appels téléphoniques (CT). Il s'agissait de mettre en évidence les caractéristiques organisationnelles qui ont des conséquences sur la santé. Quatorze facteurs organisationnels (FO) ont été identifiés comme étant les plus souvent associés aux contraintes.  Ainsi, les conditions de travail sont souvent difficiles par la conjonction de multiples facteurs, entre autres, une ambiance sonore perturbatrice, l'utilisation d'un casque, d'un microphone et d'un micro-ordinateur. Par ailleurs cette étude met en évidence que les relations entre les facteurs organisationnels et les marqueurs de santé ne sont pas directes et passent le plus souvent par la perception des contraintes.

Malgré son caractère transversal, cette étude permet de conclure sur le rôle de certains FO et l'implication de certaines contraintes dans l'apparition de problèmes de santé ouvrant des perspectives de prévention primaire et secondaire tant individuelle (dépistage, surveillance...) que collective (évaluation des conditions de travail et de la santé). Le questionnaire sur les caractéristiques organisationnelles, spécialement élaboré, sera bientôt accessible, et pourra être un instrument utile pour les évaluations de terrain.

 

Source: Chouannière, D., Boini, S., Colin, R. Conditions de travail et santé dans les centres d'appels téléphoniques. Etudes et enquêtes, Référence INRS : TF 191, 2011

 

http://www.dmt-prevention.fr/inrs-pub/inrs01.nsf/IntranetObject-accesParReference/DMT_TF%20191/$File/TF191.pdf<-->

It’s time to let the spring water run! Best masking sound in open office plans.

The performance results and subjective perceptions showed that the spring water sound was the most optimal speech masker whereas vocal music produced negative effects similar to those of speech.

Fifty-four subjects were tested in seven sound conditions: speech, silence and five masked speech conditions. The five masking sounds were filtered pink noise, ventilation noise, instrumental music, vocal music and the sound of spring water. They were superimposed on speech. In each of the seven sound conditions, the subjects performed a short-term memory task, a proofreading task and a creative thinking task and completed a questionnaire on acoustic comfort. Compared to silence condition, short-term memory performance deteriorated in speech condition and in most masked speech conditions. Compared to speech condition, performance improved when speech was masked with spring water sound. The use of constant masking sounds should be preferred in open-plan offices instead of instrumental or vocal music.

Source: Effects of Five Speech Masking Sounds on Performance and Acoustic Satisfaction. Implications for Open-Plan Offices. Haapakangas, A.; Kankkunen, E.; Hongisto, V.; Virjonen, P.; Oliva, D.; Keskinen, E. Acta Acustica united with Acustica, Volume 97, Number 4, July/August 2011 , pp. 641-655(15)

http://www.ingentaconnect.com/content/dav/aaua/2011/00000097/00000004/art00011?token=005119d4e758913af67232d45232b6c24387b4d5749634c7a783568293c6c567e504f58762f46c22d

A variety of problem-solving noise and vibration tools are at the engineer’s disposal to improve the product development process for noise and vibration

This article captures the strategies involved in addressing a system-level sound and vibration concern late in the design cycle.

A noise and vibration problem often shows itself very late in the design cycle or even after the product has been released. Noise and vibration issues can generally be separated into two categories: a problem caused by lack of compliance to a regulation or specification; or the product does not perform adequately in-situ, causing sound or vibration quality (SVQ) concerns. Measurements must be made on the product during the appropriate operating conditions, and focus is put toward characterizing the problem. Then an understanding of the sources and paths is possible and gives an understanding of the opportunities that exist to make design changes. A review of problem-solving tools is included, and the article concludes with predicting the noise and vibration performance of a product and the role of test data in this process.

 

Source: Practical Approaches to Solving Noise and Vibration Problems. Gabriella Cerrato and Paul Goodes. Sound & vibration/april 2011

 

http://www.sandv.com/downloads/1104cerr.pdf

 

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