2012-04-01 12:00 - Messages

Reliability of the anti-vibration (AV) glove test defined in ISO 10819 (1996)

The specific aims of this study are to examine the rationale behind the major revisions of the ISO standard of the anti-vibration (AV) glove test and to evaluate the major technical aspects of the revised method through an experiment. While this study failed to realize the constant-velocity spectrum proposed in the original revision, the glove vibration transmissibility values measured with a new spectrum proposed in the current study were very similar to those measured with the M and H spectra defined in the current standard, which suggests the new spectrum can greatly simplify the test without changing the original test results, and it should be adopted in the further revision of the standard. The authors noted that the glove that reduced the grip strength the least was also the one that reduced the most vibration, which suggests that the negative and positive effects of the glove can be balanced in its design.

Source : Welcome, D.E. et al. An evaluation of the proposed revision of the anti-vibration glove test method defined in ISO 10819 (1996). International Journal of Industrial Ergonomics; Volume 42, Issue 1, January 2012, Pages 143–155.

http://dx.doi.org/10.1016/j.ergon.2011.09.003

http://www.sciencedirect.com/science/article/pii/S0169814111001181

Wireless Communication : Good team communication under difficult and potentially dangerous conditions required

Team communication is absolutely essential in creating a safe, productive and effective work environment. Ambient noise can dramatically affect the clarity of team communications. First responders may be subjected to deafening siren noise while en route to a rescue operation, but they are not alone. Many industries expose workers to high noise levels on the job. Airport ground personnel must contend with the roar of jet engines. Road and construction crews must communicate against a backdrop of heavy equipment. Factory workers must talk over the noise of a manufacturing plant. These seemingly unrelated situations all have one thing in common: they require good team communication under difficult and potentially dangerous conditions. Noisy environments not only make clear communication difficult, they also pose a threat of noise-induced hearing loss. OSHA regulations require hearing protection when the time-weighted average noise level exceeds 85 dB. Recent advancements in technology have made new wireless communication headsets the best practice for enabling communication in high-noise environments. Wireless headsets reduce background noise and allow teams of almost any size to communicate clearly and effectively. Properly designed and configured, wireless headsets also leave the wearer's hands free, provide freedom of movement and eliminate the possibility of injury from entangled cords. And, because wireless headsets do not need to be plugged into a stationary intercom, team members can stay in continuous contact with each other, even when in motion. Wireless headset and intercom systems are available in a wide variety of configurations and price ranges. This article presents  how to ensure that a particular system is adequate and  the factors to be carefully considered.

Source : Reed Stager. Wireless Communication: Selection & Use to Improve Team Safety. Professional Safety- Journal of ASSE; March 2012.

http://www.asse.org/professionalsafety/best-practices_story2.php

Voir aussi : International Association of Fire Chiefs. (2002). Crew resource management: A positive change for the fire service. Fairfax, VA: Author. Retrieved July 14, 2011, from www.iafc.org/files/pubs_CRMmanual.pdf. National Fire Fighter Near-Miss Reporting System. Retrieved July 14, 2011, from www.firefighternearmiss.com. National Fire Protection Association. (2007). NFPA 1500: Standard on fire department occupational safety and health program, §7.16. Quincy, MA: Author.

Population in Michigan is exposed to noise levels with possibility of long-term adverse effects on hearing

A total of 73 000 person-hours of noise monitoring were conducted in this observation study. Median overall daily average levels were 79 and 77 dBLeqA,8,equiv , with average levels exceeding EPA recommended levels for 70% of participants. The authors concluded that a large portion of the general population is exposed to noise levels that could result in long-term adverse effects on hearing. Gender and occupation were most strongly related to exposure, though most participants in this study had occupations that are not conventionally considered noisy.

Source : Flamme, G.A. et al. Typical noise exposure in daily life. International Journal of Audiology. February 2012, Vol. 51, No. S1 , Pages S3-S11 (doi:10.3109/14992027.2011.635316)

http://informahealthcare.com/doi/abs/10.3109/14992027.2011.635316

Le local a un rôle déterminant dans l'exposition au bruit des travailleurs

Par la réverbération, le local augmente le bruit provenant des machines et affecte tout l'espace de travail. Le code du travail français fixe les caractéristiques minimales que doivent présenter les locaux. Ce document de l'INRS rappelle quelques aspects techniques, décrit comment qualifier un local, précise les exigences réglementaires et explique le principe et la mise en œuvre du traitement acoustique d'un local. Ce document annule et remplace la fiche pratique de sécurité ED 136 "Améliorer l'acoustique des locaux de travail", publiée en 2009.

Source : Traitement acoustique des locaux de travail. INRS, ED 6103, 2011.

http://www.inrs.fr/accueil/produits/mediatheque/doc/publications.html?refINRS=ED%206103

http://www.inrs.fr/default/dms/inrs/CataloguePapier/ED/TI-ED-6103/ed6103.pdf

 

A bit isolator and a chuck isolator reduce the noise radiated by the drill steel and chuck

Among underground coal miners, hearing loss remains one of the most common occupational illnesses. In response to this problem, the National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) conducts research to reduce the noise emission of underground coal-mining equipment, an example of which is a roof bolting machine. Field studies show that, on average, drilling noise is the most significant contributor to a roof bolting machine operator’s noise exposure. NIOSH OMSHR has determined that the drill steel and chuck are the dominant sources of drilling noise. NIOSH OMSHR, Corry Rubber Corporation, and Kennametal, Inc. have developed a bit isolator that breaks the steel-to-steel link between the drill bit and drill steel and a chuck isolator that breaks the mechanical connection between the drill steel and the chuck, thus reducing the noise radiated by the drill steel and chuck, and the noise exposure of the roof bolter operator. This paper documents the evolution of the bit isolator and chuck isolator including various alternative designs which may enhance performance. Laboratory testing confirms that production bit and chuck isolators reduce the A-weighted sound level generated during drilling by 3.7 to 6.6 dB. Finally, this paper summarizes results of a finite element analysis used to explore the key parameters of the drill bit isolator and chuck isolator to understand the impact these parameters have on noise.

Source : Michael, R., Yantek, D., Johnson, D., Ferro, E. and Swope, C. Development of elastomeric isolators to reduce roof bolting machine drilling noise. Noise Control Eng. J. 59, 6, pp. 591-612 (2011)

 

http://dx.doi.org/10.3397/1.3659660

http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=NCEJD5000059000006000591000001&idtype=cvips&doi=10.3397/1.3659660&prog=normal

 

Clamping force and increased bulk increases discomfort and wearing difficulty for circum-aural hearing protectors

The physical properties of circum-aural hearing protectors, such as mass, clamping force and cup volume, have an influence on the attenuation performance of the device. This paper closely examines the physical and acoustic properties 39 of hearing protectors readily available to all users. The results indicate that attenuation increases with clamping force up to a limiting value of around 11 Newtons above which expected increases in attenuation are very small for large increases in clamping force. Likewise increasing the (newly introduced term) bulk of a hearing protector (volume, mass and cup elements) increases the attenuation but, as with clamping force a limit is reached where increased bulk increases discomfort and wearing difficulty

Source : Williams, W., Seeto, M. and Dillon, H.The mechanical properties of earmuffs.Noise Control Eng. J. 60 (1), Jan-Feb 2012, p29-35

http://dx.doi.org/10.3397/1.3673768

http://scitation.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=NCEJD5000060000001000029000001&idtype=cvips&doi=10.3397/1.3673768&prog=normal

Peak values not appropriate for predicting the discomfort caused by transient vibration and experienced by standing people

For motions with high crest factors, the vibration discomfort of standing people tends to be underestimated by rms methods (with an exponent of 2) and overestimated by rmq methods (with an exponent of 4). The optimum evaluation method in this study with standing people exposed to fore-and-aft, lateral and vertical vibration had an exponent of about 3.0 for transient motions centred on 1 Hz and an exponent of about 3.5 for motions centred on 8 Hz. The findings of this study with standing people are broadly consistent with studies using different motions and different psychophysical methods with seated people.

 

Source : Olivier Thuong & Michael J. Griffin (2011): The vibration discomfort of standing persons: evaluation of random and transient motions, Ergonomics, 54:12, 1228-1239

To link to this article: http://dx.doi.org/10.1080/00140139.2011.624199

http://www.tandfonline.com/doi/pdf/10.1080/00140139.2011.624199

Low-pass filtered masking noise makes speech-in-noise tests more sensitive

An easily accessible screening test can be valuable in the prevention of noise-induced hearing loss (NIHL). The Dutch National Hearing Foundation developed ‘Earcheck’, an internet-based speech-in-noise test, presenting CVC-words in stationary broadband noise. However, its sensitivity to detect NIHL appeared to be low, 51% (Leensen et al, 2011, part 1). This study showed that Earcheck with low-pass filtered noise made the best distinction between normal hearing and NIHL, without reducing test reliability. The use of this noise condition improved the sensitivity of Earcheck to 95%. Conclusion: The use of low-pass filtered masking noise makes speech-in-noise tests more sensitive to detect NIHL in an early stage.

Source : Monique C. J. Leensen, Jan A. P. M. de Laat, Ad F. M. Snik, and Wouter A. Dreschler. Speech-in-noise screening tests by internet, Part 2: Improving test sensitivity for noise-induced hearing loss. International Journal of Audiology, November 2011, Vol. 50, No. 11 : Pages 835-848
To link to this article: http://dx.doi.org/10.3109/14992027.2011.595017

Read More: http://informahealthcare.com/doi/full/10.3109/14992027.2011.595017

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